Henri Migaud

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.

Effectiveness and tolerability of prolonged linezolid treatment for chronic osteomyelitis: a retrospective study.

BACKGROUND Linezolid is an oxazolidinone agent which is apparently well designed for treating chronic osteomyelitis, but data on effectiveness and tolerability as prolonged therapy is currently lacking. OBJECTIVE The purpose of this study was to assess the effectiveness and tolerability of linezolid in the treatment of chronic osteomyelitis. METHODS The charts of hospitalized patients who had been treated with linezolid for >4 weeks because of chronic osteomyelitis and were followed up for > or =12 months after the end of treatment were retrospectively reviewed for clinical outcome and tolerability. Cure was defined as the absence of clinical, biological, or radiological evidence of infection throughout the posttreatment follow-up. Linezolid tolerability was assessed on the basis of hematologic properties during treatment. RESULTS Of the 66 patients included, all were white (mean [SD] age, 67.7 [18.1] years; 41 men and 25 women; mean [SD] weight, 80.7 [18.6] kg). Thirty-seven (56.1%) patients had infection due to implants including 27 prosthetic joints. Pathogens were predominantly methicillin-resistant staphylococci (49/72 strains, 68.1 %). Every patient was administered N linezolid (600 mg BID) treatment for 6 to 8 days as inpatients, and then, as outpatients, they were switched to PO treatment. Fifty (75.8%) patients received a combination of linezolid and other antimicrobial agents, including rifampin (32 [48.5%]). Surgery was performed in 52 (78.8%) patients. The median hospital stay was 14 days (mean [SD], 19 [11.4] days [range, 7-70 days] ). The median duration of treatment was 13 weeks (mean [SD], 14.3 [8.2] weeks [range, 5-36 weeks]). At the end of treatment, 56 (84.8%) patients were cured, and during the post-treatment follow-up (median duration, 15 months [range, 12-36 months]), 4 relapses occurred, resulting in an overall successful cure for 52 (78.8%) patients. Reversible anemia was reported in 21 patients (31.8%), of whom 16 (24.2%) required blood transfusions. Median time from treatment initiation to anemia onset was 7.3 weeks (range, 4-12 weeks). Peripheral neuropathy was reported in 6 (9.1%) patients, of whom 4 remained symptomatic for up to 24 months after linezolid discontinuation. Other reported adverse events included nausea (6 [9.1%]), diarrhea (1 [1.5%]), and headache (2 [3.0%]), although none of these patients discontinued treatment. CONCLUSIONS In this retrospective chart review, treatment with linezolid as monotherapy or in combination with antimicrobials and/or surgery was associated with cure of chronic osteomyelitis in 84.8% of subjects at 12 weeks after the end of treatment and 78.8% at follow-up. Adverse events were reported in 51.5% of subjects, and 34.8% of subjects discontinued the study because of adverse events. The potential for severe complications justifies close monitoring of these patients.

Low Rate of Dislocation of Dual-mobility Cups in Primary Total Hip Arthroplasty

BackgroundDual-mobility (DM) cups were introduced to minimize the risk of THA dislocation. The overall rate of dislocation of DM cups (including both large and small articulations) is controversial and ranges from 0% to 5% in previous studies.Questions/purposesWe therefore recorded (1) the dislocation rate, (2) loosening and osteolysis, and (3) subsequent related revisions with DM cups.MethodsBetween 1998 and 2003, 2480 primary THAs with DM cups were undertaken in 2179 patients. The mean age was 69 years (range, 19–94 years). This group underwent specific clinical and radiographic evaluation at a minimum followup of 0.17 years (mean, 7 years; range, 0.17–11 years) to assess dislocation, reoperation, osteolysis, and cup fixation.ResultsThere were 22 dislocations (0.88%): 15 dislocations of large articulations (0.6%), with two (0.08%) recurring but only one requiring revision (0.04%), and seven intraprosthetic small articulation dislocations (0.28%), all needing revision surgery. At last followup, mean Harris hip score was 91 (range, 60–100); 2439 cups (98%) showed no signs of loosening; and 141 patients (145 hips) had osteolysis (6%). Osteolysis and cup loosening were more frequent in patients younger than 50 years at the time of surgery. The 10-year survivorship considering revision for any reason was 93% (95% CI, 91%–95%).ConclusionsDM cups had a low dislocation rate in primary THA, with a limited frequency of adverse effects. We recommend DM cups to minimize dislocation in populations at high risk for instability, but they should be avoided in younger, active patients at higher risk for osteolysis.Level of EvidenceLevel IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Inter- and intraobserver reproducibility in radiographic diagnosis and classification of femoral trochlear dysplasia

Dejour’s radiographic criteria are commonly used to diagnose and assess femoral trochlear dysplasia in case of patello-femoral instability. The aim of this study was to establish the intra- and interobserver reliability of these radiographic criteria. Sixty-eight lateral knee radiographs were examined independently by 7 observers (2 juniors, 5 seniors) to assess interobserver agreement, and the 2 juniors repeated the observations to test intraobserver agreement. These 68 true lateral views were harvested from clinical records of 64 patients who underwent a trochleoplasty because of patellofemoral instability. To evaluate the agreement on analytic data (morphologic type of trochlea) we used the kappa statistical method, and to evaluate the agreement on numerical data (depth and prominence of the trochlear groove) we used interclass correlation analysis. The “crossing sign” (between the trochear groove and the anterior aspect of both condyles) was reliable since the probability of rating as normal a pathologic trochlea was only 3.1% (0 to 8.8%). In classifying trochlear morphology interobserver agreement was slight (kappa = 0.17) and intraobserver agreement was fair (kappa = 0.3). On the other hand, the measurements of the depth and prominence of the trochlear groove were more reliable since the interclass coefficients between observers were 0.62 and 0.38 respectively. The most frequent interobserver error was related to misdiagnosis of type II. To clarify Dejour’s criteria we propose a diagnosis of type II only when 5 mm or more are measured betweeen the intersections with the medial and lateral femoral condyles. We recommand the use of the prominence of the trochlear groove to evaluate the grade of bony trochlear dysplasia.

Efficacy and tolerance of rifampicin–linezolid compared with rifampicin–cotrimoxazole combinations in prolonged oral therapy for bone and joint infections

Both linezolid and cotrimoxazole are antibiotics that are well suited for oral therapy of bone and joint infections (BJI) caused by otherwise resistant Gram-positive cocci (GPC) (resistance to fluoroquinolones, maccolides, betalactamines). However, in this context, no data are currently available regarding the safety and tolerance of these antibiotics in combination with rifampicin. The objective of this study was to compare the efficacy and safety of a combination of rifampicin and linezolid (RLC) with those of a combination of rifampicin and cotrimoxazole (RCC) in the treatment of BJI. Between February 2002 and December 2006, 56 adult patients (RLC, n = 28; RCC, n = 28), including 36 with infected orthopaedic devices (RLC, n = 18; RCC, n = 18) and 20 with chronic osteomyelitis (RLC, n = 10; RCC, n = 10), were found to be eligible for inclusion in this study. Patients who discontinued antibiotic therapy within 4 weeks of commencing treatment were considered to represent cases of treatment failure and were excluded. Rates of occurrence of adverse effects were similar in the two groups, at 42.9% in the RLC group and 46.4% in the RCC group (p = 1.00), and led to treatment discontinuation in four (14.3%) RLC and six (21.4%) RCC patients. Cure rates were found to be similar in the two groups (RLC, 89.3%, RCC, 78.6%; p = 0.47). Prolonged oral RLC and RCC therapy were found to be equally effective in treating patients with BJI caused by resistant GPC, including patients with infected orthopaedic devices. However, the lower cost of cotrimoxazole compared with linezolid renders RCC an attractive treatment alternative to RLC. Further larger clinical studies are warranted to confirm these preliminary results.

Long-term Survivorship of Hip Shelf Arthroplasty and Chiari Osteotomy in Adults

The current authors retrospectively assessed 56 hip shelf arthroplasties (48 patients) with a mean followup of 17 years (range, 15–30 years) and 89 Chiari osteotomies (82 patients) with a mean followup of 13 years (range, 6–25 years) done in adults with painful hip dysplasia. Preoperative joint space narrowing was observed in 32 of 56 shelf arthroplasties and in 67 of 89 Chiari osteotomies. Survival rates, using hip replacement as the end point, were 37′ (20′ to 54′) at 20 years for shelf arthroplasty and 68′ (54′ to 81′) at 18 years for Chiari osteotomy. The severity of preoperative arthrosis was the main factor that impaired the survivorship of shelf arthroplasty and Chiari osteotomy. With arthritic changes without joint space narrowing, the 18-year survival rates were 83′ (69′ to 97′) for shelf arthroplasty and 94′ (89′ to 99′) for Chiari osteotomy. Shelf arthroplasty is best indicated for moderate dysplasia (center edge angle >0°) without severe arthrosis. Chiari osteotomy is best suited for severe dysplasia (center edge angle <0°) especially without or with slight arthrosis. Chiari osteotomy also can be a salvage procedure when marked joint space narrowing is present but only if it is related to severe dysplasia (center edge angle <0°).

Positionnement de la cupule d'une prothèse totale de hanche par navigation sans image basée sur la cinématique articulaire : Premiers résultats avec évaluation tomodensitométrique de l'orientation des implants

Resume La plupart des systemes de chirurgie assistee par ordinateur (CAO) pour la pose d’une prothese totale de hanche (PTH) requierent une tomodensitometrie (TDM) prealable ou l’acquisition de multiples reperes osseux sur le bassin. Pour contourner ces difficultes, nous avons mis au point un systeme de CAO sans TDM base sur une approche cinematique de la hanche. Le principe est d’orienter la cupule en fonction du cone de mobilite de la hanche. Dix-huit implantations de PTH primaires ont ete assistees par ce systeme (18 coxarthroses : 3 dysplasies subluxees, 1 CDR). Deux capteurs optoelectroniques etaient fixes en percutane respectivement sur le bassin et le femur distal. L’acetabulum etait prepare a la fraise, puis le femur avec des râpes de taille croissante. La derniere râpe en place dans la diaphyse etait equipee d’une grosse tete de taille adaptee a l’acetabulum fraise. Les amplitudes de mobilite de la hanche etaient enregistrees pour determiner le « cone de mobilite des amplitudes extremes ». Le systeme permettait d’orienter la cupule afin que ce « cone de mobilite extreme » soit completement inclus dans celui de la prothese. Sur les sites d’insertion des capteurs, aucun patient n’a signale de gene et aucun hematome ou fracture n’ont ete constates. L’inegalite de longueur moyenne etait de 5,6 ± 7,5 mm (0 a 25 mm) avant l’intervention, et au recul de 0,6 ± 3 mm (-5 a 10 mm). Apres mesure TDM, l’anteversion de l’implant femoral etait de 18,2 ± 8,5 (0-31), et pour la cupule elle etait de 24,7 ± 8,8 (12-40). La somme des anteversions femorales et acetabulaire etait de 43 ± 13,1 (22-71). L’allongement de la duree operatoire qui etait de 35 a 40 minutes pour les 4 premiers cas a ete progressivement reduit a 15 a 20 minutes pour les 4 derniers cas. Cette methode, qui allonge moderement la duree operatoire, apporte une securite pour le controle de la longueur du membre et du positionnement de la cupule. Surtout l’etude demontre le fait qu’il n’y a pas une position ideale de cupule que l’on applique a tous les patients (la moitie des cas etait en dehors de la zone de securite recommandee par Lewinnek).

Component impingement in total hip arthroplasty: Frequency and risk factors. A continuous retrieval analysis series of 416 cup

INTRODUCTION Impingement is a factor of failure in total hip replacement (THR), causing instability and early wear. Its true frequency is not known; cup-retrieval series reported rates varying from 27 to 84%. HYPOTHESIS The hypothesis was that a large continuous series of THR cup removals would help determine the frequency of component impingement. OBJECTIVES The hypothesis was tested on a continuous retrospective series of cups removed in a single center, with a secondary objective of identifying risk factors. MATERIAL AND METHODS [corrected] Macroscopic examination looked for component impingement signs in 416 cups retrieved by a single operator between 1989 and 2004. Risk factors were investigated by uni- and multivariate analyses in the 311 cases for which there were complete demographic data. In these 311 cases, removal was for aseptic loosening (131 cases), infection (43 cases), instability (56 cases), osteolysis (28 cases) or unexplained pain (48 cases); impingement was explicitly implicated in only five cases (1.6%), always with hard-on-hard bearing components. RESULTS Impingement was found in 214 of the 416 cups (51.4%) and was severe (notch>1mm) in 130 (31.3%). In the subpopulation of 311 cups, impingement was found in 184 cases (59.2%) and was severe in 109 (35%). Neither duration of implant use nor cup diameter or frontal orientation emerged as risk factors. On univariate analysis, impingement was more frequently associated with revision for instability, young patient age at THR, global hip range of motion >200° or use of an extended femoral head flange (or of an elevated antidislocation rim liner), and was more severe in case of head/neck ratio<2. On multivariate analysis, only use of an extended head flange (RR 3.2) and revision for instability (RR 4.2) remained as independent risk factors for impingement. DISCUSSION Component impingement is frequently observed in cups after removal, but is rarely found as a direct indication for revision, except in case of hard-on-hard friction couples (polyethylene being the most impingement-tolerant material). Systematic use of extended head flanges and elevated antidislocation rims is not to be recommended, especially in case of excessive ROM. A good head/neck ratio should be sought, notably by increasing the head diameter in less impingement-tolerant hard-on-hard friction couples. Although not identified as a risk factor in the present study, implant orientation should be checked; computer-assisted surgery can be useful in this regard, for adaptation to the patients individual range-of-motion cone.

Distal locking stem for revision femoral loosening and peri-prosthetic fractures

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.

Improved aero-anaerobe recovery from infected pros- thetic joint samples taken from 72 patients and col- lected intraoperatively in Rosenow's broth

Introduction Recovery of the bacteria responsible for prosthetic joint infections is a major problem, which is due in part to the alteration of their ability to grow by storage during transportation to the laboratory. Methods In this prospective study, we assessed the benefit of inoculating an enriched liquid medium (Rosenows broth) with intraoperative samples from 72 patients with prosthetic joint revision due to infection. We compared the results of culture of specimens collected in a standard receptacle with the results for specimens collected in Rosenows broth. Results and interpretation 144 samples were taken by each of the 2 collection methods for subsequent culture. Concordance between standard and Rosenow samples was observed for 52 of the 58 strains cultured on agar and for 42 of the 97 strains (p < 0.001) which grew only in liquid medium. Infection would not have been diagnosed in 26 patients (almost one-third of all patients) without combining sample collection in Rosenows broth with standard collection. The bacteria that were not recovered from standard samples but which were recovered from those collected in Rosenows broth included not only strict anaerobes, in particular Propionibacterium acnes, but also coagulase-negative staphylococci and streptococci. ▪