Systematic review and meta-analysis of 16 studies (3,786 knees) quantifying the compartmental distribution of knee OA among patients already diagnosed with the condition. The central question: how often is disease truly tricompartmental versus confined to one or two compartments? Answering this question directly informs whether TKA or a partial arthroplasty is the appropriate surgical option.
Roughly 90% of knee arthroplasty patients receive TKA, a rate wildly out of proportion with the actual compartmental distribution of OA. This paper puts numbers to the mismatch: tricompartmental disease affects at most 25% of knee OA patients, and only 10% of those with high-grade changes.
When you see a patient with knee OA being worked up for arthroplasty, a systematic compartmental assessment is not optional — it is the basis for implant selection. The majority of patients will have isolated medial, isolated patellofemoral, or combined medial + patellofemoral disease, all amenable to partial arthroplasty.
For patients with K&L ≥ 3 (your actual surgical candidates), single-compartment disease is the rule at 58%, not the exception. Defaulting to TKA in this group means replacing healthy cartilage, ligament, and bone in most cases. With the added risks of higher rates of serious complications including thromboembolism, myocardial infarction, and stroke that accompany TKA over UKA.
One key caveat the authors flag: OA distribution alone does not determine the arthroplasty choice. ACL integrity, deformity, and surgeon experience all modify eligibility for partial arthroplasty. And when those factors are applied, the proportion suitable for bicompartmental replacement drops by 17 percentage points.
Systematic review and meta-analysis of 16 studies (3,786 knees) quantifying the compartmental distribution of knee OA among patients already diagnosed with the condition. The central question: how often is disease truly tricompartmental versus confined to one or two compartments? Answering this question directly informs whether TKA or a partial arthroplasty is the appropriate surgical option.
Roughly 90% of knee arthroplasty patients receive TKA, a rate wildly out of proportion with the actual compartmental distribution of OA. This paper puts numbers to the mismatch: tricompartmental disease affects at most 25% of knee OA patients, and only 10% of those with high-grade changes.
When you see a patient with knee OA being worked up for arthroplasty, a systematic compartmental assessment is not optional — it is the basis for implant selection. The majority of patients will have isolated medial, isolated patellofemoral, or combined medial + patellofemoral disease, all amenable to partial arthroplasty.
For patients with K&L ≥ 3 (your actual surgical candidates), single-compartment disease is the rule at 58%, not the exception. Defaulting to TKA in this group means replacing healthy cartilage, ligament, and bone in most cases. With the added risks of higher rates of serious complications including thromboembolism, myocardial infarction, and stroke that accompany TKA over UKA.
One key caveat the authors flag: OA distribution alone does not determine the arthroplasty choice. ACL integrity, deformity, and surgeon experience all modify eligibility for partial arthroplasty. And when those factors are applied, the proportion suitable for bicompartmental replacement drops by 17 percentage points.