Patient-Specific total knee arthroplasty for valgus osteoarthritis results in the use of minimal thickness polyethylene liners in low constraint implants.
(2025) Archives of Orthopaedic and Trauma Surgery — Vol. 145, n° 1, p. 263 [1-9] (2025)
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- (en) BACKGROUND: Correction of valgus knee deformity during total knee arthroplasty (TKA) can present numerous challenges. This study assessed the ability of a patient-specific knee design to allow easier intraoperative balancing of valgus knees in primary TKA. MATERIALS AND METHODS: This study utilized a database consisting of de-identified computed tomography (CT) scans, low constraint knee designs (CR or PS), tibial and femoral implant dimensions, and implanted polyethylene (PE) thickness for all patients who underwent primary TKA with a patient-specific knee design provided by Conformis Inc. (Boston, MA, US). Data were analyzed for knee design, coronal deformity, native posterior and distal femoral offset, and PE thickness. RESULTS: A total of 26,227 cases were included, of which 25% had valgus deformity. In the PS group, the thinnest available PE (6 mm) was used for 64% of varus cases and 68% of valgus cases (P = 0.004). There was no difference in the distribution of thin (≤ 8 mm) and thick (> 8 mm) PE between varus or valgus knees with 0-5 degrees or > 10 degrees of deformity. Knees with varus deformity of 5-10 degrees were more likely to receive a thick PE than knees with valgus deformity of 5-10 degrees. For the CR group, the thinnest available PE (6 mm) was used in 77% of varus cases and 76% of valgus cases (P = 0.12). There was no difference in the distribution of thin and thick PE between varus or valgus knees regardless of deformity. Over 99% of CR knees received PE with thicknesses 8 mm or less, regardless of degree of preoperative varus or valgus deformity. CONCLUSIONS: These results indicate that patient-specific instrumentation in TKA can facilitate valgus deformity correction without requiring increased PE thickness to achieve balancing. Patient-specific knee designs may reduce the difficulty of valgus knee correction while allowing the use of minimal thickness PEs in low constraint TKA implants.
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Pagani, N., Mazzocco, J., Thienpont, E., & Smith, E. (2025). Patient-Specific total knee arthroplasty for valgus osteoarthritis results in the use of minimal thickness polyethylene liners in low constraint implants. Archives of Orthopaedic and Trauma Surgery, 145(1), 263 [1-9]. https://doi.org/10.1007/s00402-025-05873-1 (Original work published 2025)