Objectives. The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field. Methods. The Cochrane and PubMed libraries were searched for any publications using the terms ‘hip’, ‘muscle’, ‘strength’, and ‘measurement’ in the ‘Title, Abstract, Keywords’ field. A further search was performed using the terms ‘femoroacetabular’ or ‘impingement’. The search was limited to recent literature only. Results. A total of 29 articles were reviewed to obtain information on a number of variables. These comprised the type of device used for measurement, rater standardisation, the type of movements tested, body positioning and comparative studies of muscle strength in FAI versus normal controls. The studies found that hip muscle strength is lower in patients with FAI; this is also true for the asymptomatic hip in patients with FAI. Conclusions. Current literature on this subject is limited and examines multiple variables. Our recommendations for achieving reproducible results include stabilising the patient, measuring isometric movements and maximising standardisation by using a single tester and familiarising the participants with the protocol. Further work must be done to demonstrate the reliability of any new testing method. Cite this article: E. Mayne, A. Memarzadeh, P. Raut, A. Arora, V. Khanduja. Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies: A systematic review. Bone Joint Res 2017;6:66–72. DOI: 10.1302/2046-3758.61.BJR-2016-0081

Physical functioning in patients undergoing hip surgery is commonly assessed in three ways: patient-reported outcome measure (PROM), performance test, or clinician-administered measure. It is recommended that several types of measures are used concurrently to capture an extended picture of function. Patient fatigue and burden, time, resources and logistical constraints of clinic and research appointments mean that collecting multiple measures is seldom feasible, leading to focus on a limited number of measures, if not a single one. While there is evidence that performance-tests and PROMs do not fully correlate, correlations between PROMs, performance tests and clinician-administrated measures are yet to be evaluated. It is also not known if the associations between function and patient characteristics depend on how function is measured. The aim of our study was to use different measures to assess function in the same group of patients before their hip surgery to determine 1. how well PROMs, performance tests and clinician-administrated measures correlate with one another and 2. Whether these measures are associated with the same patient characteristics.

We conducted a cross-sectional analysis of the pre-operative information of 125 participants listed for hip replacement. The WOMAC function subscale, Harris Hip Score (HHS) and walk-, step- and balance-tests were assessed by questionnaire or during a clinic visit. Participant socio-demographics and medical characteristics were also collected. Correlations between functional measures were investigated with correlation coefficients (r). Regression models were used to test the association between the patient's characteristics and each of the three types of functional measures.

None of the correlations between the PROM, clinician-administrated measure and performance tests were very high (r<0.90). The highest correlations were found between the WOMAC-function and the HHS (r=0.7) or the Walk-test (r=0.6), and between the HHS and the walk-test(r=0.7). All the other performance-tests had low correlations with the other measures(r ranging between 0.3 and 0.5).

The associations between patient characteristics and functional scores varied by type of measure. Psychological status was associated with the WOMAC function (p-value<0.0001) but not with the other measures. Age was associated with the performance test measures (p-value ranging from ≤0.01 to <0.0001) but not with the WOMAC function. The clinician-administered (HHS) measure was not associated with age or psychological status.

When evaluating function prior to hip replacement clinicians and researchers should be aware that each assessment tool captures different aspects of function and that patient characteristics should be taken into account. Psychological status influences the perception of function; patients may be able to do more than they think they can do, and may need encouragement to overcome anxiety. A performance test like a walk-test would provide a more comprehensive assessment of function limitations than a step or balance test, although performance tests are influenced by age.

For the most precise description of functional status a combination of measures should be used. Clinicians should supplement their pre-surgery assessment of function with patient-reported measure to include the patient's perspective.

Background

Since 2011, the knee service at the Nuffield Orthopaedic Centre has been offering a neutralising medial opening wedge high tibial osteotomy (HTO) to a group of patients presenting with early medial osteoarthritis of the knee, varus alignment and symptoms for more than 2 years. During development of this practice an association was observed between this phenotype of osteoarthritis and the presence of CAM deformity at the hip.

Introduction and Objective. To estimate the prevalence of acetabular ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of labral ossifications is associated with patient-related (sex, age, BMI), or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphotype). Materials and Methods. We prospectively included all patients undergoing thoracoabdominal CT over a 3-month period. After exclusion of patients with a clinical history of hip pathology and/or with signs of osteoarthritis on CT, we included a total of 150 hips from 75 patients. We analyzed the presence and the size of labral ossifications around the acetabular rim. The relationships between the size of labral ossifications and patient- and hip-related parameters were tested using multiple regression analysis. Results. The prevalence of labral ossifications in this population of asymptomatic, non-OA hips was 96% (95%CI=[80.1; 100.0]). The presence of labral ossifications and their size were correlated between right and left hips (Spearman coefficient=0.64 (95%CI=[0.46; 0.79]), p<0.05)). The size of labral ossifications was significantly associated with age (p<0.0001) but not with BMI (p=0.35), gender (p=0.05), joint space width (p≥0.53 for all locations) or any of the qualitative or quantitative parameters associated with femoroacetabular morphotype (all p≥0.34). Conclusions. Labral ossifications are extremely common in asymptomatic, non-osteoarthritic hips. Their size is not correlated with any patient-, or hip-related parameters except for the age. These findings suggest that the diagnosis of osteoarthritis or femoroacetabular impingement morphotype should not be made based on the sole presence of acetabular labral ossifications

Introduction. Osteonecrosis of the femoral head occurs in young patients. The preservation of the hip joint is vitally important, because hip arthroplasty does not guarantee satisfactory long-term results in young and active patients. Curved intertrochanteric varus osteotomy is one of several joint preserving procedures used for this disease. Methods. Between June 2004 and June 2007, 52 patients (55 hips) who had osteonecrosis of the femoral head were treated with curved intertrochanteric varus osteotomy. There were 29 men and 23 women who had a mean age at the time of osteotomy of 33 years (range, 18 to 52 years). The osteotomy was fixed with a 120 degree compression hip screw in the first 34 hips and with a 95 degree dynamic condylar screw in the remaining 21 hips. Clinical evaluation was performed using the scoring system of Merle d'Aubigne et al. Results. The mean duration of follow-up was 32 months (range, 24 to 60 months). Six patients (six hips) required a total hip arthroplasty, due to loss of fixation in two hips, shortening of the operated limb in two hips, and further collapse with persistent pain in two hips. In two patients (two hips), the plate fractured at 3 and 4 months after the operation, which was changed to a new plate. Thus, 49 of the 55 hips survived at a mean follow-up 32 months. In these hips, the mean Merle d'Aubigne hip score was 17.4 points at the latest evaluation. Conclusion. Curved intertrochanteric varus osteotomy is a satisfactory joint preserving method to treat osteonecrosis of the femoral head

Hip resurfacing procedures have gained increasing popularity for younger, higher demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesised superiority of hip resurfacing over total hip arthroplasty. The purpose of this meta-analysis was to compare the clinical and radiological outcomes and complication rates of these two procedures. A systematic review was undertaken of all published and unpublished research up to January 2010. The primary search was of the databases Medline, CINAHL, AMED and EMBASE, searched via Ovid using MeSH terms and Boolian operators ‘hip’ AND ‘replacement’ OR ‘arthroplasty’ AND ‘resurfacing’. A secondary search of unpublished literature was conducted using the databases SIGLE, the National Technical Information Service, the National Research Register (UK), the British Library's Integrated Catalogue and Current Controlled Trials databases using the same search terms as the primary search. All included studies were critically appraised with the CASP appraisal tool. In total, 46 studies were identified from 1124 citations. These included 3799 hip resurfacings and 3282 total hip arthroplasties. On meta-analysis, functional outcomes for subjects following hip resurfacing were better than or the same as subjects with a total hip arthroplasty, with significantly higher WOMAC score (Mean Difference (MD)=−2.41; 95% Confidence Interval (CI): −3.88, −0.94; p=0.001), and significantly better Harris Hip Score (range of motion component) (MD=−0.05; 95% CI: (−0.07, −0.03; p<0.0001) and overall Harris Hip Score (MD=2.51; 95% CI: 1.24, 3.77; p=0.0001) in the hip resurfacing compared to total hip arthroplasty cohorts. However, there were significantly greater incidences of heterotopic ossification (Risk Ratio (RR)=1.62; 95% CI: 1.23, 2.14; p=0.006), aseptic loosening (RR=3.07; 95% CI:1.11, 8.50;p=0.03) and revision surgery (RR=1.72; 95% CI: 1.20, 2.45; p=0.003) with hip resurfacing compared to total hip arthroplasty. The evidence-base presented with a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, potentially giving rise to assessor bias. In respect to these factors, the current evidence-base, whilst substantial in its size, may be questioned in respect to its quality in determining superiority of hip resurfacing over total hip arthroplasty

Introduction. The purpose of this study was to investigate the long-term outcome of Sugioka's transtrochanteric rotational osteotomy (TRO) for nontraumatic osteonecrosis of the femoral head. Methods. Seventy-eight patients (87 hips) were consecutively treated by TRO from 1989 to 1994. All patients followed 15 years or more were included. Four patients (4 hips) with traumatic osteonecrosis and five patients (5 hips) followed less than 15 years were excluded. A total of 69 patients (78 hips) were included. Average age at the time of operation was 42 years. There were 51 men (57 hips) and 18 women (21 hips). The average follow-up was 17 years (range, 15 to 20 years). Type of osteonecrosis was as follows: Type B; 2 hips, Type C1; 50 hips, and Type C2; 26 hips. Stage was as follows: stage 2; 29 hips, stage 3A; 34 hips, stage 3B; 13 hips, and stage 4; 2 hips. Transtrochanteric anterior rotational osteotomy was performed in 76 hips and posterior rotational osteotomy was performed in 2 hips. Clinical evaluation was evaluated by Harris hip score. Kaplan-Meier survivorship analysis was performed based on the end point of conversion to total hip arthroplasty (THA) or re-collapse. Results. Twenty-nine hips (37.2%) were converted to THA, and 38 hips (48.7%) were re-collapsed. Average Harris hip score before operation was improved from 67 to 82 points at final follow-up. The reasons for conversion to THA within five years after osteotomy were cervical fracture or fixation failure, and 10 years after osteotomy progression of osteoarthritis due to re-collapse. Kaplan-Meier survivorship at 10 years after surgery was 69.2% (95% confidence interval: 58.8-79.6) and 15 years after surgery was 61.3% (95% CI: 49.9-72.7) with THA as the end-point. Kaplan-Meier survivorship at 10 years after surgery 50.0% (95% CI: 38.6-61.4) and at 15 years after surgery 50.0% (95% CI: 38.6-61.4) when re-collapse was defined as the end point. Type C1 was significantly better than Type C2. There was no significant difference between the corticosteroid-induced and non-corticosteroid-induced patients. There was no significant difference between the patients with early and late stage. Conclusion. The long-term outcome of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head was excellent. Sixty-three percent of the hips were not converted to THA. Type C2 was a significant risk factor for TRO

In 1895 Trendelenburg described his sign to determine the integrity of hip function. We found the sign to be positive in a patient whose hip was clinically and radiologically normal, and therefore investigated this in other patients. We confirmed that a medial shift of the mechanical axis of the leg below the hip may cause a positive Trendelenburg sign. This has not been previously described

Objectives

Mechanical wear and corrosion at the head-stem junction of total hip arthroplasties (THAs) (trunnionosis) have been implicated in their early revision, most commonly in metal-on-metal (MOM) hips. We can isolate the role of the head-stem junction as the predominant source of metal release by investigating non-MOM hips; this can help to identify clinically significant volumes of material loss and corrosion from these surfaces.

In spite of extensive accounts describing the blood supply to the femoral head, the prediction of avascular necrosis is elusive. Current opinion emphasises the contributions of the superior retinacular artery but may not explain the clinical outcome in many situations, including intramedullary nailing of the femur and resurfacing of the hip. We considered that significant additional contribution to the vascularity of the femoral head may exist. A total of 14 fresh-frozen hips were dissected and the medial circumflex femoral artery was cannulated in the femoral triangle. On the test side, this vessel was ligated, with the femoral head receiving its blood supply from the inferior vincular artery alone. Gadolinium contrast-enhanced MRI was then performed simultaneously on both control and test specimens. Polyurethane was injected, and gross dissection of the specimens was performed to confirm the extraosseous anatomy and the injection of contrast. The inferior vincular artery was found in every specimen and had a significant contribution to the vascularity of the femoral head. The head was divided into four quadrants: medial (0), superior (1), lateral (2) and inferior (3). In our study specimens the inferior vincular artery contributed a mean of 56% (25% to 90%) of blood flow in quadrant 0, 34% (14% to 80%) of quadrant 1, 37% (18% to 48%) of quadrant 2 and 68% (20% to 98%) in quadrant 3. Extensive intra-osseous anastomoses existed between the superior retinacular arteries, the inferior vincular artery and the subfoveal plexus.