The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants. A consecutive series of 45 (2014 to 2019) PPRs for Paprosky III defects at rTHA were analyzed comparing the preoperative planning CT scans used to manufacture the implants with postoperative CT scans and radiographs. The anteversion (AV), inclination (IC), deviation from the preoperatively planned implant position, and deviation of the centre of rotation (COR) were explored. Early postoperative complications were recorded, and factors for malpositioning were sought. The mean follow-up was 30 months (SD 19; 6 to 74), with four patients lost to follow-up.Aims
Methods
To date, all surgical techniques used for reconstruction
of the pelvic ring following supra-acetabular tumour resection produce
high complication rates. We evaluated the clinical, oncological
and functional outcomes of a cohort of 35 patients (15 men and 20
women), including 21 Ewing’s sarcomas, six chondrosarcomas, three sarcomas
not otherwise specified, one osteosarcoma, two osseous malignant
fibrous histiocytomas, one synovial cell sarcoma and one metastasis.
The mean age of the patients was 31 years (8 to 79) and the latest
follow-up was carried out at a mean of 46 months (1.9 to 139.5)
post-operatively. We undertook a functional reconstruction of the pelvic ring using
polyaxial screws and titanium rods. In 31 patients (89%) the construct
was encased in antibiotic-impregnated polymethylmethacrylate. Preservation
of the extremities was possible for all patients. The survival rate
at three years was 93.9% (95% confidence interval (CI) 77.9 to 98.4),
at five years it was 82.4% (95% CI 57.6 to 93.4). For the 21 patients
with Ewing’s sarcoma it was 95.2% (95% CI 70.7 to 99.3) and 81.5%
(95% CI 52.0 to 93.8), respectively. Wound healing problems were
observed in eight patients, deep infection in five and clinically
asymptomatic breakage of the screws in six. The five-year implant survival
was 93.3% (95% CI 57.8 to 95.7). Patients were mobilised at a mean
of 3.5 weeks (1 to 7) post-operatively. A post-operative neurological
defect occurred in 12 patients. The mean Musculoskeletal Tumor Society
score at last available follow-up was 21.2 (10 to 27). This reconstruction technique is characterised by simple and
oncologically appropriate applicability, achieving high primary
stability that allows early mobilisation, good functional results
and relatively low complication rates. Cite this article:
