Standards for Noninferiority Trials in Orthopaedic Surgery Would Be Arbitrary: It's Time We Had Some

The Philosophy of Surgical Success and Outcomes of Cartiva Versus Fusion

Noninferiority studies in surgery are, by their very nature, reductionist. They use multiple variables to generate a yes or no answer about the new device being tested. A binary outcome is appropriate for a regulatory agency such as the Food and Drug Administration, but the clinical situation is more nuanced. It is critical to understand the underlying philosophies and choices that go into trial design when a surgeon is recommending a new device. In the case of Cartiva, any of 3 reasonable alternative means of defining surgical success would have altered the final outcome of the MOTION trial. Additionally, using a more rigorous noninferiority margin rather than adding an additional cushion based upon the argument that motion alone had extra inherent value would have also led to failure of the trial to demonstrate noninferiority.

Elimination of a Postoperative Brace Does Not Increase Complications Following Hip Arthroscopy

Background The practice of routine postoperative bracing to limit abduction and internal rotation, along with weight-bearing restrictions after hip arthroscopy (HA), varies significantly among surgeons. It is unclear whether the use of a postoperative brace improves short-term outcomes in patients undergoing HA. The purpose of this study was to determine the differences in patient outcomes before and after eliminating routine usage of a postoperative brace. Methods A retrospective review was conducted of 176 adult patients undergoing HA by a single, high-volume surgeon. The no-brace protocol was implemented in October 2020. The patients were divided into two groups: pre-implementation (January-October 2020) and post-implementation (October 2020-April 2021). Twenty-three patients that used a brace during the post-implementation period were excluded. All patients had weight-bearing restrictions with crutches for three weeks postoperatively. The primary endpoint was any complication in the first six weeks postoperatively. Results There were no significant differences in demographics between groups, although the body mass index in the brace group was higher (28.1 vs. 26.4 kg/m², p = 0.066) and the rate of additional procedures performed was higher in the brace group (55.2% vs. 40.1%, p = 0.056). There was no significant difference in postoperative outcomes between groups when looking at 90-day emergency department visits (1.7% vs. 0%, p = 0.548), complications at two (1.7% vs. 1.7%, p = 1.000) and six weeks (0% vs. 1.7%, p = 0.341) postoperatively, all complications in the first six weeks (1.7% vs. 1.7%, p = 1.000), and continued pain at six weeks (10.3% vs. 16.7%, p = 0.238). Conclusion The brace and no-brace groups were similar demographically. Patients undergoing HA with no brace and crutches experienced no significant differences in pain or complications in comparison to those receiving a traditional bracing protocol. Routine use of a postoperative brace may not be necessary in this population.

Philosophies of Surgical Care Are Embedded in Outcome Studies: An Illustrative Reanalysis of the Cartiva MOTION Trial

BACKGROUND

Subjective assumptions on the definition of surgical success are inherent to the design of clinical trials with a categorial outcome. The current study used reasonable alternative assumptions about surgical care to reassess data for the randomized controlled Cartiva trial (MOTION).

METHODS

Data from the published study were augmented by publicly accessible internal US Food and Drug Administration documents. As in the published report, 1-sided lower bound 95% CIs (LBCI95) for the difference of proportions were calculated for a series of alternative scenarios in which the assumptions underlying what constitutes surgical success were altered.

RESULTS

Using a noninferiority margin of -15%, the MOTION trial reported success based on a 1-sided LBCI95 of -10.9%. Each of the 3 independent alternative scenarios analyzed yielded results that altered the primary outcome of the trial: (1) eliminating failures based solely upon radiographs findings, thereby considering a painless pseudarthrosis as a success (1-sided LBCI95 of -15.9%), (2) considering only major surgical revision as a failure and discounting isolated hardware removal (1-sided LBCI95 of -15.1%), and (3) using a visual analog scale (VAS) pain threshold of <30 as the success criterion rather than a 30% reduction in VAS pain score (1-sided LBCI95 of -15.8%).

CONCLUSION

In this reanalysis, applying any of 3 reasonable alternative assumptions about the definition of surgical success to the data resulted in failure to prove noninferiority of Cartiva over arthrodesis, a reversal of the reported trial result. These results highlight the effect of subjective assumptions in the design of clinical trials with a categorical outcome and illustrate how differing philosophies about what constitutes surgical success can be pivotal in determining the final result.

LEVEL OF EVIDENCE

Level II, prospective comparative study.