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author:("magaud, Henri")
1.  Metal-on-Metal Bearing: Is This the End of the Line? We Do Not Think So 
HSS Journal  2012;8(3):262-269.
Background:
Recent studies have recommended the discontinuation of metal-on-metal (MoM) components in total hip arthroplasty (THA) because of adverse effects reported with large-diameter MoM THA. This is despite favorable long-term results observed with 28 and 32 mm MoM bearings.
Questions/purposes:
The aim of this study was to assess the value of calls for an end to MoM bearings as THA components. Specifically, we wish to address the risks associated with MoM bearings including adverse soft tissue reactions, metal ion release, and carcinogenic risk.
Methods:
The study evaluates the arguments in the literature reporting on MoM (adverse soft tissue reactions, metal ion release, and carcinogenic risk) and the experience of the current authors who re-introduced these bearings in 1995. They are balanced by a benefit–risk review of the literature and the authors’ experience with MoM use.
Results:
Adverse reactions to metallic debris as well as metal ion release are predictable and can be prevented by adequate design (arc of coverage, clearance), metallurgy (forged instead of cast alloy, high-carbide content), and appropriate component orientation. There is no scientific evidence that carcinogenicity is increased in subjects with MoM hip prostheses. MoM articulations appear to be attractive allowing safe hip resurfacing, decreasing the risk of THA revision in active patients, and providing secure THA fixation with cement in cages in severely deformed hips. MoM bearings in women of child-bearing age are controversial, but long-term data on metallic devices in adolescents undergoing spinal surgery seem reassuring.
Discussion:
Adequate selection of MoM articulations ensures their safe use. These articulations are sensitive to orientation. Fifteen years of safe experience with 28- and 32-mm bearings of forged alloy and high-carbide content is the main reason for retaining them in primary and revision THA.
doi:10.1007/s11420-012-9300-1
PMCID: PMC3470659  PMID: 24082870
metal-on-metal bearing; metal sensitivity; chromium; wear; cobalt, ions; hip resurfacing; pseudotumors
2.  Hip resurfacing in patients under thirty years old: an attractive option for young and active patients 
International Orthopaedics  2012;36(9):1789-1794.
Purpose
Metal-on-metal hip resurfacing is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. The concept of hip resurfacing is considered very attractive for this specific population (hard-on-hard bearing component with a large femoral head limiting the risk of dislocation, and allowing femoral bone stock preservation).
Methods
A prospective clinical trial was designed to investigate the outcome of hip resurfacing in young patients (under 30 years old). We studied 24 hips in 22 patients. Mean age at operation was 24.9 years (range 17.1–29.9). No patient was lost to follow-up.
Results
There was no revision at average follow-up of 50.6 months (44–59). Mean UCLA activity score improved from 5.5 (1–9) pre-operatively to 7.6 (1–10) postoperatively (p < 0.001). Mean Harris hip score increased from 43.9 (19–67) to 89.3 (55–100) (p < 0.001). Radiological analysis discerned no osteolysis and no implant migration.
Conclusion
The absence of short-term complications, such as mechanical failure or dislocation, is encouraging and leads us to think that mid-term results will be satisfactory. Moreover, the specific advantages of hip resurfacing (bone stock preservation, excellent stability, low risk of dislocation, large-diameter head) make the procedure a very attractive option for young subjects.
doi:10.1007/s00264-012-1555-0
PMCID: PMC3427443  PMID: 22576079
3.  Recurrence of Dislocation Following Total Hip Arthroplasty Revision Using Dual Mobility Cups Was Rare in 180 Hips Followed Over 7 Years 
HSS Journal  2012;8(3):251-256.
Background
Dual mobility (DM) cups of mobile polyethylene were introduced to prevent total hip arthroplasty (THA) dislocation, but no large series with this design to treat recurrent instability have been reported.
Purpose
Our retrospective investigation ascertained the efficiency of DM cups in correction of recurrent dislocation and assessed any adverse effects.
Methods
One hundred eighty THAs with recurrent instability were revised to DM cups in 180 patients (mean age, 67.4 ± 11.7 years; range, 19 to 92 years). Thirty-one patients (17.2%) underwent at least one earlier THA revision, and 15 (10.3%) incurred non-union of the greater trochanter. Of the initial group in 2009, 145 patients had completed evaluations which included assessment of the Harris Hip Score and a radiographic assessment at a mean follow-up of 7.7 ± 2.2 years (range, 4 to 14 years). The rate of survival was calculated considering any reason for revision as failure.
Results
At follow-up, Harris hip score was 83.9 ± 16.1 (range, 21 to 100). Dislocation of the large articulation occurred in seven hips (4.8%), and only two recurred (1.4%) (one requiring additional revision). In addition, two intra-prosthetic dislocations of the small articulation (1.4%) were observed and needed revision surgery. The large number of earlier surgeries and non-union of the greater trochanter were related to recurrent instability. Two cups (1.4%) showed signs of definite loosening; six (4.1%) presented signs of possible loosening. Twenty-nine hips manifested femoral or acetabular osteolysis (20%), but only three were severe. Eight-year survival rate considering revision for any reason was 92.6% (95% CI, 85.5–96.4%).
Conclusions
This series indicates that DM cups are a viable option to treat recurrent THA instability. Their design provides a low risk of recurrent instability without increasing mechanical complications.
doi:10.1007/s11420-012-9301-0
PMCID: PMC3470678  PMID: 23144637
hip arthroplasty; instability; dual mobility; revision; bearing; wear; polyethylene
4.  Risk Factors for Revision of Hip Arthroplasties in Patients Younger Than 30 Years 
Background
Numerous reports of THAs in patients younger than 30 years indicate a high risk of revision. Although risk factors for revision have been reported for older patients, it is unclear whether these risk factors are the same as those for patients younger than 30 years.
Questions/purposes
We therefore (1) determined function and survivorship of revision THAs performed in patients younger than 30 years, and (2) assessed the risk factors for revision THAs in this younger population by comparison with a group of patients younger than 30 years who did not undergo revision.
Patients and Methods
We retrospectively reviewed the clinical records and radiographs of 55 patients younger than 30 years (average age at revision, 24.3 years; range, 14–30 years) who underwent 77 hip revisions. Revision was performed, on average, 4.6 years (range, 0.4–12 years) after the primary THA. The results for these 55 patients (77 revision THAs) were compared with results for a nonrevised group, including 819 THAs in patients younger than 30 years. Minimum followup of the revision group was 1 year (mean, 6.2 years; range, 1–15 years).
Results
At followup after the revision, the Merle d’Aubigné-Postel score improved from 12.2 to 14.6. The rates of dislocation, neurologic lesions, and fractures were 15%, 7.8%, and 14%, respectively. The 10-year survival rate was 36% (95% confidence interval [CI], 21%–51%). Compared with the nonrevised group, the independent revision risk factors were young age at primary THA (OR 1.14 [1.07–1.19]), high number of previous surgeries (OR 5.41 [2.67–10.98]), and occurrence of at least one dislocation (OR 3.98 [1.74–9.07]). Hard-on-soft bearings had a higher risk (OR 3.42 [1.91–6.1]) of revision compared with hard-on-hard bearings.
Conclusions
Revision THAs are likely in patients younger than 30 years, and the complication rate is high. The survivorship of hip revision in this population is low and alternative solutions should be advocated whenever possible.
Level of Evidence
Level III, therapeutic study, case control study. See the Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-010-1669-x
PMCID: PMC3048251  PMID: 21086195
5.  Distal locking stem for revision femoral loosening and peri-prosthetic fractures 
International Orthopaedics  2010;35(2):275-282.
Revision total hip arthroplasty in the setting of a large proximal femoral deficiency or a peri-prosthetic fracture remains a challenging problem. We describe the development, surgical technique and the use of cementless revision stems with distal inter-locking screws to provide immediate stability of the femoral implant. Results were assessed in a large multicentre French study conducted with the french hip and knee surgery society (SFHG). We retrospectively reviewed 725 revisions using interlocking stems from 14 French orthopaedic departments. Seven different stems were used in this series. In-patient records were retrieved, and in addition to demographic data the indication for revision, the preoperative and postoperative PMA and Harris hip scores were documented. The bone deficiency was classified on the basis of the French National Orthopaedic Meeting (SOFCOT) classification. Intraoperative complications and problems if any were retrieved from operative notes. Clinical status and radiographs at the final follow-up were evaluated, paying special attention to the metaphyseal filling index. Average follow-up was 4.5 years. As for the clinical results, the mean Harris hip score at last follow-up was 81. Therefore, it increased by an average of 31 points. Bone reconstruction was assessed on the cortico-medullary index in the metaphyseal area and at mid-shaft increasing from 36 to 45 and 54 to 63, respectively. Radiologically, 637 implants were stable, and 40 demonstrated subsidence. Forty-eight implants have been revised. We found a significant relation between the metaphyseal filling index, the stability of the stem and the quality of bone reconstruction. Results were analysed with respect to three groups of stems: group 1 was a straight, partially HA-coated implant; group 2 was a curved, fully HA-coated implant; and group 3 was a curved, partially-coated implant. Group 1 showed a significantly higher rate of failure when compared with the others types of implants. Group 2 had better functional results than group 3, which in turn reported better results than group 1. With regard to implant fixation, group 2 had significantly better results. Both groups 2 and 3 induced less thigh pain than group 1. The distal interlocking stem has shown promising results for femoral revisions. The advantages are initial axial and rotational stability and consistent bony in-growth owing to hydroxyapatite coating. Distal locked stems are mainly indicated to treat complex femoral revision with severe bone loss and peri-prosthetic fractures.
doi:10.1007/s00264-010-1182-6
PMCID: PMC3032103  PMID: 21184221
6.  Outcome and Predictors of Treatment Failure in Total Hip/Knee Prosthetic Joint Infections Due to Staphylococcus aureus 
The results of the present study suggest that ASA score ≤ 2 and use of rifampin-combination therapy are two independent factors associated with favorable outcome of patients treated for total hip or knee prosthetic infections due to S. aureus.
Background. Variables associated with the outcome of patients treated for prosthetic joint infections (PJIs) due to Staphylococcus aureus are not well known.
Methods. The medical records of patients treated surgically for total hip or knee prosthesis infection due to S. aureus were reviewed. Remission was defined by the absence of local or systemic signs of implant-related infection assessed during the most recent contact with the patient.
Results. After a mean posttreatment follow-up period of 43.6 ± 32.1 months, 77 (78.6%) of 98 patients were in remission. Retention of the infected implants was not associated with a worse outcome than was their removal. Methicillin-resistant S. aureus (MRSA)–related PJIs were not associated with worse outcome, compared with methicillin-susceptible S. aureus (MSSA)–related PJIs. Pathogens identified during revision for failure exhibited no acquired resistance to antibiotics used as definitive therapy, in particular rifampin. In univariate analysis, parameters that differed between patients whose treatment did or did not fail were: American Society of Anesthesiologists (ASA) score, prescription of adequate empirical postsurgical antibiotic therapy, and use of rifampin combination therapy upon discharge from hospital. In multivariate analysis, ASA score ≤2 (odds ratio [OR], 6.87 [95% confidence interval {CI}, 1.45–32.45]; P = .04) and rifampin-fluoroquinolone combination therapy (OR, 0.40 [95% CI, 0.17–0.97]; P = .01) were 2 independent variables associated with remission.
Conclusions. The results of the present study suggest that the ASA score significantly affects the outcome of patients treated for total hip and knee prosthetic infections due to MSSA or MRSA and that rifampin combination therapy is associated with a better outcome for these patients when compared with other antibiotic regimens.
doi:10.1093/cid/cir402
PMCID: PMC3148259  PMID: 21810745
7.  THA Using Metal-on-Metal Articulation in Active Patients Younger Than 50 Years 
The main concern of patients with longer life expectancies and of patients who are younger and more active is the longevity of their total hip arthroplasty. We retrospectively reviewed 83 cementless total hip arthroplasties in 73 patients implanted with metal-on-metal articulation. All patients were younger than 50 years old (average age, 41 years) at the time of the index procedure, and 80% of the patients had an activity level graded 4 or 5 when measured with the system of Devane et al. A 28-mm Metasul articulation was used with three different cementless titanium acetabular components. At the most recent followup (average, 7.3 years), the average Merle d’Aubigné-Postel score improved from a preoperative 11.1 points to 17.4 points. We observed no radiographic evidence of component loosening. Ten acetabular components had lucency limited to one zone. The 10-year survivorship with the end point of revision (ie, exchange of at least one prosthetic or bearing component) was 100% (95% confidence interval, 90%–100%). Metasul bearings with cementless acetabular components remain promising in this high-risk younger patient population. However, additional followup strategies are recommended to determine any possible long-term deleterious effects associated with the dissemination of metallic ions.
Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-007-0045-y
PMCID: PMC2505155  PMID: 18196415
8.  First Isolation of Clostridium amygdalinum from a Patient with Chronic Osteitis 
Journal of Clinical Microbiology  2006;44(10):3842-3844.
We describe a case of osteitis caused by a new and unusual Clostridium species, Clostridium amygdalinum, an environmental, moderately thermophilic bacterium. This is the first documented report of human infection caused by this organism.
doi:10.1128/JCM.01200-06
PMCID: PMC1594748  PMID: 17021125

Results 1-8 (8)