Bone-patellar tendon-bone allograft reconstruction for peri-patellar tendon sarcomas: case series

Abstract

Introduction: Reconstruction after wide resection for a sarcoma involving the knee extensor mechanism is challenging even if the tumor is small.

Case description: We report on four consecutive peri-patellar tendon sarcomas treated similarly at a single institution. Histological diagnoses were synovial sarcoma (two cases), clear cell sarcoma and extraskeletal Ewing's sarcoma (one case each). Follow-up periods after surgery were 18-67 months. All cases underwent pre-operative radiotherapy and subsequent surgery. After preoperative radiotherapy and wide resection including the patellar tendon, bone-patellar tendon-bone allograft was fixed to the residual patella and tibial tuberosity with screws and a cable wire. Soft tissue and skin defect over allograft was covered by free antero-lateral thigh flap. Post-operatively, the operated knee was splinted straight for at least 6 weeks, and then range-of-motion exercise was gradually introduced. Except for one case with a proximal tibial stress fracture 5 months post-operatively, no complication was observed. Both bone-bone junctions between allograft and residual bones were united within 1 year after surgery. At the latest clinical follow-up, all the patients had satisfactory functions with Musculoskeletal Tumor Society score of 28-30 out of 30 points and virtually full range of motion.

Discussion and evaluation: This case series is the first to report bone-patellar tendon-bone allograft for reconstruction after tumor resection with joint preservation and with satisfactory clinical outcomes.

Conclusions: Bone-patellar tendon-bone allograft reconstruction with vascularized flap reconstruction is a viable option for peri-patella tendon sarcomas.

Keywords: Allograft; Knee extension mechanism; Patellar tendon; Reconstruction; Soft tissue sarcoma.

Fig. 1

Radiologic studies and photographs of patient 1. a T1 gadolinium-enhanced magnetic resonance images at the first presentation show inflammation in the infrapatellar fat pad after unplanned excision. b Photographs show intra-operative field before and after allograft reconstruction. White arrows and black arrows point screws and a cable wire system, respectively. c Both bone–bone junctions between allograft and residual bones were united at 11 months after surgery. T tibia, F femoral joint surface, P patella

Fig. 2

A photograph of the operated knee 4 years post-operatively (patient 1). No extension lag of the operated knee was observed

Fig. 3

Radiologic studies and photographs of patient 4. a T1 gadolinium-enhanced magnetic resonance images of at the first presentation demonstrate partial tumor invasion into the lateral cortex of the proximal tibia (arrow). b After allograft reconstruction, the proximal tibia was reinforced with a lateral proximal tibial plate and screws. c Radiographs show a stress fracture in the proximal tibia 5 months post-operatively. A black arrow and white arrow point a thin oblique fracture line and posterior fracture-associated callus formation, respectively

Fig. 4

Scheme of patellar osteotomy in this case series. Q quadriceps, PT patellar tendon, AS articular surface, # osteotomy line