Strength power and rate of force development assessment after total hip arthroplasty

Executive assessment

Strength assessment after total hip arthroplasty (THA) should quantify the capacity to produce force while preserving the identity of the assay. Hand-held peak force, joint torque, one-repetition maximum, movement power and rate of force development (RFD) are distinct measurements. A change in one cannot be substituted for change in another, and a normal limb-symmetry ratio can conceal bilateral weakness.

The most defensible clinical foundation is reproducible dynamometry of hip abductors, relevant hip extensors and knee extensors, reported on both sides with the test position, stabilization, lever arm, trial rule, units and postoperative stage. Add power or rapid-force measurement when the question requires it and the apparatus can support the claim. Performance tests such as chair rise and walking remain useful complements, but they are not isolated assays of muscle strength.

Original longitudinal studies document substantial early loss and incomplete or muscle-specific later recovery. Holm and colleagues found strength/power losses of 41–58% in the immediate postoperative assessment and 23–31% one week after surgery, despite improved self-reported symptoms. Rasch and colleagues found a persistent 15% operated-side abductor deficit at two years, although several other muscles and functional measures recovered. Approach comparisons and meta-analytic averages add context but do not supply an individual recovery deadline. [1–5]

Direct THA measurement-error evidence now includes a 2026 study of 92 primary unilateral THAs assessed before surgery and at six weeks. It reports abductor MDC values of 0.05 and 0.06 Nm/kg and hip-extensor values of 0.07 and 0.08 Nm/kg. These are based on two same-session repetitions separated by 30 seconds, with source-level formula and knee-extensor agreement inconsistencies. They should not be advertised as established between-day change thresholds or patient-valued improvement. [6]

Prognostic evidence is endpoint-specific. Preoperative strength has been associated with later mobility, falls and patient-reported outcomes. However, a proposed abductor fall threshold of 0.46 Nm/kg had only 50% specificity; several TUG thresholds define mobility categories rather than observed falls; and a high R² in a 12-patient falls study describes current measurements versus previously recalled falls. A useful rehabilitation tool should display measured capacity and uncertainty before attempting individual risk prediction. [7–16]

Scope and evidence approach

The main population is adults undergoing primary elective THA for hip OA. Preoperative testing, early postoperative impairment and later recovery are treated separately. Fracture-related replacement, hemiarthroplasty, revision, tumor reconstruction, resurfacing and bilateral surgery are not merged with primary unilateral OA THA. Mixed OA/osteonecrosis or THA/TKA sources are identified explicitly.

The report is a critical narrative review with an auditable retrieval record. Three native PubMed and three native Scopus streams addressed measurement properties, prognosis/recovery and protocol/mechanism/technology. Official ESearch/EFetch reconciliation recovered the exact PubMed result sets after connector overlap; all Scopus streams reached their provider totals. Targeted original-source and reference searches supplemented the database streams, including the June 2026 Japanese HHD study. Retrieval counts are not counts of eligible studies, and the report makes no formal systematic-review or independent dual-screening claim.

Define the measurement before interpreting the number

Force and torque

Force is expressed in newtons. A dynamometer displaying kilograms usually reports a kilogram-force equivalent, not a mass lifted through a defined joint movement. Joint torque is force multiplied by the perpendicular external lever arm and is expressed in Nm. The tested joint, force direction, sensor location and measured lever arm are therefore part of the result.

A value normalized to body mass in Nm/kg is not a percentage of body weight. Similarly, force normalized as kgf/kg, N/kg or percent body weight is not torque. In the appraised literature, Shibuya used belt-fixed HHD knee force normalized to body weight, Kamimura used a mean of three body-mass-normalized torques, Ninomiya used the best of three supine abductor trials with a long lever, and Huffman used one short-lever side-lying force measurement. Their numbers cannot be pooled or compared by changing only the unit label. [7–9, 14]

Body-mass normalization aids some comparisons but does not remove every body-size effect. A lighter person with the same absolute force will have a higher normalized value; weight change itself can therefore alter the ratio. Preserve the raw force, lever arm, torque and body mass so that normalized results can be audited. External torque is also not a direct measure of force in one named muscle or force at the implant.

Strength power and rapid force

Maximum voluntary isometric strength is the peak force or torque generated in a specified fixed position. One-repetition maximum (1RM) is the greatest load moved through a prescribed task and range. It incorporates apparatus mechanics, range, technique and tolerance. Neither alone determines how rapidly force can be produced.

Mechanical power is the rate of doing work, expressed in watts. A leg-extension power rig measures a multi-joint explosive action, not isolated hip-abductor power. A 1RM leg press without velocity or work/time measurement is strength, even if an article discusses explosive function. Chair-rise time or repetitions are performance outcomes; estimates of chair-rise power require a defined mechanical model and separate validation.

RFD is the slope of the force-time signal, commonly expressed in N/s or Nm/s. Peak RFD, average RFD over 0–100 ms and average RFD over 0–200 ms are different outcomes. A rate normalized to maximal force is different again. A slow three-second ramp to a maximum does not measure explosive force, and a dynamometer that retains only the maximum cannot retrospectively yield RFD.

Activation and muscle structure

Voluntary activation, muscle morphology and measured strength are related but distinct. Surface EMG amplitude does not directly quantify force or prove activation failure. Twitch interpolation can estimate voluntary activation under a specified stimulation protocol; CT density, volume or fatty infiltration describe tissue features rather than voluntary capacity. Low force may reflect pain, apprehension, unfamiliarity, inhibition, structural limitation or submaximal effort without identifying their relative contributions.

A 2025 study of ankle dorsiflexors assessed 26 unilateral hip-OA patients before surgery and on postoperative day 3 against 26 healthy participants. Its abstract reports bilateral activation and rapid-force deficits using twitch interpolation, electrically evoked force and RFD at 50, 100 and 200 ms. This provides direct evidence that neuromuscular impairment can extend beyond muscles adjacent to the hip, but it does not establish the same magnitude or mechanism for hip abductors or quadriceps. Full methods and stimulation details were unavailable. [17]

Population stage and safety

Surgical context and bilateral function

Record the indication, side, primary versus revision status, approach, exact surgical date, current restrictions and complications. An abductor repair, fracture or restricted reconstruction changes both eligibility and interpretation. Published maximal testing in selected fast-track patients is not blanket permission to reproduce it in every early postoperative patient.

Contralateral disease and previous replacements should be recorded explicitly. Comparing the operated limb with an asymptomatic contralateral limb answers a different question from comparison with age-matched controls. The contralateral limb can weaken through inactivity, improve with activity, or develop pain. Symmetry can improve through operated-side gain, contralateral loss or both. Always retain the two absolute values.

The 2021 abductor review deliberately excluded hand-held dynamometry and measurements outside neutral abduction, yet still included different positions, devices, approaches and indications. Its pooled trajectory therefore neither validates HHD thresholds nor represents every THA population. Fifteen of 19 studies were rated low quality under the review's modified framework, and all pooled evidence was judged low certainty. [1]

Early postoperative testing

Pain, analgesia, fatigue, nausea, orthostatic symptoms, fear and wound discomfort can change performance and feasibility over hours. Document these conditions, as well as recent mobilization and the reason for a curtailed effort. A test stopped for safety is not proof of zero force capacity.

Holm's study labeled the day after surgery Day 2 and seven days after surgery Day 8, counting the surgery day in its sequence. That terminology should not silently become two and eight full days after surgery. Thirty of 35 enrolled patients completed the protocol; exclusions included serious early complications. Its selected complete-case results do not characterize the patients most affected by complications. [2]

The clinical response to unexpectedly low force should include checking the task and symptoms rather than automatically assigning a biological deficit. New severe pain, a sudden loss of function or an unsafe position warrants clinical review and adherence to current restrictions, not repeated maximal attempts for a cleaner data point.

Clinical dynamometry protocols

Hip abductors

Choose a position the patient can safely reproduce, usually a defined supine or side-lying setup. Document hip flexion/extension, abduction, rotation, knee position, pelvic stabilization and sensor site. Short-lever testing at the distal thigh and long-lever testing near the ankle can yield different force readings for similar joint torque. Side-lying also introduces limb weight and gravity considerations that differ from supine testing.

External fixation can reduce the influence of examiner strength, but it does not eliminate all error. Belt anchor position, compliance, preload, sensor orientation, pelvic movement and patient bracing remain relevant. Manual resistance and a break test are not interchangeable with a stabilized make test. The examiner should observe substitution, including pelvic rolling, hip flexion or trunk movement, and record invalid attempts.

Ninomiya's supine protocol placed the device 2.5 cm proximal to the malleolus and used the best of three efforts; torque normalization used spina-malleolar distance. Masuda's 2026 protocol placed the sensor at the distal third of the lateral thigh, with the hip neutral, and instructed a three-second rise to maximal output. Huffman used side-lying, 10–20 degrees of hip extension, approximately 20 degrees of abduction and a distal-thigh sensor, with one five-second effort per hip. Each is clinically plausible, but they are different assays. [6, 8, 9]

Hip extensors and knee extensors

Hip-extension testing is especially sensitive to position and compensation. Prone testing with the knee flexed changes hamstring contribution relative to knee-extended or supine testing. Lumbar extension, pelvic rotation and pushing through the other leg can inflate the observed output. Early postoperative tolerance and precautions may rule out a particular setup.

Masuda tested hip extension prone with the knee at 90 degrees, a posterior distal-thigh sensor and belt fixation. Kamimura instead used supine hip flexion of 30 degrees, knee flexion of 50 degrees and a supporting wedge. A cutoff or MDC derived in one position should not be attached to the other merely because both are called hip-extension strength. [6, 7]

For knee extension, record hip and knee angles, seat and trunk stabilization, sensor position, belt anchor, gravity correction if relevant, and whether the patient can grip the support. Gagnon and colleagues studied chair-fixed knee testing in 25 THA and 25 TKA patients, with repeated measurements at 30 and 60 degrees and comparison with a Cybex device. Their abstract favored averaging three trials at 60 degrees after familiarization. Its dependability coefficients and within-session design do not provide a universal postoperative between-day MDC, and correlation with Cybex does not establish interchangeability. [18]

Repetition and reporting

Predefine familiarization, effort duration, encouragement, rest, order and aggregation. Best-of-three measures maximum observed performance and is affected by chance high trials; mean-of-three samples average repeated performance and responds differently to fatigue. A single effort can be convenient but offers no internal check on consistency. Preserve all valid attempts when feasible, not only the summary.

Reproduce the protocol at follow-up. If pain, precautions or recovery require a change, record it as a new condition. Report the raw score and change with a matched error estimate only where defensible. Do not convert a protocol change into an apparent treatment response.

Reliability absolute error and meaningful change

New direct THA evidence

Masuda and colleagues studied 92 first unilateral THAs: 81 for OA and 11 for osteonecrosis, with 12 anterior and 80 anterolateral approaches. Two clinicians with more than five years' experience performed assessments individually. At preoperative and six-week visits, each movement was repeated twice with a 30-second rest, using an Isoforce GT-300. This is within-session intrarater repeatability at two stages, not a stable between-day reliability design. [6]

The original Table 2 reports hip-extension ICC 0.97 preoperatively and 0.96 at six weeks, with MDC 0.07 and 0.08 Nm/kg. Hip-abduction ICCs were 0.96 and 0.95, with MDC 0.05 and 0.06 Nm/kg. Knee extension showed a systematic shift, so limits of agreement were reported instead of MDC. Preoperative LoA were −0.12 to 0.09 Nm/kg; at six weeks the table gives −0.06 to 0.10, whereas the abstract and narrative give −0.07 to 0.10. This discrepancy is preserved rather than silently resolved.

The printed SEM equation is SD multiplied by (1−ICC), without the square root used in the conventional ICC-based SEM expression. The reported error magnitudes are closer to a square-root calculation than to the printed formula, but rounding and unavailable raw calculations prevent a complete reconstruction. It may be a typographical error; it remains an unresolved source issue. The article also treats small SEM% as responsiveness, which is not the same as demonstrated longitudinal construct validity or patient-anchored important change.

These estimates are valuable because they are direct, stage-specific THA observations. Their appropriate use is conditional, with the same task and clear disclosure that they mainly characterize closely spaced repetition. A change from preoperative to six-week testing involves different stages and biological conditions; it is not automatically judged using one of the two same-session MDCs. The authors explicitly acknowledge that patient-reported anchors were not assessed and that an MCID remains to be established.

What the statistics mean

ICC is sensitive to between-person heterogeneity and does not by itself tell the clinician how much a repeated score can differ. SEM quantifies error under a specific model. For independent repeat measurements with equal error, the conventional individual MDC95 is 1.96 × square root of 2 × SEM. If stage-specific errors differ, equal-error assumptions require reconsideration. Limits of agreement additionally retain observed bias, and proportional error may require a scale-aware analysis.

An MDC is not proof of clinical importance, causation, treatment efficacy or lower fall risk. A small change can matter to a patient while being difficult to distinguish from error; a statistically detectable change can be too small to alter daily life. A PROM threshold used as an outcome in a strength-prediction paper is not an MIC for the strength measurement itself.

Table 1 What the statistics mean

Recovery trajectories from original studies

Immediate strength and power loss

Holm and colleagues evaluated primary unilateral OA THA through a posterior approach, using HHD hip flexion, abduction and adduction plus a Nottingham Power Rig. HHD testing used four maximal contractions with 60-second rests and retained the maximum body-mass-normalized torque. The power test used rapid leg extension from a comfortable flexed position, retained the highest W/kg and stopped after two consecutive declines or ten attempts. Available motion was used at each visit. [2]

The first postoperative assessment showed losses of 41–58%, with the greatest loss in leg-press power. One week after surgery, losses were smaller, 23–31%, but still present. Pain, thigh-volume changes and systemic inflammation did not explain the observed losses in exploratory correlations. These null correlations do not prove that pain or inhibition never contributes; the study was powered for longitudinal changes, not mechanism testing.

Power-rig results combine hip and knee action, movement range, positioning and explosive intent. They are not interchangeable with peak isometric hip force. Changes in available range can also influence the task. The study's improvement in reported symptoms alongside reduced measured capacity demonstrates why both perspectives are needed.

Approach and muscle specific recovery

Winther and colleagues followed 60 consecutively allocated patients across direct-lateral, posterior and anterior approaches through three months. Allocation occurred in sequential groups, each linked to a surgeon with expertise in that approach; implant-head size also changed during the series. The study therefore supports approach-associated differences, not a fully isolated causal effect of approach. [3]

The tests were 1RM leg press and a customized supine abduction apparatus, with increments of 10 kg and 2.5 kg. These are dynamic load tests, not HHD isometric torque or power. The leg-press methods contain conflicting wording about simultaneous bilateral use versus testing each leg individually; the side-specific results should retain that ambiguity. Early reductions were greater in the direct-lateral group; differences were not statistically significant at three months. Operated-side strength still averaged 18% lower for leg press and 15% lower for abduction than the other side. Nonsignificance between approaches is not proof of equivalent recovery.

Rasch's 20-patient posterior-approach cohort was assessed preoperatively, at six months and at two years. A fixed strain-gauge apparatus measured knee actions seated and hip actions standing with trunk support; the mean of two three-to-five-second efforts was used. Values were force in newtons, with sensor positions differing between hip and knee tasks. Their averages across actions are study-specific composites, not a standard physiological total-strength unit. [4]

Most initial deficits narrowed with time, but an approximately 15% abductor deficit persisted at two years. Functional gait and bilateral sway findings improved earlier or differently. This supports measuring the relevant muscle action rather than inferring complete recovery from pain relief, walking independence or a global score.

Judd and colleagues' cohort adds comparison with healthy peers: 26 THA patients and 19 controls, with follow-up through one year. The original abstract reports residual knee-extensor and flexor deficits of 17% and 23%, respectively, at one year, despite no statistically significant functional-test differences with the sample available. The complete article could not be recovered through permitted routes, so detailed assay and normalization specifications are not reconstructed from secondary sources. [5]

What pooled trajectories can and cannot add

Ismailidis and colleagues' review included 19 studies and 875 participants, using three comparisons: operated/nonoperated ratio, change from the preoperative baseline and comparison with healthy controls. These answer different questions. Return to baseline can still represent low capacity, and a ratio approaching one does not identify which limb changed. [1]

Pooled abductor strength improved after the first months, but studies varied in approach, position, device and population. Some standard errors were imputed from other studies' variability, and several data points were extracted from graphs. The review's cautious conclusion that deficits may persist is reasonable; its averages should not become individual targets or a fixed deadline for successful rehabilitation.

Power RFD and activation assessment

Friesenbichler and colleagues assessed 21 unilateral hip-OA patients before and six months after THA with rapid maximal contractions of hip flexors, extensors, abductors and adductors and knee flexors/extensors. The original abstract indicates that maximal and explosive asymmetries were not identical and that some hip deficits persisted after surgery while knee-extensor explosive asymmetry resolved. The full article remained unavailable, and the abstract itself has tension in its wording about which knee deficits affected maximal versus explosive strength. Exact force-time windows, onset rules and numerical thresholds are therefore not inferred. [19]

A valid rapid-force protocol requires a recorded time series with sufficient sampling, known filtering, stable fixation, a specified contraction onset and explicit rejection rules for countermovement, pretension and artifacts. Instruction to contract fast and hard differs from a gradual build to a maximum. Familiarization and multiple acceptable explosive attempts are important because a technically valid peak force can coexist with an invalid onset or early slope.

Report absolute RFD alongside maximal force and, where justified, normalized RFD. A normalized rate can improve because the denominator fell. State whether the reported rate is peak slope or mean slope over a predefined interval, and preserve the exact interval. Early force production is especially sensitive to onset and filtering choices; output from a low-rate clinical device cannot be assumed equivalent to laboratory dynamometry simply because both display N/s.

No appraised original source established a general THA-specific patient-anchored MIC for RFD or isolated power, or a validated RFD cutoff for future falls. This is a research gap in the reviewed evidence, not a reason to call rapid-force testing clinically useless. Its appropriate current role is carefully specified measurement with local repeatability testing and restrained interpretation.

Prognosis and clinical endpoints

Later mobility

Kamimura and colleagues followed 48 women with severe unilateral hip OA through posterolateral THA, with full weight bearing only from day 14. HHD testing used three three-second efforts and the mean normalized torque. Different preoperative predictors were selected for TUG at three weeks, four months and seven months. The reported development cutoffs of 0.56 Nm/kg knee extension and 0.24 Nm/kg hip abduction concern a TUG-defined mobility category at specific horizons. [7]

The 13.5-second TUG boundary was borrowed from older-adult falls literature to define good versus nongood ambulation. No prospective falls endpoint validated that boundary in the THA cohort. A small stepwise model, severe baseline disability, female-only sample and an older inpatient pathway further limit transport. These values should not become universal strength targets or discharge requirements.

Kawakami and colleagues examined 124 women and one-year TUG after primary THA. Lower preoperative contralateral abductor strength and older age were associated with TUG of at least ten seconds. This is useful evidence that the other limb matters. However, the source's HHD methods describe force in N while a regression table labels the variable Nm/kg, and its model coefficients, confidence intervals and narrative odds ratios are not fully consistent. The association can inform assessment priorities; the published numbers are not implementation-ready for a calculator. [11]

Shibuya's temporally ordered inpatient analysis included 317 primary unilateral THAs after excluding preoperative nonwalkers and postoperative complications. Knee strength was measured by belt-fixed HHD with the best of two force measurements expressed relative to body weight. The endpoint was achieving a 50-m walk without human help, allowing an aid. Its local recovery pathway and future-complication exclusions limit generalization. Strength measured within this model should not be merged with torque cutoffs from other papers. [14]

Patient reported function

Huffman and colleagues provide recent prospective evidence: 184 direct-anterior primary THAs were enrolled and 163 completed one-year follow-up. Advanced contralateral OA, prior contralateral fracture or surgery and several other conditions were excluded. One five-second side-lying HHD effort was obtained for each hip on the morning of surgery. Greater ipsilateral force was associated with later HOOS-JR and VR-12 scores in adjusted analyses. [9]

The study reports associations scaled per 5-kg force increment and secondary body-weight-normalized analyses. Its exploratory MCID result concerns achieving an 18-point HOOS-JR improvement; it does not define an important strength change. PASS analysis included only 74 patients with complete required data, much fewer than the main 163, and used Firth penalization. Odds ratios cannot be interpreted as the same percentage change in probability, especially when outcome occurrence is common.

Model interpretation also requires care. The mixed-effects model includes time interactions, so the main strength coefficient is not automatically the isolated twelve-month effect. The source reports a two-week estimate whose confidence interval excludes zero while its p value is nonsignificant, and full numerical table/supplement extraction was incomplete. Together with absent external validation and a single-effort protocol, these issues support describing a prognostic association rather than deploying an absolute risk or expected-score model.

Falls activity and tissue measures

Ninomiya's prospective cohort found lower preoperative abductor torque and prior falls associated with first-year falls. The 0.46 Nm/kg cutoff had AUC 0.702 and only 50% specificity. Regression coding/scaling are unclear, and the article incorrectly describes AUC as an individual falling probability. Neither the cutoff nor a strength gain establishes that falls will be prevented. [8]

Konishi's retrospective cohort links preoperative knee-extensor torque to later recalled falls and confidence, but its ABC measurements and fall history were obtained together years after surgery. There were 401 responders representing 438 hips, with a 60% response rate and varying postoperative exposure. Knee strength preceded outcomes, but confidence-based discrimination was concurrent; hip-level dependence and missingness further limit a future-risk interpretation. [10]

Shinonaga's 116-woman retrospective study reported an association between preoperative gluteus-medius CT density and first-year falls; the original abstract did not retain hip-abductor strength as the significant predictor. Density is a proxy for fatty infiltration, so the direction and unit of the coefficient must remain attached to the measured CT variable. This does not establish that imaging should replace dynamometry or that changing tissue density prevents a fall. Full methods were unavailable. [15]

Foucher and colleagues studied 16 people one to five years after THR, using mean torque from three five-second side-lying Biodex efforts, normalized to mass. Strength and self-reported UCLA activity were associated, but the design was cross-sectional and the authors explicitly cautioned that stronger muscles could be a consequence of greater activity. Their fatigue mediation hypothesis was not supported. The findings do not establish a prospective activity target or a causal pathway. [12]

Lin and colleagues assessed 12 THA patients around one year after surgery and related current strength and fall efficacy to recalled preceding-year falls. An R² approaching 0.92 in a small selected regression is not validated future-fall prediction. Kawano's 321-patient retrospective clinical rule instead addressed one-year self-reported UCLA activity from preoperative and early postoperative variables. Its abstract-level evidence is temporally ordered but does not establish an externally calibrated activity probability. [13, 16]

Compact prognosis table

Table 2 Compact prognosis table

Practical implementation and research priorities

A useful clinical record should contain the person's surgery and restrictions, exact postoperative timing, both limb scores, task position, device and calibration, sensor site, lever arm, fixation, repetitions, rest, encouragement, pain, invalid attempts and aggregation. Retain raw force and body mass as well as torque and normalized results. Do not silently mix kgf, N, Nm, Nm/kg and percent-body-weight values.

Table 3 Practical implementation and research priorities

For research and tool development, prioritize between-day and interrater repeatability across real postoperative stages, including people with aids, contralateral symptoms and incomplete tests. Obtain patient-relevant change anchors alongside direct muscle measurements without assuming that a PROM change is the same construct. Compare portable systems with the actual reference variable, then test whether measurement adds information beyond simple clinical assessment.

Prediction studies should define the index time and future outcome, retain complications known only after prediction, avoid univariable screening and small-sample threshold optimization, and report calibration as well as discrimination. Both limbs and repeated visits from one person must remain together during validation. A model that predicts a PROM, TUG category or activity score should not be marketed as a fall-prevention model.

Conclusions

Strength testing after THA is clinically informative when the assay is reproducible and the interpretation stays close to its evidence. Maximal force, torque, dynamic load, power, RFD and activation provide complementary information. The most valuable implementation is a bilateral, stage-aware measurement record with transparent error and protocol details. Current prognostic associations justify attention to weakness and broader function, but they do not support universal strength cutoffs, automatic fall probabilities or claims that an observed gain necessarily causes better long-term outcomes.

Primary study characteristics

Original studies and explicitly labeled contextual sources are grouped by question. Population, postoperative stage, protocol, endpoint, source access and analysis design constrain interpretation. Publications from the same cohort are not independent replications.

Framework and contextual evidence

Ismailidis P 2021

Study and population [1] Systematic review/meta-analysis used for context. 19 studies, 875 subjects; 856 THAs in 842 patients; mainly OA with some osteonecrosis and other indications; varied approaches

Protocol and timing HHD and non-neutral abduction excluded; side ratios, pre/postoperative change and healthy-control contrasts analyzed separately

Principal findings Abductor deficits may improve over 24 months but persist; low-certainty evidence

Interpretive limits Different contrasts are not equivalent; 15 of 19 studies low quality; imputed variance and graph-extracted values; does not validate HHD thresholds

Source examined Original article body retrieved

Instrumented assessment and recovery

Holm B 2013

Study and population [2] Prospective early recovery cohort. 30 of 35 enrolled patients completed all visits; primary unilateral OA THA; posterior fast-track pathway; convenience sampling; mean age 65.9

Protocol and timing One week preoperative, day after surgery labeled Day 2, seven days after surgery labeled Day 8; HHD best of four with 60-second rests; Nottingham power rig best of at most ten

Principal findings Strength/power loss 41–58% at the first postoperative test and 23–31% one week after surgery, despite improved self-report

Interpretive limits Complication-related attrition; no MDC/MIC; multi-joint power; available range varied; exploratory null correlations do not establish mechanism

Source examined Original article body retrieved

Winther SB 2016

Study and population [3] Sequentially allocated prospective approach cohort. 60 primary unilateral OA THAs; age below 70, BMI below 34; 21 direct-lateral, 19 posterior and 20 anterior

Protocol and timing 1RM leg press with 10-kg increments and customized supine abduction with 2.5-kg increments; baseline, two days, eight days, six weeks and three months

Principal findings Early approach-associated losses; three-month operated-side deficits 18% in leg press and 15% in abduction

Interpretive limits Sequential nonrandom allocation and surgeon confounding; head size changed; leg-press bilateral/individual wording conflict; 1RM is not power or RFD

Source examined Original article body retrieved

Rasch A 2010

Study and population [4] Longitudinal strength/gait/balance cohort. 20 primary unilateral OA THAs; posterior approach; baseline, six months and two years; no other lower-limb comorbidity

Protocol and timing Fixed strain-gauge force testing; mean of two 3–5-second efforts; hip actions standing and knee actions seated; 30-second platform recordings; 20-cm foot gap; unilateral rod support; mean of two best of three

Principal findings Persistent 15% abductor-force deficit at two years; other muscle deficits narrowed; bilateral sway improved, particularly with eyes closed

Interpretive limits Force in N, not torque; hand-supported unilateral balance; preoperative noncompletion; averages of different muscle actions; no patient-level MIC or prognostic model

Source examined Original article body retrieved

Judd DL 2014

Study and population [5] Longitudinal strength/function comparison; original abstract. 26 THA recipients and 19 healthy controls; follow-up at one, three, six and 12 months

Protocol and timing Isometric hip/knee testing and performance battery; detailed assay unavailable in original abstract

Principal findings At one year, knee-extensor and flexor deficits of 17% and 23%; functional comparisons not significant with available sample

Interpretive limits Full protocol unavailable; nonsignificance does not establish equivalence; not prognostic validation; issue publication 2014, online 2013

Source examined Original abstract only; full article not retrieved; PubMed/PMC/Europe PMC and publisher routes attempted without usable article body

Friesenbichler B 2018

Study and population [19] Longitudinal explosive/maximal strength study; original abstract. 21 unilateral hip-OA patients before and six months after THA

Protocol and timing Rapid maximal hip flexion, extension, abduction/adduction and knee flexion/extension

Principal findings Maximal and explosive asymmetries were not identical; some hip deficits persisted

Interpretive limits Exact onset, windows and device details unavailable; abstract knee-extensor wording ambiguous; no THA RFD error/MIC or future-fall validation

Source examined Original abstract only; full article not retrieved; publisher-reported open-access PDF not recovered

Temporiti F 2025

Study and population [17] Mechanistic perioperative case-control study; original abstract. 26 unilateral end-stage hip-OA patients and 26 controls; preoperative and postoperative day 3

Protocol and timing Ankle dorsiflexor twitch interpolation, maximal voluntary force, evoked force and RFD at 50/100/200 ms

Principal findings Bilateral activation, force and RFD impairments, including on the nonoperated side

Interpretive limits Ankle dorsiflexors are not direct hip-abductor or quadriceps evidence; full stimulation/protocol unavailable; no patient threshold

Source examined Original abstract only; full article not retrieved

Foucher KC 2018

Study and population [12] Cross-sectional strength/activity association. 16 community-dwelling THR recipients one to five years postoperative; required unassisted ten-minute walking

Protocol and timing Side-lying Biodex, three five-second efforts with 30-second rests; mean peak torque normalized to mass; PROMIS fatigue and UCLA activity

Principal findings Strength and self-reported activity associated; fatigue mediation not demonstrated

Interpretive limits Direction not established; small heterogeneous sample and self-reported activity; no validated target or prognosis

Source examined Original article body retrieved

Shibuya M 2020

Study and population [14] Retrospective temporal inpatient prognosis. 317 of 336 primary unilateral THAs; 11 preoperative nonwalkers and eight postoperative complications excluded

Protocol and timing Belt-fixed HHD knee force, best of two normalized to body weight; preoperative walking; endpoint 50 m without human help, with aids permitted

Principal findings Gait speed prognostic for local inpatient recovery; strength included in assessment context

Interpretive limits Force relative to body weight is not Nm/kg; exclusion based on future complications; local pathway; no universal strength threshold

Source examined Original article body retrieved

Clinical measurement properties and important change

Masuda K 2026

Study and population [6] Direct intrarater within-session measurement study. 92 first unilateral THAs; 81 OA and 11 osteonecrosis; 22 men and 70 women; 12 anterior and 80 anterolateral

Protocol and timing Preoperative and six weeks; two efforts 30 seconds apart; Isoforce GT-300; three-second ramp; prone knee-flexed hip extension with belt, supine distal-thigh abduction, seated belt-fixed knee extension

Principal findings ICCs at least 0.95; extension MDC 0.07/0.08 and abduction 0.05/0.06 Nm/kg; knee extension showed fixed bias and LoA

Interpretive limits Printed SEM formula lacks square root; six-week knee LoA lower bound −0.06 in table versus −0.07 in text; not between-day error; SEM% does not prove longitudinal responsiveness; no MIC

Source examined Original Japanese full PDF retrieved; protocol, printed equation and Tables 1–2 visually checked; English abstract also read

Gagnon D 2005

Study and population [18] Direct measurement study; original abstract. Convenience sample of 25 THA and 25 TKA recipients

Protocol and timing Within-session knee flexor/extensor testing at 30/60 degrees; chair-fixed versus Cybex devices; generalizability analysis

Principal findings Dependability 0.98–1.00 intertrial and 0.92–0.99 interevaluator; averaging three trials at 60 degrees recommended

Interpretive limits Original body unavailable; abstract SEM reporting insufficient for a precise implementation threshold; not interday MDC; correlation is not agreement

Source examined Original abstract only; full article not retrieved

Prognostic questions and temporal ordering

Kamimura A 2014

Study and population [7] Prospective development prognostic cohort. 48 Japanese women with severe unilateral OA and asymptomatic contralateral hips; posterolateral approach; full weight bearing from day 14

Protocol and timing HHD mean of three three-second efforts; abduction supine; hip extension supine with hip 30/knee 50 degrees; knee extension seated 90 degrees; TUG from 45-cm armless chair

Principal findings Development cutoffs 0.56 Nm/kg knee extension and 0.24 Nm/kg abduction for later TUG category; selected predictors varied by horizon

Interpretive limits Borrowed 13.5-second TUG boundary, not observed falls; small stepwise model and older pathway; source confidence-interval issues

Source examined Original article body retrieved

Ninomiya K 2020

Study and population [8] Prospective falls cohort and threshold development. 157 primary unilateral OA THAs; 142 women; age 45–75; anterolateral approach; discharge home within five days

Protocol and timing One month preoperative; supine HHD 2.5 cm above malleolus, best of three, spina-malleolar lever and body-mass normalization; SLS hands on hips, 30-second cap, best of two; first-year falls questionnaire

Principal findings 32 fallers; affected abductor torque 0.45 versus 0.60 Nm/kg; SLS did not differ; cutoff 0.46 Nm/kg, AUC 0.702, sensitivity 73.6%, specificity 50%

Interpretive limits Selected cohort; unclear odds-ratio coding/scaling; discussion incorrectly calls AUC a 70.2% individual probability; no external validation; questionnaire not verified as monthly calendars

Source examined Original article body retrieved

Huffman A 2026

Study and population [9] Prospective strength to PROM association. 184 enrolled and 163 one-year completers; primary direct-anterior THA; advanced contralateral OA and previous contralateral surgery excluded

Protocol and timing Single five-second side-lying HHD effort per hip; about 20-degree abduction and 10–20-degree extension; distal-thigh sensor; force kg; models scaled per 5 kg

Principal findings Higher preoperative force associated with HOOS-JR and VR-12; 89% achieved PROM MCID; PASS analysis included 74 patients

Interpretive limits Single effort; time-interaction interpretation; two-week CI/p discrepancy; tables/supplement not completely extracted; no external calibration; PROM MCID is not strength MIC

Source examined Original article body retrieved; numeric tables and supplementary models not fully extracted

Konishi T 2025

Study and population [10] Retrospective cohort with concurrent confidence discrimination. 401 of 673 patients responded, representing 438 hips; primary OA; posterolateral approach; mean 6.9 years postoperative

Protocol and timing Preoperative peak torque, best of two after practice; late survey of ABC, preceding-year falls and postoperative fracture history

Principal findings ABC falls cutoff 90.3%, AUC 0.703, sensitivity 61.6%, specificity 71.1%; fracture AUC 0.599; preoperative knee torque associated with fewer falls

Interpretive limits ABC and fall history concurrent; fractures use a longer exposure window; 60% response; bilateral hip-level dependence; clustering used falls itself; no external prediction validation

Source examined Original article body retrieved

Kawakami T 2024

Study and population [11] Retrospective temporal TUG-category cohort. 124 of 148 women after primary unilateral THA; mixed approaches; one-year endpoint

Protocol and timing Supine distal-thigh HHD, best of three; preoperative strength and CT; maximum-speed TUG from armless chair

Principal findings Contralateral abductor strength and age associated with one-year TUG of at least ten seconds

Interpretive limits Methods state N whereas regression table states Nm/kg; odds ratios, coefficients and CIs inconsistent; not future-fall validation; separate CT reliability CI issue

Source examined Original article body retrieved

Lin X 2022

Study and population [13] Concurrent/retrospective association, not prospective prognosis. 12 THA patients assessed around one year after surgery, plus OA-faller and healthy comparison groups

Protocol and timing Current muscle force, fall efficacy and treadmill gait related to recalled falls during the preceding year

Principal findings Strong in-sample relation of strength and fall efficacy to prior falls; high regression R²

Interpretive limits Tiny selected THA sample; backward regression, reverse causation and recall; not a model of the following year

Source examined Original article body retrieved

Shinonaga A 2025

Study and population [15] Retrospective temporal falls cohort; original abstract. 116 women with unilateral primary OA THA; 30 first-year fallers

Protocol and timing Preoperative CT gluteus-medius density and mass plus abductor strength; adjusted logistic model

Principal findings Only the CT density/fatty-infiltration proxy retained significance; OR 0.93, 95% CI 0.88–0.99

Interpretive limits Coefficient direction belongs to measured density; full methods and ascertainment unavailable; no causal inference or indication for additional CT

Source examined Original abstract only; full article not retrieved

Kawano T 2022

Study and population [16] Retrospective clinical prediction rule; original abstract. 321 primary THA recipients, including 56 men

Protocol and timing Preoperative and three-week clinical tests related to one-year UCLA activity category

Principal findings Rule includes age, activity, hip-abductor/knee-extensor strength and postoperative ten-metre walking

Interpretive limits Self-reported activity; development cutpoints/probabilities not externally validated here; original full methods unavailable

Source examined Original abstract only; full article not retrieved

Strength power and rate of force development methods and search appendix

This report is a critical narrative review, not a registered systematic review. Broad database retrieval was followed by targeted appraisal of original measurement, protocol, longitudinal recovery and prognostic evidence. Screening and extraction were not performed by two independent reviewers. No formal risk-of-bias score or GRADE certainty assessment was newly generated. Appraisal instead records population selection, task definition, reliability design, error/anchor interpretation, temporal ordering, model development and validation, and source-access limitations beside each source.

Primary elective THA for hip osteoarthritis is the principal population. Preoperative studies were eligible for baseline measurement and later postoperative endpoints. Revision, fracture-related replacement, hemiarthroplasty, resurfacing and bilateral surgery were treated as separate contexts. Mixed hip/knee or OA/osteonecrosis sources remain explicitly labeled. Treatment studies were considered only when they contributed relevant measurement or recovery information; this is not a treatment-effectiveness review.

Search date and retrieval coverage

The official PubMed union across the three streams was 427 unique records, while the Scopus union was 750. These overlap within and across databases. They must not be summed or presented as eligible-study counts. The smaller connector-only PubMed union (333) was superseded by official reconciliation.

Table 4 Search retrieval coverage

Review reference lists and bounded citation-network retrieval were used to identify additional relevant originals. These reference searches were not exhaustive citation graphs. Targeted web/publisher/repository retrieval was used to resolve known papers and source gaps; broad database queries were not rerun during manuscript preparation.

Exact executed queries

Strength power rfd measurement PubMed

("Arthroplasty, Replacement, Hip"[MeSH Terms] OR "total hip arthroplast*"[Title/Abstract] OR "total hip replacement*"[Title/Abstract]) AND ("Muscle Strength"[MeSH Terms] OR "Muscle Strength Dynamometer"[MeSH Terms] OR ("muscle strength"[Title/Abstract] OR "muscle power"[Title/Abstract] OR dynamometr*[Title/Abstract] OR isokinetic[Title/Abstract] OR isometric[Title/Abstract] OR "maximal voluntary"[Title/Abstract] OR "maximum voluntary"[Title/Abstract] OR "one repetition maximum"[Title/Abstract] OR 1RM[Title/Abstract] OR "rate of force"[Title/Abstract] OR "rate of torque"[Title/Abstract] OR RFD[Title/Abstract] OR RTD[Title/Abstract] OR "explosive strength"[Title/Abstract] OR "voluntary activation"[Title/Abstract] OR "leg power"[Title/Abstract] OR "knee extensor strength"[Title/Abstract] OR "hip abductor strength"[Title/Abstract] OR "trunk strength"[Title/Abstract] OR "trunk endurance"[Title/Abstract])) AND (reliab*[Title/Abstract] OR valid*[Title/Abstract] OR reproducib*[Title/Abstract] OR psychometr*[Title/Abstract] OR clinimetr*[Title/Abstract] OR agreement[Title/Abstract] OR "measurement error"[Title/Abstract] OR "standard error"[Title/Abstract] OR "minimal detectable"[Title/Abstract] OR "minimum detectable"[Title/Abstract] OR "smallest detectable"[Title/Abstract] OR "minimal important"[Title/Abstract] OR "minimally important"[Title/Abstract] OR "minimum important"[Title/Abstract] OR responsiv*[Title/Abstract] OR interpretabil*[Title/Abstract] OR "floor effect"[Title/Abstract] OR "ceiling effect"[Title/Abstract]) AND ("1800/01/01"[Date - Publication] : "2026/10/02"[Date - Publication])

Strength power rfd measurement Scopus

TITLE-ABS-KEY(("total hip arthroplast*" OR "total hip replacement*" OR THA OR THR) AND ("muscle strength" OR "muscle power" OR dynamometr* OR isokinetic OR isometric OR "maximal voluntary" OR "maximum voluntary" OR "one repetition maximum" OR 1RM OR "rate of force" OR "rate of torque" OR RFD OR RTD OR "explosive strength" OR "voluntary activation" OR "leg power" OR "knee extensor strength" OR "hip abductor strength" OR "trunk strength" OR "trunk endurance") AND (reliab* OR valid* OR reproducib* OR psychometr* OR clinimetr* OR agreement OR "measurement error" OR "standard error" OR "minimal detectable" OR "minimum detectable" OR "smallest detectable" OR "minimal important" OR "minimally important" OR "minimum important" OR responsiv* OR interpretabil* OR "floor effect" OR "ceiling effect")) AND PUBYEAR BEF 2027

Strength power rfd prognosis PubMed

("Arthroplasty, Replacement, Hip"[MeSH Terms] OR "total hip arthroplast*"[Title/Abstract] OR "total hip replacement*"[Title/Abstract]) AND ("Muscle Strength"[MeSH Terms] OR "Muscle Strength Dynamometer"[MeSH Terms] OR ("muscle strength"[Title/Abstract] OR "muscle power"[Title/Abstract] OR dynamometr*[Title/Abstract] OR isokinetic[Title/Abstract] OR isometric[Title/Abstract] OR "maximal voluntary"[Title/Abstract] OR "maximum voluntary"[Title/Abstract] OR "one repetition maximum"[Title/Abstract] OR 1RM[Title/Abstract] OR "rate of force"[Title/Abstract] OR "rate of torque"[Title/Abstract] OR RFD[Title/Abstract] OR RTD[Title/Abstract] OR "explosive strength"[Title/Abstract] OR "voluntary activation"[Title/Abstract] OR "leg power"[Title/Abstract] OR "knee extensor strength"[Title/Abstract] OR "hip abductor strength"[Title/Abstract] OR "trunk strength"[Title/Abstract] OR "trunk endurance"[Title/Abstract])) AND (prognos*[Title/Abstract] OR predict*[Title/Abstract] OR longitudinal[Title/Abstract] OR prospective[Title/Abstract] OR cohort[Title/Abstract] OR "follow up"[Title/Abstract] OR "follow-up"[Title/Abstract] OR recovery[Title/Abstract] OR deteriorat*[Title/Abstract] OR fall*[Title/Abstract] OR "natural history"[Title/Abstract] OR "return to work"[Title/Abstract] OR discharge[Title/Abstract] OR "risk factor"[Title/Abstract]) AND ("1800/01/01"[Date - Publication] : "2026/10/02"[Date - Publication])

Strength power rfd prognosis Scopus

TITLE-ABS-KEY(("total hip arthroplast*" OR "total hip replacement*" OR THA OR THR) AND ("muscle strength" OR "muscle power" OR dynamometr* OR isokinetic OR isometric OR "maximal voluntary" OR "maximum voluntary" OR "one repetition maximum" OR 1RM OR "rate of force" OR "rate of torque" OR RFD OR RTD OR "explosive strength" OR "voluntary activation" OR "leg power" OR "knee extensor strength" OR "hip abductor strength" OR "trunk strength" OR "trunk endurance") AND (prognos* OR predict* OR longitudinal OR prospective OR cohort OR "follow up" OR "follow-up" OR recovery OR deteriorat* OR fall* OR "natural history" OR "return to work" OR discharge OR "risk factor")) AND PUBYEAR BEF 2027

Strength power rfd protocol mechanism technology PubMed

("Arthroplasty, Replacement, Hip"[MeSH Terms] OR "total hip arthroplast*"[Title/Abstract] OR "total hip replacement*"[Title/Abstract]) AND ("Muscle Strength"[MeSH Terms] OR "Muscle Strength Dynamometer"[MeSH Terms] OR ("muscle strength"[Title/Abstract] OR "muscle power"[Title/Abstract] OR dynamometr*[Title/Abstract] OR isokinetic[Title/Abstract] OR isometric[Title/Abstract] OR "maximal voluntary"[Title/Abstract] OR "maximum voluntary"[Title/Abstract] OR "one repetition maximum"[Title/Abstract] OR 1RM[Title/Abstract] OR "rate of force"[Title/Abstract] OR "rate of torque"[Title/Abstract] OR RFD[Title/Abstract] OR RTD[Title/Abstract] OR "explosive strength"[Title/Abstract] OR "voluntary activation"[Title/Abstract] OR "leg power"[Title/Abstract] OR "knee extensor strength"[Title/Abstract] OR "hip abductor strength"[Title/Abstract] OR "trunk strength"[Title/Abstract] OR "trunk endurance"[Title/Abstract])) AND (protocol[Title/Abstract] OR biomechan*[Title/Abstract] OR kinematic*[Title/Abstract] OR kinetic*[Title/Abstract] OR symmetr*[Title/Abstract] OR asymmetr*[Title/Abstract] OR "weight bearing"[Title/Abstract] OR "weight-bearing"[Title/Abstract] OR "ground reaction"[Title/Abstract] OR "force plate"[Title/Abstract] OR "force platform"[Title/Abstract] OR sensor*[Title/Abstract] OR wearable*[Title/Abstract] OR inertial[Title/Abstract] OR acceleromet*[Title/Abstract] OR markerless[Title/Abstract] OR "motion capture"[Title/Abstract] OR camera[Title/Abstract] OR video[Title/Abstract] OR algorithm[Title/Abstract] OR electromyogra*[Title/Abstract] OR activation[Title/Abstract] OR "sampling frequency"[Title/Abstract] OR "filter cutoff"[Title/Abstract]) AND ("1800/01/01"[Date - Publication] : "2026/10/02"[Date - Publication])

Strength power rfd protocol mechanism technology Scopus

TITLE-ABS-KEY(("total hip arthroplast*" OR "total hip replacement*" OR THA OR THR) AND ("muscle strength" OR "muscle power" OR dynamometr* OR isokinetic OR isometric OR "maximal voluntary" OR "maximum voluntary" OR "one repetition maximum" OR 1RM OR "rate of force" OR "rate of torque" OR RFD OR RTD OR "explosive strength" OR "voluntary activation" OR "leg power" OR "knee extensor strength" OR "hip abductor strength" OR "trunk strength" OR "trunk endurance") AND (protocol OR biomechan* OR kinematic* OR kinetic* OR symmetr* OR asymmetr* OR "weight bearing" OR "weight-bearing" OR "ground reaction" OR "force plate" OR "force platform" OR sensor* OR wearable* OR inertial OR acceleromet* OR markerless OR "motion capture" OR camera OR video OR algorithm OR electromyogra* OR activation OR "sampling frequency" OR "filter cutoff")) AND PUBYEAR BEF 2027

Original source access and appraisal

For balance, special checks included the distinctions between original and tape-modified FSST, right/left versus operated/nonoperated step labels, supported versus unsupported unilateral stance, CoP versus CoM, cross-sectional discrimination versus future prediction, and fall-window alignment. For strength, checks included force versus torque, normalization, 1RM versus power, RFD assay definition, approach/stage selection and whether a PROM anchor defined a strength MIC.

Targeted source chasing identified Masuda et al., DOI 10.57281/jofmpt.202527, published online on 23 June 2026. Its original six-page Japanese PDF and English abstract were retrieved. Protocol, equation and Tables 1–2 were inspected visually. The printed SEM formula omits a square root, and the six-week knee-extensor LoA lower bound is −0.06 in Table 2 versus −0.07 in the narrative/abstract. The report preserves those source discrepancies. This paper was found outside the PubMed/Scopus source specification and is reported as supplemental retrieval.

Numerical claims were tied to their original stage and protocol. Reported versus derived values are distinguished; no new pooled effect was calculated. The report does not treat a statistically significant group change as an individual response, an MDC as an MIC, a correlation as agreement, a regression association as causation, an AUC as a probability, or a study using previously recorded outcomes as prospective follow-up from the index test.

Limitations of this review

Access was incomplete for several primary psychometric and rapid-force papers. The absence of a verified threshold in the appraised sources is not proof that no such evidence exists. Some relevant abstracts were indexed later than their online publication year; citations preserve publication details from the original record. Source text and table discrepancies remain visible rather than being silently corrected. Selection of deeply appraised papers was purposive and clinically focused, so the bibliography is not an exhaustive inventory of all studies in the retrieval sets.

Strength power and rate of force development source access appendix

Full-text retrieval used permitted literature-connector, open publisher, PMC/Europe PMC and institutional repository routes. Some requests returned unavailable content, provider errors, rate limits, or blocked pages. An unverified open-access URL was not treated as successful retrieval.

References

References are numbered in first citation order. Source descriptions identify the material examined and do not constitute a study quality rating. Each link identifies the original publication or explicitly named primary source version.

1. Ismailidis P, Kvarda P, Vach W, Cadosch D, Appenzeller-Herzog C, Mündermann A. Abductor Muscle Strength Deficit in Patients After Total Hip Arthroplasty: A Systematic Review and Meta-Analysis. The Journal of arthroplasty. 2021;36(8):3015-3027. DOI 10.1016/j.arth.2021.03.042 Source examined: Original article body retrieved.

Source note: SRC-c1b163c0dc7a Ismailidis P 2021

2. Holm B, Thorborg K, Husted H, Kehlet H, Bandholm T. Surgery-induced changes and early recovery of hip-muscle strength, leg-press power, and functional performance after fast-track total hip arthroplasty: a prospective cohort study. PloS one. 2013;8(4):e62109. DOI 10.1371/journal.pone.0062109 Source examined: Original article body retrieved.

Source note: SRC-8e1de3727d21 Holm B 2013

3. Winther SB, Husby VS, Foss OA, Wik TS, Svenningsen S, Engdal M, et al. Muscular strength after total hip arthroplasty. A prospective comparison of 3 surgical approaches. Acta orthopaedica. 2016;87(1):22-8. DOI 10.3109/17453674.2015.1068032 Source examined: Original article body retrieved.

Source note: SRC-d35707260a45 Winther SB 2016

4. Rasch A, Dalén N, Berg HE. Muscle strength, gait, and balance in 20 patients with hip osteoarthritis followed for 2 years after THA. Acta orthopaedica. 2010;81(2):183-8. DOI 10.3109/17453671003793204 Source examined: Original article body retrieved.

Source note: SRC-166903727563 Rasch A 2010

5. Judd DL, Dennis DA, Thomas AC, Wolfe P, Dayton MR, Stevens-Lapsley JE. Muscle strength and functional recovery during the first year after THA. Clinical orthopaedics and related research. 2014;472(2):654-64. DOI 10.1007/s11999-013-3136-y Source examined: Original abstract only; full article not retrieved; PubMed/PMC/Europe PMC and publisher routes attempted without usable article body.

Source note: SRC-0790ddbbe02a Judd DL 2014

6. Masuda K, Bito T, Ando T, Aoki T, Miyagawa T, Akiyama H. Minimal Detectable Change in Muscle Strength Assessment Using a Hand-Held Dynamometer Following and Prior to Total Hip Arthroplasty. Journal of Musculoskeletal Physical Therapy. 2026:Advance online publication, article 202527. DOI 10.57281/jofmpt.202527 Source examined: Original Japanese full PDF retrieved; protocol, printed equation and Tables 1–2 visually checked; English abstract also read.

Source note: SRC-975027027348 Masuda K 2026

7. Kamimura A, Sakakima H, Tsutsumi F, Sunahara N. Preoperative predictors of ambulation ability at different time points after total hip arthroplasty in patients with osteoarthritis. Rehabilitation research and practice. 2014;2014:861268. DOI 10.1155/2014/861268 Source examined: Original article body retrieved.

Source note: SRC-c61268adeafb Kamimura A 2014

8. Ninomiya K, Takahira N, Ikeda T, Suzuki K, Sato R, Hirakawa K. Predictors of falls in patients during the first year after total hip arthroplasty: A prospective cohort study. Health science reports. 2020;3(3):e184. DOI 10.1002/hsr2.184 Source examined: Original article body retrieved.

Source note: SRC-a75d340b9e57 Ninomiya K 2020

9. Huffman A, Burbelo A, Clark T, Annan C, Silcox DH, Bullock M. Preoperative Hip Abductor Muscle Strength Predicts Patient-Reported Functional Outcomes Following Total Hip Arthroplasty. The Journal of arthroplasty. 2026. DOI 10.1016/j.arth.2026.07.049 Source examined: Original article body retrieved; numeric tables and supplementary models not fully extracted.

Source note: SRC-38ca8e32ae9f Huffman A 2026

10. Konishi T, Hamai S, Fujita T, Hara D, Kawahara S, Motomura G, et al. Falls and Fractures After Total Hip Arthroplasty: Associations with Preoperative Physical Function and Postoperative Balance Confidence, with Insights from Cluster Analysis. JB & JS open access. 2025;10(4):e25.00233. DOI 10.2106/jbjs.oa.25.00233 Source examined: Original article body retrieved.

Source note: SRC-e60af4e6eb44 Konishi T 2025

11. Kawakami T, Imagama T, Matsuki Y, Okazaki T, Kaneoka T, Yamazaki K, et al. Preoperative abductor muscle strength on the healthy side affects the Timed Up and Go test after total hip arthroplasty in women. BMC musculoskeletal disorders. 2024;25(1):881. DOI 10.1186/s12891-024-08008-6 Source examined: Original article body retrieved.

Source note: SRC-ab0980518898 Kawakami T 2024

12. Foucher KC, Cinnamon CC, Ryan CA, Chmell SJ, Dapiton K. Hip abductor strength and fatigue are associated with activity levels more than 1 year after total hip replacement. Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 2018;36(5):1519-1525. DOI 10.1002/jor.23783 Source examined: Original article body retrieved.

Source note: SRC-a7fe8a91a43d Foucher KC 2018

13. Lin X, Wu W, Weijer RHA, Prins MR, van Dieën JH, Bruijn SM, et al. Strong relationship of muscle force and fall efficacy, but not of gait kinematics, with number of falls in the year after Total Hip Arthroplasty for osteoarthritis: An exploratory study. Clinical biomechanics (Bristol, Avon). 2022;92:105551. DOI 10.1016/j.clinbiomech.2021.105551 Source examined: Original article body retrieved.

Source note: SRC-de68397ec95d Lin X 2022

14. Shibuya M, Nanri Y, Kamiya K, Fukushima K, Uchiyama K, Takahira N, et al. The maximal gait speed is a simple and useful prognostic indicator for functional recovery after total hip arthroplasty. BMC musculoskeletal disorders. 2020;21(1):84. DOI 10.1186/s12891-020-3093-z Source examined: Original article body retrieved.

Source note: SRC-9851d96893a5 Shibuya M 2020

15. Shinonaga A, Matsumoto H, Uekawa M, Fujii K, Sato H, Furuichi S, et al. Association Between Fatty Infiltration of the Gluteus Medius Muscle and Falls After Total Hip Arthroplasty in Female Patients With Unilateral Primary Hip Osteoarthritis: A Retrospective Cohort Study. Geriatrics & gerontology international. 2025;25(12):1812-1820. DOI 10.1111/ggi.70245 Source examined: Original abstract only; full article not retrieved.

Source note: SRC-1703430e9016 Shinonaga A 2025

16. Kawano T, Nankaku M, Murao M, Goto K, Kuroda Y, Kawai T, et al. Development of a Clinical Prediction Rule to Identify Physical Activity After Total Hip Arthroplasty. Archives of physical medicine and rehabilitation. 2022;103(10):1975-1982. DOI 10.1016/j.apmr.2022.03.015 Source examined: Original abstract only; full article not retrieved.

Source note: SRC-26a83e470153 Kawano T 2022

17. Temporiti F, Adamo P, Baldracco F, Tarasconi A, Leo D, Colpani A, et al. Bilateral activation failure of ankle dorsiflexors in patients with hip osteoarthritis undergoing total hip arthroplasty. Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2025;85:103084. DOI 10.1016/j.jelekin.2025.103084 Source examined: Original abstract only; full article not retrieved.

Source note: SRC-1d13b511b23d Temporiti F 2025

18. Gagnon D, Nadeau S, Gravel D, Robert J, Bélanger D, Hilsenrath M. Reliability and validity of static knee strength measurements obtained with a chair-fixed dynamometer in subjects with hip or knee arthroplasty. Archives of physical medicine and rehabilitation. 2005;86(10):1998-2008. DOI 10.1016/j.apmr.2005.04.013 Source examined: Original abstract only; full article not retrieved.

Source note: SRC-cf6d06ebe079 Gagnon D 2005

19. Friesenbichler B, Casartelli NC, Wellauer V, Item-Glatthorn JF, Ferguson SJ, Leunig M, et al. Explosive and maximal strength before and 6 months after total hip arthroplasty. Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 2018;36(1):425-431. DOI 10.1002/jor.23626 Source examined: Original abstract only; full article not retrieved; publisher-reported open-access PDF not recovered.

Source note: SRC-185cd8029645 Friesenbichler B 2018