Relationship between physical impairments and movement patterns during gait in patients with end-stage hip osteoarthritis.

Patients with hip osteoarthritis demonstrate limited range of motion, muscle weakness, and altered biomechanics; however, few studies have evaluated the relationships between physical impairments and movement asymmetries. The purpose of this study was to identify the physical impairments related to movement abnormalities in patients awaiting total hip arthroplasty. We hypothesized that muscle weakness and pain would be related to greater movement asymmetries. Fifty-six subjects who were awaiting total hip arthroplasty were enrolled. Pain was assessed using a 0-10 scale, range of motion was assessed with the Harris Hip Score and isometric hip abductor strength was tested using a hand-held dynamometer. Trunk, pelvis and hip angles and moments in the frontal and sagittal planes were measured during walking using three dimensional motion analysis. During gait, subjects had 3.49 degrees less peak hip flexion and 8.82 degrees less extension angles (p < 0.001) and had 0.03 Nm/k*m less hip adduction moment on the affected side (p = 0.043). Weaker hip muscles were related to greater pelvis (r = -0.291) and trunk (r = -0.332) rotations in the frontal plane. These findings suggest that hip weakness drives abnormal movement patterns at the pelvis and trunk in patients with hip osteoarthritis to a greater degree than hip pain.

Relationship between strength, pain, and different measures of functional ability in patients with end-stage hip osteoarthritis.

OBJECTIVE: Performance tests and self-reported questionnaires capture different domains of function in patients with lower extremity osteoarthritis, but the impairments related to each of these domains have not been elucidated. The purpose of this study was to determine how strength and joint pain influence performance-based tests and self-reported questionnaires of functional ability of individuals with end-stage hip osteoarthritis. METHODS: Fifty-six patients scheduled to undergo unilateral total hip arthroplasty were included in this cross-sectional analysis. Subjects completed the Hip Outcome Survey (HOS) and pain in the affected hip was quantified on a scale from 0-10. Performance-based tests included the Six-Minute Walk Test (6MWT), the Timed Up & Go (TUG), and the Stair Climbing Test (SCT). Isometric strength of the hip abductors and knee extensors was tested and recorded. Hierarchical linear regressions were created to determine the contributions of pain, knee extensor strength, and hip strength for each outcome measure (TUG, 6MWT, SCT, and HOS). Height and body mass index were entered first, followed by pain, then knee extensor strength, and then hip abduction strength. RESULTS: Greater pain significantly predicted lower HOS scores, but hip strength did not significantly improve the model. Hip pain was also significantly related to TUG, SCT, and 6MWT values, but hip and knee strength explained additional variance for these performance-based measures. CONCLUSION: Self-report and performance-based measures capture different aspects of disability and are influenced by different underlying impairments. Both types of outcome measures should be used in studies that evaluate functional changes in patients with hip osteoarthritis.

Biofeedback to promote movement symmetry after total knee arthroplasty: a feasibility study.

STUDY DESIGN: Prospective analysis of a longitudinal cohort with an embedded comparison group at a single time point. OBJECTIVES: To determine the feasibility and effectiveness of an outpatient rehabilitation protocol that includes movement symmetry biofeedback on functional and biomechanical outcomes after total knee arthroplasty (TKA). BACKGROUND: TKA reduces pain and improves functional ability, but many patients experience strength deficits and movement abnormalities in the operated limb, despite outpatient rehabilitation. These asymmetries increase load on the nonoperated limb, and greater asymmetry is related to worse functional outcomes. METHODS: Biomechanical and functional metrics were assessed 2 to 3 weeks prior to TKA, at discharge from outpatient physical therapy, and 6 months after TKA in 11 patients (9 men, 2 women; mean ± SD age, 61.4 ± 5.8 years; body mass index, 33.1 ± 5.4 kg/m2) who received 6 to 8 weeks of outpatient physical therapy that included specialized symmetry training. Six-month outcomes were compared to a control group, matched by age, body mass index, and sex (9 men, 2 women; mean ± SD age, 61.8 ± 5 years; body mass index, 34.3 ± 5.1 kg/m2), that did not receive specialized symmetry retraining. RESULTS: Of the 11 patients who received added symmetry training, 9 demonstrated clinically meaningful improvements that exceeded the minimal detectable change for all performance-based functional tests at 6 months post-TKA compared to pre-TKA. Six months after TKA, when walking, patients who underwent symmetry retraining had greater knee extension during midstance and had mean sagittal knee moments that were more symmetrical, biphasic, and more representative of normal knee kinetics compared to patients who did not undergo symmetry training. No patients experienced adverse events as the result of the protocol. CONCLUSION: Adding symmetry retraining to postoperative protocols is clinically viable, safe, and may have additional benefits compared to rehabilitation protocols that focus on range of motion, strength, and return to independence. LEVEL OF EVIDENCE: Therapy, level 4.