Regarding “Concomitant Subchondral Bone Cysts Negatively Affect Clinical Outcomes Following Arthroscopic Bone Marrow Stimulation for Osteochondral Lesions of the Talus”: Going Beyond the Surface

We want to congratulate Cheng et al.1Cheng X. Su T. Fan X. Hu Y. Jiao C. Guo Q. Jiang D. Concomitant subchondral bone cysts negatively affect clinical outcomes following arthroscopic bone marrow stimulation for osteochondral lesions of the talus.Arthroscopy. 2023; Abstract Full Text Full Text PDF Scopus (4) Google Scholar on their study, which we read with great interest, applauding all efforts to find novel prognostic factors that may aid our clinical decision-making. Through this letter, we want to address several considerations that may nuance the conclusions of the article. First, for the magnetic resonance imaging assessments, the subchondral bone edema (BME) was used as the borders of the lesion for the volume measurement (Figure 1). However, this method is known to overestimate the actual size of the lesion and is prone to error because of the inconsistent presence of BME.2Deng E. Gao L. Shi W. Xie X. Jiang Y. Yuan H. Guo Q. Both magnetic resonance imaging and computed tomography are reliable and valid in evaluating cystic osteochondral lesions of the talus.Orthop J Sports Med. 2020; 82325967120946697Crossref Scopus (12) Google Scholar,3Yasui Y. Hannon C.P. Fraser E.J. et al.Lesion size measured on MRI does not accurately reflect arthroscopic measurement in talar osteochondral lesions.Orthop J Sports Med. 2019; 72325967118825261Crossref PubMed Scopus (37) Google Scholar Additionally, when observing Figure 1, it is unclear to us whether the presence of the cyst may have actually been a hyperintense signal on magnetic resonance imaging instead. This may explain why the 2 raters were not fully independent, and the measurement value was only considered when the interobserver measurement difference was less than 3 mm and the included measurements were in fact repeated until consensus was reached. Second, for the correlations presented in Figure 4, the authors chose to show only correlations between the size measurements and the Karlsson and Foot and Ankle Ability Measure (FAAM) ST scores. No other, more conventional, scores that were studied within the study population, such as the VAS for pain, the American Orthopaedic Foot & Ankle Society score, Tegner score, or the FAAM ADL score were used for the analysis. Both the Karlsson score—from origin an ankle instability score—and the FAAM-ST score have not been validated for the assessment of the treatment for osteochondral lesions of the talus (OLTs). We would greatly appreciate if information regarding the decision rule that was used to highlight these particular results would be shared. Finally, the authors present cutoff values for OLTs with cyst sizes that may indicate poor outcomes after bone marrow stimulation (BMS), based on where the regression line (with a poor correlation) meets a value of 80 on the 2 patient-reported outcomes measures, sometimes even outside of the actual data points. To the best of our knowledge, this is not a conventional way to find and evaluate thresholds (such as with a receiver operating characteristic analysis). However, the thresholds were depicted in the conclusion that “concomitant [subchondral bone cysts] negatively affected the prognosis of OLTs after BMS. OLTs with cysts, an area of 90.91 mm2, depth of 7.56 mm, and volume of 428.13 mm3 were the potential cutoff values associated with poor outcomes after BMS.” This statement carries significant weight and could potentially be interpreted as a recommendation for clinical decision-making—especially because the minimal clinically important difference values of the Karlsson and FAAM-SP scores were not taken into account in the interpretation of these results.4Çelik D. Çoban Ö. Kılıçoğlu Ö. Minimal clinically important difference of commonly used hip-, knee-, foot-, and ankle-specific questionnaires: a systematic review.J Clin Epidemiol. 2019; 113: 44-57Abstract Full Text Full Text PDF PubMed Scopus (64) Google Scholar Based on the recommendations of the STARD 2015 list of Essential Items for Reporting Diagnostic Accuracy Studies,5Bossuyt P.M. Reitsma J.B. Bruns D.E. et al.STARD 2015: An updated list of essential items for reporting diagnostic accuracy studies.BMJ. 2015; 351: h5527Crossref PubMed Scopus (1802) Google Scholar we feel that the criteria for such strong conclusions have not been met. Therefore we kindly recommend that the presented thresholds should be interpreted with caution and do not recommend application in daily practice. We hope that our aforementioned concerns will aid readers to approach the conclusion of this study with the utmost diligence, and we call for future efforts to clarify the prognostic factors of arthroscopic BMS in OLT. Download .pdf (.41 MB) Help with pdf files ICMJE author disclosure forms Author Reply to “Regarding Concomitant Subchondral Bone Cysts Negatively Affect Clinical Outcomes Following Arthroscopic Bone Marrow Stimulation for Osteochondral Lesions of the Talus: Going Beyond the Surface”ArthroscopyVol. 39Issue 11PreviewThanks to Dahmen et al for their letter regarding our publication “Concomitant Subchondral Bone Cysts Negatively Affect Clinical Outcomes Following Arthroscopic Bone Marrow Stimulation for Osteochondral Lesions of the Talus.”1 We agree that the measurement of osteochondral lesions of the talus (OLTs) is important for ensuring scientific validity in this study. In practice, we have strict measurement rules to avoid misjudging the lesion. The strategy to use the entire BME range was not employed in this study. Full-Text PDF