Cruciate retaining and posterior stabilized total knee arthroplasty in severe varus osteoarthritis knee: A match-pair comparative study in an Asian population

Background Posterior stabilized (PS) total knee arthroplasty (TKA) is advocated in severe varus osteoarthritic (OA) knees as the posterior cruciate ligament posed challenges in gap balancing. However, there is scarcity in the literature to illustrate the superiority of PS TKA over cruciate retaining (CR) TKA. Our study aims to compare the outcomes between CR and PS TKAs in patients with severe varus OA knees. Methods: A retrospective review was conducted on patients who underwent primary TKA for OA knee from 2003 to 2013. Patients with OA knees of varus tibiofemoral angle ≥15 were matched into two groups (Group CR and PS) according to age, gender, and body mass index and compared in terms of clinical (tibiofemoral alignment, range of motion, and revision rate) and functional outcome (Knee Society Scoring, Oxford Knee Score, Short Form-36 Health Survey). Results: Both Group CR ( n = 56) and PS ( n = 56) had similar pre-operative scores. Both groups achieved correction of tibiofemoral alignment from median pre-operative varus of 17.6/17.0 (CR/PS) ( p = .279) to median post-operative valgus of 4.9/4.0 (CR/PS) ( p = .408). Over 24 months, both groups were comparable in achieving significant improvement in clinical and functional outcomes. No case of revision surgery was reported (median follow-up months; CR: 65, PS: 74, p = .549). Conclusion: Both CR and PS TKAs perform similarly well in severe varus OA knee up to 2 years post-operation. Further studies are warranted to assess the long-term outcome between the two implant designs.

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Cruciate retaining versus posterior stabilized total knee arthroplasty for the treatment of valgus osteoarthritis?

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00231 ◽

2019 ◽

Vol 7 (6_suppl4) ◽

pp. 2325967119S0023

Author(s):

Max Ettinger ◽

Peter Savov ◽

Henning Windhagen ◽

Evelyn Mielke ◽

Tilman Calliess

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Oxford Knee Score ◽

Valgus Knee ◽

Posterior Stabilized ◽

Cruciate Retaining ◽

Early Revision ◽

Koos Score ◽

Total Knee

Aims and Objectives: The debate of cruciate retaining (CR) versus posterior stabilized (PS) designs in total knee arthroplasty (TKA) is ongoing. With the posterior cruciate ligament retained, the TKA is supposed to function better in terms of proprioception, balance and kinematics. In contrast to that, PS designs are supposed to lead to higher degrees of flexion and a better femoral rollback. It is known, that the preoperative deformity negatively correlates with inferior results following TKA. When balancing a valgus knee, Ranawat et al. suggest to address the PCL in the first place. It is known that in 60% of valgus knees 1-2 soft tissue releases are necessary in order to achieve neutral alignment. Up to date no study exists, reporting the outcome of CR versus PS TKA in valgus knees. Thus, it was purpose of this study to evaluate the mid term outcome of CR versus PS TKA for the treatment of valgus OA in groups between 3°-6° of valgus, 7-10° of valgus and >10° of valgus. Materials and Methods: With the KOOS score as the primary endpoint, a sample size of 117 cases (78 CR and 39 PS) was needed in order to get a statistical power of 80%.Between 01-2011 and 03-2014 a total of 248 patients with a preoperative valgus >3° were treated with a CR TKA (167 cases) or a PS TKA (81 cases) of the same manufacturer (Stryker Triathlon, Stryker, Kalamazoo USA). CR patients were divided into the following groups: Preoperative valgus >3°-6°, 7°-10° and >10°. PS patients were divided into the following groups: Preoperative valgus >3°-6°, 7°-10° and >10°. The KOOS Score and the Oxford Knee score was collected at the time of follow up. For the CR and PS group failure rates and failure etiologies were analyzed. Patients demographics and were collected as well. Results: 141 patients were included into this study (97 CR and 44 PS cases). The CR group had a mean follow up of 57 weeks, the PS group had a follow up of 52weeks. In the CR group, 11/97 (11%) patients were revised due to a.p. instability, whereas 2/44 (5%) patients were revised in the PS group due to infection or aseptic loosening. There was no difference regarding OKS and the KOOS score between the two groups. Further, there was no difference regarding patients demographics and no correlation between the BMI and the clinical outcome. Conclusion: The most important findings of this study are that the CR group showed a significant higher early revision rate, whereas the clinical mid term follow up results are equal. The CR version of the used system showed significantly higher early failure due to a.p. instability.

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