Reply to letter to the editor: subchondral calcium phosphate is ineffective for bone marrow edema lesions in adults with advanced osteoarthritis.

W e thank Dr. Wyland and appreciate his interest in our study. We would like to respond to the concerns raised in his letter to the editor [2]. We agree with Dr. Wyland that reporting the outcome in five separate subscales (symptoms; pain; function, daily living; function, sports and recreational activities; quality of life), enhances interpretation. However, as stated by Roos and colleagues [7], even though it makes it impossible to closely monitor the stages of rehabilitation, the calculation of a total KOOS score can show an improvement. Due to the fact that our objective was to report the general patient-relevant outcome at a minimum of 6 months postoperatively (and not to optimize rehabilitation), we decided to report a single score in this initial retrospective case series. Dr. Wyland noted that ‘‘the grading system described by Mitsou et al. and previously by Tegner actually evaluated the success of ACL reconstruction, not knee osteoarthritis treatments.’’ Due to lack of a specific patient-reported outcome score for treatment evaluation of subchondral bone marrow edema lesions, we decided to use the Tegner-Lysholm Score which, as correctly stated by Dr. Wyland, was initially developed and validated for ACL injuries. The rationale behind our decision lies in the fact that in up to 80% of ACL-ruptured knees, bone marrow edema lesions are present [3, 4]. We also feel that the critique by Bengsston and colleagues [1] on the sensitivity of the Tegner Lysholm Score regarding ACL injuries and other lower extremity conditions corroborates as opposed to discredits our choice. The grading of the score allows a more critical analysis of the outcome [1]. Dr. Wyland also correctly noted that ‘‘... there was no discussion of surgical revisions in evaluating clinical failure or surgeon learning curve, which one would expect to influence failure rates.’’ Within the confines of manuscript length, we reported the followup data that was available for this retrospective study; none of the patients had revisions. However, three patients were lost to followup. Also, the minimum followup to be included in this (RE: Chatterjee D, McGee A, Strauss E, Youm T, Jazrawi L. Subchondral calcium phosphate is ineffective for bone marrow edema lesions in adults with advanced osteoarthritis. Clin Orthop Relat Res. 2015;473:2334–2342). Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. D. Chatterjee MD (&), A. McGee MD, E. Strauss MD, T. Youm MD, L. Jazrawi MD Orthopaedic Surgery, NYU Langone Medical Center, 333 East 38th Street 4th Floor, New York, NY 10016, USA e-mail: Dipal.Chatterjee@nyumc.org; dipal.chatterjee@gmail.com Reply to Letter to the Editor Published online: 24 September 2015 The Association of Bone and Joint Surgeons1 2015