Dolph Houben

45 Vascularized Bone Grafts, a closer look at the free fibula flap 2 Functional outcome (MSTS) The Musculoskeletal Tumor Society scoring system (MSTS) is a disease-specific measure for the physical and mental health outcome after limb-sparing surgery in the lower extremity. The MSTS scoring system consists of six domains, scored on a 0 to 5 scale, and transformed into an overall score ranging from 0 to 100 percent score (or 0-30 points) with a higher score indicating better function. A review of 35 vascularized free fibula grafts for the reconstruction of lower extremity defects after malignant tumor resection demonstrated a mean score of 88 percent [74] . When vascularized fibular grafts are used in lower extremity reconstruction and protected with a cryopreserved allograft the mean MSTS reaches 87.8 percent found in a systematic review of 123 patients [75] . Factors that influence the outcome Multiple factors play an important role to achieve final bone union, reduce complications and re- operations. A review of vascularized bone grafts for both upper and lower extremity reconstruction demonstrated that rigid internal fixation and use of additional bone graft results in significantly better union scores [23] . Significant risk factors found in literature for non-union are the use of Tabacco, post-operative chemo/radiotherapy, and reconstruction performed for osteomyelitis [1, 66, 74] . A trend toward more non-union is found for those patients who have diabetes and patients with an age above 40 years [23] . Complications Donor site complications Complications related to the donor site reported in literature for free fibula harvest include (chronic) pain, altered gait, weakness, contracture of the flexor hallucis longus, compartment syndrome, peroneal nerve palsy, valgus deformity, arterial insufficiency, and spontaneous fracture of the ipsilateral tibia. Donor site complications are generally fairly minimal and a review of 132 free fibula grafts demonstrated donor site complications in 8 percent of the patients [1] . Although a compartment syndrome after fibula harvest is rare, a split skin graft must be used to close the wound when an osteocutaneous fibula is harvested. [60] . An extensive review of 247 lower limbs from which a free fibula was harvested was evaluated specifically on donor site morbidity. This review showed mild weakness in 10 percent of the patients and sensory deficit in 5-12 percent of the patients. Chronic pain was present in 9 percent of the patients [76] . Although donor site complications are mostly transient and generally an acceptable trade for successful limb salvage. A known complication is children is a valgus deformity of the ankle after fibula harvest. To prevent this complication, fusion of the distal tibiofibular joint just proximal to the physis must be performed [77] . Occasional flexor hallucis contractures may require tendon lengthening or tenotomy.