Gluteus medius and minimus activity during stepping tasks: Comparisons between people with hip osteoarthritis and matched control participants.

BACKGROUND: Altered gluteus minimus (GMin) activity has been identified in people with hip osteoarthritis (OA) during gait with some evidence of altered gluteus medius (GMed) activity in patients with advanced OA. It is not known whether these muscles also exhibit altered activity during other functional tasks. RESEARCH QUESTION: Does gluteal muscle activity during stepping tasks differ between people with hip OA and healthy older adults? METHODS: Participants included 20 people with unilateral hip OA and 20 age-and sex-matched controls. Muscle activity in the three segments within GMed and two segments of GMin were examined using intramuscular electromyography during step-up, step-down and side-step tasks. RESULTS: Participants in the OA group demonstrated reduced muscle activity early in the step-up task and a later time to peak activity in most muscle segments. Greater activity was identified in anterior GMin in people with hip OA during the side-step task. A delay in time to peak activity was identified in most muscle segments in people with OA during the side-step task. SIGNIFICANCE: For participants with OA, reduced activity in most muscle segments and increased time spent in double limb stance during the step-up task could reflect the decreased strength and pain associated with single limb stance on the affected limb. This study provides further evidence of altered function of the deep gluteal muscles in people with hip OA and highlights the importance of addressing these muscles in rehabilitation.

Exploring the relationship between body mass index, mental health and outcomes of a regional physiotherapy-led post-arthroplasty review clinic.

OBJECTIVE: To determine whether 12-month hip and knee outcomes of a regional arthroplasty clinic were comparable to results from metropolitan-based clinics, and to explore a possible relationship between body mass index and depression to identify groups at risk of not achieving optimal outcomes. DESIGN: A prospective observational study. SETTING: A regional physiotherapy-led post-arthroplasty review clinic. PARTICIPANTS: Patients after hip or knee replacement. INTERVENTIONS: Patients underwent either total hip or total knee joint arthroplasty. MAIN OUTCOME MEASURES: SF-12 Health Survey, Oxford Hip/Knee Scale, 10-minute walk test, knee range of motion, body mass index and the Hospital Anxiety and Depression Scale. RESULTS: Physical outcomes were comparable to those reported by metropolitan-based clinics. People with a high body mass index showed most improvement in the severity of depression compared to those with a lower body mass index. CONCLUSION: It is important to consider the long-term effects of obesity on arthroplasty outcomes.

Comparison of gluteus medius and minimus activity during gait in people with hip osteoarthritis and matched controls.

The gluteal muscles act as stabilizers of the hip joint and are important for the maintenance of hip function. Atrophy and weakness of the gluteal muscles have been identified in people with hip OA, but it is not known whether these muscles also exhibit altered activity patterns. The aim of this study was to compare gluteal muscle activity in people with hip OA and healthy older adults. Fine-wire intramuscular electrodes were inserted into the three segments of gluteus medius (GMed) and two segments of gluteus minimus (GMin) in 20 participants with unilateral hip OA and 20 age- and gender-matched controls. Electromyographic activity of these muscle segments was examined during walking along a 10 m walkway. Peak amplitude, average amplitude, and time to peak were compared between groups during the stance phase of the gait cycle. During early stance, the OA group demonstrated a higher burst of activity in posterior GMin (P = 0.02) and trends toward a higher peak in anterior GMin. Both groups displayed peak activity in anterior GMin in the early stance phase in contrast to previous reports in young adults. This early burst of muscle activity was more pronounced with increasing severity of OA. No differences were identified in GMed activity. While altered GMin activity is associated with aging, these changes were more pronounced in participants with hip OA. To reduce disability associated with hip OA, future rehabilitation programs should consider targeted gait strategies and exercises for GMin.

Atrophy of hip abductor muscles is related to clinical severity in a hip osteoarthritis population.

Osteoarthritis mainly affects weight-bearing joints such as the hip and knee and is the most common form of arthritis. Greater muscle atrophy with fatty infiltration of gluteal muscles and decreased hip abduction strength has previously been identified with increasing severity of radiological hip OA. However, it is well documented that radiographic findings of OA do not always correlate with clinical severity. The aim of this secondary analysis was to examine whether atrophy and strength of gluteus maximus (GMax), medius (GMed), minimus (GMin), and tensor fascia lata (TFL) is associated with the clinical severity of OA. Twenty participants with unilateral hip OA and 20 age- and sex-matched asymptomatic controls were classified on the basis of clinical severity (mild, moderate-severe and asymptomatic groups) using the Oxford hip score. Muscle volumes of GMax, GMed, GMin, and TFL were determined using magnetic resonance imaging and expressed as asymmetry between limbs. A hand-held dynamometer was used to identify hip rotation and abduction strength. Regression analyzes were used to identify the association between muscle asymmetry and patient-reported severity of hip OA. Both symptomatic groups (mild and moderate-severe) demonstrated significant asymmetry in GMax (P < 0.01) and GMin (P < 0.01). GMed asymmetry was associated with only the moderate-severe symptomatic group. Hip abduction strength was reduced in both symptomatic groups. Gluteal muscle atrophy was associated with the clinical severity of OA. Clinical severity could be a useful tool for clinicians interpreting likely gluteal muscle changes and planning rehabilitation strategies for hip OA patients. Clin. Anat. 31:507-513, 2018. © 2018 Wiley Periodicals, Inc.

Structure and function of the abductors in patients with hip osteoarthritis: Systematic review and meta-analysis.

BACKGROUND: Hip osteoarthritis (OA) is a major cause of morbidity. Rehabilitation for this population focuses on strengthening the hip muscles, particularly the abductors, however the deficit in function of these muscles is unclear. OBJECTIVES: To review the evidence for the differences in structure and function of hip abductors (gluteus medius and minimus and tensor fascia lata) in hip OA. METHODS: A systematic review was conducted using MEDLINE, AMED, CINAHL and SportDISCUS, from the earliest date to September 2013. Studies that compared hip OA patients with controls, or the unaffected contralateral hip were included. Studies needed to report data on an outcome related to gross gluteal muscle function. RESULTS: An initial yield of 141 studies was reduced to 22 after application of inclusion/exclusion criteria. Meta-analysis confirmed greater hip abductor strength in the control group (standardized mean difference = SMD -0.93, 95%CI -1.70 to -0.16) and the unaffected limb (SMD -0.26, 95%CI -0.48 to -0.04). Meta-analyses showed no differences in muscle size either between groups or limbs. Few electromyography studies have been reported and meta-analysis was not possible. CONCLUSION: Hip abductor strength is reduced in OA patients when compared to healthy controls and to the unaffected limb. Data on muscle size and activity is limited.

Correlation of MAPT scores with clinical and radiographic assessment of patients awaiting THR/TKR.

BACKGROUND: The Multi-attribute Arthritis Prioritisation Tool (MAPT) score is used as a tool to prioritize referrals to specialist clinics and care given to patients with hip and knee problems. Our pilot study aimed to determine the extent of any relationship between the MAPT scores and the clinician's assessment of severity of disease in terms of surgical waiting list (SWL) categories and radiological assessment. METHODS: This is a retrospective study of patients with symptomatic hip or knee osteoarthritis (OA) that were referred via the orthopaedic waiting list project between January and July 2009 to the Bendigo Health's orthopaedic outpatients clinic and were waitlisted for a total hip replacement (THR)/total knee replacement (TKR). The MAPT score was calculated and the Surgical waitlist Category was obtained from the surgical booking office. The radiographs of all these patients were reviewed and graded independently according to the Kellgren and Lawrence radiographic grading for severity of arthritis. The relationships between MAPT score, SWL category and the Kellgren and Lawrence radiographic grades were examined using graphical methods and Kendall's tau correlation coefficients. RESULTS: There were 62 patients in the study. The Kendall-tau sample correlation coefficient between MAPT score and the radiographic grade is τ(b) = -0.091 (P = 0.330) and between MAPT score and SWL category is τ(b) = 0.007 (P = 0.951). CONCLUSIONS: The sample data suggests that there is no significant relationship between the MAPT score and radiographic severity of OA, or between MAPT score and surgical waitlist category of patients with OA waitlisted for a THR/TKR.