Large-head metal-on-metal (MoM) total hip replacements
(THR) have given rise to concern. Comparative studies of small-head
MoM THRs over a longer follow-up period are lacking. Our objective
was to compare the incidence of complications such as infection,
dislocation, revision, adverse local tissue reactions, mortality
and radiological and clinical outcomes in small-head (28 mm) MoM
and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients.
The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were
performed in women, with a mean follow-up of 115 months (18 to 201).
There were 883 MoM and 2458 CoP bearings. Crude incidence rates
(cases/1000 person-years) were: infection 1.3 In conclusion, we found similar results for small-head MoM and
CoP bearings up to ten years post-operatively, but after ten years
MoM THRs had a higher risk of all-cause revision. Furthermore, the
presence of an adverse response to metal debris seen in the small-head
MOM group at revision is a cause for concern. Cite this article:
A recent review of the literature on metal-on-metal total hip arthroplasties (THA) revealed the lack of comparative clinical studies with a sufficient sample size and the inclusion of patient-reported outcomes as well as patient activity levels. We conducted a prospective cohort study including all metal-on-metal and conventional polyethylene (PE)-ceramic THAs with an uncemented cup (Morscher press-fit cup), a 28mm head and operated upon via a lateral approach at our University hospital between 1/1999 and 12/2008. Only THAs for primary osteoarthritis were included. The study population is part of the Geneva Hip Arthroplasty Registry, a prospective cohort followed since 1996. The following outcomes were compared between the two groups (metal-on-metal=group 1 vs. PE-ceramic bearing=group 2): (1) Complication rates with respect to infection, dislocation and revision, (2) Radiographic outcomes (presence of linear or focal femoral osteolysis, loosening), and (3) Clinical outcomes (Harris Hip score increase, SF-12, activity and patient satisfaction evaluation, presence of groin pain). Patients operated between 1/1999 and 12/2004 were evaluated five years postoperatively by an independent assessor. Cox regression analysis was used to compare incidence rates while adjusting for differences in baseline characteristics.Introduction
Methods
Large diameter metal on metal cups have been used in total hip arthroplasty advocating superior results with respect to dislocation rates, range of motion and long term survival. The Durom cup used as part of the Durom hip resurfacing system has been incriminated with poor short term results sometimes correlated to incorrect positioning of either the femoral or acetabular component. Our objective was to evaluate short term results of the Durom cup used in conjunction with standard stems. We prospectively followed all patients with a large diameter metal-on-metal articulation (Durom) and a standard stem operated upon between 9/2004 and 9/2008. Patients were seen at follow-up for a clinical (Harris hip score=HHS, UCLA scale and patient satisfaction), radiographic and questionnaire assessment.Introduction
Methods
We conducted a longitudinal study including patients with the same type of primary hybrid total hip replacement and evaluated patient activity and femoral osteolysis at either five or ten years post-operatively. Activity was measured using the University of California, Los Angeles scale. The primary outcome was the radiological assessment of femoral osteolysis. Secondary outcomes were revision of the femoral component for aseptic loosening and the patients’ quality of life. Of 503 hip replacements in 433 patients with a mean age of 67.7 years (30 to 91), 241 (48%) were seen at five and 262 (52%) at ten years post-operatively. Osteolytic lesions were identified in nine of 166 total hip replacements (5.4%) in patients with low activity, 21 of 279 (7.5%) with moderate activity, and 14 of 58 (24.1%) patients with high activity. The risk of osteolysis increased with participation in a greater number of sporting activities. In multivariate logistic regression adjusting for age, gender, body mass index and the inclination angle of the acetabular component, the adjusted odds ratio for osteolysis comparing high In conclusion, of patients engaged in high activity, 24% had developed femoral osteolysis five to ten years post-operatively.
None of the patients required cup revision for aseptic loosening. Complications included 12 dislocations and 3 deep infections resulting in 2 total revisions. In 3 patients the stem was revised for aseptic loosening at a mean of 63 months. At 10-years the survivorship was 98.6% (95% CI 96.7; 99.4) with endpoint revision for any cause. Mean total wear was 0.89 mm (±0.5). 32 cups (18.8%) with a cup inclination >
45° had a mean wear of 1.06 mm (±0.5), whereas 138 cups (81.2%) with inclination <
45° had a mean wear of 0.86 mm (±0.5), p=0.036. In 16 cases osteolytic defects around the stem were present. The outcome scores at 10 years were: HHS 85.9 (±14.1), WOMAC pain 70.7 (±24.7), WOMAC function 68.8 (±24.5), SF-12 physical score 40.3 (±9.2) and mental score 47.0 (±10.4). Ninety-four percent of the patients were satisfied or very satisfied.
More than a million hip replacements are carried out each year worldwide, and the number of other artificial joints inserted is also rising, so that infections associated with arthroplasties have become more common. However, there is a paucity of literature on infections due to haematogenous seeding following dental procedures. We reviewed the published literature to establish the current knowledge on this problem and to determine the evidence for routine antibiotic prophylaxis prior to a dental procedure. We found that antimicrobial prophylaxis before dental interventions in patients with artificial joints lacks evidence-based information and thus cannot be universally recommended.
We present two patients with swelling of the groin following metal-on-metal total hip replacement without radiological signs of component loosening. MRI in both patients showed a round shaped intrapelvic lesion ventral to the femoral head. During surgery we found cystic structures filled with fluid and necrotic masses. After resection the metal head and insert were changed to a ceramic head and a polyethylene insert. Although two different kinds of CoCrMo alloy were used in the metal-on-metal THR (Sikomet: low carbon content-Metasul: high carbon content) histopathological analysis in both cases showed typical morphological signs of hypersensetively determined inflammation. Despite the distinct soft tissue reaction bony component integration was unaffected. In our opinion open resecion of the cystic lesion and changing of the metal-on-metal articulation is the treatment of choice. As we do not have any reliable testing for clinical use to predict a hypersensitive reaction to metal wear after implantation of metal-on-metal THR this articulation surface should not be used in cases where allergy to metal is suspected.
We have assessed the long-term results after operative and non-operative treatment of undisplaced and displaced calcaneal fractures. At a mean of 6.5 years, we reviewed 70 patients with a calcaneal fracture who were divided into four groups: group 1, 18 patients with undisplaced fractures and a normal Böhler’s angle (BA) who had been treated non-operatively; group 2, 23 with intra-articular fractures and a BA <
10° who had been treated non-operatively; group 3, 13 with intra-articular fractures and a BA >
10° who had been treated surgically; and group 4, 16 with intra-articular fractures and a BA <
10° who had been treated surgically. The results were assessed by a clinical score considering pain, return to work, return to physical activity, change in shoe-wear and the requirement for subtalar arthrodesis. Patients with undisplaced calcaneal fractures had a good outcome. Those with displaced fractures treated surgically who presented at follow-up with a BA >
10° had a satisfactory functional outcome and those with displaced fractures who had non-operative treatment had a poor outcome. The poorest outcome was consistently seen in patients who were treated operatively without restoration of BA. Open reduction and internal fixation of intra-articular calcaneal fractures can only be expected to benefit those patients in whom nearly anatomical reconstruction is obtained.