Abstract
Knee stiffness is a well-recognised postoperative problem that has been reported to occur in 6% to 15% of all patients who undergo total knee arthroplasty (TKA), and there are multiple preoperative, intraoperative, and postoperative risk factors that may predispose patients to postTKA knee stiffness. Preoperative risk factors include poor baseline range of motion (ROM), obesity, and a history of previous knee surgery and/or trauma. Potential intraoperative risk factors for having a stiff knee are malalignment, gap imbalance, and under-resection of patella. Possible postoperative risk factors include heterotopic ossification, pain, poor patient motivation, and poor physical therapy compliance. Three commonly used adjuvant treatments for this condition are custom knee devices, Botox, and ASTYM. These treatment modalities are most effective when used within 6 weeks after surgery. Multiple case series have reported that CKD can improve range of motion while maximising patient-reported functional outcomes. Botox can improve range of motion by paralyzing the muscle where the contracture is located. ASTYM therapy has recently been reported to resolve muscle contractures by effectively stimulating tissue turnover, scar tissue resorption, and regeneration of the normal soft tissue structure. When these adjuvant therapies fail, manipulation under anesthesia has been reported to be efficacious in restoring some of the original ROM. If this fails, there are surgical treatment options such as arthroscopic debridement, surgical release, revision TKA, or peroneal nerve release.
