Temporary External Fixation Can Stabilize Hip Transposition Arthroplasty After Resection of Malignant Periacetabular Bone Tumors
Authors: Kunisada Toshiyuki , Fujiwara Tomohiro , Hasei Joe , Nakata Eiji , Senda Masuo , Ozaki Toshifumi 
Published: April 2019

Abstract

Background
The choice of reconstructive procedure to restore limb function is challenging after internal hemipelvectomy. Hip transposition arthroplasty, also known as resection arthroplasty, removes a malignant or aggressive tumor of the pelvis and acetabulum after which the remaining femoral head is moved proximally to the lateral surface side of the sacrum or the underside of the resected ilium after internal hemipelvectomy. It may provide reasonable functional results and have some advantages such as lowering the risk of an infected implant compared with other reconstructions because no foreign implants are used. Hip transposition is generally managed with prolonged bed rest or immobilization postoperatively to stabilize the soft tissue surrounding the remaining femur. Because enabling patients to be mobile while the soft tissues heal might be advantageous, we reviewed our experience with an external fixation for this procedure.

Questions/purposes
(1) Does temporary external fixation facilitate postoperative physiotherapy in patients who undergo hip transposition arthroplasty? (2) What functional Musculoskeletal Tumor Society (MSTS) scores were achieved at short term in a small series of patients treated with hip transposition and temporary external fixation? (3) What were the complications of using external fixation in a small series of patients who received it for malignant tumors?

Methods
Between 2008 and 2012, we treated seven patients (three men and four women; median age, 37 years; age range, 18–53 years) with acetabular resection for malignant bone tumors; all were managed with a hip transposition, initially stabilized using external fixation. No other types of procedures were used for this indication in this period. Minimum followup in this retrospective study was 45 months, except for one patient who died at 18 months (range of followup duration, 18–90 months; median followup, 57 months), and no patients were lost to followup. The pins for external fixation were inserted into the affected side of the femur and the healthy contralateral ilium. External fixation was removed 6 weeks postoperatively and weightbearing was started at that time. Preoperative chemotherapy was administrated in four patients, but postoperative chemotherapy was delayed since it was given after external fixation removal in three patients. The postoperative rehabilitation course and functional results were assessed by chart review, functional results were determined using MSTS scores, tallied by physiotherapists who were not part of the surgical team, and complications were ascertained through chart review. Major complications were defined as complications that were treated with additional operations, such as deep infection, or ones that could cause severe postoperative dysfunction, such as nerve injury.

Results
With temporary external fixation, standing next to a bed was achieved in median 7 days (range, 6–9 days) postoperatively, transferring to a wheel chair in median 8 days (range, 6–28 days), and gait training using parallel bars in median 15 days (range, 7–48 days). At most recent followup, three patients could walk without a crutch or cane, three could walk with a cane, and one could walk with a crutch. The median MSTS score at most recent followup (median, 57 months) was 63%. Two patients had complications that resulted in reoperations; one had a wound dehiscence, and one had an abdominal herniation that gradually developed, and which was reconstructed using polypropylene mesh 2 years after pelvic resection. Two patients had nerve palsies that recovered by the end of the first year. All patients had pin tract infections that resolved with nonsurgical approaches.

Conclusions
Hip transposition with temporary external fixation can stabilize the bone soft tissue after pelvic resection. Although we did not have a comparison group of patients, we believe that external fixation facilitates early postoperative physiotherapy and rehabilitation and provides good functional results without major surgical complications. Because it delays the resumption of chemotherapy, more patients with longer followup are needed to determine whether this will be associated with poorer oncologic results.

Level of Evidence
Level IV, therapeutic study.