Summary

High tibial osteotomy can help return stability to a chronically unstable mal-aligned knee without the need for further ligament reconstruction in patients with low velocity injury.

Abstract

Introduction

High tibial osteotomy (HTO) is an established treatment to correct mal-alignment prior to or concurrent with ligament reconstruction in chronic multiple ligament knee injury patients. The mal-alignment can preexist or result from the injury.
Hypothesis

Aim

Open wedge HTO can achieve accurate over-correction of varus deformity with sufficient improvement in knee function that a subsequent ligament reconstruction was not necessary in patients with chronic multiple ligament knee injury after 5 years of surgery.

Methods

Twenty four knees in twenty four patients with with combined grade 3 postero-lateral complex (PLC), anterior cruciate ligament (ACL) / posterior cruciate ligament (PCL) instability and varus alignment of the knee treated with open wedge HTO. All twenty four knees had grade 3 postero-lateral instability. Twelve patients had concurrent ACL deficiency. Eight patients had concurrent PCL deficiency. Four patients had combined ACL and PCL deficiency. Postero-medial open wedge HTO was done for the ACL deficient knees to decrease the tibial slope. Antero-medial open wedge HTO was done for the PCL deficient knees to increase the tibial slope. Primary outcome measure / endpoint was over-correction of 5º valgus over 5 years after surgery as assessed by hip knee ankle angle (HKA). Secondary objectives were radiological measures of tibial slope (TS), Insall Salvati ratio (IS) and Blackburn Peel ratio (BP) were assessed pre-operatively and 5 years after surgery. Clinical outcome measures; visual analogue scale and KOOS score were measured 1year, 3 years and 5 years post-operatively.

Results

HKA changed from 3.5º varus to 11.2º valgus (p = 0.000). No statistically significant difference was found in TS (p= 0.9), IS (p=0.75) and BP (p=0.59). Only 12.5% showed patella baja (BP <0.54). 66.7 % of patients were clinically satisfied after 5 years and needed no further surgical intervention. All patients who required a second stage ligament reconstruction after healing the osteotomy and rehabilitation had high-velocity knee injury.

Conclusion

The logical conclusion is that an osteotomy can help return stability to a chronically unstable mal-aligned knee. This could be a valid option for patients with low velocity injury in such a difficult situation.
Key Words:
high tibial osteotomy, multiple ligament injured knee, low velocity injury, ligament reconstruction.