Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation. A total of 122 patients who underwent reconstruction following resection of periacetabular tumour between January 2011 and January 2020 were studied. The risk factors for dislocation were investigated with univariate and multivariate logistic regression analysis on patient-specific, resection-specific, and reconstruction-specific variables.Aims
Methods
Peri-acetabular tumour resections and their subsequent
reconstruction are among the most challenging procedures in orthopaedic
oncology. Despite the fact that a number of different pelvic endoprostheses
have been introduced, rates of complication remain high and long-term
results are mostly lacking. In this retrospective study, we aimed to evaluate the outcome
of reconstructing a peri-acetabular defect with a pedestal cup endoprosthesis
after a type 2 or type 2/3 internal hemipelvectomy. A total of 19 patients (11M:8F) with a mean age of 48 years (14
to 72) were included, most of whom had been treated for a primary
bone tumour (n = 16) between 2003 and 2009. After a mean follow-up
of 39 months (28 days to 8.7 years) seven patients had died. After
a mean follow-up of 7.9 years (4.3 to 10.5), 12 patients were alive,
of whom 11 were disease-free. Complications occurred in 15 patients.
Three had recurrent dislocations and three experienced aseptic loosening.
There were no mechanical failures. Infection occurred in nine patients,
six of whom required removal of the prosthesis. Two patients underwent
hindquarter amputation for local recurrence. The implant survival rate at five years was 50% for all reasons,
and 61% for non-oncological reasons. The mean Musculoskeletal Tumor
Society score at final follow-up was 49% (13 to 87). Based on these poor results, we advise caution if using the pedestal
cup for reconstruction of a peri-acetabular tumour resection. Cite this article:
We evaluated the oncological and functional outcome
of 18 patients, whose malignant bone tumours were excised with the
assistance of navigation, and who were followed up for more than
three years. There were 11 men and seven women, with a mean age
of 31.8 years (10 to 57). There were ten operations on the pelvic
ring and eight joint-preserving limb salvage procedures. The resection
margins were free of tumour in all specimens. The tumours, which
were stage IIB in all patients, included osteosarcoma, high-grade
chondrosarcoma, Ewing’s sarcoma, malignant fibrous histiocytoma
of bone, and adamantinoma. The overall three-year survival rate
of the 18 patients was 88.9% (95% confidence interval (CI) 75.4
to 100). The three-year survival rate of the patients with pelvic malignancy
was 80.0% (95% CI 55.3 to 100), and of the patients with metaphyseal
malignancy was 100%. The event-free survival was 66.7% (95% CI 44.9
to 88.5). Local recurrence occurred in two patients, both of whom
had a pelvic malignancy. The mean Musculoskeletal Tumor Society
functional score was 26.9 points at a mean follow-up of 48.2 months
(22 to 79). We suggest that navigation can be helpful during surgery for
musculoskeletal tumours; it can maximise the accuracy of resection
and minimise the unnecessary sacrifice of normal tissue by providing
precise intra-operative three-dimensional radiological information.
