Despite a large body of literature the optimal choice of bearing surface for total hip arthoplasty (THA) remains controversial. To avoid the brittleness and squeaking noted with ceramic-on-ceramic and the metal ion release associated with metal-on-metal (MOM) articulations, a novel hybrid coupling of ceramic-on-metal (COM) has been introduced. The purpose of this study was to compare changes in serum metal ion levels and the functional performance of COM and MOM bearing combinations. Eighty-six patients (86 hips) undergoing THA between April 2009 and October 2010 were randomized to COM or MOM bearing couplings. All received identical uncemented acetabular shells and femoral components from two experienced surgeons using the same operative technique. Demographic and peri-operative data were recorded. Serum cobalt and chromium levels, renal function and disease specific outcome scores (Oxford Hip, Harris Hip, UCLA activity) were assessed at baseline, 6 and 12 months post-operatively. Patients and outcome assessors remained blinded. Mean age of the total cohort was 62.5 years. Randomization successfully matched groups for age, Body Mass Index, baseline serum Cobalt and Chromium levels, and pre-operative functional performance scores. One-year data is currently available for 25 of 44 COM and 26 of 42 MOM patients. No significant difference in serum cobalt (P value = 0.81) and chromium (P value = 0.66) levels between groups was noted. Improvements in outcome scores (Oxford Hip, Harris Hip, UCLA activity) were equivalent (P values 0.16 – 0.46). At 1-year, COM and MOM hip arthroplasty articulations appear equivalent in terms of function and serum metal ion levels. Data collection out to 5-years post-surgery continues.
The aim of this study is to determine evidence-based guidelines on functional outcomes following common thoracolumbar injuries using a synthesis of systematic literature reviews and consensus expert opinion A questionnaire was created comprising five cases representative of common thoracolumbar injuries (a thoracic compression fracture, a flexion distraction injury and burst fractures each with varied location, patient demographics and treatment strategies). For each scenario five questions about expected functional outcomes were posed. Questionnaires were distributed to the Spine Trauma Study Group. Responses were combined with available data from a systematic review of the same injuries and outcomes to create consensus evidence based guidelines. The survey was completed by 31 (57%) of 53 surgeons representing 20 centres across North America. The systematic reviews identified 49 appropriate studies. One year following a L1 burst fracture, a heavy laborer, treated with protective mobilization (cast or brace) has a 40% chance of being pain free, 70% chance of regaining pre-injury range of motion, can expect to be re-employed within 4–6 months and be able to participate in high impact exercise and contact sport with no or minimal limitation. Length of inpatient stay averages 4–5 days. One year following posterior short segment stabilization of a L1 bust fracture in a college football player, there is an expected 45% chance of being pain free and 55% chance of regaining pre-injury ROM. While an ultimate return to high impact exercise and contact sports is anticipated, 32% of experts expect the injury to end a college football career. Results for the other trauma scenarios are included. This combination of literature and expert opinion represents the best available evidence on functional prognosis after thoracolumbar trauma. By providing consistent, accurate information surgeons and other care path providers will help patients develop realistic expectations, which may shape and improve their ultimate outcome.
