A prospective randomised controlled trial of cemented and uncemented tibial baseplates: functional and radiological outcomes.

INTRODUCTION: With the success of uncemented fixation in younger patients undergoing total hip arthroplasty and the growing demand for total knee arthroplasty (TKA) in a younger cohort of patients, there has been an increasing interest in cementless tibial baseplate fixation. We sought to determine whether there was a clear advantage to the use of three different forms of tibial baseplate fixation. The primary outcome of this study was survivorship and secondary outcomes were functional and radiological outcomes, up until 10 years. MATERIALS AND METHODS: We conducted a randomised controlled trial and recruited 224 patients with 274 knees. Patients underwent TKA by a single surgeon utilising a standard surgical technique. All patients received a cruciate retaining TKA with a cementless femoral component, and were randomised to receive either a cemented tibial component, a pegged porous coated cementless tibial component with screws or a cementless tantalum monoblock tibial component with pegs. Patient reported outcome measures (PROMS), radiological data and survivorship were assessed until 10 years post-operatively. RESULTS: Pre-operative range of motion, alignment and PROMS were similar between the three groups. The use of cemented, cementless with screws or cementless with pegs fixation options, lead to differences in functional outcomes. There was greater improvement in the Oxford score and Knee Society Score in patients who received a cemented baseplate compared to tantalum and the pegged porous groups. However, radiological and survival outcomes were similar in all three groups. Overall survivorship was 99.6%, with one knee with cementless tibial fixation and screws revised for subsidence at 3 years. There were no cases of venous thromboembolism, periprosthetic fracture or infection. CONCLUSIONS: Irrespective of tibial fixation method, functional and radiological outcomes remain similar at follow-up at 10 years, with no clear difference in outcome between each group. Each method of fixation also had excellent survivorship over this period and should reassure surgeons that whichever method of fixation they choose, long-term outcomes are likely to be satisfactory.

Predictors of total hip replacement in community based older adults: a cohort study.

OBJECTIVE: The purpose of this study is to describe predictors of total hip replacement (THR) in community dwelling older adults. A better understanding of predictors of THR can aid in triaging patients and researching preventative strategies. DESIGN: At baseline, participants had assessment of radiographic OA and cam morphology (from pelvic radiographs), shape mode scores and hip bone mineral density (BMD; from dual energy X-ray absorptiometry (DXA)). After 2.6 and 5 years, participants reported hip pain using WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), and had hip structural changes assessed using magnetic resonance imaging (MRI). Risk of THR was analysed using mixed-effect Poisson regression. RESULTS: Incidence of THR for OA over 14 years was 4.6% (37/801). As expected, WOMAC hip pain and hip radiographic OA both predicted risk of THR. Additionally, shape mode 2 score (decreasing acetabular coverage) (RR 1.83/SD; 95% CI 1.1-3.04), shape mode 4 score (non-spherical femoral head) (RR 0.59/SD; 95% CI 0.36-0.96), cam morphology (α > 60°) (RR 2.2/SD; 95% CI 1.33-3.36), neck of femur BMD (RR 2.09/SD, 95% CI 1.48-2.94) and bone marrow lesions (BMLs) increased risk of THR (RR 7.10/unit; 95% CI 1.09-46.29). CONCLUSION: In addition to hip pain and radiographic hip OA, measures of hip shape, cam morphology, BMD and BMLs independently predict risk of THR. This supports the role of hip bone geometry and structure in the pathogenesis of end stage hip OA and has identified factors that can be used to improve prediction models for THR.

The association between hip bone marrow lesions and bone mineral density: a cross-sectional and longitudinal population-based study.

OBJECTIVE: To describe the cross-sectional and longitudinal association between hip Bone marrow lesions (BMLs) and bone density. DESIGN: 198 subjects with a right hip MRI and dual-energy X-ray absorptiometry (DXA) scans conducted at two time points, approximately 2.6 years apart were included. MR images were used to assess hip BML presence and size (cm(2)) while DXA scans were used to determine bone mineral density (BMD) of the total hip, spine and femoral neck. RESULTS: Fifty-five subjects (28%) had either a femoral and/or acetabular BML. Cross-sectionally, acetabular BMLs were associated with 5-6% lower total hip [P = 0.01] and femoral neck BMD [P < 0.001]. Resolving acetabular BMLs were associated with a 1-2% increase in BMD at hip [P = 0.05] and femoral neck [P = 0.01]. In contrast, resolving femoral BMLs were associated with a 4% lower and incident femoral BMLs with 3% higher femoral neck BMD [P = 0.04, P < 0.001 resp.]. Finally, each 1 cm(2) change femoral BMLs was associated with increase in femoral neck BMD: +0.03 g/cm(2), 95% confidence intervals (CI): +0.00, +0.05, and enlarging acetabular BMLs was associated with decrease in hip: -0.01 g/cm(2), 95% CI: -0.03, -0.00 and femoral neck BMD: -0.01 g/cm(2), 95% CI: -0.03, -0.001. CONCLUSION: Hip BMLs were associated with local BMD (hip and femoral neck) but not with spine BMD and these associations vary according to site. BML prevalence and change was low in this study, hence these findings need confirmation. However, we hypothesize that these associations represent a combination of changes related directly to the BML pathology or changes adjacent to the disease process.