Better early functional outcome after short stem total hip arthroplasty? A prospective blinded randomised controlled multicentre trial comparing the Collum Femoris Preserving stem with a Zweymuller straight cementless stem total hip replacement for the treatment of primary osteoarthritis of the hip

Objectives Primary aim was to compare the functional results at 3 months and 2 years between short and conventional cementless stem total hip arthroplasty (THA). Secondary aim was to determine the feasibility of a double-blind implant-related trial. Design A prospective blinded randomised controlled multicentre trial in patients with osteoarthritis of the hip. All patients, research assistants, clinical assessors, investigators and data analysts were blinded to the type of prosthesis. Population: 150 patients between 18 and 70 years with osteoarthritis of the hip, 75 in the short stem and 75 in the conventional stem group. Mean age: 60 years (SD 7). Interventions: The Collum Femoris Preserving short stem versus the Zweymuller Alloclassic conventional stem. Main outcome measures The Dutch version of the Hip Disability and Osteoarthritis Outcome Score (HOOS). Secondary outcomes measures: Harris Hip Score, the Physical Component Scale of the SF12, the Timed Up and Go test, Pain and the EQ-5D. Feasibility outcomes: continued blinding, protocol adherence and follow-up success rate. Results No significant difference between the two groups. Mean HOOS total score in the short stem group increased 32.7 points from 36.6 (95% CI 32.9 to 40.2) preoperatively to 69.3 (95% CI 66.4 to 72.1) at 3 months follow-up. Mean HOOS total score in the conventional straight stem group increased 36.3 points from 37.1 (95% CI 33.9 to 40.3) preoperatively to 73.4 (95% CI 70.3 to 76.4) at 3 months follow-up. 91.2% of patients remained blinded at 2 years follow-up. Both protocol adherence and follow-up success rate were 98%. Conclusions Functional result at 3 months and 2 years after short stem THA is not superior to conventional cementless THA. There were more perioperative and postoperative complications in the short stem group. Direct comparison of two hip implants in a double-blinded randomised controlled trial is feasible. Trial registration number NTR1560

Can dual mobility cups prevent dislocation without increasing revision rates in primary total hip arthroplasty? A systematic review

International audienceBackground: Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970s by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well-conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rates of revision were not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary THA with a DM cup or a UP cup.Methods: We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies.Results: The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11-16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5.935 DM cups and 217.362 UP cups were included. In the case-control studies, one (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p = 0.009, IQR = 0.00-7.00). Nine (1.6%) revisions, of which zero due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p = 0.046, CI = −16.93-5.73). In the registry studies 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3.332 (1.5%) revisions were reported (p = 0.275, IQR = 41.00-866.25), of which 1.093 (32.8%) due to dislocation (p = 0.050, IQR = 3.50-293.25).Conclusion: This review suggests lower rates of dislocation and lower rates of revision for dislocation in favor of the DM cups. Concluding, DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints. Level of evidence: III, systematic review of level III studies

The responsiveness and minimal important change of the western Ontario shoulder instability index and oxford shoulder instability score

BACKGROUND: Patient-reported outcome measurements (PROMs) are widely used to evaluate functional limitations. Considering PROMs for shoulder instability, information is lacking with regard to what constitutes a relevant change from baseline scores. OBJECTIVES: To evaluate the responsiveness of the Western Ontario Shoulder Instability Index (WOSI) and the Oxford Shoulder Instability Score (OSIS) and estimate their minimal important change (MIC). METHODS: One hundred five consecutive patients with shoulder instability completed 5 PROMs at baseline and at 6-month follow-up. The PROMs included the WOSI and OSIS, the Simple Shoulder Test, the Oxford Shoulder Score, and the Disabilities of the Arm, Shoulder and Hand assessment. Patients also rated their functional change on an anchor question at follow-up. Responsiveness was evaluated by testing 9 hypotheses regarding predefined correlations between the changes in PROM scores, by calculating the area under the receiver operating characteristic curve and by calculating the standardized response mean and effect size statistics. The MIC was determined by identifying the optimal cutoff on the receiver operating characteristic curve. RESULTS: Seven out of 9 hypotheses (78%) were confirmed; as expected, a high correlation (0.77) was found between change scores of the WOSI and OSIS, whereas the correlations of the change scores of the WOSI and OSIS with those of general shoulder PROMs were slightly lower (0.61-0.75). The area under the curve was 0.83 (95% confidence interval: 0.75, 0.91) for the OSIS and 0.82 (95% confidence interval: 0.74, 0.90) for the WOSI. The MIC was about 6 points for the OSIS and about 14 points for the WOSI. CONCLUSION: Both the WOSI and OSIS are able to measure change in shoulder function in patients with shoulder instability. The estimated MIC is 6 points for the OSIS (on a scale from 0 to 48) and 14 points for the WOSI (on a scale from 0 to 100)