PAPER 102: ROTATIONAL OSTEOTOMY OF THE PROXIMAL TIBIA FOR MAL-TRACKING/DISLOCATION OF THE PATELLA

Abstract

Purpose: Mal-tracking or dislocation of the patella is often the result of abnormal anatomy. Understanding the anatomy will clarify the treatment options available. The common anatomical causes of dislocation range from the valgus knee to patella alta and external tibial torsion. External tibial torsion results in symptoms ranging from patello-femoral pain to subluzation or dislocation. Many patients become symptomatic after an injury and recognition of the anatomical pathology helps in the treatment decision.

Method: A retrospective study was carried out on 232 rotational high tibial osteotomies in 221 patients operated on between 1990–2004. The pre-operative degree of external tibial torsion and ‘Q’ angle was noted. The extent of any patello-femoral pathology was documented, as well as the degree of correction. Assessment was carried out using the HSS score and the Lysholm score. Notation was made of prior surgery, including arthroscopy, patella tendon tarnsfer and patellectomy.

Results: Of the 232 cases, 80% showed good to excellent results with resolution of patello-femoral pain and instability. Ten percent had residual pain but no instability and 20 cases proceeded to total knee replacement. The best results were seen in cases of pain and instability with minimal patello-femoral arthritis. Some cases with end-stage patello-femoral arthritis were improved with the improvement in quadriceps function via reduction in the ‘Q’ angle.

Conclusion: Rotational osteotomy of the proximal tibia for symptomatic patella instability secondary to significant external tibial torsion results in good to excellent results in 80% of cases.