Sarwar Mahmood

Association between changes in global femoral offset after total hip arthroplasty and function, quality of life, and abductor muscle strength : A prospective cohort study of 222 patients

Background and purpose — There is no consensus on the association between global femoral offset (FO) and outcome after total hip arthroplasty (THA). We assessed the association between FO and patients’ reported hip function, quality of life, and abductor muscle strength. Patients and methods — We included 250 patients with unilateral hip osteoarthritis who underwent a THA. Before the operation, the patient’s reported hip function was evaluated with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and quality of life was evaluated with EQ-5D. At 1-year follow-up, the same scores and also hip abductor muscle strength were measured. 222 patients were available for follow-up. These patients were divided into 3 groups according to the postoperative global FO of the operated hip compared to the contralateral hip, as measured on plain radiographs: the decreased FO group (more than 5 mm reduction), the restored FO group (within 5 mm restoration), and the increased FO group (more than 5 mm increment). Results — All 3 groups improved (p < 0.001). The crude results showed that the decreased FO group had a worse WOMAC index, less abductor muscle strength, and more use of walking aids. When we adjusted these results with possible confounding factors, only global FO reduction was statistically significantly associated with reduced abductor muscle strength. The incidence of residual hip pain and analgesics use was similar in the 3 groups. Interpretation — A reduction in global FO of more than 5 mm after THA appears to have a negative association with abductor muscle strength of the operated hip, and should therefore be avoided.

The Influence of Leg Length Discrepancy after Total Hip Arthroplasty on Function and Quality of Life: A Prospective Cohort Study

We investigated whether patients with lengthening (> 9 mm), restoration (between 9 mm lengthening and 5 mm shortening) or shortening (> 5 mm) of the operated leg after total hip arthroplasty (THA) had different function (WOMAC score), quality of life (EQ-5D), residual hip pain, use of shoe lift and walking aid and leg length discrepancy (LLD) awareness, 12-15 months postoperatively. All patients had a significant postoperative improvement in WOMAC and EQ-5D regardless the LLD. However, the lengthening group showed less improvement in WOMAC, more use of shoe lift, residual hip pain and LLD awareness compared with the other two groups. No differences in EQ-5D were found. In spite of the improvement in function and quality of life, lengthening had adverse effects and should therefore be avoided.

Dual mobility cups for preventing early hip arthroplasty dislocation in patients at risk: experience in a county hospital

Dislocation remains a major concern after hip arthroplasty. We asked whether dual mobility cups (DMC) would improve early hip stability in patients with high risk of dislocation. We followed 34 patients (21 females, 13 males) treated between 2009 and 2012 with cemented DMC for hip revisions caused recurrent hip prosthetic dislocation or as a primary procedure in patients with high risk of instability. Functional outcome and quality of life were evaluated using Harris Hip Score and EQ-5D respectively. We found that the cemented DMC gave stability in 94%. Seven patients (20%) were re-operated due to infection. One patient sustained a periprosthetic fracture. At follow-up (6 to 36 months, mean 18), the mean Harris hip score was 67 (standard deviation: 14) and mean EQ-5D was 0.76 (standard deviation: 0.12). We concluded that treating patients with high risk of dislocation with DMC can give good stability. However, complications such as postoperative infection can be frequent and should be managed carefully.

Validity, reliability and reproducibility of plain radiographic measurements after total hip arthroplasty

BackgroundIn total hip arthroplasty (THA), radiographic preoperative planning and postoperative evaluation of acetabular component, femoral offset (FO) and leg length discrepancy (LLD) require good validity, interobserver reliability and intraobserver reproducibility. In this study, we evaluated the validity of the Sundsvall method of FO measurement and the interobserver reliability and intraobserver reproducibility of measurement of FO, LLD, acetabular cup inclination and anteversion.Material and methodsNinety patients with primary unilateral osteoarthritis (OA) were included in this prospective study. On postoperative radiographs FO by the Sundsvall method (femoral axis-pelvic midline), FO by a standard method (femoral axis-hip rotational centre-teardrop point), LLD (inter-teardrop line-lesser trochanter), acetabular cup inclination (on AP view the angle between the cup rim and transischial line) and anteversion (on lateral view the angle between the face of acetabulum and a line perpendicular to the horizontal plane) were measured. The interobserver reliability and intraobserver reproducibility were calculated for three independent observers. The concurrent validity and degree of prediction of the Sundsvall method are measured by comparing its results with the standard method.ResultsThe interobserver reliability of all measurements was excellent (ICC >0.80), except for LLD, which was substantial (ICC = 0.79). The intraobserver reproducibility of all measurements was excellent (ICC > 0.80). The concurrent validity of the Sundsvall method compared to the standard method was good with a positive correlation.ConclusionThe Sundsvall method is as reliable as the standard method. The evaluated radiographic measurement methods have the required validity and reliability to be used in clinical practice.

Direct lateral vs posterolateral approach to hemiarthroplasty for femoral neck fractures

INTRODUCTION Adopting the direct lateral (DL) instead of the posterolateral (PL) approach in hip arthroplasty for femoral neck fracture (FNF) patients could lower the rate of prosthetic dislocation. However, little is known about how the approach influences the functional outcome. HYPOTHESIS We hypothesized that both approaches would give comparable results. MATERIAL AND METHODS In a prospective cohort study, we enrolled 185 hips (183 patients, 128 women, median age 84 years) with a displaced FNF. Subjects were assigned to treatment using DL (n=102) or PL approach (n=83) with a hemiarthroplasty (HA). Functional outcome was assessed by Harris Hip Score (HHS), Western Ontario and McMaster Universities Arthritis (WOMAC) index, pain numeric rating scale (PNRS) for pain, mortality and hip complications. Patients were followed-up after 1 year. RESULTS The HHS was 71 (SD 18) in the DL group and 72 (SD 17) in the PL group (P=0.59). We found no difference in WOMAC, PNRS and mortality. Seven patients (6.9%) in the DL group and 11 patients (13.3%) in the PL group had undergone a major reoperation (adjusted OR 0.51; 95% CI, 0.18-2.07; P=0.23). DISCUSSION In this prospective cohort study, patients treated with HA for FNF using either the DL or PL approaches had comparable functional outcome after 1 year. The PL approach had a tendency towards a higher reoperation rate. TYPE OF STUDY Prospective cohort study. LEVEL OF PROOF Level 2.

Leg lengthening and femoral-offset reduction after total hip arthroplasty: where is the problem – stem or cup positioning?:

Background Restoration of femoral offset (FO) and leg length is an important goal in total hip arthroplasty (THA) as it improves functional outcome. Purpose To analyze whether the problem of postoperative leg lengthening and FO reduction is related to the femoral stem or acetabular cup positioning or both. Material and Methods Between September 2010 and April 2013, 172 patients with unilateral primary osteoarthritis treated with THA were included. Postoperative leg-length discrepancy (LLD) and global FO (summation of cup and FO) were measured by two observers using a standardized protocol for evaluation of antero-posterior plain hip radiographs. Patients with postoperative leg lengthening ≥10 mm (n = 41) or with reduced global FO >5 mm (n = 58) were further studied by comparing the stem and cup length of the operated side with the contralateral side in the lengthening group, and by comparing the stem and cup offset of the operated side with the contralateral side in the FO reduction group. We evaluated also the inter-observer and intra-observer reliability of the radiological measurements. Results Both observers found that leg lengthening was related to the stem positioning while FO reduction was related to the positioning of both the femoral stem and acetabular cup. Both inter-observer reliability and intra-observer reproducibility were moderate to excellent (intra-class correlation co-efficient, ICC ≥0.69). Conclusion Post THA leg lengthening was mainly caused by improper femoral stem positioning while global FO reduction resulted from improper positioning of both the femoral stem and the acetabular cup.