4.O.06 EXTRA-ARTICULAR BONE- OR SOFT TISSUE TUMOUR RESECTION OF THE KNEE JOINT; RESULTS IN 34 PATIENTS

Abstract

Limb-sparing surgery has become the preferred surgical treatment of malignant bone tumours of the knee. In patients with intra-articular extension of their tumour, extra-articular limb sparing surgery can prevent the knee from amputation. In a retrospective study between January 1985 and December 2007, we performed 34 extra-articular tumour resections of the knee-joint for a bone- or soft tissue tumour in the distal femur or proximal tibia with (suspect) intra-articular tumour extension into the knee on MRI. Contra-indications were extension of the tumour into the extensor mechanism and/or tumour involvement of the neurovascular bundle. Osteosarcoma (23/34) was the most common primary malignancy. Mean age was 36 years (17–70) and the mean follow up was 9 years (1–19).

Patient survival rates at 5 years and 10 years are 78% and 58% respectively, mean patient survival was 47 months (8–211). In 12 (35%) patients, the primary implanted prosthesis failed during follow up. Prosthetic survival rates including minor revision surgery were 63% at 5 years and 36% at 10 years. Six (18%) patients had local recurrence of their malignancy, 5 of them in the popliteal fossa. Local recurrence was significantly correlated with marginal margins (P< 0.05). Fifteen patients had major complications (44%) mainly deep infection in proximal tibia resections and aseptic loosening in distal femur resections. Aseptic loosening was significantly correlated with non HA-coated stems (P< 0.05). Functional outcome scores according to MSTS (mean 81, (65–93)) and TESS (mean 85, (56–98)) of survivors are good.

Our results suggest that extra-articular tumour resections of the knee-joint can provide a functional endoprosthesis and can be an alternative for primary amputation. However it is a technical demanding procedure with acceptable local recurrence and high complication rates in patients with, in general, poor survival.