Introduction: We present preliminary short term results of medial opening wedge high tibial osteotomy with hemicallotasis using a monolateral external fixator, combined with microfracturing, in younger active patients with established Grade IV medial compartment osteoarthritis.

Methods: Prospectively collected data was analysed for 28 consecutive knees in 27 patients undergoing this procedure. Mean age was 47 years (range 28 to 64), follow up was 23 months (range 7 to 61).

Results: Mean Lysholm scores improved from 63.6 before surgery (range 42 to 85) to 81.6 at latest follow-up (range 46.5–100) (p< 0.001). Similarly, the mean Tegner activity scale improved from 1.7 (range 1 – 4) to 3.3 (range 1 – 6) (p< 0.001). Average IKDC score at last follow-up was 68 (range 35.6 – 100). Mean pain score (visual analogue scale 0 to 10) improved from 5.5 pre-operatively (range 1 – 9), to 3.5 at latest follow-up (range 0 – 8) (p< 0.001). All but 4 patients reported improved pain scores.

Superficial pin site infection occurred in 6 patients (21.4%) and settled with oral antiobiotics in all cases. One patient had persistent patellofemoral (PF) pain.

Discussion: The use of hemicallotasis for high tibial osteotomy (HTO) in association with extensive microfracturing of the medial compartment provides a viable, minimally invasive method for management of the young active patient with medial compartment osteoarthritis, without the risk of serious complications. In the short term even with advanced full thickness cartilage damage, this provides effective pain relief, helps put off more major arthroplasty alternatives and improves activity levels.

Introduction: We present preliminary short term results of medial opening wedge high tibial osteotomy with hemicallotasis using a monolateral external fixator, combined with microfracturing, in younger active patients with established Grade IV medial compartment osteoarthritis.

Methods: Prospectively collected data was analysed for 28 consecutive knees in 27 patients undergoing this procedure. Mean age was 47 years (range 28 to 64); follow up was 23 months (range 7 to 61).

Results: Mean Lysholm scores improved from 63.6 before surgery (range 42 to 85) to 81.6 at latest follow-up (range 46.5–100) (p< 0.001). Similarly, the mean Tegner activity scale improved from 1.7 (range 1–4) to 3.3 (range 1–6) (p< 0.001). Average IKDC score at last follow-up was 68 (range 35.6–100). Mean pain score (visual analogue scale 0 to 10) improved from 5.5 pre-operatively (range 1–9), to 3.5 at latest follow-up (range 0–8) (p< 0.001). All but 4 patients reported improved pain scores, one of whom had patellofemoral pain. Superficial pin site infection occurred in 6 patients (21.4%) and settled with oral antibiotics in all cases.

Discussion: The use of hemicallotasis for high tibial osteotomy in association with extensive microfracturing of medial compartment provides a viable, minimally invasive method for management of the young active patient with medial compartment osteoarthritis, without the risk of serious complications. In the short term even with advanced full thickness damage, this provides effective pain relief, helps put off more major arthroplasty alternatives and allows patients an improved activity level. The external fixator provides a very stable functional stabilization, superior to other available methods of internal fixation.