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Abstract & Commentary
Synopsis: Simple excision of the OCD fragment with debridement of the crater was successful in 85% of the patients, especially if the lesion was smaller than 2 cm2.
Source: Aglietti P, et al. Results of arthroscopic excision of the fragment in the treatment of osteochondritis dissecans of the knee. Arthroscopy. 2001;17(7):741-746.
Osteochondritis dissecans (OCD) is a common cause for adolescent knee pain and swelling. The etiology remains undetermined, but hypotheses have included direct trauma or microtrauma, ischemia, and genetic and dysplastic causes. Patients typically complain of pain, swelling, giving way, and occasional locking. Once an individual’s growth plates have closed, the chance for spontaneous healing is almost nil. Surgical intervention has included both fixation and excision of the fragment, and decision making has been complicated by some of the newer articular cartilage procedure options.
Aglietti and colleagues in Italy treated 31 patients over a 17-year period for isolated OCD of the knee involving unstable fragments that were either partially or completely detached (grade III or IV lesions). Twenty-two of these knees underwent an arthroscopic excision of the fragment with debridement or curettage of the crater. Two knees were excluded for associated ligamentous pathology leaving a study group of 20 patients. The decision to excise the fragment was based upon the OCD fragment being too small or comminuted for internal fixation, existing loose fragment with size mismatch, or a subchondral sclerotic radiographic border indicating a poor prognosis for healing.
All 20 patients were available for clinical and radiographic evaluation to include the international cartilage repair society scale and weightbearing radiographics at an average follow-up of 9 years (6-17 years). The combined subjective and objective evaluation showed good or excellent results in 85% of the patients. Only 1 patient showed more than 2 grades of worsening by Fairbank’s changes radiographically. Forty-five percent showed worsening of 1 grade only. All but 2 patients noted improved function. In looking for predictive factors that would lead to a better outcome, they determined that lesions smaller than 2 cm2 had the best prognosis for excision.
Comment by David R. Diduch, MS, MD
Despite the new advances in articular cartilage treatment modalities, to include osteochondral plug transfer and chondrocyte autotransplantation, we must remember that simpler solutions may still be best. Aglietti et al have demonstrated that simple excision of an unstable, nonfixable OCD fragment yields good or excellent results 85% of the time. This is particularly true if the lesion is less than 2 cm2. That is due in large part to the fact that the lesion would then involve a minimal portion of the weightbearing area of the femoral condyle. This is an inexpensive and relatively simple procedure to perform and should be considered if the indications are appropriate.
However, it is also important to stress that whenever possible, these OCD fragments should be fixed and stabilized. In my experience, I have learned to be aggressive with use of local bone graft with curettage at the base of the lesion to provide an optimal healing environment before fixation. However, we all encounter lesions that are fragmented and cannot be repaired. Before we embark upon expensive articular cartilage treatment options, we should consider simple excision if appropriate. Of note, these patients were kept partial weightbearing for 8 and sometimes 12 weeks if the lesion involved a major weightbearing portion of the knee. It is unclear whether it would have made a difference if patients were not compliant given that there is no control group. This certainly does add some morbidity to the procedure and should be taken into consideration.