Custom or patient-specific knee replacement uses pre-operative CT or MRI imaging to create personalised cutting guides and, in some systems, a custom-manufactured implant matched to the patient's unique knee anatomy.
Pre-operative imaging (CT or MRI) is obtained. For patient-specific instrumentation (PSI): 3D-printed cutting blocks are manufactured to match the patient's knee, guiding bone cuts without intramedullary alignment rods. For true custom implants: the prosthesis itself is designed and manufactured to match the patient's specific anatomy. The surgical procedure is otherwise similar to standard TKR. The operation takes a similar time to conventional surgery.
Custom instrumentation may be recommended to improve alignment accuracy, avoid intramedullary canal violation (reducing fat embolism risk), reduce surgical steps, and in patients with unusual anatomy (previous fracture, extra-articular deformity, hardware in the canal).
All standard non-operative options for knee arthritis. Standard (off-the-shelf) TKR with conventional, navigated, or robotic instrumentation are surgical alternatives.
Pre-operative CT or MRI (four to six weeks before surgery for guide manufacture). Standard pre-assessment.
Potentially improved implant positioning accuracy. Reduced intraoperative steps. No canal violation (for PSI). For true custom implants: theoretically better fit and kinematics. Long-term outcome data is still maturing.
All standard risks apply.
Four to six weeks for guide or implant production.
Additional CT radiation dose.
Manufacturing error. Backup conventional instruments should always be available.
Infection, blood clots, stiffness, loosening.
Same as standard TKR.
Identical to standard TKR.
Same as standard TKR.
Custom instrumentation improves positioning accuracy in some studies. Whether this translates to better long-term outcomes or patient satisfaction compared to well-performed standard, navigated, or robotic TKR is not yet proven. It is particularly useful for patients with unusual anatomy.