Abductor Muscle Strength Deficit in Patients After Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Monitoring Hip Joint Muscle Function in Osteoarthritis Patients Following Arthroplasty: A Prospective Cohort Study

Background/Objectives: Osteoarthritis (OA) is a chronic and progressive joint disease, leading to functional limitations and significantly impairing the quality of life. Muscle weakness, reduced mobility, and compensatory biomechanical changes are common consequences, further exacerbating functional decline. The aim of this study was to assess the impact of hip osteoarthritis on muscle functionality and to evaluate the effectiveness of hip arthroplasty using the MyotonPro device to measure key biomechanical parameters, i.e., tension, stiffness, and flexibility. Methods: This cohort study included 40 patients (17 women and 23 men; mean age 64.55 ± 10.49 years) with advanced hip OA (Kellgren-Lawrence grade III-IV) undergoing hip arthroplasty. Measurements of muscle tension (F), stiffness (S), and flexibility (D) in the gluteus maximus, rectus femoris, and biceps femoris were performed at three time points: before surgery, on postoperative days 8-10, and one month after hospital discharge. Pain (VAS), balance (Tinetti scale), and functional ability (WOMAC index) were also assessed. Results: Hip arthroplasty significantly reduced pain levels (VAS: 6.38 ± 0.28 preoperatively to 1.88 ± 0.22 postoperatively, p < 0.001) and improved functional ability (WOMAC: p < 0.001). Muscle tension and stiffness of the gluteus maximus initially increased after surgery (tension: 11.57 ± 0.32 to 12.15 ± 0.38, p = 0.009), reflecting compensatory stabilization but decreased by the final evaluation. Flexibility improved significantly over time (p = 0.014). The biceps femoris muscle exhibited a significant reduction in tension one month postoperatively (p = 0.015), alongside decreased stiffness (p = 0.015) and enhanced flexibility. The rectus femoris muscle showed minor changes in biomechanical properties, with no statistically significant differences detected. Conclusions: Osteoarthritis significantly impacts muscle function, reducing the gluteus muscle tension and stiffness, which compromises joint stability and triggers compensatory activity in the rectus femoris and biceps femoris muscles. Postoperative rehabilitation is essential for improving flexibility and addressing compensatory muscle tension.

Association between Quadriceps Muscle Strength and the Forgotten Joint Score after Total Hip Arthroplasty

BACKGROUND

Total hip arthroplasty (THA) effectively enhances hip function and alleviates pain in patients who have osteoarthritis, improving their quality of life. The Forgotten Joint Score-12 (FJS-12), a patient-reported outcome measure, has recently gained attention as a method for assessing joint awareness during daily activities following THA; however, the association between muscle strength, specifically quadriceps muscle strength, and the FJS-12 has not been fully investigated.

METHODS

This cross-sectional study involved 624 patients who underwent THA at a single center in Japan. The mean patient age was 67 years (range, 43 to 94), and 85.3% of the cohort were women. We aimed to investigate the association between quadriceps muscle strength and the FJS-12 (measured at 12 months postoperatively) using multiple regression analyses adjusted for variables such as pain and leg length discrepancy.

RESULTS

The mean FJS-12 was 72.2, and the mean quadriceps muscle strength was 1.2 Nm/kg. Higher quadriceps muscle strength was significantly associated with better FJS-12 outcomes (β = 0.28, P < 0.001). Conversely, increased pain and perceived leg length discrepancy were negatively associated with lower FJS-12 values.

CONCLUSIONS

Our findings indicate that quadriceps muscle strength is a crucial determinant of joint awareness as measured using the FJS-12 in patients undergoing THA. These results highlight the potential benefits of targeted rehabilitation to enhance quadriceps muscle strength, which may help patients undergoing THA experience less joint awareness in their daily activities.

A Preliminary Study on Kinetic Analysis of Ground Reaction Force and Impulse During Gait in Patients With Total Hip Replacement and Implication for Rehabilitation

BACKGROUND

There is little research done on ground reaction forces (GRF) in terms of 3D impulses after total hip replacement (THR). This study aimed to investigate the GRFs and 3D impulses in four sub-phases of stance during gait in the patients undergoing THR.

METHODS

A total of 10 pain-free THR patients and 10 healthy people were recruited. This is an observational and retrospective study. The gait data was collected between 2008 and 2014 and analyzed between 2020 and 2024. All the participants were included in the three-dimensional gait analysis. Gait parameters, phase durations, GRFs and impulses' key values during gait were calculated in four sub-phases of stance. Statistical comparisons were performed with generalized linear models including age, gender, body mass index and walking speed as interactive factors.

RESULTS

It is found that (1) cadence, walking speed, stride length and step width in THR group were significantly decreased in compared with control group; (2) the THR decreased loading response duration in operative side and pre-swing duration in non-operative side compared with the control group, but the THR's two sides have similar duration proportions in sub-stance phases; (3) the THR group had lower GRFs than the control group in vertical direction but higher in the medial-lateral direction; (4) in operative side, the THR's impulses in loading response phase were lower than the control group in anterior-posterior direction, and (5) in non-operative side, the THR's impulse in pre-swing phase in anterior-posterior direction was higher than the control side.

CONCLUSION

The THR group showed slower walking speeds than the control group. The reasons could be from the decreased impulse in loading response phase, the decreased 2nd peak of GRF and the decreased pre-swing impulse in vertical direction in operative side. Clinicians are suggested to consider the information provided when designing relevant rehabilitation exercises on the related muscles and functions.

Hip Abductor Muscle Strength in Patients After Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Impaired hip abductor muscle strength indirectly leads to changes in knee kinematics and may cause pain or functional limitations after total knee arthroplasty (TKA). This study aimed to evaluate and quantify hip abductor muscle strength deficits after TKA and investigate external factors influencing hip abductor muscle strength after TKA.

METHODS

A comprehensive literature search was performed, and clinical studies reporting hip abductor muscle strength after primary TKA were included. We performed meta-analyses to assess the relative hip muscle strength of the operated leg compared to the contralateral limb and the change from preoperative to postoperative values across multiple time points. We also assessed the pooled absolute hip muscle strength across the following time points: preoperatively, up to two months, two to six months, and more than six months postoperatively. There were 15 studies involving 823 patients that met our inclusion criteria.

RESULTS

Compared with preoperative values, patients had a mean strength deficit of 18.0% (95% confidence interval (CI) [-30.8 to -5.2] at up to two months postoperatively, a non-significant deficit of 11.3% (CI [-32.7 to 10.2]) at two to six months postoperatively and an increase of 18.4% (CI [2.7 to 34.1]) at ≥ six months postoperatively. Compared with the contralateral side, patients had a mean abductor strength deficit of 11.5% (CI [-16.2 to -6.9]) preoperatively, 23.2% (CI [-27.6 to -18.8]) at up to two months postoperatively, a non-significant deficit of 10.8% (CI [-23.2 to 1.6]) at two to six months postoperatively and no difference (0.6% (CI [-4.2 to 5.4]) more than six months postoperatively. The study quality was low to moderate.

CONCLUSIONS

Hip abductor muscle strength is reduced preoperatively in patients undergoing TKA, continues to decrease in the immediate postoperative period, but fully recovers within six to 12 months. Although these data can be used to guide patient education and rehabilitation planning, they should be interpreted with caution due to the heterogeneous and limited high-quality evidence.

Identifying Deficits in Hip and Knee Muscle Strength on the Surgical and Nonsurgical Sides in Women up to 12 Months After Total Hip Arthroplasty

OBJECTIVE

Regaining hip and knee muscle strength is important after total hip arthroplasty (THA). However, it is unclear if muscles other than those of the operated hip also lose strength. This study aimed to identify deficits in hip and knee strength on the surgical and nonsurgical sides in female patients up to 12 months after THA.

METHODS

Participants were 91 female patients who had hip osteoarthritis and underwent unilateral THA. Forty-six community-dwelling women who were asymptomatic were selected as control participants. Patients with locomotor disorders or postsurgical complications were excluded. Maximal isometric strength of the hip flexors, extensors, and abductors and knee extensors and flexors on the surgical and nonsurgical sides were measured before THA and 3, 6, and 12 months thereafter.

RESULTS

Twelve months after THA, hip flexion, extension, and abduction strength on the surgical side were 84.6%, 83.5%, and 76.2%, respectively, of those in individuals who were asymptomatic; at the same time point, those on the nonsurgical side were 94.8%, 83.9%, and 79.4%, respectively. Knee extension strength on the surgical side was 89.3% of that in individuals who were asymptomatic. Compared to individuals who were asymptomatic, nearly all muscles showed significantly lower strength on both sides up to 6 months after THA.

CONCLUSION

At 12 months after THA, hip and knee strength on both the surgical and nonsurgical sides did not recover to the level observed in individuals who were asymptomatic. In particular, hip abductor strength on the surgical and nonsurgical sides were 76% and 79%, respectively, of that in individuals who were asymptomatic.

IMPACT

At 12 months after THA, hip and knee strength on the surgical and nonsurgical sides did not recover to the level observed in individuals who were asymptomatic, suggesting that the nonsurgical side may be inappropriate as a control to assess strength recovery on the surgical side.

Hip Abductor Muscle Strength Recovery: A Comparison Between Joint Replacement Surgery and Internal Fixation Surgery

Introduction Proximal femoral fractures are common fractures of the hip that are considered a major healthcare concern globally; these include subtrochanteric, intertrochanteric, and the neck of the femur fractures. Internal fixation surgery and joint replacement surgery are the two most common intervention techniques used to treat these fractures. Consequently, weakness in the hip abductor muscle post-surgery may lead to implant loosening, necessitating revision of the surgery. In light of this, this study aimed to compare hip abductor strength recovery outcomes between joint replacement surgery and internal fixation surgery. Methodology A comparative study was performed over six months at the Department of Orthopaedics and Physiotherapy. Based on the inclusion and exclusion criteria and anticipating potential dropouts, a total of 56 patients were included in the study, and their hip abductor strength was measured using a sphygmomanometer. The patients were classified into two groups: Group A or Group B as per the type of hip surgery. Group A included 29 patients who underwent joint replacement surgeries involving either cemented or uncemented total hip arthroplasty (THA) or hip hemiarthroplasty (HHA). Group B comprised 27 patients who were operated on using either proximal femoral nail (PFN) or dynamic hip screw (DHS). Results The cohort consisted of 36 males and 20 females, with a mean age of 51.71 years. The overall mean value of hip abductor muscle strength at postoperative day (POD) three in the internal fixation group was 65.06 ±5.98, which progressed to 107.51 ±24.76 after six months; in the joint replacement surgery group, it was 70.03 ±12.46 at POD three, which progressed to 113.11 ±21.27 after six months. The age-wise distribution demonstrated that the patients in the age group of 18-50 years demonstrated progressive results: from 65.33 ±4.9 at POD three to 105.95 ±22.71 after six months in the internal fixation group; from 66.82 ±7.72 at POD three to 109.59 ±22.54 after six months in the joint replacement group. Moreover, patients aged above 50 years showed progression from 64.80 ±6.98 at POD three to 103.33 ±27.30 after six months in the internal fixation group, and from 69.58 ±14.75 at POD three to 108.22 ±20.62 after six months in the joint replacement group. Conclusions Our findings revealed that joint replacement surgery resulted in greater improvements in the hip abductor muscle strength compared to internal fixation surgery in the immediate postoperative period and during follow-ups. Additionally, younger patients exhibited better strength-related outcomes in comparison to the elderly population regardless of the type of surgery.

Predictors of physical activity recovery after total hip arthroplasty: a prospective observational study

PURPOSE

Little is known about the changes and the factors in physical activity as following total hip arthroplasty (THA). There are potential discrepancies between subjective and objective measurements of physical activity. Thus, our porpose is to compare objective and subjective measurements of activity levels in patients undergoing THA preoperatively, three months and one year following surgery, and investigated the factors that predicts the objective activity level after THA.

METHODS

This prospective observational study included 42 patients with unilateral symptomatic hip osteoarthritis who underwent THA. The objective activity level (step counts, sit-to-stands, and upright time) by using a tri-axial accelerometer, PRO (Oxford hip score; OHS and University of California, Los Angeles activity score; UCLA score), and muscle volume around the hip joint by using preoperative computed tomography were measured.

RESULTS

The number of steps, OHS, and UCLA score before, at three months, and one year after THA averaged 5092, 6532, and 6545 steps, 30.3, 43.0, and 44.2 points, and 3.4, 4.8, and 4.6 points, respectively, with significant postoperative increases (P < 0.05). No significant difference was found between three months and one year postoperatively. In multivariate analysis, younger age and higher preoperative contralateral gluteal medius volume were the predictors of higher postoperative step counts (P < 0.05).

CONCLUSIONS

Physical activity, including step counts, OHS, and UCLA score increased significantly until three months after unilateral THA. Early surgical intervention before contralateral muscle declines and preoperative rehabilitation including contralateral side may additionally improve postoperative activity levels.

Gait function assessed using 3D gait analysis in patients with cervical spinal myelopathy before and after surgical decompression: a systematic review and meta-analysis

BACKGROUND

Degenerative cervical myelopathy (DCM) is the most common cause of cervical spinal cord dysfunction in adults and the result of chronic degenerative changes of the cervical spine. The compression of the spinal cord can lead to ischemia, inflammation, and neuronal apoptosis with a consequent impairment of the neurological function. Gait impairment is one of the most frequent signs of DCM.

PURPOSE

To investigate the changes in spatio-temporal gait parameters assessed using 3D gait analysis in patients affected by DCM compared with healthy controls and the effect of surgical decompression on these parameters.

STUDY DESIGN/SETTING

Systematic review and meta-analysis.

PATIENT SAMPLE

The meta-analysis included 267 patients with DCM and 276 healthy controls.

OUTCOME MEASURES

Spatio-temporal parameters of gait were assessed. The primary outcome was gait speed; the secondary outcomes were cadence, stride length, step width, stride time, single-limb support time, and double-limb support time.

METHODS

Studies reporting spatial and/or temporal gait parameters measured using 3D gait analysis in patients with DCM were included. Data sources were Embase, Medline, and the Core Collection of Web of Science. Meta-analyses were performed to investigate the influence of surgical decompression in patients measured before and after surgery as well as to compare gait parameters of patients with DCM with controls.

RESULTS

Thirteen studies reporting on 267 patients with DCM and 276 healthy controls met the inclusion criteria. Seven studies compared patients with DCM with healthy controls, three studies compared gait in patients with DCM before and after surgical decompression, and three studies performed both comparisons. Compared with healthy controls, patients with DCM had slower gait speed (Standardized Mean Difference (SMD), -1.49; 95% confidence interval (CI) [-1.86; -1.13]; p<.001), lower cadence (SMD, -0.78; 95%CI [-1.00; -0.56]; p<.001), shorter stride length (SMD, -1.27; 95%CI [-1.53, -1.01]; p<.001), greater step width (SMD, 0.98; 95%CI [0.42, 1.54]; p=.003), longer stride time (SMD, 0.77; 95%CI [0.37, 1.16]; p=.009), single-limb support phase (SMD, -0.68; 95%CI [-1.06; -0.29]; p=.011), and double-limb support phase (SMD 0.84; 95%CI [0.35, 1.32]; p=.012). After surgical decompression, patients with DCM showed an improvement in gait speed (SMD, 0.57 (95%CI [0.29; 0.85]; p=.003) and no significant differences in other spatio-temporal parameters.

CONCLUSIONS

Patients with DCM have clearly different spatio-temporal gait parameters than healthy controls. Gait speed is the only spatio-temporal gait parameter that improves significantly after surgical decompression suggesting that gait speed may be an important clinical outcome parameter in patients with DCM.

Early Recovery of Physical Function After Total Hip Arthroplasty in a Patient With Osteopetrosis: A Case Report

Osteopetrosis is an uncommon and inherited disorder. Some disease-specific characteristics, such as diffuse osteosclerosis and a high incidence of fractures, may potentially affect postoperative rehabilitation. This report presents a case of successful rehabilitation early after total hip arthroplasty for osteopetrosis. A 56-year-old Japanese man, who was diagnosed with osteopetrosis at the age of 11, underwent total hip arthroplasty in the right hip. Full weight-bearing was allowed on the day after the operation; the postoperative rehabilitation program was proceeded based on a standard program as done after total hip arthroplasty for osteoarthritis. A shoe lift in the left leg was used in supervised walking training to correct the imbalanced alignment due to leg length discrepancy. The patient could walk independently with a cane 17 days after the operation. Three weeks after the operation, the patient demonstrated comfortable and maximal walking speed of 1.11 and 1.34 m/s, respectively, and maximal hip abductor muscle strength of 3.96 kgf･m, both of which were better than those before the operation. There were no adverse events during the postoperative rehabilitation course. These findings suggest the safety and efficacy of standard rehabilitation programs after total hip arthroplasty even in individuals with osteopetrosis. In addition, it may be important to consider the whole-body condition in the rehabilitation of individuals with osteopetrosis.

Effects of Electromyographic Biofeedback-Assisted Exercise on Functional Recovery and Quality of Life in Patients after Total Hip Arthroplasty: A Randomized Controlled Trial

The goal of the trial was to examine the effects of adding electromyographic biofeedback (EMG-BF) to the conventional program of physiotherapy after total hip arthroplasty (THA) on functional recovery and quality of life. The trial was designed as a prospective, interventional, single-blinded randomized controlled study. Ninety patients were randomized into an experimental group (EG) (n = 45; mean age 63.9 ± 8.8) and control group (CG) (n = 45; mean age 63.9 ± 9). All patients received 21 days of physiotherapy which consisted of therapeutic exercise (land-based and aquatic), electrotherapy, and education. Electromyographic biofeedback was added to a portion of the land-based exercise in EG. The Hip Disability and Osteoarthritis Outcome Score (HOOS), Numeric Rating Scale (NRS), Short Form Health Survey-36 (SF-36), use of a walking aid, 30 s chair stand test (CST) as well as the Timed Up and Go (TUG) test were used for outcome measurement. A higher proportion of the participants in both groups did not need a walking aid after the intervention (p < 0.05). All participants improved their 30 s CST and TUG results (p < 0.001), as well as their NRS and HOOS scores (p < 0.05). No significant differences between the groups were found. There were no additional benefits from adding EMG-BF to the conventional physiotherapy protocol.

Effects of perioperative exercise therapy combined with nutritional supplementation on functional recovery after fast-track total hip arthroplasty

BACKGROUND

The combination of exercise therapy combined with nutritional supplementation (Nutr) is widely used for frail or sarcopenic older persons. However, the effects of Nutr in elderly patients after fast-track total hip arthroplasty (THA) are unknown. This study examined the effects of perioperative Nutr on muscle strength, functional performance, and quality of life (QOL) in frail elderly women after fast-track THA.

METHODS

A total of 58 frail elderly women aged 65-80 years scheduled for unilateral primary THA were randomly allocated to two groups: the physical exercise (Ex) combined with Nutr (Ex + Nutr; n = 29) group, and the Ex alone (Ex; n = 29) group. Protein and vitamin D supplements were provided daily from 4 weeks preoperatively to 8 weeks postoperatively (12 weeks) to the patients in the Ex + Nutr group, whereas the Ex group did not receive any supplements. Surgery and postoperative rehabilitation programmes during intervention were identical in both groups. Hip abductor and knee extensor muscle strength, functional performance (Timed Up & Go test, Harris Hip Score), and QOL (Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire) were assessed at baseline and at 12 weeks (8 weeks postoperatively).

RESULTS

After the intervention, hip abductor muscle strength on the contralateral leg and knee extensor muscle strength on both sides significantly improved in the Ex + Nutr group compared to the Ex group (p = 0.03, 0.01, and 0.01, respectively). However, hip abductor muscle strength on the operated side did not differ significantly between the groups (p = 0.23). There were no significant differences in functional performance and QOL.

CONCLUSION

Ex + Nutr does not have an additional effect on the improvement of hip abductor strength, functional performance, and QOL compared to Ex alone after fast-track THA. However, significant improvements were observed in the strength of some muscles after fast-track THA.

TRIAL REGISTRATION

UMIN 000042964.

THE IRB APPROVAL

This study was approved by the Mirai Iryo Reesearch Center (approval number TGE1602-115).

Abductor muscle function after anterolateral approach in patients with unilateral end-stage hip osteoarthritis undergoing total hip arthroplasty: A prospective study

Background

Total hip arthroplasty (THA) is a successful procedure for treating end-stage hip osteoarthritis (OA). Regarding the surgical approach for THA, the anterolateral (AL) approach, which requires anterior hemimyotomy of the gluteus medius muscle, has shown a long-term favorable outcome. However, to date, complete information related to hip abductor muscle outcomes after the AL approach is unavailable. This study therefore aimed to evaluate the postoperative outcome of patients who undergo THA using the AL approach in terms of hip abductor muscle recovery, pain, function, and muscle healing status.

Methods

Twenty patients diagnosed with unilateral end-stage hip OA underwent cementless THA with the AL approach. All patient procedures were performed by a single surgeon. Preoperative and postoperative data were collected at 2-week, 6-week, 3-month, and 6-month follow-up periods. Hip abductor muscle power was measured via handheld dynamometer. The healing of the musculotendinous repair was evaluated with magnetic resonance imaging at 9 months.

Results

After THA, hip abductor muscle power in the operated hip significantly increased as early as 3 months post-procedure when compared with the preoperative value (p < 0.05). The other parameters-including pain score, Harris hip score, and WOMAC score-significantly improved as early as 2 weeks post-operation (p < 0.05). In all patients, MRI scans showed good healing of the muscle repair site without a gap in the gluteus medius muscle. However, three patients (15%) had some fibrosis and tendon swelling at the repair site.

Conclusion

This study demonstrated that patients with end-stage hip OA could experience significantly improved hip abductor motor function as early as 3 months after undergoing THA with the AL approach. Moreover, despite patients experiencing anterior hemimyotomy of the gluteus medius muscle, no significant complications emerged at the muscle repair site in the AL approach.

Association of preoperative variables of ipsilateral hip abductor muscles with gait function after total hip arthroplasty: a retrospective study

Background

This study aimed to identify the association of preoperative variables of ipsilateral hip abductors with gait function after total hip arthroplasty (THA).

Methods

This study enrolled 42 patients who underwent unilateral primary THA for osteoarthritis. Gait speed and Timed Up-and-Go test were conducted 6 months postoperatively. Preoperative composition of the glutei medius and minimus and the upper portion of gluteus maximus was evaluated by computed tomography. Cross-sectional area ratio of individual composition to the total muscle was calculated. Preoperative variables associated with gait speed and Timed Up-and-Go test after THA were identified by using stepwise regression analysis.

Results

Faster gait speed and shorter Timed Up-and-Go test correlated with smaller cross-sectional area of low-density lean tissue or intramuscular adipose tissue (low-density lean tissue plus intramuscular fat) in the glutei medius and minimus and lower cross-sectional area ratio of low-density lean tissue to the total glutei medius and minimus. Faster gait speed and shorter Timed Up-and-Go test also correlated with larger cross-sectional area of lean muscle mass in the gluteus maximus, higher cross-sectional area ratio of lean muscle mass to the total gluteus maximus, and lower cross-sectional area ratio of intramuscular fat or intramuscular adipose tissue to the total gluteus maximus. Faster gait speed additionally correlated with larger total cross-sectional area of the gluteus maximus. Regression analysis showed that the total cross-sectional area of the gluteus maximus and the low-density lean tissue cross-sectional area of the glutei medius and minimus were the explanatory variables of gait speed and Timed Up-and-Go test after THA, respectively.

Conclusions

There was a potential association between preoperative composition of ipsilateral hip abductors and gait function 6 months after THA. This study indicates a predictive role of preoperative assessment of ipsilateral hip abductor composition in the recovery of gait function after THA.

Objective monitoring of functional recovery after total knee and hip arthroplasty using sensor-derived gait measures

Background

Inertial sensors hold the promise to objectively measure functional recovery after total knee (TKA) and hip arthroplasty (THA), but their value in addition to patient-reported outcome measures (PROMs) has yet to be demonstrated. This study investigated recovery of gait after TKA and THA using inertial sensors, and compared results to recovery of self-reported scores of pain and function.

Methods

PROMs and gait parameters were assessed before and at two and fifteen months after TKA (n = 24) and THA (n = 24). Gait parameters were compared with healthy individuals (n = 27) of similar age. Gait data were collected using inertial sensors on the feet, lower back, and trunk. Participants walked for two minutes back and forth over a 6m walkway with 180° turns. PROMs were obtained using the Knee Injury and Osteoarthritis Outcome Scores and Hip Disability and Osteoarthritis Outcome Score.

Results

Gait parameters recovered to the level of healthy controls after both TKA and THA. Early improvements were found in gait-related trunk kinematics, while spatiotemporal gait parameters mainly improved between two and fifteen months after TKA and THA. Compared to the large and early improvements found in of PROMs, these gait parameters showed a different trajectory, with a marked discordance between the outcome of both methods at two months post-operatively.

Conclusion

Sensor-derived gait parameters were responsive to TKA and THA, showing different recovery trajectories for spatiotemporal gait parameters and gait-related trunk kinematics. Fifteen months after TKA and THA, there were no remaining gait differences with respect to healthy controls. Given the discordance in recovery trajectories between gait parameters and PROMs, sensor-derived gait parameters seem to carry relevant information for evaluation of physical function that is not captured by self-reported scores.

MRI Findings of Muscle Damage after Total Hip Arthroplasty Using the Complete Muscle Preserving Anterolateral Supine Approach

Background and Objectives: We performed anterolateral total hip arthroplasty (ALS THA) with the purpose of complete muscle-tendon preservation without muscle-tendon dissection. This study aimed to evaluate muscle damage in the periprosthetic hip joint muscles of patients undergoing ALS THA at 1-year post-operative hip magnetic resonance imaging (MRI). Materials and Methods: We evaluated changes in the muscle cross-sectional area (M-CSA) and fatty atrophy of the periprosthetic muscles. We also assessed the Harris hip score on pre-operative and 12-month post-operative MRI in 66 patients who underwent ALS THA. The grade of M-CSA atrophy was classified into no atrophy, slight atrophy, moderate atrophy, and severe atrophy. Fatty atrophy was classified as improved, no change, and worsened using the Goutallier classification. Results: More than 90% of patients’ M-CSA had no atrophy in the obturator internus (Oi), obturator externus (Oe), gluteus medius (Gmed), and gluteus minimus (Gmin), and some improvement was observed in terms of fatty atrophy. In contrast, M-CSA of the tensor fascia latae (TFL) muscle was clearly decreased, and there was no improvement in the TFL fatty atrophy. However, the presence or absence of TFL atrophy did not affect clinical outcome. Conclusions: We performed the complete muscle preserving procedure, ALS THA, with attention to preserving the Oi and Oe by direct visual confirmation and gentle treatment of the Gmed and Gmin with effective retraction. Post-operative M-CSA atrophy evaluation on MRI showed that the Oi, Oe, Gmed, and Gmin were satisfactorily preserved; however, the TFL was clearly atrophic. In the ALS approach, where entry is made between Gmed and TFL, atrophy of the TFL due to superior gluteal nerve injury must be tolerated to some extent.

Incidences and circumstances of falls among women following total hip arthroplasty on long-term follow-up

BACKGROUND

Patients who undergo total hip arthroplasty have an increased risk of falls during the first postoperative year. However, it is unclear whether patients after total hip arthroplasty will continue to be at high risk of falls more than 1 year postoperatively. To better understand whether the risk of falls changes after a 1-year period, we investigated the incidences and circumstances of falls in women patients for 5 years after total hip arthroplasty.

METHODS

This longitudinal prospective cohort study analyzed 65 women with severe hip osteoarthritis who underwent total hip arthroplasty. The incidences and circumstances of falls before total hip arthroplasty and at 1, 2, and 5 years postoperatively were investigated. We assessed the Harris Hip Score and evaluated hip pain and ambulatory ability using a self-administered questionnaire.

RESULTS

The incidences of at least one fall were 30.8%, 26.2%, 23.1%, and 30.8% before and 1, 2, and 5 years after surgery, respectively. Among the circumstances of falls from pre-surgery to 5 years post-surgery, there was a significant difference in the direction of falls; however, there were no significant differences in the location, time, cause, and type of injury. Most falls occurred indoors by tripping or loss of balance during the daytime. Among the participants who had falls almost half sustained injuries, and approximately 10% of falls resulted in fractures each year. Although self-reported hip pain, ambulation, and the Harris Hip Score significantly improved in women after total hip arthroplasty compared to pre-surgery, there was no significant difference in the incidences of falls from 1 to 5 years post-surgery.

CONCLUSION

Women who underwent total hip arthroplasty continued to have an increased risk of falls and fall-induced injuries for 5 years postoperatively. Preventive measures against falling to reduce fall-induced injuries in the long term are required for women after total hip arthroplasty.