Knee arthrodesis using a vascularized fibular rotatory graft after tumor resection

Free fibula flap for lower limb salvage after tumour resection

Context:

Post-tumour resection lower limb salvage.

Aim/Introduction:

Resection of tumours of the femur and tibia around the knee and ankle joints results in large bony defects. Often arthrodesis is an alternative; in case, adequate functional motors cannot be preserved or due to economic constraints. Thus, in an immunocompromised patient, the vascularised fibula is the best form of reconstruction. The vascularised fibular flap (pedicled/free) can be used in combination with an allograft. We refer to such a combination reconstruction as ‘allocombo’. The vascularised fibular graft hypertrophies in due course of time, and till that period, the allograft provides the required mechanical strength to allow early ambulation.

Subjects and Methods:

A retrospective study of 24 cases of vascularised fibular graft for lower limb reconstruction was conducted from February 2003 to March 2014. The average defect size was 15.5 cm and the average length of fibula harvested was 24.35 cm. A total of 19 free fibular flaps and 5 pedicled fibula were done. Mean age was 26 years. Fibula was nestled in the allograft obtained from the tissue bank.

Results:

The mean follow-up time was 52 months. Free flap success rate was 96%. Successful healing was achieved at 45 ends (97.8%). Radiological evidence of union at osteotomy sites occurred at an average of 6.8 months. Eight patients eventually succumbed to disease. At the final follow-up, the mean Musculoskeletal Tumour Society functional score of the evaluable patients was 26 (range 20–30).

Conclusions:

Pedicled fibula is a good option if the defect is within 14 cm of the knee joint at the femoral end. The vessels have to curve around the fibular head, thus its removal improves the reach of the pedicle. The flap is easy to harvest with predictable vascular anatomy and it can provide a large amount of vascularised bone and skin paddle. It results in early ambulation, rehabilitation and reduced morbidity. We realised that fixation is easier and chances of vascular injury are less in free as compared to pedicled fibula.

Is there a role for knee arthrodesis with modular endoprostheses for tumor and revision of failed endoprostheses?

BACKGROUND

Knee arthrodeses are performed to treat infection after arthroplasty and tumors requiring extensive soft tissue resection. Many techniques have been described, but most have important disadvantages. Currently, endoprosthetic arthrodesis implants are available, but little is known about them.

QUESTIONS/PURPOSES

Our objective was to analyze a series of knee arthrodeses with a modular prosthetic system to evaluate (1) survivorship of the implant, (2) complications, (3) whether survivorship differed between arthrodeses done for primary tumor resection and revision reconstructions, and (4) whether survivorship differed based on the presence of previous infection or the use of a gastrocnemius flap.

METHODS

We present 32 patients with modular knee arthrodeses; arthrodeses were performed in 25 patients with tumors and in seven patients without tumors. There were 14 implants done at the time of tumor resection and 18 for revision of failed implants. Survivorship and complications were analyzed with Kaplan-Meier curves. Log-rank test was used for comparison between primary and revision implants, not infected and previously infected implants, and use or nonuse of a gastrocnemius flap.

RESULTS

Survivorship of arthrodeses with modular endoprostheses was 50% and 25% at 5 and 10 years, respectively. There were nine infections (29%) and one implant fracture (3%). Amputation as final surgery was required in 8 patients (six owing to infection and two to oncologic failures). There was no significant difference in survivorship between arthrodeses done for primary tumor resection and as a salvage procedure for failed implants. No differences were found between patients with and without prior infection or with and without a gastrocnemius flap.

CONCLUSIONS

Survivorship of a modular arthrodesis implant was 50% at 5 years owing to a high complication rate. Infection is the most common cause of failure of oncologic and revision implants. Implant fracture is a rare occurrence. Modular segmental arthrodesis provides a stable construct for patients in whom limb preservation is possible but a hinged device is contraindicated as a result of major muscle resection.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.