Device-length changes and implant function following surgical implantation of the KineSpring in cadaver knees

[Unloading with insoles, orthotics and braces : Pre-operative leg axis correction or independent treatment?]

BACKGROUND

Knee osteoarthritis (OA) is a leading joint disease. In most of the early stages it does not involve the whole knee joint. Often, symptoms only or mainly concern the medial compartment combined with a slight varus malalignment.

OBJECTIVES

Do valgus braces or laterally wedged insoles influence biomechanics and thus improve pain and function in patients with medial OA? Does the OA grade, severity of malalignment or patient's body weight predict the efficacy of the above-mentioned conservative treatment options?

MATERIALS AND METHODS

The current literature was reviewed in regard to biomechanical changes to joint loading and their correlation to clinical results.

RESULTS

Valgus braces and laterally wedged insoles reduce knee adduction moment, varus malalignment and analgesic consumption. Some authors suggest that mainly an alteration in muscle activity (diminished muscle co-contractions) is responsible for pain relief. Body weight and severity of varus malalignment did not influence treatment results; a significant correlation with OA severity was shown only for laterally wedged insoles. For both devices, compliance problems - especially long-term - should be considered, and conclusive evidence of positive clinical effects cannot be stated.

CONCLUSIONS

Despite positive evidence in the current literature, a recommendation for or against valgus (unloader) braces in medial OA is not possible due to inconclusive results. Laterally wedged insoles are not recommended. Especially the long-term results are doubtful, and are possibly related to lacking compliance.