Computer-assisted unicompartmental knee arthroplasty using dedicated software versus a conventional technique
- 458 Downloads
The aim of this study was to retrospectively compare the results of two matched-paired groups of patients who had undergone a medial unicompartmental knee arthroplasty (UKA) performed using either a conventional or a non-image-guided navigation technique specifically designed for unicompartmental prosthesis implantation.
Thirty-one patients with isolated medial-compartment knee arthritis who underwent an isolated navigated UKA were included in the study (group A) and matched with patients who had undergone a conventional medial UKA (group B). The same inclusion criteria were used for both groups. At a minimum of six months, all patients were clinically assessed using the Knee Society Score (KSS) and the Western Ontario and McMaster Osteoarthritis Index (WOMAC) index. Radiographically, the frontal-femoral-component angle, the frontal-tibial-component angle, the hip-knee-ankle angle and the sagittal orientation of components (slopes) were evaluated. Complications related to the implantation technique, length of hospital stay and surgical time were compared.
At the latest follow-up, no statistically significant differences were seen in the KSS, function scores and WOMAC index between groups. Patients in group B had a statistically significant shorter mean surgical time. Tibial coronal and sagittal alignments were statistically better in the navigated group, with five cases of outliers in the conventional alignment technique group. Postoperative mechanical axis was statistically better aligned in the navigated group, with two cases of overcorrection from varus to valgus in group B. No differences in length of hospital stay or complications related to implantation technique were seen between groups.
This study shows that a specifically designed UKA-dedicated navigation system results in better implant alignment in UKA surgery. Whether this improved alignment results in better clinical results in the long term has yet to be proven.
KeywordsUnicompartmental knee arthroplasty Computer-assisted
Conflict of interest
Alfonso Manzotti, Chris Pullen and Pietro Cerveri have no conflict of interest. Norberto Confalonieri has a financial relationship with DePuy (Warsaw, IN, USA) to develop the Monet software for UKA navigation.
- 16.Perlick L, Bathis H, Tingart M, et al. (2004) Minimally invasive unicompartmental knee replacement with a nonimage-based navigation system 28:193–71Google Scholar
- 17.Weber P, Crispin A, Schmidutz F, Utzschneider S, Pietschmann MF, Jansson V, Müller PE (2013) Improved accuracy in computer-assisted unicondylar knee arthroplasty: a meta-analysis. Knee Surg Sports Traumatol Arthrosc 23. [Epub ahead of print]Google Scholar
- 19.Ahlbäck S (1968) Osteoarthrosis of the knee. A radiographic investigation. Acta Radiol Diagn (Stockh) 277:7–72Google Scholar
- 20.Insall JN, Dorr LD, Scott RD, Scott WN (1998) Rationale of the Knee Society Clinical Rating System. Clin Orthop 248:13–14Google Scholar
- 21.Bellamy N, Buchanan WW, Goldsmith CH, Campbell J, Stitt LW (1988) Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip and knee. J Rheumatol 15:1833–1840PubMedGoogle Scholar
- 25.Newman JH, Ackroyd CE, Shah NA (2001) Unicompartmental or total knee replacement ? J Bone Joint Surg 80B:862–865Google Scholar
- 28.Prime MS, Palmer J, Khan WS (2011) The National Joint Registry of England and Wales. OrthopedicsGoogle Scholar