Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures.Aims
Methods
Reconstruction of the acetabulum after resection of a periacetabular
malignancy is technically challenging and many different techniques
have been used with varying success. Our aim was to prepare a systematic
review of the literature dealing with these techniques in order
to clarify the management, the rate of complications and the outcomes. A search of PubMed and MEDLINE was conducted for English language
articles published between January 1990 and February 2017 with combinations
of key search terms to identify studies dealing with periacetabular
resection with reconstruction in patients with a malignancy. Studies
in English that reported radiographic or clinical outcomes were
included. Data collected from each study included: the number and
type of reconstructions, the pathological diagnosis of the lesions,
the mean age and follow-up, gender distribution, implant survivorship, complications,
functional outcome, and mortality. The results from individual studies
were combined for the general analysis, and then grouped according
to the type of reconstruction. Aims
Patients and Methods
Conventional cemented acetabular components are
reported to have a high rate of failure when implanted into previously
irradiated bone. We recommend the use of a cemented reconstruction
with the addition of an acetabular reinforcement cross to improve
fixation. We reviewed a cohort of 45 patients (49 hips) who had undergone
irradiation of the pelvis and a cemented total hip arthroplasty
(THA) with an acetabular reinforcement cross. All hips had received
a minimum dose of 30 Gray (Gy) to treat a primary nearby tumour
or metastasis. The median dose of radiation was 50 Gy (Q1 to Q3:
45 to 60; mean: 49.57, 32 to 72). The mean follow-up after THA was 51 months (17 to 137). The cumulative
probability of revision of the acetabular component for a mechanical
reason was 0% (0 to 0%) at 24 months, 2.9% (0.2 to 13.3%) at 60
months and 2.9% (0.2% to 13.3%) at 120 months, respectively. One
hip was revised for mechanical failure and three for infection. Cemented acetabular components with a reinforcement cross provide
good medium-term fixation after pelvic irradiation. These patients
are at a higher risk of developing infection of their THA. Cite this article:
Metal-on-metal hip bearings are being implanted into younger patients. The consequence of elevated levels of potentially carcinogenic metal ions is therefore a cause for concern. We have determined the levels of cobalt (Co), chromium (Cr), titanium (Ti) and vanadium (Va) in the urine and whole blood of patients who had had metal-on-metal and metal-on-polyethylene articulations We found significantly elevated levels of whole blood Ti, Va and urinary Cr in all arthroplasty groups. The whole blood and urine levels of Co were grossly elevated, by a factor of 50 and 300 times respectively in patients with loose metal-on-metal articulations when compared with the control group. Stable metal-on-metal articulations showed much lower levels. Elevated levels of whole blood or urinary Co may be useful in identifying metal-on-metal articulations which are loose.
