Outcomes of complex primary total knee arthroplasties performed with custom cutting guides

Background: Total knee arthroplasty (TKA) is particularly challenging in patients with marked deformities or existing hardware due to the inability to use traditional instrumentation. One potential technique to mitigate this obstacle is the use of patient-specific cutting guides. The purpose of this study was to evaluate the use of custom cutting guides in complex primary TKAs. Methods: Twenty complex TKAs performed in 18 patients were identified. Of these, 11 were performed in patients with existing hardware, three in patients with dwarfism, three in patients with post-traumatic deformities, two in a patient with multiple epiphyseal dysplasia, and one in a patient with a large deformity from Blounts disease. All prior hardware was retained. One patient died from unrelated causes three months following surgery. The remaining patients were followed for a mean of 5.2 years (range: 1.29.7 years). Results: One patient sustained a non-displaced, medial tibial plateau fracture intraoperatively that was successfully treated with plating. Mean operative time was 112.1(boolean OR) 44.4 min, and mean hospital stay was 2.7(boolean OR) 1.6 days. Average deviation from the mechanical axis improved from 10.(5) over bar pre-operatively to 3.(1) over bar postoperatively (P < 0.001). Average Knee Society Scores improved from 48.1 to 77.4 points (P < 0.001). Mean extension improved from 5.(9) over bar to 1.(4) over bar (P = 0.049). Two patients subsequently required a manipulation under anesthesia, and one patient had delayed wound healing that resolved without surgery. Conclusions: Custom cutting guides are a viable option in complex primary TKAs where the use of traditional instrumentation would be challenging.