Abstract
Stiffness after total knee replacement remains a significant factor in a suboptimal result after total knee arthroplasty. Interference with function including stair climbing, arising from a seated position, driving and return to activities of daily living and recreational sports are all compromised when stiffness results after knee replacement. The key indicator for resultant range of motion after knee replacement remains knee motion prior to surgery. A knee with limited motion prior to surgery will rarely achieve the same motion as a fully mobile knee and the patient should be counseled to this ultimate result. Patients with prior knee surgery, post-traumatic knee arthritis also tend to be stiffer after knee replacement. If a knee is stiff after replacement it is key to determine if there is a mechanical impediment to motion (e.g. implant sizing problem, overstuffing of the patellofemoral joint) and revision knee replacement to address this problem will be necessary and is best done when recognised.
When referring to a stiff knee after replacement flexion less than 90 degrees is generally accepted. Management of the knee with limited motion after knee replacement should first be treated with manipulation of the knee under anesthesia. Timing of manipulation is key to its success and if a patient is not progressing after 4–6 weeks manipulation is generally indicated. Manipulation can be performed up to 6–12 months after replacement but ultimate motion is negatively impacted by delay as scar tissue becomes more indurated and fixed.
Arthroscopic lysis of adhesions can be performed in the recalcitrant knee but in my experience will generally improve motion in the 10- to 15-degree range, if at all. In patients with persistent and disabling stiffness, open resection with radical scar excision can be performed and if there is not an implant sizing issue this may improve motion. It is important to rapidly mobilise these patients after surgery with early flexion to beyond 90 degrees with use of optimal analgesia to allow vigorous early motion. At time of open lysis of adhesions revision of components should be performed if there is any question of need to do this to improve range of motion.
