A case series of robotic TKA in stiff knees using the imageless CORI system: technical strategies and early...

Preoperative stiffness in the knee joint significantly compromises outcomes after total knee arthroplasty (TKA). Robotic-assisted TKA (raTKA) using the imageless CORI system may offer precision in alignment and gap balancing, especially in difficult cases with limited range of motion (ROM). We present a case series of 25 knees in 22 patients with preoperative ROM < 50°, all treated using the imageless CORI robotic system (Smith & Nephew). All patients had advanced osteoarthritis or inflammatory arthritis and underwent primary TKA through a standard medial parapatellar approach with posterior cruciate-sacrificing implants. Postoperative follow-ups were conducted at 15 days, 3 months, 6 months, 1 year, and 2 years, with evaluation of ROM, Knee Society Score (KSS), and Visual Analog Score (VAS). Mean preoperative ROM was 38.7° ± 5.4 (range: 28°-45°). At final follow-up, all patients showed significant improvement in ROM, with a mean of 110.2° ± 6.2. KSS improved from a mean of 32 to 84, and VAS decreased from a mean of 8.2 to 1.6. Varus deformity was corrected in all patients. No cases of postoperative neurovascular complications, patellar tendon injuries, or manipulations under anesthesia were noted. The CORI robotic system offers a promising strategy for managing preoperatively stiff knees. It allows precise bone cuts and real-time soft tissue balancing with minimal releases, reducing complications, and improving functional outcomes. Further controlled studies are needed to establish its long-term advantages.