COMPARISON OF UKA AND HIGH TIBIAL OSTEOTOMY. A PROSPECTIVE SHORT TERM RESULT

Abstract

Introduction: This paper presents the short term results of 56 (28 males and 28 females) consecutive Unicompartimental Knee Arthroplasties (UKAs) and 54 (29 males and 25 females) High Tibial Opening Wedge Osteotomies (HTOs), performed in two centres (Toronto-Canada and Torino-Italy), between 2001 and 2004.

The aim of this prospective study was to compare UKAs to HTOs, in terms of clinical and functional Results: Materials and Methods:

In all UKAs we implanted an Accuris prosthesis (Smith& Nephew, Memphis TN), in all HTOs we performed a medial opening wedge osteotomy, according to the surgical technique and syntesized with a Puddu Plate (Arthrex, Naples FL).

We evaluated all patients preoperatively and at 6 months postoperatively, at 1 year, 2 years and at the last follow-up visit (mean 3,5 years for UKAs and 2,5 years for HTOs), using the Knee Society Score (KSS) and the WOMAC (Western Ontario and McMaster Universities) Score.

Results: The mean age at operation was 55 years for the HTO group and 65 years for the UKA group.

Postoperative program for the HTO group was: 4 weeks of CPM (continuous passive movement), partial weight-bearing al 4 weeks (30–50% of body weight) and then full weight-bearing at 8 weeks postoperatively.

In the UKA group, full weight bearing was allowed immediately after operation.

We observed only one significant complication postoperatively: an early infection in an HTO patient. We thought this complication was not related to the treatment chosen, but to external factors, so we decided to exclude this patient from our study.

In the HTOs group, the KSS knee score (KS) and function score (FS) improved from respectively 38 and 55 preopertively to 76 and 91 at the final follow-up evaluation, while in the UKA group KS increased from 43 to 93 and FS increased from 50 to 84.

The WOMAC Score improved from respectively 48 (HTO Group) and 45 (UKA Group) preoperatively to 15 (HTO Group) and 14 (UKA Group) at the final follow-up evaluation.

Discussion and conclusion: According to both scores (Womac and KSS), the two groups did not differ significantly at 1 year, 2 year and last followup evaluation, considering the different ages of the patients (55 years of the HTO Group versus 64 years of the UKA group).

Comparison of study groups shows good outcome at early and mid-term follow-up. All patients had scores rated good to excellent (both KSS and WOMAC).

However, we found a little difference in KSS between the two groups: UKAs have a higher Knee Score (better knee assessment), while HTOs have a significantly higher Functional Score (better performances, maybe due to a more “anatomic saving” procedure).

This data suggests that the UKAs have better knee assessment, meanwhile the HTOs have better function. Given that, both treatments lead to a good to excellent outcome at early followup.