Outcome of severe fixed-flexion deformity of the knee managed by ring fixator

Objective The aim was to assess the effectiveness of gradual correction of severe flexion deformity of the knee by Ilizarov fixator. Background Acute correction of severe knee-flexion contractures (KFC) with soft-tissue release, osteotomy, or both may lead to serious complications. In contrast, gradual correction of KFC, a circular frame, and a constrained hinge, avoids acute stretch injury to soft tissues, with a low recurrence rate. Patients and methods Between March 2011 and February 2017, 16 patients with 21 affected knees included 12 male and four female patients, the age ranged from 4 to 58 years, and mean (20.81 years), unilateral in 11 patients, and bilateral in five patients. The etiology was maltreated deep burns in two patients, four patients with arthrogryposis multiplex congenita, one had systemic lupus erythematosis, two had poliomyelitis, two complicated femoral lengthening, two had fibular hemimelia, complicated trauma in one case, and septic arthritis in two patients. Only gradual correction by Ilizarov fixator was used, except in one case where additional corrective osteotomy was done for hyperextended distal femur. Results The mean duration of the fixator was 3.9 months (range: 3–8 months). The follow-up period ranged from 4 to 48 months after frame removal with a mean of 10.8 months. Extension range significantly increases from the mean of −83°, to a mean of −4.7° at late follow-up (P<0.05). Mean flexion range was 35.9° that improved at late follow-up to a mean of 63.3°. The arc of motion postoperative was nearly the same of the preoperative with a mild increase. Two cases had recurrence of the KFC (15°) and knee subluxation, four cases had reversible excessive arthodiastasis of the knee joint, and two cases had epiphyseal injury in proximal tibia during the early stages of correction of the deformity. Conclusion Gradual distraction of the contracted tissues around the knee joint by Ilizarov fixator is a highly efficient and safe method that can address all components of intractable severe flexion contracture of the knee joint whatever the etiology of the deformity. There is a significant increase in the extension range and low recurrence rate compared with any other treatment method converting a nonambulant patient to an active ambulant one with a low complication rate.