Does low-constraint mobile bearing knee prosthesis give satisfactory results for severe coronal deformities? A five to twelve year follow up study
- 259 Downloads
Severe varus and valgus knee deformities traditionally are replaced with constrained implants, with a number of disadvantages. We present our results in this challenging group using a low constraint deep-dish mobile bearing implant design.
One hundred fifty-four patients (170 arthroplasties) who underwent primary TKA using a deep-dish, mobile bearing posterior-stabilized implant for severe varus (HKA < 170°) or valgus (HKA > 190°) deformity between 2004 and 2009 were evaluated at a mean of 6.6 years post-operatively (minimum of 5 years).
Alignment improved from a pre-operative mean (±SD) varus deformity of 167.4° (±2.6°) and a mean (±SD) valgus deformity of 194.1° (±4.0°) to an overall mean (±SD) post-operative mechanical alignment of 178.6° (±3.2°). Twenty-three patients had post-operative varus alignment, five patients had post-operative valgus alignment and 134 knees were in neutral alignment (within 3° spread). Clinical scores at final follow-up were excellent (IKS score 93.8 (±7.4) and function score 82.4 (±20.2)). Three patients were re-operated upon: one deep infection, one periprosthetic fracture and one revision at 144 months for aseptic loosening of the femoral component. No patient was revised for instability or implant failure. The survival rate at five years was 99.4% and at ten years 98.6%.
Satisfactory outcomes can be achieved in patients with substantial varus or valgus deformities using low constraint deep-dish mobile bearing implant, standard approach and appropriate soft tissue releases.
KeywordsLOW-constraint MOBILE bearing Severe coronal deformity Total knee arthroplasty
- 1.Bruyere O, Ethgen O, Neuprez A et al (2012) Health-related quality of life after total knee or hip replacement for osteoarthritis: a 7-year prospective study. Arch Orthop Trauma Surg 132:1583–1587. doi:10.1007/s00402-012-1583-7
- 8.Insall J, Dorr L, Scott R, Scott W (1989) Rationale of the knee society clinical rating system. Clin Orthop Relat Res 248:13–4Google Scholar
- 9.Ahlbäck S (1968) Osteoarthrosis of the knee. A radiographic investigation. Acta Radiol Diagn Suppl 277:7–72Google Scholar
- 10.(2015) A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing. https ://www.R-project.org/
- 19.Insall JN, Binazzi R, Soudry M, Mestriner L (1985) Total knee arthroplasty. Clin Orthop Relat Res 192:13–22Google Scholar
- 22.Keblish PA (1991) The lateral approach to the valgus knee. Surgical technique and analysis of 53 cases with over two-year follow-up evaluation. Clin Orthop Relat Res 271:52–62Google Scholar