2006 ASPS Abstract



Management of Oncologic Defects of the Knee with Free Tissue Transfer

 

Ronen Avram, MD, Joseph J. Disa, MD, Babak J. Mehrara, MD, and Andrea L. Pusic, MD, MHS, Peter G. Cordeiro, MD.

INTRODUCTION:

Malignant tumors of the knee pose a significant challenge from both ablative and reconstructive standpoints. Given the excellent functional outcomes reported with limb-sparing surgery, there exists an obligation within the surgical community to achieve curative resections of aggressive extremity tumors while preserving useful limb function. Though articular defects are managed by the ablative team, the reconstructive surgeon may be called upon to treat resultant soft-tissue defects. If local flaps are unavailable or insufficient, one must rely on free tissue transfer for wound closure.

With the advent of microsurgery, improved prosthetic design and adjuvant treatment protocols, limb-sparing surgery has proven to be a safe and effective mode of treatment throughout many centers. The options afforded by microvascular surgery have enabled the orthopedic surgeon to undertake both complicated tumor extirpation and secondary revision-type procedures.

Numerous authors have described their experience with extremity sarcomas but few studies focus on free tissue transfer as a means of reconstructing the soft tissue defects of the knee following tumor ablation. Horowitz et al. (1992) reviewed their experience with knee sarcomas during a transition period when free tissue transfer (FTT) became available at their institution. Outcomes of patients treated prior to FTT availability compared poorly with the FTT group. Weinberg et al. (1993) published a series of 26 patients with free tissue transfers used in limb-sparing procedures for malignant tumors of the knee. One flap failure occurred and five patients developed either a recurrence or a complication necessitating an above-knee amputation. All reconstructions in Weinberg’s series were immediate. Reece et al. (1994) described their experience with free tissue transfer for lower extremity salvage in the context of immediate versus delayed reconstruction. In their series, however, there were only 2 patients with tumors around the knee.

The purpose of this study was to describe our experience of 28 patients who underwent free flap reconstruction of the knee between February 1989 and June 2005 at a tertiary cancer center.

METHODS:

This was a retrospective review (1989 – 2005) of patients reconstructed with free tissue transfer after limb sparing resection of malignant knee tumors. A retrospective chart review, as well as review of data from a prospectively maintained free flap database was performed for each patient. Between February of 1989 and May of 2005, 28 patients underwent free tissue transfer for coverage of knee defects. Among the data collected was patient age, sex, date of procedure, tumor histology, location, immediate vs delayed plastic surgery involvement, use of endoprosthesis, allograft, autograft, type of free flap, defect dimensions, flap dimensions, recipient vessels, adjuvant treatment, smoking history, mobility, follow-up period and flap complications. Institutional approval for the study was obtained from the research ethics board.

RESULTS:

Of the 28 free tissue transfers, 19 were performed in a delayed fashion whereas 9 were for immediate reconstruction. There were 16 males and 12 females. The average age was 35.7 years. The latissimus dorsi was utilized in 21 of the patients and the rectus abdominis in the remaining seven. Review of the medical records revealed bilateral thoracotomies in three patients, thus precluding the use of the latissimus dorsi flap. Twenty four patients had undergone joint reconstruction. Twenty one of twenty four joint reconstructions were carried out with endoprostheses. Four of these were complimented with autograft and another three with allograft. Three joint reconstructions were accomplished with allograft only. Of the 19 delayed reconstructions, ten were performed for infected and/or exposed prostheses. Five patients had experienced wound breakdown with impending prosthetic exposure shortly after the initial procedure. Two patients required revision of loose hardware and two patients had developed a recurrence in a previously operated and heavily scarred tissue bed. Adjuvant therapy was used in nineteen patients of which fourteen received pre-operative chemotherapy. Three patients presented with metastatic disease (lung) and seven patients developed lung metastases during the study period. Seventeen patients achieved ambulation without assistance and an additional seven could ambulate with the aid of a cane or crutches. There were no complete flap failures. One flap required re-exploration in the operating room for presumed venous thrombosis. There was no thrombosis discovered and flap congestion was attributed to extrinsic compression. Five patients had experienced partial flap failures. Two of these patients were treated conservatively but 3 required a return trip to the operating room for adequate debridement and wound closure. Of the latter group, one was discovered to have an exposed prosthesis which required revision. There were 3 wound infections. Two of these patients had prosthetic joint reconstruction and required revision of their prosthesis. Induction chemotherapy did not predispose to infection. Though the majority of partial failures were associated with induction chemotherapy (n=4), chi-square analysis did not reveal any significance (p=0.2). Twenty seven of twenty eight limbs were salvaged with only one patient requiring an above knee amputation for early tumor recurrence.

CONCLUSIONS:

As treatment protocols evolve and life expectancy of sarcoma patients improves, limb preservation has become a significant component of extremity sarcoma treatment. The options afforded by microvascular surgery have enabled the orthopedic surgeon to undertake both complicated tumor extirpation and secondary revision-type procedures. Our series includes 19 delayed/secondary reconstructions which is the largest available in the literature. There were no major flap losses and a fairly high rate of ambulation was achieved in both immediate and delayed reconstructions. Therefore, we conclude that free flap reconstruction of the knee following tumor ablation is a safe and reliable procedure enabling very high limb-salvage rates.

REFERENCES:

Horowitz SM, Lane JM, Healey JH. Soft-tissue management with prosthetic replacement for sarcomas around the knee. Clin Orthop Relat Res 275:226-31, 1992.

Reece GP, Schusterman MA, Pollock RE, et al. Immediate vs. delayed free-tissue transfer salvage of the lower extremity in soft tissue sarcoma patients. Ann Surg Onc Jan(1):11-17, 1994.

Weinberg H, Kenan S, Lewis MM, et al. The role of microvascular surgery in limb-sparing procedures for malignant tumors of the knee. Plast Reconstr Surg 92(4):692-8, 1993.

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