Abstract
The use of constrained condylar components (CCK) in primary total knee arthroplasty is infrequent and unusual. The usual indications are a severe fixed valgus deformity with a stretched or incompetent medial collateral ligament (MCL). This may occur in an elderly female patient with valgus osteoarthritis, advanced rheumatoid arthritis, or other less common disorders: polio, Parkinson's disease, and Paget's disease involving the knee. It may also be seen in younger patients with post-traumatic arthritis. Beware of the patient with a prior history of a knee injury in which staples were placed at the medial epicondyle of the femur or proximal tibia, indicating likely MCL injury, or a knee with extensive medial joint heterotopic ossification. An unusual indication for a primary CCK component is inadvertent injury or sectioning of the MCL during the procedure. This can occur with over-zealous medial ligament release or division with the saw during the posterior femoral condylar or proximal tibial resection. This has been reported to occur in <1% to 2.7% of knees. Treatment alternatives are to attempt repair and brace the knee or perform “internal bracing” with a CCK component. The author strongly favors the use of CCK components in this situation. We permit early full-weightbearing and range of motion, without restrictions. Careful intraoperative attention to component rotation is crucial to avoid patellar complications. The results of CCK components by the author and others have demonstrated a high rate of survival at 10 years, even in younger patients.
