A retrospective study was conducted to investigate the changes in metal ion levels in a consecutive series of Birmingham Hip Resurfacings (BHRs) at a minimum ten-year follow-up. We reviewed 250 BHRs implanted in 232 patients between 1998 and 2001. Implant survival, clinical outcome (Harris hip score), radiographs and serum chromium (Cr) and cobalt (Co) ion levels were assessed.

Of 232 patients, 18 were dead (five bilateral BHRs), 15 lost to follow-up and ten had been revised. The remaining 202 BHRs in 190 patients (136 men and 54 women; mean age at surgery 50.5 years (17 to 76)) were evaluated at a minimum follow-up of ten years (mean 10.8 years (10 to 13.6)). The overall implant survival at 13.2 years was 92.4% (95% confidence interval 90.8 to 94.0). The mean Harris hip score was 97.7 (median 100; 65 to 100). Median and mean ion levels were low for unilateral resurfacings (Cr: median 1.3 µg/l, mean 1.95 µg/l (< 0.5 to 16.2); Co: median 1.0 µg/l, mean 1.62 µg/l (< 0.5 to 17.3)) and bilateral resurfacings (Cr: median 3.2 µg/l, mean 3.46 µg/l (< 0.5 to 10.0); Co: median 2.3 µg/l, mean 2.66 µg/l (< 0.5 to 9.5)). In 80 unilateral BHRs with sequential ion measurements, Cr and Co levels were found to decrease significantly (p < 0.001) from the initial assessment at a median of six years (4 to 8) to the last assessment at a median of 11 years (9 to 13), with a mean reduction of 1.24 µg/l for Cr and 0.88 µg/l for Co. Three female patients had a > 2.5 µg/l increase of Co ions, associated with head sizes ≤ 50 mm, clinical symptoms and osteolysis. Overall, there was no significant difference in change of ion levels between genders (Cr, p = 0.845; Co, p = 0.310) or component sizes (Cr, p = 0.505; Co, p = 0.370). Higher acetabular component inclination angles correlated with greater change in ion levels (Cr, p = 0.013; Co, p = 0.002). Patients with increased ion levels had lower Harris hip scores (p = 0.038).

In conclusion, in well-functioning BHRs the metal ion levels decreased significantly at ten years. An increase > 2.5 µg/l was associated with poor function.

Cite this article: Bone Joint J 2013;95-B:1332–8.

INTRODUCTION

Metal-on-metal hip resurfacing (MoMHRA) requires a new standardized radiographic evaluation protocol. Evaluation of the acetabular component is similar to total hip arthroplasty but the femoral component requires different criteria since there is no component in the femoral canal and the metallic femoral implant overlies the junctions between bone-cement and cement-prosthesis. Lucencies around the metaphyseal HRA femoral stem can be described with the femoral zonal system into 3 peg-zones (Amstutz' et al) but this doesn't account for bony changes of the femoral neck away from the stem. This study proposes a new femoral zonal system for radiographic HRA assessment. We tested the efficacy of radiographs in identifying a problem by reviewing 711 radiographs of resurfaced hips and correlating radiographic features to outcome.

Obesity is strongly linked to osteoarthritis; can affect the outcome of total knee arthroplasty and can increase the load on the components with reduction of the implant’s survivorship.

The purpose of this study is to compare clinical and radiographic outcomes in obese (defined as BMI > 30) and non obese patients.

The Knee Society scoring system and WOMAC was used to evaluate the knees preoperately and at latest follow up.

With a follow up ranging from 1 to 5 years, Knee Society score and WOMAC for the patients who were obese were lower than non obese patients.

Non progressive radiolucent lines were located adjacent to the tibial component in the group of obese patients, but without clinical significance.

Shoulder replacement has increased exponentially over the past decades due to good results reported in literature and improvement of surgical technique and devices efficacy. Previous studies suggested the effectiveness of shoulder replacement in fractures, assessing objective parameters as range of motion and radiographic images and evaluating the of postoperative complications and subsequent revision; pain relief, physical function level and health related quality of life (QoL) improvement were often left out. A prospective study was conducted on 21 patients surgically treated with shoulder emiarthroplasty for proximal humeral fractures (18 women and 3 men, mean age at follow-up 70 years – range: 57–82). The purpose of the present study is to collect the patient-relevant outcomes in a homogeneous sample (for surgeon, surgery, implant, inclusion-exclusion criteria, neurological status) of patients who underwent shoulder replacement for proximal humeral fractures. Preoperatively patients were evaluated through x-rays (trauma series), Ct-scans were performed when necessary for surgical decision. Postoperatively, two independent examiners examined all patients clinically and radiographically. For patient-oriented standardized measure SF-36, DASH (Disability of Arm, Shoulder and Hand questionnaire), ASES (American Shoulder and Elbow Surgeon), OSQ (Oxford Shoulder Questionnaire) and SST (simple Shoulder test) were chosen. Outcomes of our series were statistically compared with literature data and widely analyzed. This kind of data are unavailable in literature and could represent the first step towards the definition of outcome for this kind of procedure.