Constrained total hip megaprosthesis for primary periacetabular tumors.
BACKGROUND
Limb-salvage reconstruction for periacetabular malignant tumors is one of the most challenging problems in orthopaedic oncology. Reconstructive options include resection arthroplasty, endoprosthesis, allograft, recycled autobone graft, arthrodesis, and pseudarthrosis. However, no standard procedure exists because of rarity and clinical variability of the disease. We previously developed a megaprosthetic system with a constrained total hip mechanism (C-THA).


OBJECTIVE
We evaluated (1) survival of patients and C-THA; (2) postoperative function; and (3) complications.


METHODS
We retrospectively reviewed 25 patients with primary periacetabular tumors treated using C-THA between 1985 and 2009. There were 18 male and seven female patients with a median age of 44 years (range, 16-72 years). They included 11 chondrosarcomas, eight osteosarcomas, two giant cell tumors of bone (one locally aggressive benign, one malignant), and others in four. Surgical margin was wide in 18 patients, marginal in five, and intralesional in two. The minimum postoperative followup for survivors was 32 months (median, 163 months; range, 32-285 months).


RESULTS
The 10-year overall survival rate of all patients was 47%. C-THA implants survived in 19 of 25 patients at last followup. Twenty-one patients acquired ambulatory activity. There were seven local recurrences, resulting in hemipelvectomy in one patient. Postoperative complications included deep infection in eight of the 25 patients, dislocation in four, and aseptic loosening in two, necessitating five revision surgeries and three implant removals.


CONCLUSIONS
Our observations suggest C-THA using an acetabular reconstruction cup is a useful reconstructive option after resection of periacetabular malignant tumors despite frequent postoperative complications.


METHODS
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Osaka University Orthopaedic Oncology Group, Osaka, Japan, uedat@onh.go.jp.
Takafumi
T
Ueda
Shigeki
S
Kakunaga
Satoshi
S
Takenaka
Nobuhito
N
Araki
Hideki
H
Yoshikawa
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D001696:Biomechanical Phenomena; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D020878:Device Removal; D005260:Female; D006428:Hemipelvectomy; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D023821:Limb Salvage; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D019651:Plastic Surgery Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D020127:Recovery of Function; D012086:Reoperation; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult