Partial or total replacement of a unicompartmental knee prosthesis by another unicompartmental knee prosthesis: a reasonable option? About 22 cases.

Twenty-two patients who received primary unicompartmental knee arthroplasties (21 medial and 1 lateral) were reoperated between 2001 and 2010 for partial or total replacement of their implant without using a TKA. Of the 21 patients (1 bilateral) reoperated for PE insert wear (11), PE fracture (3), infection (2), and loosening or malposition (6), 3 patients died and 2 were lost to follow up. The remaining 17 cases had their clinical scores significantly improved. Only one re-revision occurred and consisted of a simple change of PE insert at 9 years, on a very heavy and very active patient. It therefore seems possible and reasonable for now to continue partial or total replacement of unicompartmental knee arthroplasty by another unicompartmental knee arthroplasty without using a TKA.

[Joint prosthesis infection with Staphyococcus lugdunensis: 7 cases]. / Infections à Staphylocoque lugdunensis sur prothèses articulaires: à propos de 7 cas.

Staphylococcus lugdunensis was described in Lyon in 1988. This coagulase-negative staphylococcus is the cause of diverse infections which are often severe, particularly in the field cardiology where numerous publications are available for reference. The severity of S. lugdunensis infection is related to specific virulence factors associated with significant adherence properties despite good sensitivity to antibiotics. Publications dealing with joint prosthesis infections are sparse and the reports available have noted failure of treatment unless the prosthesis is removed. S. lugdunensis can easily be identified with an Api Id 32 Staph battery from BioMerieux. We analyzed seven cases of joint prosthesis infections with S. lugdunensis observed between 1991 and 2005. Four chronic infections were managed using the classical schema of implant removal then reimplantation, using a two-stage procedure for three and a single stage for one. Combined with adequate antibiotic treatment, this method was successful in all four cases. We did however have three cases of failure (two were secondary to a probable hematogenic infection and the other an early postoperative infection); these cases were operated on by early lavage and antibiotic therapy without success.

[Intra-prosthetic dislocation of the Bousquet dual mobility socket]. / Luxation intra-prothétique dans la cupule à double mobilité de Bousquet. A propos de 7 cas.

PURPOSE OF THE STUDY: The Bousquet system is a dual mobility head-polyethylene polyethylene-metal cup socket. The polyethylene insert retaining the femoral head moves in the noncemented metal cup, increasing both mobility and stability. MATERIAL AND METHOD: Between 1989 and 1997, seven cases of intra-prosthetic dislocation (six patients) were observed. The femoral head escaped from the polyethylene insert due to wear. On the average, this complication occurred ten Years after implantation. Risk of dislocation was high in six of the seven hips. All patients had a large sized stem screwed into the femoral neck. There was a characteristic radiological aspect with loss of the concentric head metal cup configuration. The head was applied against the upper wall of the metal cup. RESULTS: Surgical replacement was undertaken early in six patients by simply changing the insert without modifying the other stable components. Outcome remained good at three to eight Years. One patient underwent late surgery. The insert and the cup were replaced with a classical implant. Functional outcome was good but recurrent dislocation occurred. DISCUSSION: At mid-term, intra-prosthetic dislocation of dual mobility sockets appears to be exceptional. Dislocation results from polyethylene wear leading to failure of the insert to retain the prosthetic head. Wear is favored by direct phenomena (direct contact between neck and insert which can occur early if there is a small difference in the head and neck diameters) or indirect phenomena (factors limiting polyethylene metal-cup mobility). Surgical treatment is necessary. If undertaken early, replacement with a modular head and insert can be sufficient if the prosthesis has not loosened but the metal cup may have to be replaced in the event of metal-metal contact between the head and the cup. Prosthesis loosening, wear of the metal cup, or an identified cause of dislocation imply replacing the failing implants. Implantation of the dual mobility system is particularly interesting for patients with a high risk of dislocation or a chronically unstable hip prosthesis. Careful technique is required to reduce or retard the risk of intra-prosthetic dislocation. CONCLUSION: Intra-prosthetic dislocation of a dual mobility socket is an exceptional complication at mid-term. Surgical treatment is required but may be limited to simple insert replacement. Systematic use of this type of implant in young subjects must be carefully examined, but for us, the risk of dislocation does not outweigh the advantages of this original concept of dual mobility. This type of socket remains an useful preventive technique for high-risk hips or for curative treatment of recurrent dislocation.

[Ten-year surveillance of nosocomial surgical site infections in an orthopedic surgery department]. / Bilan de 10 ans de surveillance du taux d'infections du site opératoire dans un service d'orthopédie.

PURPOSE OF THE STUDY: Surveillance of nosocomial surgical site infections was instituted in our department in June 1991. We report our first nine years experience. MATERIAL AND METHODS: This study concerned the first 9 years (June 1991-June 2000) of a surveillance program designed to monitor nosocomial surgical site infections in our orthopedic surgery department. During this period 9,696 patients underwent surgery, including 2745 for hip replacements and 1016 for knee replacements. The diagnosis of infection was based on the Centers of Disease Control criteria. Beginning in 1997, the program was widened to include all indications for prophylactic antibiotics, being limited before that time to indications for arthroplasty and spinal surgery. RESULTS: The overall rate of infection was 1.25%; 0.55% for hip arthroplasty and 1.77% for knee arthroplasty. The rate of infection among hip surgery patients over the last 5 years was much higher for prosthesis revision (2.37%) than for first-intention implantations (0.16%). The majority of the isolated strains were Gram-positive (84%) including Staphylococcus sp. found in 65% of the cases. Multiple-strains were found in 23% of the infections. The rate of infection improved very significantly over the last five years both for knee arthroplasty and spinal surgery. The rate remained unchanged for hip arthroplasty. DISCUSSION: This 10-year survey enabled us to analyze the difficulties encountered and pinpoint errors or insufficiencies in data recording. We were also able to identify measures to be taken concerning patient follow-up. The improvement in the rate of infection over time appears to be multifactorial, undoubtedly related to wider use of prophylactic antibiotics, progress in hygiene and sterilization methods with institution of a quality assurance program, and team awareness. CONCLUSION: Surveillance of nosocomial infections is a recommended practice. We have found that the information provided can be beneficial if the data is statistically sound, pointing out the need for progress in patient follow-up.

[Progressive limb lengthening with a centromedullary nail versus an external fixator: experimental study in sheep]. / L'allongement progressif des membres par clou mécanique centro-médullaire d'allongement: étude expérimentale chez le mouton.

PURPOSE OF THE STUDY: Progressive limb lengthening with an external fixator often leads to pin-related complications. A new technique allowing progressive lengthening with a centromedullary nail without external fixation has been developed. This original double-locked device consists of matching male and female components fitted with a continuous thread. Lengthening is achieved via a one-way ratchet system. Twelve back-and-forth movements produce 1.25 mm lengthening. MATERIAL AND METHODS: We tested this new device on 20 sheep and compared results with external fixation lengthening in 20 other sheep. The animals were divided into groups for sacrifice on days 5, 10, 20, 45 and 90. Serial x-ray were obtained for all animals. In the 45-day and 90-day groups, histomorphometric (trichrome goldner coloration and polarized light microscopy) and densitometric studies were also performed. Bone mineral density (BMD) was determined and bone trabecular density (BTD) and trabecular bone volume (TBV) were expressed in percent of bone trabecular surface area. RESULTS: Mean lengthening in the 45-day and 90-day groups was 39 mm for the nail and 20 mm for external fixation (1 mm/day). At 90 days, 3 sheep out of 4 had consolidated radiologically with external fixation and 2 out of 4 with the nail. BMD was slightly better for external fixation (0.811 vs 0.695/cm(2)). This difference could probably be attributed to the greater lengthening obtained with the nail. At 45 days, BMD was the same (0.6 g/cm(2)) for both devices. BTD was nearly two-fold higher for the nail compared with external fixation (59.65% vs 32.61% at 90 days), most probably due to primary bone formation. The histomorphometric study allowed an analysis of the osteoid border. Bone quality obtained in the bone regenerate with the nail was superior to that obtained with external fixation. Primary bone formation resulted from membrane ossification with direct transformation of fibroblasts into osteoblasts. CONCLUSION: This work demonstrated that progressive lengthening can be achieved with a specifically designed centromedullary nail without iterative opening of the operative site. Tolerance to this type of device and quality of the bone regenerate are altogether satisfactory.

[Traction-mobilization in 2-stage treatment of infected total knee prosthesis. Apropos of 12 cases]. / Traction-mobilisation dans les changements en deux temps des prothèses totales de genou infectées. A propos de 12 cas.

INTRODUCTION: A two stages reimplantation is advised by most authors in salvage of infected total knee arthroplasty. This treatment is more difficult, but seems more successful in controlling infection. It set the problem of the attitude between the two operative stages: an antibiotic cement spacer is usually used, but articular mobilization is not possible, except with an articulating spacer. MATERIAL AND METHODS: Since 1989, we use traction-mobilisation between the two operative stages, with mobilization under traction up to 50 degrees, and on edge of bed up to 70-90 degrees, till the reimplantation. We used this method on 12 cases of chronic infection in total knee arthroplasty. The reimplantation was done 34 to 47 days later. The reimplantation was more easy and more comfortable in approach and exposition, and post operative mobilisation easier. RESULTS: We did not have any recurrence of infection in this patients, but the follow up is too short for some of them. One prosthesis was removed for mechanical failure. The mean range of motion is 86 degrees at two months, 96 degrees at one year. DISCUSSION: The antibiotic cement spacer presents the disadvantage of leaving material in a potentially infected environment. It does not allow mobilisation, except using an articulating spacer. Traction-mobilisation keep articular flexion, allows mobilization, and does not leave any material in articulation. But this method has the disadvantage of requiring an hospital care between the two stages: that is reasonable if the delay is short. CONCLUSION: Traction mobilization seems to be an alternative to cement spacer. It makes the reimplantation easier, facilitates post operative recovery of mobility, and does not seem to increase recurrence of infection.

[Revision of infected total hip prostheses by ablation reimplantation of an uncemented prosthesis. 57 case reports]. / Reprise des prothèses totales de hanche infectées par ablation réimplantation d'une prothèse sans ciment. Expérience de 57 cas.

PURPOSE OF THE STUDY: 57 cases of infected total hip prosthesis treated by removal of the implant and implantation of unncemented prosthesis, were studied to evaluate functional and sepsis results. MATERIAL AND METHODS: 57 patients treated by reimplantation of an uncemented total hip prosthesis after removal of the infected prosthesis were observed. 16 patients underwent a single-stage exchange, 41 a two-stage reimplantation. 46 cases were analysed for infection findings (clinical, radiological and biological assessment) and only 34 cases for functional evaluation (PMA scale, Harris score) with a mean follow-up of 6.6 years. The antibiotic therapy was adapted to each patient but generally, the treatment was prolonged. RESULTS: At follow-up time (which might be too short in time), only 2 patients had a recurrence of infection. One had a single-stage exchange (reoperated by two stage exchange with a good final result at 6 years follow-up), the other a two-stage exchange. In both cases we found that postoperative antibiotic therapy was inadequate. Functional results were better with PMA scale (23 good results of 34) than with Harris score (14 excellent or good results only). 5 patients were reoperated for mechanical implant failure. DISCUSSION: Since 1991, we adopted a standardized procedure to treat chronic infected total hip prosthesis including: routine preoperative aspiration of symptomatic prosthesis; removal of the implant and around debridement followed at a later date (6 weeks) by reimplantation using uncemented implants (hydroxyapatite coated implant). Postoperative antibiotic therapy has to be massive (parenteral bitherapy for at least 21 days after each operative stage) and has to last 6 months after reimplantation. This procedure seems reliable and corroborate the validity of two-stage treatment. The using of uncemented implants allows a good bone reconstruction and does not seem to increase the risk of septic recurrence. CONCLUSION: It is quite difficult to find a hard and fast rule in infected prosthesis treatment, because many factors can influence results. The proposed procedure seems reliable, even if antibiotherapy is long and hard, but requires a strong collaboration between bacteriologist infectiologist and surgeon.

[Troublesome radiologic changes after reconstructive fixation of the anterior cruciate ligament with resorbable interference screws]. / Evolution radiologique inquiétante après fixation des plasties de ligament croisé antérieur par vis d'interférence résorbables.

The authors report worrisome radiological changes which were noted after implantation of absorbable interference screws in ligamentoplasty at the knee joint. Seventeen screws were implanted between September 1995 and July 1996, in eleven patients (average age 27) who were operated upon for chronic anterior knee instability. They underwent a modified Kenneth Jones procedure using autografts with absorbable interference screws (Acufex in 2 cases and Bio-interférix in 9 cases). Significant enlargement of bone tunnels and bony sclerosis of their edges were noted in every patient, but without any modification in the positioning of the graft. No clinical instability was observed in any of the patients, with one to two years follow-up. Publications on this topic are scarce except for one author who reported enlargement of bone tunnels after using bone-patellar tendon-bone allografts. Resorption of absorbable screws probably induces a marked inflammatory reaction, with radiological changes reminiscent of those sometimes observed after tendon allografts. Although the radiological changes reported here may not affect the graft fixation, the authors have reverted to using metallic interference screws.

[Results of posterior lumbar intersomatic fusion in the treatment of isthmic spondylolisthesis. Apropos of 27 cases followed over more than 10 years]. / Résultats de l'arthrodèse lombaire intersomatique par voie postérieure dans le traitement du spondylolisthésis isthmique. A propos de 27 cas revus avec un recul de plus de 10 ans.

PURPOSE OF THE STUDY: Posterior lumbar interbody fusion (PLIF) as described by Cloward, with laminectomy of the entire separate neural arch in spondylolisthesis, is a difficult operation. The purpose of this study is to evaluate the results of PLIF with autologous bony graft, without reduction or instrumentation in grade I and II spondylolisthesis. MATERIAL: The authors report the results of a series of 36 cases of spondylolisthesis (out of a series of 160 cases) operated on with PLIF, after a minimum of 10 years of follow-up (mean: 11.8 years, 10-16 years). 9 patients were lost for follow-up, 27 had been examined clinically and radiologically. 19 males and 8 females. Mean age 29.6 years (14 to 50). The series consisted in 24 lumbo-sacral disc and 3 L4-L5 disc fusion. Before operation, 25 patients suffered backache and 20 had sciatic. Mean preoperative listhesis according to Boxall was 29 per cent. METHODS: PLIF had been done with autologous bony graft and neural decompression without reduction. The thickness of the space had been restored with special progressive distractor. Postoperative back cast was used during 6 months. RESULTS: Postoperative nerve roots complications occurred in 4 cases and were regressive within 3 months. Results were excellent in 17 cases, good in 7 cases and poor in 3 cases. Patients returned to work after 9.8 months (13.6 months for heavy work). 26 patients had solid tomographic interbody fusions. No additional subluxation was noted. In 10 per cent of the cases the graft was partially crammed. In 7 cases a degenerative aspect of the upper disc was noted (symptomatic in 6 cases). The sagittal balance of the spine evaluated with a specific index showed persistent abnormality in 50 per cent of the cases but PLIF brought a significant improvement in 26 per cent. DISCUSSION: The rate of fusion is better than in series using bony allografts and better than in series using anterior interbody fusion. The analysis of the adjacent discs shows that it is not necessary to extend fusion to the upper disc. Instrumentation had not been used in this series but a cast seems to be indispensable. Instrumentation with plates and pedicular screws should be able to give more stability but is often responsible of iatrogenic lesions at the articular facets. CONCLUSION: This study confirms the good results obtained by PLIF with nerve roots decompression in spondylolisthesis. Fusion is stable and does not accelerate degenerative lesion of the upper disc.

[Treatment of osteoid osteoma by CT-controlled percutaneous drill resection. Apropos of 27 cases]. / Traitement de l'ostéome ostéoïde par forage résection percutané sous contrôle tomodensitométrique (F.R.O.P.). A propos de 27 cas.

PURPOSE OF THE STUDY: Osteoid osteoma is a benign tumor requiring excision due to pain, usually severe and invalidating. Surgical "en bloc" resection is not always easy. Complete resection of the nidus is required to prevent recurrence while at the same time a limited resection should also be used to avoid a pathological fracture or a growth plate injury in children. In order to achieve these 2 goals, we have developed an alternative method: CT guided drill resection. This method is reported with special reference to its technical aspects. MATERIAL AND METHODS: Twenty seven patients (16 children and 11 young adults) were treated during a seven year period (June 87 through June 94) and observed clinically and radiologically with an average two-year follow-up (range one to three years). Osteoid osteoma was localized mainly in the lower limb: Femoral neck (or head): 10 cases, 3 in the acetabulum; Femoral shaft: 6 cases; Tibial shaft: 4 cases. Diagnosis was based on clinical features and imaging: radioisotope bone scan and computed tomography in all cases--angiography in 3 patients to assess the diagnosis more accurately. The procedure was performed under general anesthesia (a short hospitalization is needed). The nidus was first localized by Computed Tomography, then approached and resected through a small percutaneous incision. A special device has been manufactured in order to remove a bone cylinder containing the nidus. It was thus possible to perform histological studies of the specimen and confirm the diagnosis. Histological confirmation was possible in 50 per cent of the cases. No complication (except a case of transient extensor hallucis palsy) was observed in this series, 24 patients healed completely; pain disappeared immediately, and the control CT scan returned to normal after a one-year follow-up. In 3 patients, because of a technical error, the nidus was not totally removed. These patients underwent a second procedure, which was effective. DISCUSSION: This method is a good alternative to the direct surgical approach because of its technical advantages: precision in nidus localization and minimal bone resection; consequently, one should underline the practical benefits for the patient: short hospitalization, immediate full weight bearing, quick return to socio-economic activities. Furthermore, some localizations of the nidus which are difficult to reach (for instance the acetabulum) represent a good indication for the method. Accurate pre-operative diagnosis has now become possible with recent advances in imaging techniques but still remains "uncertain". The resection of the specimen allows confirmation of the diagnosis is most of cases. This procedure should ideally be performed by a team (orthopedic surgeon and a radiologist): collaboration instead of competition is in fact the best way to progress in this field of "interventionnal radiology".

[Neurological complications of surgery for spinal deformities]. / Les complications neurologiques de la chirurgie des déformations du rachis.

The aim of this study was to precisely analyse the physio-pathogenic mechanisms, bring to light the risk factors, and find a more practical way of proceeding in spinal surgery. Out of 667 spinal instrumentation surgical operations carried out between 1980-1989, we found 33 (4.8 per cent) neurological complications and have divided them into 2 groups: 7 peripheral complications, 26 cord and central complications. After further analysis, especially of the cord complications (2.5 per cent), we were able to pick out the factors which influence the rate of neurological complications and their evolution: secondary aetiology and the kyphotic composition of spinal deformation, and above all the notion of cord at risk. The delay of cord complications and especially the relation between the severity of the neurological syndrome and its evolution is extremely important. Somesthesic evoked potential monitoring confirmed that per operative diagnosis of a cord injury is possible. The steps to take when confronted with neurological complications, depend on the results of many examinations: pre and post-operative neurological evaluations electrophysiological exploration of the cord and neuro radiological explorations (myelography, scanner and IRM). This helps to complete aetiology and eliminate mechanical causes, which are the only positive indications of iterative surgery. The problems of instrumentation removal in emergency and the legal-medical aspect brought on by this type of complication are discussed.