Osteochondritis Dissecans of the Knee Associated With Mechanical Overload.

BACKGROUND: Osteochondritis dissecans (OCD) of the knee is a rare but potentially incapacitating disorder in which subchondral bone detaches, leading to an osteochondral fragment that can become unstable and progress into a loose body. The exact cause is unknown, although several biological and mechanical factors have been described. PURPOSE: To provide insight into epidemiological data of a large cohort of patients affected by OCD of the knee and to identify potential factors contributing to the cause of this disorder. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 236 patients (259 knees) affected by OCD were included in our Knee Registry (2005-2022) and retrospectively analyzed. Patient characteristics were extracted from the medical records. Location and International Cartilage Regeneration & Joint Preservation Society grade (1-4) of OCD were assessed using magnetic resonance imaging. If available, a full-leg standing radiograph was used to assess alignment. Additionally, a statistical scoring system for instability risk was created. RESULTS: A total of 263 OCD lesions were identified in 259 knees, 66.2% on the medial femoral condyle (MFC), 26.6% on the lateral femoral condyle (LFC), 3.8% on the trochlea, 2.7% on the patella, and 0.8% on the lateral tibia plateau. Male patients made up 57.6% of the sample, which had a mean age of 21.8 years. A very high percentage of patients (77.1%; n = 182) practiced sports, of whom 67.6% (n = 123) were engaged in high-impact sports. The location of the OCD lesions and the leg alignment (n = 110) were significantly correlated: MFC lesions were associated with more varus than valgus alignment (47.5% vs 11.3%) and patients with LFC lesions had more valgus than varus alignment (46.7% vs 20.0%; P = .002). Based on age, smoking, sports activity, and preceding trauma, a multivariable scoring system (0-11 points) was created. An increased risk of lesion instability was associated with an increased score: 29.0% at 0 points and 97.0% at 11 points. CONCLUSION: This study provides detailed epidemiological data for 236 patients affected by OCD of the knee. Older age, smoking, inactivity, and preceding trauma were predictive for instability of OCD lesions. There was an association between OCD of the MFC and varus malalignment and between OCD of the LFC and valgus malalignment. This finding, in combination with the high percentage of patients practicing high-impact sports, suggests an important role for mechanical overload in the pathogenesis of OCD.

Clinical study of the novel FlexitSystem implant for high tibial open wedge osteotomy.

The FlexitSystem implant is a novel implant used in open wedge high tibial osteotomy. A clinical safety study was performed. Retrospectively 50 patients were analyzed who were treated with an open wedge high tibial osteotomy and the new FlexitSystem implant, with a minimal follow-up of one year. Complication rate, radiographic outcomes and implant removal were investigated. One patient underwent a revision surgery because of loss of correction and non-union. The complication rate was 10.0%. No other radiographic complications (screw breakage, implant failure) were found. In 24 patients (48%) the FlexitSystem implant was removed at a mean follow-up of 12.6 months (range 2.6 till 24.0 months). The mean reason was irritation of the implant. The FlexitSystem implant is a clinical safe and stable implant for an open wedge high tibial osteotomy, with a low complication rate. The rate of implant irritation requiring removal remained high.

Revisions of extensive acetabular defects with impaction grafting and a cement cup.

BACKGROUND: Loosening of acetabular components often leads to bony defects. Management of extensive acetabular bone loss in hip revision arthroplasty can be a tremendous challenge. QUESTIONS/PURPOSES: We asked whether a reconstruction with impacted bone grafts will provide a durable and pain-free function in extensive acetabular defects. We specifically determined the (1) survival rates with the end point of revision for any reason, aseptic revision, and radiographic loosening; (2) visual analog scale (VAS) pain score, Harris hip score (HHS), and the Oxford Hip Questionnaire score (OHQS); (3) number of repeat revisions; (4) complications; and (5) radiographic loosening, wear, and radiolucencies. PATIENTS AND METHODS: We retrospectively followed 25 patients (27 hips) with extensive acetabular defects. No patient was lost to followup. Two patients died during followup. Minimum followup was 3 years (mean, 8.8 years; range, 3-14.1 years). RESULTS: Three patients (three hips) underwent repeat revision surgery and another two patients (two hips) had radiographically loose hips. The 10-year survival rate was 88% (95% confidence interval, 74.2%-100%) with the end point acetabular revision for any reason and 95% (95% confidence interval, 86.0%-100%) with the end point acetabular revision for aseptic loosening. The mean HHSs were 55 points before surgery and 72 points postoperatively. CONCLUSIONS: Acetabular reconstruction with impaction bone grafting and a cemented cup is a reliable technique with a 10-year survival rate of 88% in patients with extensive acetabular deficiencies. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.