Chronic infection of unicompartmental knee arthroplasty: one-stage conversion to total knee arthroplasty.

BACKGROUND: The main reasons for revision of unicompartmental knee arthroplasty (UKA) are loosening, wear, extension of osteoarthritis to another compartment, and infection. There have been no studies of the management of infected UKA, whose incidence varies from 0.2% to 1%. Our objective was to describe infection-related and mechanical outcomes of chronic UKA infection managed by one-stage conversion to total knee arthroplasty (TKA). PATIENTS AND METHODS: Consecutive patients with chronic UKA infection managed by one-stage conversion to TKA between January 2003 and December 2010 were included in a retrospective single-center study. All patients also received appropriate dual antibiotic therapy intravenously for 6 weeks then orally for 6 additional weeks. RESULTS: During the study period, among 233 cases of infected knee arthroplasty managed at our center, 9 met the study inclusion criteria. The UKA was medial in 6 patients, lateral in 2, and patellofemoral in 1. Median age was 67 years (range, 36-83 years) and median infection duration was 9months. In 5 patients, previous treatment with synovectomy, joint lavage, and antibiotics had failed. The following bacteria were identified: oxacillin-susceptible Staphylococci, n=6 (S. epidermidis, n=4; S. capitis, n=1; and S. lugdunensis, n=1); nutritionally deficient Streptococcus, n=1; Enterococcus durans, n=1; and Escherichia coli, n=1. Median follow-up was 60 months (range, 36-96 months). No patient experienced recurrent infection or required revision surgery for infection. No medical complications limiting the use of appropriate antibiotic therapy were recorded. The mean preoperative knee and function scores were 60 and 50, respectively; corresponding mean postoperative values were 75 and 65, respectively. DISCUSSION: UKA infection involves both the prosthesis and the native cartilage, neither of which can be treated conservatively in chronic forms. After identification of the causative organism, synovectomy and joint excision followed by same-stage TKA and combined with appropriate antibiotic therapy for 3 months is effective. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Ceramic-on-ceramic total hip arthroplasty: is squeaking related to an inaccurate three-dimensional hip anatomy reconstruction?

Many factors were incriminated in the squeaking generation in ceramic-on-ceramic total hip arthroplasty (THA), including the cup positioning and design. However, the influence of the stem orientation has not been investigated and the true three-dimensional hip anatomy has never been compared to the contralateral healthy hip. Three patients, who underwent unilateral ceramic-on-ceramic THA, complained of squeaking. CT-scans were performed to compare the true three-dimensional hip anatomy to the contralateral healthy hip. All patients presented evidence of posterior neck-rim impingement with a two-fold increase in the global anteversion (above 75°) comparatively to the healthy hip. The excess of anteversion was on the cup side in 2 cases and on the stem side in 1 case. We conclude that squeaking in ceramic-on-ceramic THA could be related to a poor accuracy of 3D hip anatomy reconstruction which generated a posterior impingement and subsequent anterior edge loading because of excessive global anteversion.

Continuous high-dose vancomycin combination therapy for methicillin-resistant staphylococcal prosthetic hip infection: a prospective cohort study.

Few data are available on treatment and outcome of methicillin-resistant (MR) staphylococcal prosthetic joint infections. Vancomycin remains the treatment of choice for these infections, but its efficacy and safety in bone-and-joint infections are insufficiently documented. We conducted a prospective cohort study on 60 patients treated between November 2002 and December 2008 for chronic MR staphylococcal (44 S. epidermidis, nine other coagulase-negative Staphylococcus and seven S. aureus) prosthetic hip infections (PHIs). Twenty-two patients had previously undergone surgery for their PHI and 21 had previously received antibiotics. All patients had surgery (exchange arthroplasty for 58 patients, resection arthroplasty for two) and received an antibiotic regimen combining high-dose continuous intravenous vancomycin infusion (target serum concentration 30-40 mg/L) with another antibiotic for 6 weeks, followed by an additional 6 weeks of oral intake. Two years after surgery, infection was considered cured in 41 (68%) patients and only two relapses occurred after one-stage exchange arthroplasty. Nineteen (32%) patients experienced nephrotoxicity that was generally mild (RIFLE class R for 14 patients, class I for four patients and class F for one patient) and most often reversible. Continuous high-dose intravenous vancomycin combination therapy is an effective, feasible and reasonably safe treatment of chronic MR staphylococcal PHI.

Infected total hip arthroplasty revision: one- or two-stage procedure?

INTRODUCTION: Better outcomes have been reported for two-stage total hip arthroplasty (THA) revision for infection. However, one-stage revision arthroplasty remains an attractive alternative option since it requires only one operation. A decision tree has been developed by the authors in order to determine which type of surgical procedure can be performed safely. The goal of this study was to assess this decision tree for THA replacement in the case of a peri-prosthetic infection. HYPOTHESIS: A one-stage procedure may be as successful as a two-stage procedure provided some criteria are fulfilled. METHODS: A prospective study included 84 patients, all diagnosed with infected THA who had prosthesis replacement. A one-stage exchange was performed in 38 cases and a two-stage procedure in 46 cases. A two-stage procedure was decided in the case of important bone loss or unidentified germ. Postoperatively, patients received intravenous antibiotics (six weeks), then oral antibiotics (six weeks). The main evaluation criterion was the rate of infection eradication at 2 years minimal follow-up since surgery. If new infection was suspected, a hip aspiration was performed to determine whether it was non-eradication (same germ) or a new re-infection (other germ), which was not considered as a failure. RESULTS: The initial infection was cured in 83 out of 84 patients (98.8%), 38 (100%) for the one-stage group and 45 (97.8%) for the two-stage group. Three patients were re-infected with different germs in the two-stage group. Eighty out of 84 (95.2%) patients were infection free, all patients (100%) of the one-stage group and 42 patients (91.3%) of two-stage group. DISCUSSION: If some selection criteria were respected, a high success rate in THA replacement for infection may be achieved with a one-stage procedure. It permits to reduce the costs with no loss of chance for the patients. The decision tree was validated. LEVEL OF EVIDENCE: Level III; prospective case control study.

Total hip arthroplasty dislocation rate following isolated cup revision using Hueter's direct anterior approach on a fracture table.

INTRODUCTION: Instability is a major complication after revision total hip arthroplasty. Studies in the literature have shown that the dislocation rate after primary arthroplasties by anterior approach on a fracture table is satisfactory, but the rate of instability following revision surgery is not known. HYPOTHESIS AND AIMS: We hypothesized that the Hueter direct anterior approach would result in a lower rate of postoperative dislocation following revision surgery. This hypothesis was tested in a series of isolated acetabular component replacements. PATIENTS AND METHODS: Seventy-three consecutive isolated acetabular component replacements were performed between January 2000 and December 2007. Twelve revisions using constrained liners or dual mobility cups were excluded, thus 61 revisions in 59 patients, mean age 65.8-year-old (range 27-86) were included. The indications for revision arthroplasty were: 51 (83.6%) cases of aseptic loosening, five (8.2%) non-integration of cementless cups, three (4.9%) cases of instability, one (1.6%) case of impingement with the psoas and one (1.6%) case of excessive (3cm) lengthening. Acetabular bone defects were moderate, with 12 stage I, 26 stage II, 19 stage III, and only four stage IV defects on the SOFCOT bone stock deficiency score. There was no acetabular reconstruction in 18 cases, while there were four isolated reconstruction cages and 39 cages with a graft. The replacement cup was cemented in 52 cases and cementless in nine. Inclination and anteversion were measured by the Pradhan method on standard X-rays. RESULTS: Results were evaluated after a mean follow-up of 2.4 years±1.7 years (1-7 years). Four dislocations were observed (6.6%) all anterior and early in the postoperative period (less than 2 months): three patients had a single episode of dislocation and one patient again underwent revision cup replacement by Hueter anterior approach for recurrent anterior dislocation. The only factor associated with a risk of dislocation was a high body mass index: 29.7±0.8 in the group with dislocation compared to 25.6±3.2 in the group without (P=0.008). A high number of prior interventions was also a significant risk factor (P=0.045). On the other hand, there was no difference in cup inclination or femoral offset between the group with dislocation and that without. DISCUSSION: Although the rate of dislocation is higher than after primary THA by anterior approach, it remains acceptable for revision THA and is similar to rates observed with other approaches. The literature does not clearly establish that one surgical approach is better than another in terms of instability. This study was limited by the absence of CT-scan measurements of component orientation both preoperatively to evaluate the femoral component which is preserved, as well as during follow-up to evaluate cup angle and compare the groups with and without dislocation. CONCLUSION: The Hueter direct anterior approach is a viable option for isolated cup revision, as long as femoral loosening has been excluded, and the orientation of the preserved femoral component is known. LEVEL OF EVIDENCE: Level IV; retrospective study.

Infected total hip arthroplasty treated by an irrigation-debridement/component retention protocol. A prospective study in a 12-case series with minimum 2 years' follow-up.

INTRODUCTION: Treatment of infection after total hip replacement (THR) is complex and costly. Debridement with component retention is an attractive solution. Success rates in the literature vary widely (18-90%) according to patient selection criteria. The present prospective study assessed the selection criteria used in our department. METHODS: A prospective study included all patients (n=210) surgically managed for infection following THR between November 2002 and December 2008. Patients underwent debridement in case of acute infection: i.e., early postoperative infection within 1 month of THR, or secondary hematogenic infection with less than 2 weeks' evolution. Beyond this deadline or in case of implant loosening, implant replacement was performed. The debridement series thus comprised 12 patients (mean age, 69 ± 11.3 years; mean evolution from contamination was 4.8 ± 3.5 days). Bacteriologically adapted antibiotherapy was administered for 6 weeks intravenously followed by 6 weeks per os. Mean follow-up was 40 ± 23 months. No patient was lost to follow-up. The success criterion was apparent eradication of infection at a minimum 2 years, defined by absence of clinical, biological or radiological signs of infection and of death attributable to infection or treatment. Where infection was suspected, hip aspiration or peroperative sampling determined recurrence (identical bacterium) or reinfection (different bacterium). RESULTS: There were nine cures (75%) and three failures. Mean Postel Merle d'Aubigné Score, at end of follow-up, was 17 ± 2. The three failures involved the same bacteria (two streptococci [one group B, one group G] and one Enterococcus faecalis) as implicated in the primary infection. DISCUSSION: The present results are comparable to those in the literature but poorer than for implant exchange. The technique remains, however, an interesting alternative, allowing less complex surgery and lower cost. CONCLUSION: Patient selection criteria need refining so as to increase success rates with this technique. LEVEL OF EVIDENCE: Level IV; prospective non-randomized non-comparative study.

Arthroplasty following a septic arthritis history: a 53 cases series.

INTRODUCTION: The most feared complication of arthroplasty after septic arthritis (active or quiescent) on a degenerative joint is septic failure, but this risk is difficult to assess. The aim of the present study was to analyze the results of arthroplasties after septic arthritis of native knee and hip joints, in terms of functional results and infection control and to seek eventual risk factors of failure. PATIENTS AND METHODS: Fifty-three cases of septic arthritis treated by arthroplasty (31 knees and 22 hips) were retrospectively included. In case of evolutive septic arthritis (30 cases: 17 knees and 13 hips) failing to react to conservative treatment, arthroplasty was performed in a 2-stage procedure (a mean interval of 6 weeks between stages, and an associated antibiotic therapy for a mean 3 months were routinely respected). In case of previous arthritis considered to be cured (23 cases: 14 knees and nine hips), arthroplasty was performed with a 1-stage procedure, observing a mean interval of 5 years after the initial septic arthritis, and antibiotic therapy maintained until definitive microbiological results were obtained from joint cultures samples at surgery. No patients were lost to follow-up; minimum follow-up was 2 years, for a mean of 5 years. The final results were assessed in terms of functional outcome (on PMA functional score for hips and IKS score for knees) and successful eradication of infection. RESULTS: Two-stage arthroplasty was successful in 26 of the 30 cases of evolutive septic arthritis (87%), while the 1-stage procedure was successful in 22 of the 23 cases of quiescent septic arthritis (95%) (NS). Functional results were very good. No significant difference in functional outcome or successful eradication of infection was found between the 1- and 2-stage procedures. No significant difference in final outcome in terms of infection eradication was found between knees and hips. No clinical, microbiological or treatment-related criteria emerged as risk factors for septic failure. DISCUSSION: Arthroplasty after septic arthritis of the knee or hip using the present protocol (2-stage implantation in case of evolutive septic arthritis and a 1-stage procedure in case of quiescent septic arthritis) achieved very good functional results with a success rate of 87% for sepsis control in evolutive septic arthritis and of 95% in quiescent septic arthritis. LEVEL OF EVIDENCE: Level IV retrospective or historical series.

Total hip arthroplasty revision due to infection: a cost analysis approach.

INTRODUCTION: The treatment of total hip arthroplasty (THA) infections is long and costly. However,the number of studies in the literature analysing the real cost of THA revision in relation to their etiology, including infection, is limited. The aim of this retrospective study was to determine the cost of revision of infected THA and to compare these costs to those of primary THA and revision of non-infected THA. MATERIALS AND METHODS: We performed a retrospective cost analysis for the year 2006 using an identical analytic accounting system in each hospital department (according to internal criteria) based on allotment of direct costs and receipts for each department. From January to December 2006, 424 primary THA, 57 non-infected THA revisions and 40 THA revisions due to infection were performed. The different cost areas of the patient's treatment were identified.This included preoperative medical work-up, medicosurgical management during hospital stay,a second stay in an orthopedic rehabilitation hospital (ORH) and post-hospitalisation antibiotic therapy after revision due to infection, as well as home-based hospitalisation (HH) costs, if this was the selected alternative option. We used the national health insurance fee schedule found in the "Common classification of medical procedures" and the "General nomenclature of professional procedures" applicable in France since September 1, 2005. Hospital costs included direct costs (hospital overhead costs) and indirect costs, (medical, surgical, technical settings and net general service expenses). The calculation of HH costs and ORH costs were based on the average daily charge of these departments. The cost of primary THA was used as the reference.We then compared our surgical costs with those found for the corresponding comparable hospital stay groups (Groupes homogènes de séjour). RESULTS: The average hospital stay (AHS) was 7.5 +/- 1.8 days for primary THA, 8.9 +/- 2.2 days for non-infected revisions and 30.6 +/- 14.9 days for revisions due to infection. The rate of transfer to a rehabilitation hospital (ORH) was 55% for primary THA, 77% in non infected revision cases and 65% in revisions due to infection. Moreover, 30% of these infected THA were prescribed HH. Non-infected THA revisions cost 1.4 times more than primary THA. THA revisions due to infection cost 3.6 times more than primary THA. DISCUSSION: The economic impact of THA infections is considerable. The extra costs are mainly due to an extended hospital stay and to longer rehabilitation consuming significant substantial human and material resources. CONCLUSION: The cost of treating infected THA is high. Treatment strategies should therefore be optimised to increase the success rate and minimise total costs. LEVEL OF EVIDENCE: Level IV. Economic and decision analyses, retrospective study

[Dental care and joint prostheses]. / Soins bucco-dentaires et prothèses articulaires.

PURPOSE OF THE STUDY: Infectious dental foci and oral dental care constitute one of the leading causes of arthroplasty infection after infections involving the skin and the urinary tract. There is however no formal evidence confirming the relationship between oral or dental care and arthroplasty infection. MATERIAL AND METHODS: We reviewed 44 cases of arthroplasty infection secondary to dental infections and searched for data in the literature. In our series, no risk factor could be identified for 24 cases. The median disease-free interval was five years and mean time from the oral-dental procedure to the first signs of prosthesis infection was one month. Tooth extraction was the most common oral-dental procedure involved (n=19). Most of the infections were caused by a single agent, predominantly Streptococci sp. (n=24) and Staphylococci sp. (n=12). DISCUSSION: It is well known that dental-related bacteriemia is a spontaneous daily event even without dental procedures. It is also probable that spontaneous bacteriemia induced by daily activities is much more frequent than dental-care induced bacteriemia. The presence of foreign material diminishes local antibacterial defense systems increasing the risk of hematogeneous contamination of the joint prosthesis after dental care. The oral flora is also modified in immunodepressed subjects, particularly carriage of Staphylococcus aureus in the oral cavity which is significantly more frequent in patients with rheumatoid arthritis. These changes increase the risk of contamination after dental care. For arthroplasty infection, the pathogenic power of Staphylococci sp. is certainly greater than that of Streptococci sp. even if the inoculum is less abundant. Antibiotic prophylaxis during dental care in patients with an arthroplasty remains a controversial subject and the most appropriate antibiotic remains to be defined. Successive episodes of spontaneous bacteriemia arising from an oral-dental foci are probably the main cause of arthroplasty infections, more so than bacteriemia triggered by dental care. CONCLUSION: Antibiotic therapy is not indicated for routine dental care in the majority of patients but is recommended whenever there is a high risk of arthroplasty contamination. In the event of oral-dental infection, antibiotic therapy is necessary. The recommendations proposed by the ADA and the AAOS were revised in 2003. The most important point is to obtain and maintain a good state of oral hygiene. For prevention, awareness of the risk is essential, for the patient, the orthopedic surgeon and the primary care physician alike. Regular dental visits are necessary.

[Infection on continuous bone of lower limb: 127 cases]. / Infection osseuse sur os continu au niveau du membre inférieur: a propos de 127 cas.

PURPOSE OF THE STUDY: Infection on continuous bone is a specific diagnostic and therapeutic entity. Treatment requires debridement of infected and necrotic soft tissue and bone, dead space management, effective antibiotic therapy in the bone and good skin coverage with well-vascularized tissues. Results of treatment of infection on continuous bone of the lower limb are presented in this series. MATERIAL AND METHODS: This retrospective series included 127 cases of osteomyelitis affecting continuous bone of the lower limb (tibia or femur). Septic nonunion and infected arthroplasties were excluded. All patients underwent surgery. The therapeutic protocol was based on debridement, filling of the osteomyelitic cavity as needed (flap, bone grafting, foreign material) and skin cover (by direct closure or flap). Antibiotics were given systematically. Patients were reviewed at minimum two years follow-up. RESULTS: Osteomyelitis was located on the tibia in 66% and was posttraumatic in 75% of cases. Localized osteomyelitis (type III of the Cierny-Mader anatomic classification) was found in 50% of patients. Staphylococcus aureus was the causal agent in 66% of cases. Flaps were performed in more than half of cases and most of them were local flaps. Systematic antibiotic therapy was given for an average three months. With an average four years follow-up, eradication of the infection was obtained in 80% of patients. Ten patients were lost to follow-up. No statistical difference was noted for final outcome according to the physiological hoste class, the anatomic localization (tibia or femur), bacteriological findings, duration of antibiotics, use of flaps, or filling of the osteomyelitic cavity. Treatment of type I and II osteomyelitis was more successful than type III or IV infection (NS). Failure rate increased with the number of previous surgical procedures (p=0.02). DISCUSSION: Infection on continuous bone is a characteristic entity, rarely clearly separated from other bone infections in reported series that combine these infection with septic nonunions and infected arthroplasties. Surgery is essential and is based on quality debridement. The use of flaps (for both dead space management and skin coverage) improves the results for the treatment of such infections but long-term follow-up is needed for a more accurate assessment of success rate.

[Results of reimplantation for infected total knee arthroplasty: 107 cases]. / Résultats des changements de prothèse de genou pour infection: à propos de 107 cas.

PURPOSE OF THE STUDY: The purpose of this study was to assess the results of reimplantations of total knee arthroplasties complicated by infection. Outcome was assessed in terms of eradicated infection and function. MATERIAL AND METHODS: This retrospective multicentric study included 107 cases of infected total knee arthroplasties treated by changing the implants. Seventy-seven patients had a two-stage revision and thirty had a one-stage procedure. Patients were reviewed with a minimal 2-year and an average 52-month follow-up. RESULTS: Revision arthroplasty (one- or two-stage) eradicated infection in two out of three patients. With a two-year follow-up, revision arthroplasty was successful in 77% of patients without any sepsis risk factor, in 65% of patients with one risk factor and in 33% of patients with at least two risk factors. After reimplantation for total knee arthroplasty infection, overall function outcome was good (KS knee score: 74.8 after two-stage revision and 75.5 after one-stage revision, NS). After two-stage procedures, the knee outcome was excellent in one-third of patients, good in another third and fair or poor in the final third. After one-stage reimplantation, 40% of the knees had an excellent outcome, 30% a good outcome and 30% a fair or poor outcome. Regarding functional outcome, overall results were fair (KS function score 62.5 for one-stage and two-stage revisions). Functional outcome was fair or poor in 42% of patients with a two-stage procedure and in 55% of patients with a one-stage revision (NS). DISCUSSION: Our study was unable to disclose any difference between one-stage and two-stage revision for eradicating infection. Unfavorable systemic and local conditions decreased the rate of success after revision total knee arthroplasty for infection. Length of infection before reimplantation, number of surgical procedures and bacterial virulence or resistance were not, in our series, predicting factors for failure of septic revision total knee arthroplasty. No difference was found for the clinical and functional results between one-stage and two-stage procedures. Functional outcome was fair or poor for half of the patients after septic revision total knee arthroplsty. The use of an external device between the two procedures for two-stage revision significantly decreased the functional outcome compared with the use of a spacer. Articulated spacers did not offered any advantage compared with a static spacer for functional outcome.

[Coxitis after surgical excision of intracapsular osteoid osteoma of the femur neck]. / Coxite après exérèse chirurgicale d'un ostéome ostéoïde intracapsulaire du col fémoral.

A case of destructive arthropathy of the hip with onset two years after surgical removal of an intracapsular osteoid osteoma of the femoral neck is reported. Coincidental occurrence in the same joint of an osteoid osteoma and a destructive arthropathy of unknown etiology cannot be ruled out. However, another hypothesis which deserves discussion is that self-perpetuating synovitis was triggered by the release of mediators of inflammation due to presence of the osteoid osteoma.

[Traumatic atlanto-occipital luxation. Value of new radiologic signs (apropos of 2 cases)]. / Luxation traumatique occipito-atloïdienne. Intérêt de nouveaux signes radiologiques (à propos de deux cas).

Two cases atlanto-occipital dislocation with survival are reported. The displacement was anterior. One case was associated only with some pyramidal signs and was diagnosed fourteen months after the injury. The other was associated with immediate tetraplegia. Both cases were treated by occipitocervical fusion with plate fixation. The second case was reduced during operation. A review of the literature has shown that dislocation with anterior displacement is more severe than with posterior displacement. The diagnosis is always difficult. The authors show the importance of certain radiological signs such as the curved anterior line joining the odontoid process to the occiput. The need to reduce the displacement in old lesions is discussed.