Total knee arthroplasty (TKA) is one of medicine's most successful elective procedures — with a large evidence base, 90%+ patient satisfaction in appropriately selected patients, and implants lasting 15–20 years. LDRT does not compete with arthroplasty for patients who are appropriate surgical candidates. This page explains who each option is for.
TKA is most strongly indicated for severe OA (KL grade 3–4), significant functional limitation, failure of conservative management, and fitness for surgery. Patient satisfaction at 10 years exceeds 90% in most national registries. Pain relief is typically dramatic and sustained. The evidence base is enormous for implants, surgical approaches, and rehabilitation — though it carries an important asymmetry (see below).
TKA has never been tested in a sham-controlled trial. Pacheco-Brousseau et al. (Cochrane, 2026) — systematic review of TKA versus non-surgical care — found only one eligible RCT (Skou 2015, n=100, unblinded, Danish). Skou ST et al. (NEJM, 2015): TKA plus non-surgical care versus non-surgical care alone; 100 patients. KOOS4 improvement: 32.5 (TKA arm) vs. 16.0 (non-surgical arm) at 12 months — a large effect. Limitations: small, unblinded, not sham-controlled, single country. Tran AA, Prasad V (J Comp Eff Res, 2023) confirmed that no sham-controlled surgical trial for TKA exists. This does not mean TKA is ineffective — it clearly produces large measured benefits — but the absence of sham control means the contribution of placebo and expectation effects to its measured benefit has not been isolated.
The 2026 ARS AUC describes the patient who fills the gap: a 72-year-old with KL grade 3 bilateral knee OA, refractory to conservative management, pharmacologic therapy, and intra-articular injections (both corticosteroids and HA), who is not an arthroplasty candidate due to significant comorbid cardiac disease. This patient has no standard escalation path. LDRT is presented as an appropriate option.
Patients who are not arthroplasty candidates due to cardiac, pulmonary, renal, or other comorbidities; patients with earlier-stage disease (KL 1–2) where surgery would be premature; patients deferring surgery who need bridging symptom management; patients who have declined surgery; patients managing the contralateral knee conservatively after unilateral arthroplasty.
Makarova et al. 2025 10-year randomized follow-up: 62% less structural X-ray progression; 2023 analysis: 67% risk reduction for TKA at 9 years. Preliminary; not independently replicated at that endpoint. LDRT does not preclude future arthroplasty.
Choosing between conservative management (including LDRT) and arthroplasty is a shared decision involving symptom burden, functional limitation, surgical risk, and patient preferences. Discuss with both a radiation oncologist and the orthopedic surgeon involved in your care.
Related: All comparisons | Am I a candidate? | Knee OA overview
Medically reviewed by: Robert Warren Floyd, M.D., Ph.D. — Resident Physician, Radiation Oncology, The University of Texas MD Anderson Cancer Center. Last reviewed: August 2, 2026. Independent personal project — not affiliated with or endorsed by MD Anderson Cancer Center. Funding & independence disclosure.