Chronic knee pain often stems from the gradual deterioration of articular cartilage, a smooth tissue that cushions the ends of bones in the joint. This wearing away, most commonly due to osteoarthritis, results in bone-on-bone friction, causing stiffness and significant discomfort. When non-surgical treatments like physical therapy, medication, and injections fail to provide lasting relief, surgical intervention becomes necessary to restore function. Knee resurfacing is a targeted surgical procedure that addresses this joint damage.
The Concept of Knee Resurfacing
Knee resurfacing is a form of arthroplasty that focuses on repairing only the damaged surface of the knee joint rather than replacing the entire structure. The procedure involves carefully removing the worn-out cartilage and a thin section of underlying bone from the affected area.
The goal is to preserve the majority of the patient’s healthy bone and surrounding soft tissues. The removed surfaces are fitted with artificial components, typically made of metal and surgical-grade plastic, which function as the new, smooth gliding surface. Preservation of the patient’s original ligaments maintains the natural stability and feel of the joint. This targeted technique makes the procedure less invasive than a complete joint replacement.
Scope of the Implant
Knee resurfacing most accurately refers to a partial knee replacement, medically known as a Unicompartmental Knee Arthroplasty (UKA). The knee joint is divided into three distinct compartments: the medial (inner side), the lateral (outer side), and the patellofemoral (the area under the kneecap). In a UKA, the surgeon addresses damage confined to only one of these three compartments, replacing only that specific surface.
This contrasts with a Total Knee Arthroplasty (TKA), which replaces all three compartments of the joint with artificial components. TKA is necessary when the arthritis is widespread and affects the entire knee. The UKA replaces a single defective compartment with an implant, leaving the other two healthy sections intact. The limited scope of the UKA results in reduced surgical trauma and better preservation of natural knee function.
Determining Patient Candidacy
Candidacy for partial knee resurfacing requires the damage to be localized and the surrounding structures to be healthy. The patient must have symptomatic osteoarthritis confined to only one of the three knee compartments, confirmed through physical examination and imaging tests. If the damage is spread across multiple areas, a total knee replacement becomes the appropriate option.
A requirement for UKA is the presence of intact and functional knee ligaments, particularly the anterior cruciate ligament (ACL). These ligaments provide the inherent stability that the partial implant relies upon, whereas a TKA often compensates for ligament instability. Patients must also have a preserved range of motion, able to bend the knee to at least 90 degrees, and exhibit minimal fixed angular deformity. Individuals with inflammatory conditions like rheumatoid arthritis are not suitable candidates for this localized approach.
Post-Surgical Recovery and Rehabilitation
Recovery from partial knee resurfacing is typically faster and less demanding compared to a total knee replacement due to the minimally invasive nature of the surgery. Patients are often encouraged to begin putting weight on the treated leg immediately following the procedure. Physical therapy (PT) is a cornerstone of the recovery process, often starting right in the recovery room to ensure the knee regains full extension and mobility.
The early phase of rehabilitation focuses on managing pain and swelling while working to achieve a functional range of motion. Many patients are able to transition from using a walker or crutches to walking without assistance within the first one to two weeks. While a total recovery may take several months, patients undergoing partial resurfacing typically return to most normal daily activities within four to six weeks, which is significantly quicker than the timeline for a total knee replacement.