Contralateral hip and knee gait biomechanics are unchanged by total hip replacement for unilateral hip osteoarthritis

Effects of hip osteoarthritis on lower body joint kinematics during locomotion tasks: a systematic review and meta-analysis

Introduction

Motion analysis can be used to gain information needed for disease diagnosis as well as for the design and evaluation of intervention strategies in patients with hip osteoarthritis (HOA). Thereby, joint kinematics might be of great interest due to their discriminative capacity and accessibility, especially with regard to the growing usage of wearable sensors for motion analysis. So far, no comprehensive literature review on lower limb joint kinematics of patients with HOA exists. Thus, the aim of this systematic review and meta-analysis was to synthesise existing literature on lower body joint kinematics of persons with HOA compared to those of healthy controls during locomotion tasks.

Methods

Three databases were searched for studies on pelvis, hip, knee and ankle kinematics in subjects with HOA compared to healthy controls during locomotion tasks. Standardised mean differences were calculated and pooled using a random-effects model. Where possible, subgroup analyses were conducted. Risk of bias was assessed with the Downs and Black checklist.

Results and Discussion

A total of 47 reports from 35 individual studies were included in this review. Most studies analysed walking and only a few studies analysed stair walking or turning while walking. Most group differences were found in ipsi- and contralateral three-dimensional hip and sagittal knee angles with reduced ranges of motion in HOA subjects. Differences between subjects with mild to moderate and severe HOA were found, with larger effects in severe HOA subjects. Additionally, stair walking and turning while walking might be promising extensions in clinical gait analysis due to their elevated requirements for joint mobility. Large between-study heterogeneity was observed, and future studies have to clarify the effects of OA severity, laterality, age, gender, study design and movement execution on lower limb joint kinematics.

Systematic Review Registration

PROSPERO (CRD42021238237).

Stabilization and compensation strategy of the hip angle during gait in hip-osteoarthritis patients from the perspective of whole-body movement synergy

BACKGROUND

The implementation of a strategy to control the hip angle during gait is important to avoid disease progression in patients with hip osteoarthritis (OA).

RESEARCH QUESTION

Do patients with hip OA tend to stabilize their hip angles by a combination of whole-body movements during gait in terms of variability?

METHODS

A public gait dataset comprising 80 asymptomatic participants and 106 patients with hip OA was used. Uncontrolled manifold analysis was performed using the joint angles as elemental variables and the hip joint angles as performance variables. The synergy index ΔV, variances of elemental variables that did not affect the performance variable (VUCM) and of those that affected the performance variable (VORT), and index of covariation strategy (COV) were calculated in sagittal and frontal plane. A one-sample t-test for statistical parametric mapping (SPM) analysis was used for ΔV and COV. Two-sample t-tests of SPM analyses were used for ΔV, VUCM, and VORT to compare the two groups.

RESULTS

In both planes, the ΔV and COV were significantly larger than zero in both groups (p < 0.001). In the sagittal plane, the VORT was higher in the hip OA group than in the control group after 77 % of stance phase. In the frontal plane, the hip OA group had larger ΔV and VUCM after last half and last quartile of stance phase compared to the control group, respectively. The VORT was smaller in the hip OA group than in the control group.

SIGNIFICANCE

The hip angle was stabilized in the hip OA group in the frontal plane but insufficiently stabilized in the sagittal plane; however, the patients changed their hip angle during the early phase of stance. The combination of whole-body movements contributed to the stabilization of hip angle.

Lower limb joint loading in patients with unilateral hip osteoarthritis during bipedal stance and the effect of total hip replacement

Osteoarthritis of the hip is a common condition that affects older adults. Total hip replacement is the end-stage treatment to relief pain and improve joint function. Little is known about the mechanical load distribution during the activity of bipedal stance, which is an important daily activity for older adults who need to rest more frequently. This study investigated the distribution of the hip and knee joint moments during bipedal stance in patients with unilateral hip osteoarthritis and how the distribution changed 1 year after total hip replacement. Kinematic and kinetic data from bipedal stance were recorded. External hip and knee adduction moments were calculated and load distribution over both limbs was calculated using the symmetry angle. Preoperatively, the non-affected limb carried 10% more body weight than the affected limb when standing on two legs. Moreover, the mean external hip and knee adduction moments of the non-affected limb were increased compared to the affected limb. At follow-up no significant differences were observed between the patients' limbs. Preoperative and postoperative changes in hip adduction moment were mainly explained by the combination of the vertical ground reaction force and the hip adduction angle. Stance width also explained changes in the hip and knee adduction moments of the affected leg. Furthermore, as with walking, bipedal standing also showed an asymmetric mechanical load distribution in patients with unilateral hip osteoarthritis. Overall, the findings suggest the need for preventive therapy concepts that focus not only on walking but also on optimizing stance towards a balanced load distribution of both legs.

Mechanical energy fluctuation in lower limbs during walking in participants with and without total hip replacement

Mechanical energy fluctuation of the segments of lower limbs during walking has not been fully investigated. It was hypothesized that the segments may work as a pendulum, i.e. the kinetic and potential energies exchanged out of phase. This study aimed to investigate energy changes and recovery during gait in hip replacement patients. The gait data for 12 participants with total hip replacement and 12 age-matched control was compared. The kinetic, potential and rotative energies for whole lower limb and thigh, calf and foot, were calculated. The effectiveness of a pendulum effect was analysed. Gait parameters (speeds and cadence) were calculated. The results showed that the thigh had significant effectiveness as a pendulum during gait with energy recovery coefficient of approximately 40% while the calf and foot were less like a pendulum during gait. In comparison, energy recoveries of lower limbs in the two groups were not significantly different. If the pelvis was considered as an approximate to the centre of mass, however, the control group had a higher energy recovery than total-hip-replacement group by roughly 10%. This study concluded that, unlike centre of mass energy recovery, the mechanical energy recovery mechanism in the lower limbs during walking is not affected after total hip replacement.

Mechanical energy fluctuation in lower limbs during walking in participants with and without total hip replacement

Mechanical energy fluctuation of the segments of lower limbs during walking has not been fully investigated. It was hypothesized that the segments may work as a pendulum, i.e. the kinetic and potential energies exchanged out of phase. This study aimed to investigate energy changes and recovery during gait in hip replacement patients. The gait data for 12 participants with total hip replacement and 12 age-matched control was compared. The kinetic, potential and rotative energies for whole lower limb and thigh, calf and foot, were calculated. The effectiveness of a pendulum effect was analysed. Gait parameters (speeds and cadence) were calculated. The results showed that the thigh had significant effectiveness as a pendulum during gait with energy recovery coefficient of approximately 40% while the calf and foot were less like a pendulum during gait. In comparison, energy recoveries of lower limbs in the two groups were not significantly different. If the pelvis was considered as an approximate to the centre of mass, however, the control group had a higher energy recovery than total-hip-replacement group by roughly 10%. This study concluded that, unlike centre of mass energy recovery, the mechanical energy recovery mechanism in the lower limbs during walking is not affected after total hip replacement.

Multiscale biomechanics of the biphasic articular cartilage in the natural hip joint during routine activities

BACKGROUND AND OBJECTIVE

The investigation of the biomechanical behaviour of the articular cartilage (AC) under physiological loading is important to understand the joint function and onset of pathologies. This study aimed to develop a multiscale computational modelling approach and apply the approach to investigate the time-dependant biphasic behaviour of the AC in the natural hip joint under repetitive physiological loading over 80 cycles amongst six routine activities.

METHODS

A subject-specific musculoskeletal multibody dynamics (MBD) model was developed based on the anthropometry and motion capture data collected for a male subject. A corresponding FE model of the natural hip joint with biphasic AC was created based on the bone geometries exported from the MBD model. A multiscale computational modelling was then developed to couple the MBD model and the FE model and used to investigate the time-dependant biphasic behaviour of the AC under subject-specific physiological loading over 80 cycles amongst six routine activities.

RESULTS

The results showed that for all the activities considered, the interstitial fluid pressure in the AC supported over 80% of the loading. The maximum values of the peak contact pressure and peak fluid pressure for the whole cycle increased firstly and then remained stable over time from the 1st cycle to the 80th cycle. At these instants, the contact areas were located at the centre region of the AC. By contrast, when the contact area was located at the edge of the AC, these peak pressures were found to increase over time for some of the activities (squat, ascending stairs, descending stairs) but decrease for the other activities (normal walking, standing up, sitting down).

CONCLUSION

This study for the first time developed a multiscale computational modelling approach to couple a musculoskeletal MBD model of the body and a detailed FE model of the natural hip joint with biphasic AC, which enabled the evaluation of time-dependant biphasic behaviour of the AC under realistic physiological loading conditions. The study may have important implications in biomechanical studies of human cartilage to understand the joint function and biomechanical factors related to joint disease, and to support the development of cartilage substitution.

High hip center arthroplasty in the treatment of severe hip dysplasia: Are knee and ankle compromised?

BACKGROUND

There is limited information about the effect of hip center location on gait parameters of knee and ankle. This study aimed to compare anatomical vs. high hip center arthroplasty according to gait parameters of knee and ankle and investigate whether the high hip center has any adverse effect on these joints or not.

METHODS

20 patients who underwent unilateral total hip arthroplasty (Group 1; 10 patients with anatomical reconstruction, Group 2; 10 patients with high hip center) due to Crowe type III-IV developmental dysplasia of the hip and completed 2 years of follow-up were included. The patients were examined by 3-D gait analysis.

FINDINGS

The maximum extension of the knee on the operated side was lower in Group 2 (p = 0.044). Longitudinal knee joint force was higher in Group 2 on both operated (p = 0.041) and non-operated sides (p = 0.031). Lateral knee joint force was also higher in Group 2 (p = 0.023). No significant difference was detected in ankle parameters.

INTERPRETATION

Unilateral high hip center has been shown to restrict the dynamic knee range of motion on the operated side and increase the knee load on both sides, thus putting the knees at risk for osteoarthritis.

LEVEL OF EVIDENCE

Level III, Retrospective comparative study.

Mid-long-term results of total knee arthroplasty followed by ipsilateral total hip arthroplasty versus total hip arthroplasty subsequent to ipsilateral total knee arthroplasty: a case-control analysis

Background

The aim of the present study was to compare the outcomes of patients who underwent different sequences of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods

We retrospectively identified 47 patients who underwent TKA followed by ipsilateral THA (THA-TKA) and 36 patients who received THA subsequent to ipsilateral TKA (TKA-THA) for rheumatoid arthritis or osteoarthritis between January 2008 and April 2014. Twenty-eight patients were selected for each group after case-control matching with preoperative demographics and protheses of THA. Clinical scores, radiographic results, complication rates, and survivorship were compared. The median duration of follow-up was 110 (range 80–149) months.

Results

Both groups showed significant improvement in Harris Hip Scores, Knee Society Score, and Short Form-12 at the last follow-up compared to baseline (p < .001). At the last follow-up, all clinical scores were actually lower in the THA-TKA group, but those differences were not statistically significant. Otherwise, there was no significant difference in radiological alignment or complication rates. The survivorship of THA and TKA in the THA-TKA group was 94.7 and 95.7%, respectively, compared with 92.4 and 100.0% in the TKA-THA group at 8 years (log rank, p = .939 and .187).

Conclusions

Patients who underwent ipsilateral THA and TKA with different sequences achieved similar favorable outcomes. Total joint arthroplasty can be performed safely with excellent outcomes in patients with a history of prior ipsilateral THA or TKA.

Trial registration

The trial was registered in the Chinese Clinical Trial Registry (ChiCTR2000035147) dated 2 August 2020.

Individuals with Unilateral Mild-to-Moderate Hip Osteoarthritis Exhibit Lower Limb Kinematic Asymmetry during Walking But Not Sit-to-Stand

Asymmetry during gait is associated with the evolution of secondary osteoarthritis. Kinematic asymmetry has been reported in advanced stages of hip osteoarthritis but has not been evaluated in earlier stages of the disease or has it been directly compared with unilateral and bilateral hip osteoarthritis. Our objective was to evaluate within-group symmetry and compare between-group asymmetry for three-dimensional pelvis, hip, knee, and ankle kinematics during walking and sit-to-stand in individuals with unilateral mild-to-moderate hip OA, bilateral mild-to-moderate hip osteoarthritis, and healthy controls. Twelve individuals with unilateral mild-to-moderate hip OA, nine individuals with bilateral mild-to-moderate symptomatic and radiographic hip OA, and 21 age-comparable healthy controls underwent three-dimensional motion analysis during walking and sit-to-stand. Pelvis and lower limb joint angles were calculated using inverse kinematics and between-limb symmetry was assessed for each group. Any resulting asymmetries (most affected minus contralateral limb) were compared between groups. Participants with unilateral hip osteoarthritis exhibited significantly less hip extension (7.90°), knee flexion (4.72°), and anterior pelvic tilt (3.38°) on their affected limb compared with the contralateral limb during the stance phase of walking. Those with unilateral hip osteoarthritis were significantly more asymmetrical than controls for sagittal plane hip and pelvis angles. No significant asymmetries were detected within- or between-groups for sit-to-stand. Individuals with unilateral hip osteoarthritis exhibited lower limb asymmetries consistent with those reported in advanced stages of disease during walking, but not sit-to-stand. Consideration of the possible negative effects of gait asymmetry on the health of the affected and other compensating joints appears warranted in the management of hip OA.

Knee Load Distribution in Hip Osteoarthritis Patients After Total Hip Replacement

Reduced external knee adduction moments in the second half of stance after total hip replacement have been reported in hip osteoarthritis patients. This reduction is thought to shift the load from the medial to the lateral knee compartment and as such increase the risk for knee osteoarthritis. The knee adduction moment is a surrogate for the load distribution between the medial and lateral compartments of the knee and not a valid measure for the tibiofemoral contact forces which are the result of externally applied forces and muscle forces. The purpose of this study was to investigate whether the distribution of the tibiofemoral contact forces over the knee compartments in unilateral hip osteoarthritis patients 1 year after receiving a primary total hip replacement differs from healthy controls. Musculoskeletal modeling on gait was performed in OpenSim using the detailed knee model of Lerner et al. (2015) for 19 patients as well as for 15 healthy controls of similar age. Knee adduction moments were calculated by the inverse dynamics analysis, medial and lateral tibiofemoral contact forces with the joint reaction force analysis. Moments and contact forces of patients and controls were compared using Statistical Parametric Mapping two-sample t-tests. Knee adduction moments and medial tibiofemoral contact forces of both the ipsi- and contralateral leg were not significantly different compared to healthy controls. The contralateral leg showed 14% higher medial tibiofemoral contact forces compared to the ipsilateral (operated) leg during the second half of stance. During the first half of stance, the lateral tibiofemoral contact force of the contralateral leg was 39% lower and the ratio 32% lower compared to healthy controls. In contrast, during the second half of stance the forces were significantly higher (39 and 26%, respectively) compared to healthy controls. The higher ratio indicates a changed distribution whereas the increased lateral tibiofemoral contact forces indicate a higher lateral knee joint loading in the contralateral leg in OA patients after total hip replacement (THR). Musculoskeletal modeling using a detailed knee model can be useful to detect differences in the load distribution between the medial and lateral knee compartment which cannot be verified with the knee adduction moment.

Prior unilateral total hip arthroplasty does not influence the outcome of ipsilateral total knee arthroplasty

PURPOSE

To assess the influence of a prior well-functioning unilateral primary total hip arthroplasty (THA) on the functional outcome of a subsequent ipsilateral primary total knee arthroplasty (TKA).

METHODS

A retrospective case-control study of 92 patients older than 60 years underwent unilateral primary TKA after a prior ipsilateral THA (THA-TKA group) and 92 matched patients underwent only TKA (TKA group). Clinical assessments were performed using the Knee Society Scores (KSS) and Harris Hip Score (HSS), quality of life by the Reduced Western Ontario and MacMaster Universities (WOMAC) and Short-Form 12 (SF-12) questionnaires. Radiological evaluation was also performed.

RESULTS

Median follow-up after TKA was 7.2 (range 5-9) years. There were no significant differences between groups in baseline data at the TKA time. The mean gains in KSS were similar in both groups. At the last follow-up, there were no significant differences in WOMAC-pain or SF12-physical scores, but the WOMAC-function (p = 0.003) and SF12-mental (p = 0.018) scores were significantly better in the isolated TKA group. At the last follow-up, there were no significant differences in the radiological knee alignment or component positions. For aseptic reasons, the TKA survival at 8 years in the TKA group was 95.8 (95% CI 87.8-100%), and 96.6% (95% CI 91.8-100%) in the THA-TKA group (ns).

CONCLUSION

A well-functioning unilateral THA does not influence on the functional outcome of a subsequent ipsilateral TKA. This finding can help clinicians when counseling patients with hip and knee osteoarthritis.

LEVEL OF EVIDENCE

III.

Kinematic Gait Analysis After Primary Total Hip Replacement: A Systematic Review: Gait After Total Hip Replacement: A Systematic Review

Total hip replacement (THR) is a surgical procedure indicated for patients affected by severe hip osteoarthritis. Although this technique has proved to be effective in relieving pain and restoring function, gait limitations may persist following this procedure. The objective of this systematic review was to evaluate gait kinematics after THR and compare the results with those of the pre-operative state and with healthy control individuals. PubMed/MEDLINE, Embase, Web of Science, CENTRAL and Scopus databases were searched until December 2019. Methodological quality and internal validity score of each study were assessed using the PEDro and the Newcastle-Ottawa scales. In all, ten studies met our inclusion criteria. Following THR, statistically significant improvements were seen in dynamic hip and knee range of motion of both the affected and the contralateral limb, single-limb support time symmetry, step length, stride length, walking speed and gait pattern. However, deficits were observed in all the previous parameters, as well as in hip adduction angle in comparison with healthy subjects. In conclusion, gait patterns improve after THR in comparison with the pre-operative state, although there are deficits relative to healthy individuals.

Is the Pelvis-Thorax Coordination a Valuable Outcome Instrument to Assess Patients With Hip Osteoarthritis?

Objective: The evaluation of the disease severity in hip osteoarthritis (OA) patients being currently based on subjective instruments. It would be of interest to develop more objective instruments, for example based on gait analysis. The aims of this study were to explore if pelvis-thorax coordination parameters could be valuable instrument outcomes to achieve this evaluation by assessing their reliability, discriminant capacity and responsiveness.

Methods: Three groups of subjects; healthy, hip OA patients with severe disease (defined as indication to surgery), hip OA patients with less severe disease (no indication to surgery) were included. Hip OA patients with severe disease were evaluated before and 6 months after surgery. Subjects had to perform a gait analysis at comfortable speed, and pelvis-thorax coordination was evaluated. The correlations with clinical and structural parameters, as well as reliability, discriminant capacities and responsiveness, were assessed.

Results: The pelvis-thorax coordination in the coronal plane during walking was correlated to clinical and to structural severity in hip OA patients (R² = 0.13). The coronal plane coordination allowed to discriminate healthy subjects from all hip OA patients (sensibility = 0.86; specificity = 0.59). Moreover, when comparing OA patients only, coronal plane coordination allows to discriminate patients with indication of surgery from those with no indication of surgery (sensibility = 0.72; specificity = 0.72). Moreover, the pelvis-thorax coordination demonstrated an excellent reliability and a good responsiveness.

Conclusion: Changes in the pelvis-thorax coordination might refer to different mechanisms, from analgesia to motor control plasticity, and might be a possible explanation for the weak correlation between structure and symptoms in hip OA patients. Moreover, such parameter might be used as an objective outcome in hip OA clinical trials.

Clinical Trials Registration:www.ClinicalTrials.gov, identifier: NCT02042586 and NCT01907503.

The effects of preoperative chronic opioid use in total hip arthroplasty

BACKGROUND

Perioperative opioid use is becoming an increasingly concerning topic in total joint arthroplasty (TJA). The current study aims to add to the paucity of prior studies that have detailed perioperative opioid use patterns and the effects of preoperative chronic opioid use among a cohort of total hip arthroplasty (THA) patients.

METHODS

A retrospective analysis of 256 consecutive patients who underwent a THA at our institution between February 2016 and June 2016 was performed. Two cohorts were compared: patients deemed 1) preoperative chronic opioid users, and 2) non-chronic users. Variables compared included baseline characteristics, quality metrics, and patients' opioid use histories 3 months prior to surgery and 6 months following surgery.

RESULTS

Of the 256 patients, 54 (21.1%) patients were identified as preoperative chronic opioid users. Baseline characteristics including age, gender, BMI, and ASA scores were similar between both cohorts. Discharge disposition, value-based purchasing (VBP) costs, length of stay (LOS), emergency room visits, and postoperative office visits were similar between the two cohorts. Readmission rates (30-day, 90-day, and 6-month) were significantly higher (p < 0.05) in the chronic opioid users cohort. By the 6-month postoperative time period, chronic opioid users were consuming approximately 100-times the morphine equivalents than non-chronic users.

CONCLUSIONS

The current study demonstrates that a substantial proportion of preoperative chronic opioid users continue to consume large amounts of opioids up to 6-months following THA surgery. Furthermore, preoperative chronic use is significantly associated with poorer quality outcomes, specifically with respect to readmission rates.

LEVEL OF EVIDENCE

Level II, Prognostic Study.

The effect of conjoint tendon release on gait after direct anterior total hip arthroplasty

INTRODUCTION

There has been considerable interest in the direct anterior (DA) approach to total hip arthroplasty (THA) recently. To facilitate exposure of the proximal femur it is sometimes necessary to release the conjoint tendon.

AIM

To prospectively investigate whether release of the conjoint tendon has an impact on gait in the early postoperative period.

METHODS

We measured gait velocity, stride length, single-limb support and single-limb support symmetry preoperatively, at discharge from the hospital, and 2, 6 and 12 weeks and postoperatively. Participants also completed the Timed Up and Go and a series of questionnaires (WOMAC, SF-12, Harris Hip Score, and pain VAS) at each visit.

RESULTS

36 participants undergoing a DA THA with a single surgeon were enrolled in this study. 22 participants had a release of the conjoint tendon during their surgery. We found no differences between the groups for any gait, patient-reported or surgical outcomes (p < 0.05). There was a total of 3 complications reported in the release group, and 1 complication in the group that did not have a release.

CONCLUSION

Although the conjoint tendon has an important role in the biomechanics of the hip, we found release of the conjoint tendon during the DA approach for THA to have no impact on gait or patient reported outcomes within 12 weeks post-surgery. Therefore, if the exposure of the proximal femur is limited, a low threshold for release of the conjoint tendon is recommended to improve visualisation.

Gait Analysis Reveals that Total Hip Arthroplasty Increases Power Production in the Hip During Level Walking and Stair Climbing

BACKGROUND

total hip arthroplasty (THA) is associated with decreased pain and improved function, including increased walking speed, but it does not always improve overall joint mechanics during activities of daily living such as level walking and stair climbing. The hip's ability to generate power to move and allow for smooth and efficient forward motion is critical to success after surgery. Although osteoarthritis (OA) of the hip limits the power of the affected joint, it is not known whether other joints in the affected limb or in the contralateral limb need to produce more power to compensate. Additionally, it is not known whether alterations in the production of power before and after surgery are gender-specific.

QUESTIONS/PURPOSES

(1) Is there a change in the power production of the bilateral ankles, knees, and hips during level walking before and after patients undergo unilateral THA, and are there important gender-specific differences in these findings? (2) How do these findings differ for stair climbing?

METHODS

Three-dimensional motion and ground reaction force data were collected for 13 men and 13 women who underwent primary, unilateral THA. This was a secondary analysis of previously collected data on gait mechanics from 60 patients who underwent THA. In the initial study, patients were included if they were scheduled to undergo a primary, unilateral THA within 4 weeks of the study and were able to walk without an assistive device. Patients were recruited from the practices of four surgeons at a single institution from 2008 to 2011. Patients were included in the current study if they were enrolled in the previous study, attended all three assessment visits (preoperative and 6 weeks and 1 year postoperative), and, during the preoperative visit, were able to walk without using an assistive device and climb stairs without using a handrail. Patients walked and ascended stairs at a self-selected speed at the three assessment visits. The power of each ankle, knee, or hip was calculated in Visual 3D using kinematic and kinetic data collected using motion capture. Power for each joint was normalized to the total power of the bilateral lower limbs by dividing the individual joint power by the total lower-extremity joint power. A mixed-model repeated-measures ANOVA was used to determine differences in normalized joint power for the ankle, knee, and hip, based on gender, limb (surgical-side versus nonsurgical-side) and timepoint (preoperative and 6 weeks and 1 year postoperative).

RESULTS

Surgical-side absolute (preoperative: -0.2 ± 0.2 [CI, -0.3 to -0.2], 1 year postoperative: -0.5 ± 0.3 [CI, -0.6 to - 0.5]; p < 0.001) and normalized (preoperative: 0.05 ± 0.04 [CI, 0.03-0.06], 1 year postoperative: 0.08 ± 0.04 [CI, 0.06-0.09]; p = 0.020) hip power production increased during walking. Surgical-side absolute (preoperative: 1.1 ± 0.3 [CI, 1.0-1.3], 1 year postoperative: 1.6 ± 0.2 [CI, 1.3-2.0]; p = 0.005) and normalized (preoperative: 0.16 ± 0.04 [CI, 0.14-0.18], 1 year postoperative: 0.21 ± 0.06 [CI, 0.18-0.24]; p = 0.008) hip power production increased during stair climbing, while nonsurgical ankle absolute (preoperative: 0.9 ± 0.5 [CI, 0.6 - 1.2], 1 year postoperative: 0.6 ± 0.3 [CI, 0.4-0.8]; p = 0.064) and normalized (preoperative: 0.13 ± 0.06 [CI, 0.10-0.16], 1 year postoperative: 0.08 ± 0.04 [CI, 0.06-0.10]; p = 0.015) power decreased during stair climbing after THA. No consistent effect of gender was observed.

CONCLUSIONS

In this gait-analysis study, power was improved in hip joints that were operated on, and power production in the ipsilateral and contralateral ankles and ipsilateral hips was reduced during level walking and stair climbing. The success of surgical intervention must be based on restoring reasonable balance of forces in the lower limb. Patients with OA of the hip lose power production in this joint and must compensate for the loss by producing power in other joints, which then may become arthritic. To determine future interventions, an understanding of whether changes in forces or joint angle affect the change in joint power is needed. Based on these results, THA appeared to effectively increase hip power and reduce the need for compensatory power production in other joints for both men and women in this patient cohort.

LEVEL OF EVIDENCE

Level I, prognostic study.

Gait analysis in patients after bilateral versus unilateral total hip arthroplasty

BACKGROUND

Gait abnormalities were reported in patients after total hip arthroplasty (THA). One-stage bilateral THA was introduced for bilateral hip pathologies, showing similar clinical and surgical outcome to unilateral procedure. However, no studies analyze the gait features after bilateral THA surgery compared to unilateral THA.

RESEARCH QUESTION

Are there differences in gait characteristics between bilateral and unilateral THA patients and are there differences between these cases and asymptomatic age-matched healthy subjects?

METHODS

In this prospective observational study, thirty-five patients with bilateral (n = 18) or unilateral THA (n = 17) and twenty asymptomatic age-matched volunteers were studied. Participants underwent three-dimensional gait analysisin order to detect gait spatial-temporal and kinematic (Gait Variable Score - GVS) parameters. Mobility (Timed Up and Go - TUG), fear of movement (Tampa Scale of Kinesiophobia - TSK) and pain during walking (Numeric Rating Scale - NRS) were also assessed. Patients were evaluated the day before surgery and at seven days, whereas healthy subjects underwent a single evaluation. ANOVA was used to assess differences between the three groups at each time-point and within-group differences in bilateral and unilateral groups.

RESULTS

At baseline, no differences between the two groups of patients were found. As expected, their gait spatial-temporal and kinematic parameters and functional variables were impaired with respect to healthy subjects, both before and after surgery. After surgery, GVS Pelvic-TILT closer to normative values, longer stance and shorter swing phases were found in bilateral cases compared to unilateral patients. Moreover, a higher NRS score was found in bilateral patients, whereas TUG and TSK revealed no differences between the two groups of patients.

SIGNIFICANCE

The current findings, focusing on short-term effectiveness of bilateral THA, could assist physiotherapists in selecting the best ambulation training and an appropriate rehabilitation approach immediately after surgery.

Muscular strength and function after total hip arthroplasty performed with three different surgical approaches: one-year follow-up study

BACKGROUND

Surgical approach influences short-term muscular strength, and leg-strength asymmetry has been demonstrated after total hip arthroplasty (THA). We evaluated muscular strength, physical function and patient-reported outcome measures (PROMs) up to 12 months postoperatively, in patients operated on using 3 different surgical approaches.

METHODS

60 patients scheduled for primary THA were allocated to the direct lateral (DLA), posterior (PA) or anterior (AA) approach. The following parameters were evaluated: leg press and abduction strength, pain, 6-minute walking test, Harris Hip Score and Hip disability and Osteoarthritis Outcome Score - Physical Function Shortform (HOOS-PS).

RESULTS

Abduction strength in the DLA group was significantly more reduced than the PA and AA groups 12 months postoperatively (p < 0.001). A significant interleg difference in abduction (p < 0.01) and leg press (p < 0.03) persisted in all groups up to 6 months, and up to 12 months in the DLA (p < 0.05). In the AA group, interleg difference in leg press was present up to 12 months (p = 0.01). Pain scores were higher in the DLA than the AA group at 6 months (p = 0.01). Patients in the PA group had better HOOS-PS score than those in the DLA group 3 months postoperatively (p = 0.02). No intergroup differences in pain or PROMs were found 12 months postoperatively.

CONCLUSION

Patients operated via the DLA had reduced muscular strength, HOOS-PS scores and higher pain scores than those who underwent PA and AA type surgery. The non-operated leg was significantly stronger than the operated leg in all groups 6 months postoperatively and this persisted up to 12 months postoperatively for the DLA and AA groups. Clinical Trial Protocol number: ClinicalTrials.gov (NCT01506024).

The contralateral knee may not be a valid control for biomechanical outcomes after unilateral total knee arthroplasty

BACKGROUND

Although unilateral symptoms and unilateral total knee arthroplasty (TKA) are common, many patients have bilateral radiographic osteoarthritis (OA). Because the contralateral (non-operated) limb is often used as a comparison for clinical and biomechanical outcomes, it is important to know if the presence of OA influences movement patterns in either limb.

RESEARCH QUESTION

The purpose of this study was to compare bilateral sagittal plane biomechanics between subjects with and without contralateral knee OA after unilateral TKA.

METHODS

Fifty-three subjects who underwent unilateral TKA underwent three-dimensional gait analysis 6-24 months after surgery participated in this cross-sectional study. Kellgren-Lawrence (KL) OA severity in the contralateral limb was measured, and subjects were classified into either a non-OA (KL 0 or 1) or OA (KL 2-4) group. Mixed-model ANOVA tests with factors of group and limb were used to compare biomechanical measures. In the presence of a significant interaction effect, post-hoc comparisons were performed.

RESULTS

The OA group had more knee flexion at initial contact, less knee flexion and extension excursions, and less knee extension in the contralateral limb compared to the non-OA group. The non-OA group had significant differences between limbs, with more knee flexion at initial contact, less knee joint excursion, and less peak knee extension on the operated limb compared to the contralateral limb, whereas there were no limb differences for the OA group. Kinetic variables were not different in the ANOVA models.

SIGNIFICANCE AND INTERPRETATION

Subjects with contralateral knee OA have more symmetrical gait, although they adopt a more abnormal and stiff-legged gait pattern bilaterally. Researchers and clinicians should consider radiographic disease severity, not just symptoms, in the contralateral limb when identifying appropriate subject samples for unilateral biomechanical studies. Symmetrical movement patterns between limbs after surgery should not be the sole factor upon which movement recovery is based.

Gait asymmetries in unilateral symptomatic hip osteoarthritis and their association with radiographic severity and pain

INTRODUCTION:

Little is known about the loading patterns in unilateral hip osteoarthritis (OA) and their relationship to radiographic severity and pain. We aimed to examine the loading patterns at the hips of those with unilateral symptomatic hip OA and identify associations between radiographic severity and pain with loading alterations.

METHODS:

61 subjects with symptomatic unilateral hip OA underwent gait analyses and evaluation for radiographic severity (Kellgren-Lawrence [KL]-grade) and pain (visual analogue scale) at bilateral hips.

RESULTS:

Hip OA subjects had greater range of motion and higher hip flexion, adduction, internal and external rotation moments at the contralateral, asymptomatic hip compared to the ipsilateral hip ( p < 0.05). Correlations were noted between increasing KL-grade and increasing asymmetry of contralateral to ipsilateral hip loading ( p < 0.05). There were no relationships with pain and loading asymmetry.

DISCUSSION:

Unilateral symptomatic hip OA subjects demonstrate asymmetry in loading between the hips, with relatively greater loads at the contralateral hip. These loading asymmetries were directly related to the radiographic severity of symptomatic hip OA and not with pain.

CONCLUSION:

Additional research is needed to determine the role of gait asymmetries in disease progression.

Knee motion and muscle activation patterns are altered in hip osteoarthritis: The effect of severity on walking mechanics

BACKGROUND

Knee function is impaired in individuals with moderate hip osteoarthritis. How this extends to those undergoing total hip arthroplasty is unknown despite the common requirement for knee arthroplasty in this population. The study purpose was to determine whether sagittal plane knee joint movements and quadriceps and hamstring activation patterns differ between individuals with either moderate or severe unilateral hip osteoarthritis, and between ipsilateral and contralateral knees.

METHODS

20 individuals with moderate osteoarthritis and 20 with severe osteoarthritis were recruited. Sagittal knee motion and surface electromyograms from the hamstrings and quadriceps were collected during treadmill walking at a self-selected speed. Principal component analysis captured amplitude and temporal sagittal plane motion and EMG waveform features. Student's t-tests and Analysis of Variance determined between group differences and within/between group leg differences.

FINDINGS

The severe groups' contralateral knee was in greater flexion at initial contact and demonstrated a movement profile of a longer stance phase (p < 0.001). The severe group had reduced sagittal plane knee motion (p < 0.0001); more so in the ipsilateral knee (p < 0.0001). The severe group had greater hamstring (p = 0.009) and quadriceps activation (p < 0.001) overall, specifically mid-stance quadriceps bilaterally (p = 0.002). Ipsilateral sagittal plane knee motion was reduced in both groups. Compared with those with moderate osteoarthritis, individuals with severe osteoarthritis walk with reduced sagittal plane knee motion bilaterally, suggesting prolonged contralateral stance, and elevated mid-stance hamstring and quadriceps activation.

INTERPRETATION

Altered kinematics and muscle activity could contribute to a greater mechanical demand on the contralateral knee in those with more severe hip osteoarthritis.

Long-term hip loading in unilateral total hip replacement patients is no different between limbs or compared to healthy controls at similar walking speeds

Variation in hip joint contact forces directly influences the performance of total hip replacements (THRs). Measurement and calculation of contact forces in THR patients has been limited by small sample sizes, wide variation in patient and surgical factors, and short-term follow-up. This study hypothesised that, at long-term follow-up, unilateral THR patients have similar calculated hip contact forces compared to controls walking at similar (self-selected) speeds and, in contrast, THR patients walking at slower (self-selected) speeds have reduced hip contact forces. It was further hypothesised that there is no difference in calculated hip contact forces between operated and non-operated limbs at long-term follow-up for both faster and slower patients. Gait analysis data for THR patients walking at faster (walking speed: 1.29 ± 0.12 m/s; n = 11) and slower (walking speed: 0.72 ± 0.09 m/s; n = 11) speeds were used. Healthy subjects constituted the control group (walking speed: 1.36 ± 0.12 m/s; n = 10). Hip contact forces were calculated using static optimisation. There was no significant difference (p > 0.31) in hip contact forces between faster and control groups. Conversely, force was reduced at heel strike by 19% (p = 0.002), toe-off by 31% (p < 0.001) and increased at mid-stance by 15% (p = 0.02) for the slower group compared to controls. There were no differences between operated and non-operated limbs for the slower group or the faster group, suggesting good biomechanical recovery at long-term follow-up. Loading, at different walking speeds, presented here can improve the relevance of preclinical testing methods.

Abnormal loading of the hip and knee joints in unilateral hip osteoarthritis persists two years after total hip replacement

A total hip replacement (THR) is a common and routine procedure to reduce pain and restore normal activity. Gait analysis can provide insights into functional characteristics and dynamic joint loading situation not identifiable by clinical examination or static radiographic measures. The present prospective longitudinal study tested whether 2 years after surgery a THR would restore dynamic loading of the knee and hip joints in the frontal plane to normal. Instrumented gait analysis was performed shortly before surgery and approximately 2 years after THR on 15 unilateral hip osteoarthritis (OA) patients. 15 asymptomatic matched individuals were recruited as healthy controls. Results showed that abnormal joint loading persisted 2 years after THR. The 2nd external knee adduction moment in terminal stance in the affected (-34%, p = 0.002, d = 1.22) and non-affected limb (-25%, p = 0.035, d = 0.81) was lower compared to controls and thus indicated a shift in the knee joint load distribution from medial to lateral. A correlation analysis revealed that a smaller hip range of motion explained 46% of 2nd knee adduction moment alterations. In contrast, the 2nd external hip adduction moment in terminal stance was postoperatively higher in the affected (+22%, p = 0.007, d = 1.04) and non-affected limb (+22%, p = 0.005, d = 1.05). Here, 51% of 2nd hip adduction moment alterations can be explained with a greater hip adduction angle. Patients with a THR may therefore be at higher risk for abnormal joint loading and thus for the development of OA in other joints of the lower extremities. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Longitudinal joint loading in patients before and up to one year after unilateral total hip arthroplasty

Abnormal kinematics and kinetics have been reported in hip osteoarthritis (OA) patients before and after total hip arthroplasty (THA). These changes can affect the loading of the ipsilateral hip, as well as the contralateral hip and knee joint. As it is not clear how hip and knee loading evolves in THA patients during the first year after surgery, the goal of this study is to define how joint loading changes in patients before and at three evaluation times after THA surgery. Musculoskeletal modelling in combination with gait analysis data was used to calculate hip and knee contact forces in 14 patients before and 3-, 6- and 12-months after unilateral THA, as well as in 18 healthy controls. Results showed that bilateral hip and knee loading were decreased compared to controls, both before and after THA surgery. Loading symmetry was altered compared to controls at 3-months post-surgery for the hip and at all evaluation times, except for 6-months post-surgery, for the knee, with ipsilateral joint loading decreased compared to the contralateral side. To conclude, 12-months after THA joint loading was not normalized, with both hip and knee loading in patients decreased compared to controls. Therefore, no overloading of the ipsi- or contralateral hip and knee joint was found before and up to one year after unilateral THA.

Gait symmetry and hip strength in women with developmental dysplasia following hip arthroplasty compared to healthy subjects: A cross-sectional study

Introduction

Untreated unilateral developmental dysplasia of the hip (DDH) results in asymmetry of gait and hip strength and may lead to early osteoarthritis, which is commonly treated with a total hip arthroplasty (THA). There is limited knowledge about the obtained symmetry of gait and hip strength after the THA. The objectives of this cross-sectional study were to: a) identify asymmetries between the operated and non-operated side in kinematics, kinetics and hip strength, b) analyze if increased walking speed changed the level of asymmetry in patients c) compare these results with those of healthy subjects.

Methods

Women (18–70 year) with unilateral DDH who had undergone unilateral THA were eligible for inclusion. Vicon gait analysis system was used to collect frontal and sagittal plane kinematic and kinetic parameters of the hip joint, pelvis and trunk during walking at comfortable walking speed and increased walking speed. Furthermore, hip abductor and extensor muscle strength was measured.

Results

Six patients and eight healthy subjects were included. In the patients, modest asymmetries in lower limb kinematics and kinetics were present during gait, but trunk lateral flexion asymmetry was evident. Patients’ trunk lateral flexion also differed compared to healthy subjects. Walking speed did not significantly influence the level of asymmetry. The hip abduction strength asymmetry of 23% was not statistically significant, but the muscle strength of both sides were significantly weaker than those of healthy subjects.

Conclusions

In patients with a DDH treated with an IBG THA modest asymmetries in gait kinematics and kinetics were present, with the exception of a substantial asymmetry of the trunk lateral flexion. Increased walking speed did not result in increased asymmetries in gait kinematics and kinetics. Hip muscle strength was symmetrical in patients, but significantly weaker than in healthy subjects. Trunk kinematics should be included as an outcome measure to assess the biomechanical benefits of the THA surgery after DDH.

A Comparison of Walking Gait Following Mechanical and Kinematic Alignment in Total Knee Joint Replacement

BACKGROUND

Although previous studies have compared radiological, pain, and function scores in kinematically aligned (KA) and mechanically aligned (MA) total knee arthroplasty (TKA), no previous studies have undertaken a three-dimensional (3D) gait analysis in these groups. This study compared kinematic and kinetic variables recorded during level walking in patients at least 2 years post-surgery who underwent an MA or KA procedure.

METHODS

Utilizing a 9-camera motion analysis system, gait analysis was undertaken on 29 patients (MA = 15, KA = 14). A 9-camera motion analysis system was used to collect 3D kinematic data of the involved and uninvolved limbs during walking at a self-selected speed. Additionally, 3D ground reaction forces and moments during the stance phase were recorded, and an inverse dynamics approach was utilized to analyze these data.

RESULTS

There were no significant differences in spatial-temporal variables between MA and KA groups (P > .05). Local minima and maxima for knee joint angles were not significantly different (P > .05) across involved and uninvolved legs and MA/KA groups in any of the 3 planes of motion. Principal component analysis revealed a significant difference (P < .05) in the transverse plane moment in late stance. No other significant differences were observed for knee, hip, or ankle joint moments.

CONCLUSION

Differences in gait parameters across the KA and MA groups at 2 years post-surgery were insufficient to support either one of the operative procedures over the other.

Unilateral hip osteoarthritis: The effect of compensation strategies and anatomic measurements on frontal plane joint loading

In order to reduce pain caused by the affected hip joint, unilateral hip osteoarthritis patients (HOAP) adopt characteristic gait patterns. However, it is unknown if the knee and hip joint loading in the non-affected (limb_non-affected ) and the affected (limb_affected ) limb differ from healthy controls (HC) and which gait parameters correlate with potential abnormal joint loading. Instrumented 3D-gait analysis was performed on 18 HOAP and 18 sex, age, and height matched HC. The limb_non-affected showed greater first and second peak external hip adduction moments (first HAM: +15%, p = 0.014; second HAM: +15%, p = 0.021, respectively), than seen in HC. In contrast, the second peak external knee adduction moment (KAM) in the limb_affected is reduced by about 23% and 30% compared to the limb_non-affected and HC, respectively. Furthermore, our patients showed characteristic gait compensation strategies including reduced peak vertical forces (pvF), a greater foot progression angle (FPA), and reduced knee range of motion (ROM) in the limb_affected . The limb_affected was 5.6 ± 3.8 mm shorter than the limb_non-affected . Results of stepwise regression analyses showed that increased first pvF explain 16% of first HAM alterations, whereas knee ROM and FPA explain 39% of second KAM alterations. We therefore expect an increased rate of progression of OA in the hip joint of the limb_non-affected and suggest that the shift in the medial-to-lateral knee joint load distribution may impact the rate of progression of OA in the limb_affected . The level of evidence is III. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1764-1773, 2017.

Gait Kinematic Deviations in Patients With Developmental Dysplasia of the Hip Treated With Total Hip Arthroplasty

Comprehensive gait analysis of patients with Crowe type II and III developmental dysplasia of the hip (DDH) after successful total hip arthroplasty (THA) is lacking in the literature. This study evaluated gait function in joint kinematics after unilateral and bilateral THA in patients with DDH. In addition, the effect of high cup position on gait function was investigated. A total of 16 unilateral and 15 bilateral cementless THA patients due to DDH and 10 healthy participants comprised the study population. Levels of superior displacement of the acetabular cup and leg-length discrepancy after THA were measured. Three-dimensional gait analysis for patients who underwent THA was performed at least 1 year postoperatively. Range of motion (ROM), particularly sagittal (flexion/extension) and frontal (adduction/abduction) hip joint ROM, was significantly lower in both the unilateral and bilateral groups than in healthy participants. Sagittal (flexion/extension) hip ROM in patients with DDH was greater in the unilateral group than in the bilateral group. A significant influence of high acetabular cup position on hip joint kinematics was not observed in the unilateral subgroups (mean level of cup superior displacement was 11.8 mm). In contrast, a significant influence of high acetabular cup position on hip joint kinematics was observed in the bilateral subgroups (mean level of cup superior displacement was 21.3 mm). The functional symmetry and cup superior displacement within 12 mm in patients with DDH after unilateral THA contributed to the restoration of normal hip biomechanics. [Orthopedics. 2017; 40(3):e425-e431.].

Preoperative gait mechanics predict clinical response to total hip arthroplasty

Some patients do not have an adequate clinical response to total hip arthroplasty (THA) for reasons that are not fully understood. Identifying modifiable factors that are associated with nonresponse could lead to new ways to identify and treat potential nonresponders. This study investigated whether any preoperative gait characteristics were associated with THA clinical response, and whether or not there were corresponding postoperative gait differences in THA nonresponders compared to responders. A secondary analysis was conducted of 124 subjects (age 61 ± 10 years; 64 female/60 male), evaluated before and 1 year after primary unilateral THA, using quantitative gait analysis and Harris Hip Scores (HHS). Responders and nonresponders were identified using the OMERACT-OARSI responder criteria, modified for use with the HHS. Pre- and postoperative dynamic sagittal plane range of motion (ROM) and 3D peak external moments were compared, for responders and nonresponders, using t-tests and logistic regression. 11.3% of subjects were nonresponders. Before surgery, the ROM was 26% higher for nonresponders than responders, but the peak external rotation moment was 30% lower (p = 0.003-0.043). Preoperative gait and HHS predicted response with a sensitivity of 71.4% and a specificity of 99.1%. There were persistent postoperative deficits in the peak external rotation moment in nonresponders compared to responders (p = 0.028). This study showed that gait analysis, where available, can augment clinical scores in predicting THA response. Moreover, it suggests that further analysis of the subtle role of transverse plane hip mechanics could lead to interventions to promote better THA response. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:366-376, 2017.

Passive hip movement measurements related to dynamic motion during gait in hip osteoarthritis

Reduced sagittal plane range of motion (ROM) has been reported in individuals with hip osteoarthritis (OA) both during walking and passive testing. The purpose of this study was to determine if a relationship exists between hip extension ROM recorded during gait and passive hip extension ROM in individuals with moderate and severe hip OA, in comparison to an asymptomatic group. Sagittal plane hip ROM was calculated using skin surface marker trajectories captured during treadmill walking at self-selected speed. Passive hip ROM was measured using standardized position and recording procedures with a goniometer. Sagittal plane extension, flexion, and overall ROM were measured dynamically and passively. A two-way mixed model analysis of variance determined significant differences between groups and between passive and dynamic ROM (α = 0.05). Pearson correlations determined relationships between passive and dynamic ROM. Significant group by ROM interactions were found for flexion and extension ROM (p < 0.05). For extension, the severe OA group had less dynamic and passive ROM compared to the other groups and greater passive than dynamic ROM (p < 0.05). For flexion, significant differences in passive ROM existed between all three groups (p < 0.05) whereas no differences were found for dynamic flexion (p < 0.05). Significant correlations between dynamic and passive hip extension were found in the moderate (r = 0.596) and severe OA (r = 0.586) groups, and no correlation was found in the asymptomatic group (r = 0.139). Passive ROM explains variance in dynamic ROM measurements obtained during gait in individuals with moderate and severe hip OA which have implications for the design of treatment strategies targeting walking pathomechanics. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1790-1797, 2016.

The Effect of Hip Arthroplasty on Osteoarthritic Gait: A Blinded, Prospective and Controlled Gait Study at Fast Walking Speeds

BACKGROUND

Painful unilateral cox arthrosis results in excessive forces passing through the "good leg." The impact of hip arthroplasty on contralateral leg gait has not been fully explored. We measured patients gait before and after arthroplasty, to answer 3 questions: (1) Are peak forces for the good legs outside the normal range? (2) Does arthroplasty protect contralateral limbs by reducing peak forces? and (3) Does arthroplasty result in a more symmetric and normal gait at fast walking speeds?

METHODS

This prospective, controlled study, assessed ground reaction forces before and 13 months (range, 6-21 months) after hip arthroplasty.

RESULTS

Peak ground reaction force in contralateral hips fell (1.45-1.38 times body weight, P = .04), whereas symmetry index maximum weight acceptance improved postoperatively (12.2 ± 11 vs 1.3 ± 6, P < .001).

CONCLUSION

Although gait becomes more symmetrical, patients still experience higher peak loads than matched controls. These high forces may offer an explanation to the progression of arthrosis in lower limbs.

Lower Limb Loading during Gait in Patients Long Period after Total Hip Arthroplasty Revision

The aim of the study was to assess lower limb loading during walking after unilateral total hip arthroplasty (THA) revision. Twenty-three THA revision subjects (12 men, 11 women) were divided into three groups according to time since surgery as 1 to 6 years, 6 to 11 years, and over 11 years. Two force plates were used to measure the ground reaction force during the stance phase. On the operated limb, compared to nonoperated limb, we found lower first vertical peak in the group of 1 to 6 years after revision and lower propulsion peak in the group of 6 to 11 years since revision. In the group of 11 years since THA revision, no significant difference was found. With advancing years after surgery, the stance phase duration got reduced and propulsion peak increased in the operated limb; minimal vertical force decreased and the time of minimal vertical force increased in the nonoperated limb. The study findings suggest the tendency to a more gradual and safer weight acceptance on the operated limb during the first years after THA revision, followed by limitation of foot propulsion. Despite this fact, lower limb loading can be considered as symmetrical across the whole measured period.

Do persons with asymmetric hip pain or radiographic hip OA have worse pain and structure outcomes in the knee opposite the more affected hip? Data from the Osteoarthritis Initiative

PURPOSE

To determine if asymmetry between hips in pain or radiographic osteoarthritis (RHOA) is associated with worse pain and joint space narrowing (JSN) at baseline and longitudinally in knees contralateral to more affected hips.

METHODS

We studied 279 participants in the Osteoarthritis Initiative with baseline asymmetry between hips in pain and 483 with asymmetry in RHOA none of whom had a hip replacement for ≥4 years after baseline. RHOA assessed from pelvis radiographs was categorized as none, possible or definite and hip pain on most days of a month in the past year as present/absent. Knee pain (WOMAC scale) and JSN (fixed flexion radiographs) were categorized as none, mild and moderate-severe. We compared knees contralateral and ipsilateral to more affected hips on baseline knee pain and JSN using clustered multinomial regression and on change in knee pain and JSN over 4-5 years using generalized linear and logistic estimating equations.

RESULTS

Knees contralateral to painful hips had less baseline pain ("moderate-severe" vs "none", relative risk ratio [RRR]: 0.39, 95% CI = 0.27-0.57), but greater baseline JSN ("moderate-severe" vs "none", RRR: 1.62, 95% CI = 1.09-2.38) and greater worsening of pain during follow-up (P = 0.001). Knees contralateral to hips with worse RHOA had nonsignificant trends for greater baseline JSN (P = 0.10) and JSN progression (P = 0.17).

CONCLUSION

These findings provide limited support for the hypothesis that early asymmetry in hip pain and RHOA is associated with worse pain and structural outcomes in knees contralateral to the more affected hip.

Relationship of unilateral total hip arthroplasty (THA) to contralateral and ipsilateral knee joint degeneration - a longitudinal 3T MRI study from the Osteoarthritis Initiative (OAI)

OBJECTIVE

To evaluate the association of prevalent unilateral total hip arthroplasty (THA) with worsening of degenerative knee abnormalities and clinical outcomes in the ipsilateral and contralateral knee.

METHODS

Both knees of 30 individuals in the Osteoarthritis Initiative (OAI) with unilateral THA (n = 14 left, n = 16 right) at baseline were assessed at baseline and at 4-year follow-up for Whole-organ MR Imaging Scores (WORMS), cartilage T2 relaxation times (only available for right knees), Western Ontario and McMasters Universities Arthritis Index (WOMAC) scores and upper leg isometric strength. Right knees of 30 individuals without THA were analyzed as controls. Contralateral knees were compared to ipsilateral knees with paired t-tests and to control knees with multivariate regression analysis adjusting for covariates.

RESULTS

In paired analyses, compared to ipsilateral knees, contralateral knees had higher WORMS total (P = 0.008) and cartilage scores (P = 0.007) at baseline. Over 4 years contralateral knees worsened more on WORMS total score (P = 0.008). Cartilage T2 values were higher in knees contralateral to the THA (baseline, P = 0.02; follow-up, P < 0.001). Contralateral knees had greater declines in knee extension strength (P = 0.04) and had a trend for greater worsening in WOMAC pain, stiffness, function and total scores (P = 0.04-0.09). Similar results were found comparing contralateral knees with control knees in multivariate regression models.

CONCLUSIONS

Prevalent unilateral THA is associated with an greater progression of degenerative findings for the knee contralateral to THA.

Knee joint motion and muscle activation patterns are altered during gait in individuals with moderate hip osteoarthritis compared to asymptomatic cohort

BACKGROUND

Knee replacements are common after hip replacement for end stage osteoarthritis. Whether abnormal knee mechanics exist in moderate hip osteoarthritis remains undetermined and has implications for understanding early osteoarthritis joint mechanics. The purpose of this study was to determine whether three-dimensional (3D) knee motion and muscle activation patterns in individuals with moderate hip osteoarthritis differ from an asymptomatic cohort and whether these features differ between contra- and ipsilateral knees.

METHODS

3D motions and medial and lateral quadriceps and hamstring surface electromyography were recorded on 20 asymptomatic individuals and 20 individuals with moderate hip osteoarthritis during treadmill walking, using standardized collection and processing procedures. Principal component analysis was used to derive electromyographic amplitude and temporal waveform features. 3D stance-phase range of motion was calculated. A 2-factor repeated analysis of variance determined significant within-group leg and muscle differences. Student's t-tests identified between group differences, with Bonferroni corrections where applicable (α=0.05).

FINDINGS

Lower sagittal plane motion between early and mid/late stance (5°, P=0.004, effect size: 0.96) and greater mid-stance quadriceps activity was found in the osteoarthritis group (P=0.01). Compared to the ipsilateral knee, a borderline significant increase in mid-stance hamstring activity was found in the contra-lateral knee of the hip osteoarthritis group (P=0.018).

INTERPRETATION

Bilateral knee mechanics were altered, suggesting potentially increased loads and knee muscle fatigue. There was no indication that one knee is more susceptible to osteoarthritis than the other, thus clinicians should include bilateral knee analysis when treating patients with hip osteoarthritis.

Gait Characteristics, Symptoms, and Function in Persons With Hip Osteoarthritis: A Longitudinal Study With 6 to 7 Years of Follow-up

STUDY DESIGN

Longitudinal laboratory study.

OBJECTIVES

(1) To compare gait characteristics between individuals with early-stage hip osteoarthritis who underwent total hip replacement (THR) and those who did not undergo THR, and (2) to evaluate whether gait characteristics, function, and symptoms declined among individuals who did not undergo THR during a 6- to 7-year follow-up.

BACKGROUND

The natural history of symptoms, function, and gait changes secondary to hip osteoarthritis, including potential differences at an early stage of disease, is unknown.

METHODS

Forty-three individuals (mean age, 58.9 years) with radiographic and symptomatic hip osteoarthritis participated. Outcome measures included 3-D gait analysis; self-reported pain, stiffness, and function; hip range of motion; and the six-minute walk test. Baseline comparisons between individuals who later underwent THR and those who did not undergo THR were made using independent t tests or Mann-Whitney U tests. Comparisons of baseline measures and 6- to 7-year follow-up for the nonoperated individuals were conducted with paired-samples t tests or Wilcoxon signed-rank tests (P<.05).

RESULTS

Twelve (27.9%) of the 43 individuals initially evaluated had not undergone THR at the 6- to 7-year follow-up. At baseline, these individuals had larger sagittal plane hip and knee joint excursions, larger joint space width, lower body mass index, and superior self-reported function compared with the individuals who later underwent THR. At the 6- to 7-year follow-up, the individuals who did not undergo THR exhibited no decline in gait characteristics, minimum joint space, or overall function. Furthermore, their self-reported pain had significantly decreased (P = .024).

CONCLUSION

Individuals who did not undergo THR during a 6- to 7-year follow-up period did not exhibit a decline in gait, function, or symptoms compared to those who underwent THR. These findings are suggestive of a phenotype of hip osteoarthritis with a very slow disease progression, particularly in regard to pain.

LEVEL OF EVIDENCE

Prognosis, level 1b.

Asymmetries and relationships between dynamic loading, muscle strength, and proprioceptive acuity at the knees in symptomatic unilateral hip osteoarthritis

Introduction

High joint loading, knee muscle weakness, and poor proprioceptive acuity are important factors that have been linked to knee osteoarthritis (OA). We previously reported that those with unilateral hip OA and bilateral asymptomatic knees are more predisposed to develop progressive OA in the contralateral knee relative to the ipsilateral knee. In the present study, we evaluate asymmetries in muscle strength and proprioception between the limbs and also evaluate relationships between these factors and joint loading that may be associated with the asymmetric evolution of OA in this group.

Methods

Sixty-two participants with symptomatic unilateral hip OA and asymptomatic knees were evaluated for muscle strength, joint position sense and dynamic joint loads at the knees. Muscle strength and proprioception were compared between limbs and correlations between these factors and dynamic joint loading were evaluated. Subgroup analyses were also performed in only those participants that fulfilled criteria for severe hip OA.

Results

Quadriceps muscle strength was 15% greater, and in the severe subgroup, proprioceptive acuity was 25% worse at the contralateral compared to ipsilateral knee of participants with unilateral hip OA (P <0.05). In addition, at the affected limb, there was an association between decreased proprioceptive acuity and higher knee loading (Spearman’s rho = 0.377, P = 0.007) and between decreased proprioceptive acuity and decreased muscle strength (Spearman’s rho = −0.328, P = 0.016).

Conclusions

This study demonstrated asymmetries in muscle strength and proprioception between the limbs in a unilateral hip OA population. Early alterations in these factors suggest their possible role in the future development of OA at the contralateral ‘OA-predisposed knee’ in this group. Furthermore, the significant association observed between proprioception, loading, and muscle strength at the affected hip limb suggests that these factors may be interrelated.

The influence of visual feedback on the mental representation of gait in patients with THR: a new approach for an experimental rehabilitation strategy

Due to total hip replacement (THR), patients reveal abnormal gait patterns which post-operative do often not return to "normal". The restoration towards normal gait reduces stress on the adjacent joints which consequently reduces risk of osteoarthrosis development. Motor-performance is related to the structure of the movement in long-term memory, thus it seems to be essential to imprint correct gait patterns in there. Mental representation structures can develop over the course of training and visual feedback presumably helps regaining a better representation of gait in long-term memory. The purpose of this study is to evaluate the effect of visual feedback on mental representation in patients with THR. In a randomized controlled trial, 20 women (57 ± 6 years) with THR have been enrolled. Subjects were randomly assigned to a control group (CG) or intervention group (IG). Additionally to inpatient treatment, all subjects participated in a standardized gait training including either an intervention based on verbal information from a physiotherapist (CG) or an intervention based on real-time visual feedback (IG). Mental representation was measured in pre-test and post-test using the structure-dimensional analysis. Results indicate significant improvements in mental representation of gait in the post-test only in IG, suggesting that beneficial effects were provoked by visual feedback.

Gait and gait-related activities of daily living after total hip arthroplasty: a systematic review

BACKGROUND

Differences in the performance of gait and gait-related activities of daily living are known to persist after total hip arthroplasty compared to healthy controls, but the specific underlying deficits (spatiotemporal, kinematics and kinetics) are not completely understood. This review aimed to map the differences between patients and controls, and between the operated and non-operated limbs during various activities of daily living.

METHODS

A computerized search with broad search terms was performed in the MEDLINE database. Primary inclusion criteria were: primary osteoarthritis as indication, comparison with healthy controls or comparison between the operated and the non-operated limbs, and follow-up period at least six months after surgery.

FINDINGS

The literature search yielded 2177 citations, of which 35 articles were included. Compared to controls, reductions were identified in the operated hip in sagittal range of motion, peak extension, sagittal power generation, abduction moment and external rotation moment. During stair ascent, these reductions did not become more apparent, although deficits in hip kinetics in all three planes were found. Walking speed and step length were reduced compared to controls at longer-term follow-up, but not at short-term follow-up.

INTERPRETATION

The hip abduction moment deficit was present both in level walking and in stair ascent in total hip arthroplasty patients compared to controls. Reduced sagittal hip power generation and external rotation moment were also found, of which the clinical relevance remains to be established. Due to a low number of studies, many of the longer-term effects of THA on gait and gait-related ADL are not yet accurately known.

Outcome of unilateral ankle arthrodesis and total ankle replacement in terms of bilateral gait mechanics

Previous studies assessed the outcome of ankle arthrodesis (AA) and total ankle replacement (TAR) surgeries; however, the extent of postoperative recovery towards bilateral gait mechanics (BGM) is unknown. We evaluated the outcome of the two surgeries at least 2 years post rehabilitation, focusing on BGM. 36 participants, including 12 AA patients, 12 TAR patients, and 12 controls were included. Gait assessment over 50 m distance was performed utilizing pressure insoles and 3D inertial sensors, following which an intraindividual comparison was performed. Most spatiotemporal and kinematic parameters in the TAR group were indicative of good gait symmetry, while the AA group presented significant differences. Plantar pressure symmetry among the AA group was also significantly distorted. Abnormality in biomechanical behavior of the AA unoperated, contralateral foot was observed. In summary, our results indicate an altered BGM in AA patients, whereas a relatively fully recovered BGM is observed in TAR patients, despite the quantitative differences in several parameters when compared to a healthy population. Our study supports a biomechanical assessment and rehabilitation of both operated and unoperated sides after major surgeries for ankle osteoarthrosis.

Minimizing preoperative and postoperative limping in patients after total hip arthroplasty: relevance of hip muscle strength and endurance

OBJECTIVE

The aim of this study was to test the hypothesis that hip muscle function (strength and endurance) improves after total hip arthroplasty and is important for minimizing limping gait.

DESIGN

Fifty-two patients who underwent total hip arthroplasty were assessed before and 6 mos after receiving a unilateral total hip endoprosthesis (Adaptiva stem with a Harris-Galante acetabular component). Severity of limping was assessed using a 4-point ordinal scale. Pain was assessed using a standardized ordinal scale. Eccentric, concentric, and isometric muscle strength and endurance of the hip extensors, flexors, adductors, and abductors were measured using a dynamometer.

RESULTS

Postoperative limping severity and pain were significantly lower and postoperative muscle strength and endurance were significantly higher than the preoperative values (P < 0.05). The association between impaired muscle strength and endurance and limping severity was stronger postoperatively than preoperatively. This association was stronger for the hip extensor and flexor muscles than for the hip adductor and abductor muscles. Pain level was not associated with postoperative limping severity.

CONCLUSIONS

Hip extensor and flexor muscle strength and endurance seem to be relevant for minimizing postoperative limping in patients after total hip arthroplasty. Rehabilitation programs should include exercises aimed at improving hip extensor and flexor strength and endurance to improve gait function.

Compensation by nonoperated joints in the lower limbs during walking after endoprosthetic knee replacement following bone tumor resection

BACKGROUND

Endoprosthetic knee replacement is often used to preserve joint function in patients with bone tumors of the distal femur or proximal tibia. Recently, because of improved oncologic outcome, surgeons are focusing more on the functional outcome of patients with musculoskeletal tumors. We hypothesized that patients who have undergone endoprosthetic knee replacement are forced to compensate for deficiency in their operated joint during walking. In this study, we investigated differences in gait kinematics, kinetics, and energetics between patients with endoprosthetic knee replacement and healthy subjects.

METHODS

We performed gait analysis for 8 patients who underwent endoprosthetic knee replacement after bone tumor resection and 8 matched healthy subjects. Gait kinematics, kinetics, and energetics of patients' ipsilateral and contralateral limbs were compared with those of healthy subjects by using Dunnett's test.

FINDINGS

Compared with healthy subjects, patients showed increased negative joint power around the ipsilateral ankle, greater second peak in the contralateral vertical ground reaction forces, and abnormal hip movement on both sides after initial contact.

INTERPRETATION

Patients tended to compensate for dysfunction of the reconstructed knee by muscles around the ipsilateral ankle and contralateral hip, with increased load on the contralateral limb during walking. These differences could lead to secondary impairments. Further analysis, including musculoskeletal simulation and assessment of long-term functional outcome with regard to secondary musculoskeletal impairment, is needed to verify the significance of the change in gait and to determine the need for special care for secondary musculoskeletal dysfunction in these patients.

Changes in gait patterns and muscle activity following total hip arthroplasty: a six-month follow-up

BACKGROUND

Appropriate gait function is an important determinant of the outcome of total hip arthroplasty and relies on appropriate joint motion and muscle activity. The purpose of this study was to test the hypothesis that 6-month postoperative dynamic joint range of motion, time-distance measures and muscle activity in the operated limb in patients undergoing total hip arthroplasty differ from preoperative levels and are more similar to those observed postoperatively in the contralateral limb and in healthy subjects.

METHODS

Basic time-distance gait measurements, knee and hip kinematics and electromyographic activity from eight hip muscles were obtained preoperatively and 6 months postoperatively in 52 patients undergoing total hip arthroplasty and in 24 age-matched healthy subjects during treadmill walking.

FINDINGS

Postoperative dynamic hip range of motion for the operated limb (confidence interval differences [-3.9°; -2.3°]) and postoperative knee range of motion for both limbs (operated: [-8.4°; -5.6°]; contralateral: [-8.1°; -5.3°]) in patients with total hip arthroplasty were significantly lower than values for the control subjects (P<0.001). Postoperative gait in patients with total hip arthroplasty was more symmetric than preoperative gait. Preoperative and postoperative electromyographic intensities were higher in patients with total hip arthroplasty than values for the control subjects (P<0.001), and patients had different EMG patterns compared to the control group.

INTERPRETATION

Pre- and postoperative differences not only in hip but also in knee kinematics emphasize the importance of evaluating the dynamic outcome of total hip arthroplasty by assessing joint motion of all lower extremity joints in both legs.

Does hip implant positioning affect the peak external adduction moments of the healthy knees of subjects with total hip replacements?

After unilateral total hip replacement (THR) for hip osteoarthritis (OA), knee OA incidence or progression is common. The contralateral knee is at particular risk, and some have speculated that abnormal THR-hip biomechanics contributes to this asymmetry. We investigated the relationships between operated-hip joint geometry or gait variables and the peak external knee adduction moments-an indicator of knee OA risk-in 21 subjects with unilateral THRs. We found that the peak adduction moment was 14% higher on the contralateral versus the ipsilateral knee (p = 0.131). The best predictors of ipsilateral knee adduction moments were superior-inferior joint center position and operated-hip peak adduction moment (adj R(2)  = 0.291, p = 0.017). The sole predictor of the contralateral knee adduction moment was the medial-lateral hip center position (adj R(2)  = 0.266, p = 0.010). A postoperative medial shift of the hip center was significantly correlated with a lower postoperative contralateral/ipsilateral knee adduction moment ratio (R = 0.462, p = 0.035). Based on these relationships, we concluded that implant positioning could influence the biomechanical risk of knee OA progression after THR. Although implant positioning decisions are necessarily driven by other factors, it may be appropriate to assess individual THR candidate's knee OA risk and adjust perioperative management accordingly.

An alternative patellar fracture fixation: a biomechanical study

OBJECTIVES

The purpose of this study is to compare open reduction and internal fixation of the patella with a locking plate and tension-band construct (PF) versus cannulated screws and tension-band fixation (SF). The hypothesis is that both constructs will have similar failure loads with simulated extension loading.

METHODS

Transverse patellar fractures were created in 10 cadaveric pairs of legs and were fixed with either PF or SF. Dual-energy X-ray Absorptiometry (DXA) scans of all calcanei measured bone mineral density (BMD). Using an MTS 810 servohydraulic testing machine, each leg cycled to full extension 10 times before loading to failure. A differential variable reluctance transducer measured the distraction of the patella. Data were analyzed using paired t test analysis and bivariate analysis for Pearson correlation coefficients.

RESULTS

There was no difference in the BMD between the PF and the SF groups (P = 0.367). No measurable differences occurred during the 10 cycles, and load at clinical failure was not significantly different between the 2 fixation groups (P = 0.38). Stiffness during the final loading cycle was significantly higher for the SF group (P = 0.008). Ultimate strength of fixation was significantly higher in PF group (P = 0.048). BMD was not correlated to the ultimate strength of SF (P = 0.112), but was correlated for PF (P = 0.025).

CONCLUSIONS

Based on our results, PF provides comparable strength to SF, and it seems to be a safe and effective alternative to the current gold standard.

The progression of end-stage osteoarthritis: analysis of data from the Australian and Norwegian joint replacement registries using a multi-state model

OBJECTIVE

The incidence of joint replacements is considered an indicator of symptomatic end-stage osteoarthritis (OA). We analysed data from two national joint replacement registries in order to investigate whether evidence of a pattern of progression of end-stage hip and knee OA could be found in data from large unselected populations.

DESIGN

We obtained data on 78,634 hip and 122,096 knee arthroplasties from the Australian Orthopaedic Association National Joint Replacement Registry and 19,786 hip and 12,082 knee arthroplasties from the Norwegian Arthroplasty Register. A multi-state model was developed where individuals were followed from their first recorded hip or knee arthroplasty for OA to receiving subsequent hip and/or knee arthroplasties. We used this model to estimate relative hazard rates and probabilities for each registry separately.

RESULTS

The hazard rates of receiving subsequent arthroplasties in non-cognate joints were higher on the contralateral side than on the ipsilateral side to the index arthroplasty, especially if the index was a hip arthroplasty. After 5 years, the estimated probabilities of having received a knee contralateral to the index hip were more than 1.7 times the probabilities of having received a knee ipsilateral to the index hip.

CONCLUSION

The results indicate that there is an association between the side of the first hip arthroplasty and side of subsequent knee arthroplasties. Further studies are needed to investigate whether increased risk of receiving an arthroplasty in the contralateral knee is related to having a hip arthroplasty and/or preoperative factors such as pain and altered gait associated with hip OA.