A scientific approach to optimal treatment of cruciate ligament injuries

389 Correspondence A scientific approach to optimal treatment of cruciate ligament injuries Open Access-This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. Sir—Which is the most effective treatment strategy for injuries to the anterior cruciate ligament (ACL) of the knee? This is the topic of an editorial in Acta Othopaedica in which Aspenberg (2010) reflects on a study by Frobell and colleagues (2010). The editorial headlines that ACL injuries are surgically over-treated. We think that this cannot be concluded, as there are severe problems with the measurement properties of the score systems that are used by Frobell et al. Frobell et al. found no significant difference between ACL deficient patients randomized to a rehabilitation regimen with early ACL reconstruction and patients randomized to rehabilitation with delayed ACL reconstruction " when needed ". The outcome score was a modified version (KOOS-4) of the Knee injury and Osteoarthritis Outcome Score (KOOS). We have shown that only 2 of the 5 subscales in the original version of KOOS fulfill the criteria of a unidimensional measurement scale when applied to ACL reconstructed patients (Comins et al. 2008). KOOS-4 differs from KOOS in that the domain to assess daily function (ADL) has been removed, and consists of 25 items distributed across 4 domains. The scores from each domain are added and divided by 4 to equally weight them. This summed and weighted total score is compared across groups (Frobell et al. 2010). But summing the scores from the separate subscales in KOOS is not justifiable (Comins et al. 2008). Among other problems we found ceiling effects in many items, and we concluded that KOOS is insufficient as a tool to evaluate function in ACL reconstructed patients 20 weeks after operation. There is no evidence to support the use of KOOS-4 to measure and compare outcome scores for these patients. Tegner Activity Score and SF-36, which were also used in the study of Frobell et al. may have the same type of problems as KOOS regarding measurement properties (Hobart et al. 2002, Baron et al. 2006, Hagell et al. 2008). In-depth interviews of 22 of the patients randomized in Frobells study to rehabilitation and optional reconstruction showed that many had joined the study to bypass the waiting list for surgery (Thorstensson et al. 2009). Patients …