Ilizarov technique for severe knee flexion contracture in juvenile rheumatoid arthritis

Background: Severe flexion contracture deformity of the knee joint is often found in patients with rheumatoid arthritis (RA), which severly limiting the walking ability. Total knee arthroplasty (TKA) is a good option, but it is difficult and complicated to perform TKA, especially for juvenile patients with severe flexion deformity. There are limited reports about management of severe knee flexion contracture (KFC) of RA with Ilizarov technique. Purpose: The aim of this study was to retrospectively analyzed the results of Ilizarov technique for the juvenile rheumatoid arthritis (JRA) patients with severe knee flexion contracture (KFC). Materials and methods: From March 2000 to October 2018, nine patients (15 knees) with severe knee flexion contracture (KFC) of JRA who underwent Ilizarov knee joint distraction technique were reviewed retrospectively. There were 4 male (6 knees), 5 female (9 knees) with an average age of 15 years old (12-19years old). However, 6 cases also had equinus deformity, whose foot and ankle joint distraction device were installed simultaneously. The mean preoperative KFC and ROM angle of the knee were 48.8 +/- 16.7 degrees (mean +/- standard deviation) and 41.6 +/- 15.3 degrees, respectively. Preoperative VAS score (Visual analogue score) and HSS score (hospital for special surgery knee score) were 7.7 +/- 2.5 and 37.4 +/- 11.2, respectively. Results: The average time of follow-up was 47.6 +/- 21.3 months. All the patients achieved full correction of flexion contracture at the end of distraction. At the last follow-up, the mean flexion degree and ROM were 12.1 +/- 11.7 degrees and 23.5 +/- 19.3 degrees respectively, which were significantly different compared with preoperative condition. The total duration of ring fixation application was 10-21 weeks, with an average time of 14.3 weeks. The mean VAS and HSS score at the last follow-up were 1.4 +/- 1.2 and 71.5 +/- 7.3, which were significantly improvement to the preoperative condition. There were no severe complications during treatment in this study. Pin tract infection occurred in 7 cases during the knee joint distraction and the infection were controlled after slowing down the distraction speed and wrapping with alcohol gauze at the interface between the fixing pin and the skin. Conclusion: Ilizarov method is an effective and safe procedure to treat severe KFC in JRA which can correct deformities, relieve pain and improve the function of weight bearing. Pin tract infection and knee joint stiffness and even fusion are common problems, but correction of deformity of the knee using Ilizarov technique has possible positive outcome for possible further surgery if necessary. Translational potential: Our study shows that Ilizarov knee joint distraction for treatment of severe KFC in JRA is effective and safe. It is concluded that this method offers a new option for juvenile rheumatoid arthritis.