Association of synovial fluid and urinary C2C-HUSA levels with surgical outcomes post-total knee arthroplasty.

OBJECTIVES: After total knee arthroplasty (TKA), ∼30% of knee osteoarthritis (KOA) patients show little symptomatic improvement. Earlier studies have correlated urinary (u) type 2 collagen C terminal cleavage peptide assay (C2C-HUSA), which detects a fragment of cartilage collagen breakdown, with KOA progression. This study determines whether C2C levels in urine, synovial fluid, or their ratio, are associated with post-surgical outcomes. METHODS: From a large sample of 489 subjects, diagnosed with primary KOA undergoing TKA, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores were collected at baseline (time of surgery) and one-year post-TKA. Baseline urine (u) and synovial fluid (sf) were analysed using the IBEX-C2C-HUSA assay, with higher values indicating higher amounts of cartilage degradation. For urine, results were normalised to creatinine. Furthermore, subjects' changes in WOMAC scores were categorised based on percent reduction in pain or improvement in function, compared to baseline, such that >66.7%, >33.3 to ≤66.7%, and ≤33.3% denoted "strong", "moderate" and "mild/worse" responses, respectively. Associations of individual biofluid C2C-HUSA levels, or their ratio, with change in WOMAC pain and function scores up to one-year post-TKA, or category of change, were analysed by linear, logistic, or cumulative odds models. RESULTS: Higher baseline uC2C-HUSA levels or a lower ratio of baseline sfC2C-HUSA to uC2C-HUSA were associated with improvements in WOMAC pain by linear multivariable modelling [odds ratio -0.40 (95% confidence interval -0.76, -0.05) p = 0.03; 0.36 (0.01, 0.71), p = 0.04, respectively], while sfC2C-HUSA alone was not. However, lower ratios of sfC2C-HUSA to uC2C-HUSA were associated with improvements in WOMAC function [1.37 (0.18, 2.55), p = 0.02], while sfC2C-HUSA and uC2C-HUSA alone were not. Lower ratios of sfC2C-HUSA to uC2C-HUSA were also associated with an increased likelihood of a subject being categorised in a group where TKA was beneficial in both univariable [pain, 0.81 (0.68, 0.96), p = 0.02; function, 0.92 (0.85, 0.99), p = 0.035] and multivariable [pain, 0.81 (0.68, 0.97) p = 0.02; function, 0.92 (0.85, 1.00), p = 0.043] ordinal modelling, while sfC2C-HUSA and uC2C-HUSA alone were not. CONCLUSIONS: Overall, ratios of baseline sfC2C-HUSA to uC2C-HUSA, and baseline uC2C-HUSA, may play an important role in studying post-TKA surgical outcomes.

Publication of sports medicine-related randomized controlled trials registered in ClinicalTrials.gov.

BACKGROUND: There is increasing evidence that a significant proportion of randomized trials in medicine, and recently in orthopaedics, do not go on to publication. PURPOSE: The objectives of this study were (1) to determine publication rates of randomized controlled trials in sports medicine that have been registered with ClinicalTrials.gov (CTG) and (2) to compare the registration summaries of randomized trials on CTG with final published manuscripts on pertinent methodological variables. STUDY DESIGN: Systematic review. METHODS: Two independent investigators searched ClinicalTrials.gov for all closed and completed trials related to sports medicine until June 2009 using a text search strategy. The authors then searched for publications resulting from these registered trials in peer-reviewed journals that are indexed with MEDLINE and/or EMBASE as of February 2012 based on study authors and key words provided in the study protocol. Details of primary outcomes and secondary outcomes, study sponsors, and sample size were extracted and compared between registrations and publications. RESULTS: Of 34 closed and completed trials registered on CTG, there were 20 resultant publications in peer-reviewed journals (58.8%). There was no significant relationship between source of funding and rate of publication (P > .05). The authors found a discrepancy between the CTG registration summary and the manuscript in at least one methodological variable (primary/secondary outcomes, inclusion/exclusion criteria, sample size) in 16 of 20 (80.0%) articles and a discrepancy in the primary outcome in 8 of 20 (40.0%) published trials. CONCLUSION: Although registration of sports medicine trials in CTG does not consistently result in publication or disclosure of results at 32 months from the time of study completion, observed publication rates are higher than in other orthopaedic subspecialties. Changes are also frequently made to the final presentation of eligibility criteria and primary and secondary outcomes that are not reflected in the registered trial data.