Subperitoneal approach in revision arthroplasty for acetabular component protrusion: Analysis of practices within the French Hip and Knee Society (SFHG).

INTRODUCTION: The complications related to revision for acetabular component protrusion with material migrating into the intrapelvic region remain rare but potentially serious. Today, the literature reports no epidemiological data on the subperitoneal approach (SPA) in revision total hip arthroplasty (RTHA) for protrusion. Therefore we conducted a retrospective study on a large revision arthroplasty database to answer the following questions: (1) What is the frequency of this approach in this population? (2) What are the factors related to this procedure? (3) Is morbidity and mortality of the SPA higher than for an isolated conventional approach? HYPOTHESIS: Major protrusions with material in the superomedial quadrant (SMQ) have a higher probability of being operated using a SPA. MATERIAL AND METHODS: This multicenter retrospective study included 260 cases of THA with endopelvic protrusion of material at least 15mm inside the Kohler line. The degree of protrusion was assessed on the AP pelvic X-ray with the construction of the SMQ. The reason for the subperitoneal approach, the duration of surgery, and the preoperative exams were also collected. RESULTS: Nineteen procedures out of the 260 RTHAs included (7.8%) had a SPA in addition to the approach for the revision THA. The frequency of the SPA varied among centers (range: 1.7-50%). In four cases, the SPA was indicted to care for a vascular complication identified preoperatively. For one patient, the SPA was indicated intraoperatively. The other indications were either to extract the implant (n=7) or prevent a potential intraoperative assault of neurovascular structures (n=9). The cases presenting major protrusion on the AP X-ray with material in the SMQ were more often operated through the SPA (12/19; 63.2%) than cases with no SMQ involvement (4/241; 1.7%) (P<0.001). Vascular structures were explored with imaging in 15 out of 19 (88.9%) of the SPA cases versus 26 out of 177 (14.7%) of the revisions without the SPA (41 with no information in the non-SPA group) (P<0.001). Early mortality (before 45 days) of patients who had undergone the SPA (1/19; 5.3%) was not significantly different than for the patients who had not undergone the SPA (3/241; 1.2%) (P=0.26). Although the duration of surgery was longer in the SPA group (210±88 [range: 70-360] versus 169±52 [range: 60-300]; P=0.04), bleeding was not greater in the SPA group (1488±1770mL [range: 500-5000mL]) than in the non-SPA group (1343±987mL [range: 75-3500mL]; p>0.05). DISCUSSION: Despite the limitations related to the retrospective and multicenter design of this study, to our knowledge it is the only one that examines SPA procedures within the context of severe material protrusion with THA. Based on these results, it seems preferable to plan for SPA every time there is an acetabular protrusion in the SMQ, after exploration with CT angiography. The SPA does not result in greater mortality or morbidity. LEVEL OF EVIDENCE: IV, retrospective study.

Femoral revision with a primary cementless stem.

INTRODUCTION: The use of a primary cementless component is a tempting option for revision total hip arthrosplasty (reTHA), however, the results of this type of revision have not been clearly determined. The goal of this retrospective study was to determine: if revision with a primary anatomical cementless femoral stem gives adequate bone fixation; the rate of secondary subsidence or recurrent loosening; the survival rate with this device. HYPOTHESIS: Revision with a primary anatomical cementless femoral stem results in a low rate of subsidence and recurrent loosening. MATERIALS AND METHODS: This retrospective series of 43 reTHA performed between 1994 and 2012 included 43 patients, mean age 66 years old (37-90) with a minimum follow-up of 24months. There were grade 1 (n=24) or 2A (n=19) bone defects according to the Paprosky classification. The causes of revision were: aseptic loosening in 27, septic loosening in 6, malposition of the implant in 7 and periprosthetic fractures in 3. Clinical (Postel Merle d'Aubigné [PMA] and Harris scores), and radiological (subsidence) assessment was performed, as well as survival analysis (with a 95% confidence interval). RESULTS: All components were changed through posterolateral approach without femorotomy. In four cases de-escalation (use of a primary component for secondary revision of a prior revision component) was performed. There were no perioperative fractures or perforations. After a mean 47months (24-134), the mean PMA score increased from 10 (5-15) to 16 (11-18), and the Harris score from 58 (20-80) to 85 (66-96). Radiological assessment did not show any extensive radiolucencies or secondary subsidence. Only 3 components were placed in a varus position, with no clinical consequences. One patient had subsequent revision for recurrent dislocations. Estimated survival at 80months by Kaplan-Meier analysis was 85% (CI 95%: 64-100%). DISCUSSION: There are very few studies in the literature (7 series) on this topic, which shows the reluctance of surgeons to use this technique. Placement of a primary femoral stem requires good metaphyseal bone quality for primary stability. Thus, the indication is limited to Paprosky 1 and 2A stages. Revision surgery must be performed by endofemoral approach requiring good preoperative planning, as well as knowledge of the explanted component and a revision component must be available, if necessary, in the operating room. LEVEL OF EVIDENCE: Retrospective study, level 4.

Outcomes and prognostic factors in revision hip arthroplasty for severe intra-pelvic cup protrusion: 246 cases.

BACKGROUND: The outcome of revision total hip arthroplasty (THA) for intra-pelvic cup protrusion is unclear. Hence, we conducted a large retrospective study to clarify the surgical strategy (hip lever arm and cup mechanical fixation) and the outcomes of reconstruction for severe intra-pelvic cup protrusion. HYPOTHESIS: We hypothesized that restoration of the anatomic hip centre in such acetabular revisions decreased the risk of recurrent loosening. MATERIAL AND METHODS: The study included 246 THA procedures (in 220 patients), with a follow-up of 5.2 ± 4.9 years (1-24.2) after the index surgery. Bone loss was estimated using the SOFCOT classification (grade III or IV in 80% of cases) and the Paprosky classification (IIIA or IIIB in 58% of cases). Quality of the reconstruction was assessed on X-rays according to the correction of the protrusion and position of the hip centre of rotation. RESULTS: After a clinical follow-up of at least 5 years, with a mean of 9.9 ± 4.1 years (5-24 years), the mean Postel-Merle d'Aubigné score was 14.2 ± 3.1 and the mean Harris Hip Score was 78.0 ± 18.7. Cup protrusion was partially or completely corrected in every case and cup position was normal in 27 (11%) cases. The centre of rotation was within 10mm of the physiological position in 158 (64.2%) cases, acceptable in 77 (31.3%) cases, ascended in 9 (3.7%) cases, and worsened in 1 (0.4%) case. Revision for cup or cup and femoral failures was required in 24 (9.8%) cases. Cumulative survival rates with cup loosening as the endpoint were 88.5% after 5 years, 79.9% after 10 years, and 63.9% at last follow-up at 13.6 years. DISCUSSION: Our hypothesis that restoration of anatomic hip centre decreased the risk of recurrent loosening was not verified: success or failure in restoring the normal centre of rotation did not correlate significantly with final cup status. Recurrent aseptic loosening was the cause of failure in 9.8% of cases. Ensuring long-term effective mechanical stability had a greater impact on global outcomes than restoring an ideal centre of rotation.

Prosthetic joint infection: A pluridisciplinary multi-center audit bridging quality of care and outcome.

BACKGROUND: Care to patients with prosthetic joint infections (PJI) is provided after pluridisciplinary collaboration, in particular for complex presentations. Therefore, to carry out an audit in PJI justifies using pluridisciplinary criteria. We report an audit for hip or knee PJI, with emphasis on care homogeneity, length of hospital stay (LOS) and mortality. PATIENTS AND METHODS: Fifteen criteria were chosen for quality of care: 5 diagnostic tools, 5 therapeutic aspects, and 5 pluridisciplinary criteria. Among these, 6 were chosen: surgical bacterial samples, surgical strategy, pluridisciplinary discussion, antibiotic treatment, monitoring of antibiotic toxicity, and prevention of thrombosis. They were scored on a scale to 20 points. We included PJI diagnosed between 2010 and 2012 from 6 different hospitals. PJI were defined as complex in case of severe comorbid conditions or multi-drug resistant bacteria, or the need for more than 1 surgery. RESULTS: Eighty-two PJI were included, 70 of which were complex (85%); the median score was 15, with a significant difference among hospitals: from 9 to 17.5 points, P < 0.001. The median LOS was 17 days, and not related to the criterion score; 16% of the patients required intensive care and 13% died. The cure rate was 41%, lost to follow-up 33%, and therapeutic failure 13%. Cure was associated with a higher score than an unfavorable outcome in the univariate analysis (median [range]): 16 [9-18] vs 13 [4-18], P = 0.002. CONCLUSIONS: Care to patients with PJI was heterogeneous, our quality criteria being correlated to the outcome.

Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties.

INTRODUCTION: Osteotomy of the anterior tibial tubercle (TT) is well known as the approach to difficult knees, in particular those with a low patella, but it has a poor reputation. PATIENTS AND METHODS: This technique was used 21 times in 20 patients (10 males and 10 females) with a mean age of 71 years (range, 42-90 years) for 14 prosthesis revisions (three for septic loosening, 11 for aseptic loosening) and seven knees that had not anteriorly received prior implants (three osteotomies, one synovectomy). The surgical technique included a long (7 cm), thick (>1 cm) fragment retaining its lateral muscle hinge with compression fixation using two screws. In cases with a low patella, the TT was proximally displaced, with amplitude limited by the tibial baseplate. Follow-up was clinical and radiological, lasting a mean 54 months (range, 8-195 months). The clinical results were assessed using the IKS score and the radiological results using the measurement of the patellar index according to the protocol described during the Lyon Knee Days. RESULTS: The mean preoperative IKS scores were: knee, 57.5±22.4; function, 42.6±21.5 (total, 100±33.9); postoperative scores: knee, 84±11.6; function 65±28 (total, 149±32.9). The joint range of motion increased from 73±34.9 to 88±21.1 for a mean gain of 15±23.1. We found a traumatic nondisplaced tibia fracture around a tibial stem, treated conservatively, two stress fractures of the immediate proximal part overhanging the TT with no consequences, one case of stiffness (not related to the osteotomy), and one case of localized skin necrosis on a knee that had undergone several surgeries (secondary scarring). No cases of malunion or migration of the TT were noted. The mean deliberate proximal migration obtained was 13 mm±6 (range, 8-33 mm). The patellar index increased from 0.18±0.20 (range, -0.39 to 0.57) to 0.33±0.19 (range, -0.13 to 0.60). DISCUSSION: This series shows that the indications are rare but invaluable, facilitating the approach and most particularly making it possible to modify the position of the patella, thus contributing to increasing the joint range of motion. Fixation with two screws carries no risk of disassembly if the technique is rigorous. Patellar translation is limited by the tibial tray.

[Femoral neck fractures in patients over 50 years old]. / Les fractures du col du fémur après 50 ans.

INTRODUCTION: Despite many papers and instructional course lectures, therapeutic guidelines are not clearly defined about treatment of femoral neck fractures. The aim of this multicentric French symposium was to prospectively study the results of current therapeutic options in order to propose scientifically proven options. MATERIAL AND METHODS: Three prospective studies were carried out in order to answer to these questions: (1) is it possible with anatomical reduction and stable fixation to lower the non union and osteonecrosis rate? (2) is functional treatment of Garden 1 fractures successful in more than 65 years patients? (3) what criteria are useful to choose the kind of arthroplasty for more than 65 years patients? RESULTS: For the 64 patients between 50 and 65 years old included in the first study, 44 ORIF and 17 prostheses were performed. No open reduction was performed in this series despite a 34% malreduction rate. The risk for displacement after functional treatment of Garden 1 fractures is 31%. For patients over 65 years old, almost fractures are treated in this series by an arthroplasty. The one-year mortality rate after displaced femoral neck fracture was 17%. Functional results were better in total hip prosthesis group than in bipolar or unipolar group. Non cemented stems were not safer than cemented ones in frail patients. DISCUSSION AND CONCLUSIONS: For young patients, ORIF should be the treatment of choice: the initial displacement and its effects on the femoral head vascularisation, the quality of reduction and fixation are the two most significant factors for good outcome. For Garden 1, fractures in patients 65 years old or more, it is proposed to performed an internal fixation despite in two thirds of the cases, it should be unnecessary because non identification of predictive factors of failure. For patients over 65 years old, the type of arthroplasty to perform in displaced fractures is to be chosen according to the preoperative mobility and comorbidities. Because of acetabular erosion with long-term follow-up, it is clearly indicated to perform total hip replacement for patients with life expectancy of 10 years or more. For frail patients, unipolar arthroplasty is the best option. The place for bipolar or uncemented implants is not yet well-defined and more prospective trials are needed. In this multicentric study, results appear quite different in terms of mortality, or functional status. These differences seem to be related to technical choice, geriatric care, nutritional consideration or surgical organisation, all factors that may be of major importance for prognostic.

[Tibial diaphysis fractures below a total knee prosthesis]. / Fractures diaphysaires du tibia sous une prothèse totale du genou.

The fractures of the tibial diaphysis below a total knee prosthesis are a surgical challenge and intra medullary nailing seems impossible. For the SOFCOT 2005 symposium on peri prosthetic fractures we reviewed our files: six cases were found and analysed. These fractures are rare: 5 cases from the symposium (out of 96 periprosthetic fractures at the knee) are reported plus a more recent one. They were observed in elderly (over 70) women except two cases of rheumatoid arthritis. All the patients were osteoporotic either due to aging or to a long duration corticosteroid treatment. All happened after minor trauma (fall from height). The fractures were classified as SOFCOT C1: letter C means diaphyseal below the prosthetic keel or stem, number 1 means: a well-fixed implant. Intra medullary nailing became the preferred treatment over time. A good analysis of the preoperative lateral radiograph of the knee shows if there is room enough for the nail between the prosthetic keel and the anterior tibial tuberosity, the nail remaining outside the synovium. Bone healed as usually for this type of fracture without impairment of knee or ankle function. However the patients became more dependent. In some instances, an unusual type of fracture may need an unusual treatment.

[Fence grafting for acetabular reconstruction with a cementless cup]. / Greffe en palissade pour recentrage acétabulaire dans les reprises par implant sans ciment.

Acetabular reconstruction is difficult after loss of bone stock and socket remodeling. Several techniques have been proposed ranging from a metal backing to allografting. We propose fence grafting. After explantation, the acetabulum is carefully cleaned of all interface tissue and precisely measured. If the vertical diameter is clearly greater than the anteroposterior diameter, a tricortical graft is harvested from the iliac crest and modeled to perfectly fit between the anterioinferior iliac spine and the residual posterior wall as well as the fundus medially. One or two oblique screws are inserted for stabilization. Any superior bone loss is filled by bone substitute (without mechanical value). The acetabulum is then reamed from the obturator foramen sparing the anterior and posterior columns. Residual bony defects are filled with cancellous bone. A hemispheric cup is then press fit and maintained with two or three screws. We performed this procedure in eight patients with SO.F.C.O.T. stage III acetabular loosening with segmentary bone loss and an oval acetabular cavity. Clinical follow-up was more than four years. The Postel-Merle-d'Aubigné score improved from 9.8 to 15.7 on average. Radiographically, there were no implant mobilization or migration and no circumferential lucent lines were observed. A nearly anatomic position was achieved in all cases except two (technical imperfection). At more than one-year follow-up, the grafts could not be distinguished from adjacent bone. For us, high-positioned or jumbo cups do not offer a satisfactory reconstruction option. There is a risk of compression with allografts from a head bank. We have not used the cemented metal-backed solution nor impacted grafts. The major drawback with fence grafting is the iliac harvesting (possible residual limping because of the extensive disinsertion of the gluteus medius. The reliable acetabular reconstruction is the major advantage. This technique is not simply an acetabular block widened laterally but it decreases the vertical dimension. This is a reliable but minute technique which allows true long-lasting reconstruction of the acetabulum.

[Computer-assisted positioning of the acetabular cup for total hip arthroplasty based on joint kinematics without prior imaging: preliminary results with computed tomographic assessment]. / Positionnement de la cupule d'une prothèse totale de hanche par navigation sans image basée sur la cinématique articulaire: Premiers résultats avec evaluation tomodensitométrique de l'orientation des implants.

PURPOSE OF THE STUDY: Most navigation systems for computer-assisted total hip arthroplasty (THA) require prior computed tomography (CT) or acquisition of multiple bone landmarks on the pelvis. In order to avoid these problems, we developed a computer-assisted navigation system without CT based on a kinematic approach to the hip joint. The principle is to orient the cup in relation to the cone describing the hip joint range of motion. The purpose of this work was to analyze preliminary results. MATERIAL AND METHODS: Eighteen primary THA were implanted with the system (16 women, two men, mean age 68 +/- 7.8 years, age range 54-83 years, 18 degenerative hip disease). Two optoelectronic captors were fixed percutaneously on the pelvis and the distal femur. The acetabulum was prepared first followed by the femur using reamers and broaches of increasing size. The last broach placed in the femur was equipped with a large head adapted to the newly prepared acetabulum. The range of hip motion was recorded to determine the maximal range of motion cone. The acetabular cup was thus positioned in order the prosthesis range of motion included entirely the maximal range of motion of the hip joint. RESULTS: One patient fell three weeks after implantation causing posterior dislocation; there was no recurrence. The Postel-Merle-d'Aubligné score improved from 8 +/- 2.9 (range 3-12) preoperatively to 17 +/- 0.8 (range 16-18) at last follow-up. None of the patients complained about the captor insertion and there were no cases of hematoma or fracture. Operative time was 35-40 minutes longer for the first four cases and was progressively reduced 15-20 minutes for the last four cases. Mean leg length discrepancy was 5.6 +/- 7.5 mm (range 0-25) before implantation and 0.6 +/- 3 mm (range -5 to 10 mm) at last follow-up. CT-scan measurements revealed a mean anteversion of the femoral implant of 18.2 +/- 8.5 degrees (range 0-31). Anatomic anteversion of the cup (measured from the pelvis landmark and thus independently of the position of the pelvis) was 24.7 +/- 8.8 degrees (range 12-40). The sum of the femoral and anatomic acetabular anteversions was 43 +/- 13.1 degrees (range 22-71). Anteversions were 16 degrees for the cup and 16 degrees for the stem for the one case of dislocation. CONCLUSION: This method can be used in routine without lengthening operative time significantly. It safely controls leg length and helps position the cup. This study demonstrated that there is no ideal position for the cup which can be used for all patients. Because of the wide range of inclination and anteversion figures, half of the cases were outside the safety zone recommended by Lewinnek.

Should we resurface the patella in total knee replacement? Experience with the Nex Gen prothesis.

Patellar resurfacing is a controversial issue in primary total knee replacement. So, we took advantage of a large study to try and answer this question. An open prospective multicentric study was conducted about the outcome of the Nex Gen Total Knee prosthesis with clinical and radiological follow-up at regular intervals (1, 2 and 5 years). The data were centrally collected and analyzed by independent observers. A total of whole 5,915 cases were included (487 in the French group); incidences of patello-femoral pain were observed in both French and international groups and compared between cases with or without resurfaced patellae. Only osteoarthritic cases were selected for this particular study. Statistical analysis was performed using a Pearson's Chi-square test with a 95% confidence interval. The frequency of preoperative pain was significantly higher in the French group; 85.1% versus 66.6% (p<0.05). No patello-femoral pain appeared in preoperatively painless patients in the French group. The frequency of lateral patellar release was similar in both groups. 35.7% of the patellae were resurfaced in the international group versus 98.8% in the French one. At 2 years, patello-femoral pain was observed in 6.3% of cases in the former group versus 0.7% in the latter one. The risk of having patello-femoral pain was 9.45 times higher in the international group. When considering resurfaced cases in both groups the risk of having anterior knee pain was not significantly different (p=0.35). In the French group, one case out of nine (11.1%) with patello-femoral pain had not been resurfaced, while 129 cases out of 151 (85.4%) had not had a resurfacing in the international group. This emphasizes the effect of patellar implant on pain. Although patello-femoral pain is multifactorial, this analysis tool is powerful in getting rid of the "center effect " (cf Swedish register). Even if a longer follow-up for confirmation is needed, our data favor patellar resurfacing with this type of implant in spite of the fact that the trochlear design was considered as anatomical.

[Progressive intra-acetabular dislocation of bipolar hip prostheses: four cases]. / Dissociation progressive intra prothétique d'une prothèse intermédiaire de hanche. A propos de 4 cas.

Certain complications, such as acetabular erosion or cup dissociation, are specific to bipolar prostheses. Progressive intra-acetabular dislocation has not been reported to date. We report 4 cases. Four elderly women developed progressive intra-acetabular dislocation after implantation of a bipolar prosthesis for femoral neck fractures. The metal-backed cup verticalized progressively and the ball gradually dislocated into the acetabulum, eroding it. Revision was undertaken with a hemispheric bone ingrowth cup and partial grafting. Follow-up was then uneventful. This phenomenon is different from the acute intra-acetabular dislocation that may occur after rupture of the anti-dissociation mechanism (polyethylene ring) incorporated in the design of new implant models, or after dissociation between the ball and the cup during closed reduction of a dislocation, the cup catching on the acetabular rim. It is not due to a variation in the neck-head angles (we observed varus, valgus, and neutral angles) nor to a problem between the modular head and the neck (at the morse cone taper). For us, the cause of this progressive intra-acetabular dislocation is poor cup design associated with a weak retention system. If the centers of the inner and outer spheres are superimposed, the cup has a natural tendency to drop into varus because of its weight. This becomes even worse if the center of the outer sphere is medial to the ball center. The cup should be designed so that the center of the outer sphere (bipolar cup) lies lateral to the center of the inner sphere (ball) creating a valgus torque for the cup. Designing a bipolar cup is not as a simple matter as it may seem. We emphasize the importance of the position of the rotation centers.

[Osseous reconstruction of the patella with screwed autologous graft in the course of repeat prosthesis of the knee]. / Reconstruction osseuse de la patella par autogreffe vissée au cours des reprises des prothèses du genou.

PURPOSE OF THE STUDY: The aim of this study was to propose an original way of solving the infrequent but difficult problem of a thin patellar remnant. After removal of the loose patellar button of a knee prosthesis, several options are available: patellectomy should be avoided because of unpredictable results; patelloplasty may be the solution if bone quality is too poor and can allow for its improvement with time; recementing a new implant needs the remaining patella to be thick enough (more than 10 millimeters). MATERIAL AND METHODS: We advised reconstruction with an autologous monocortical iliac bone graft, harvested from the medial cortex of the anterior iliac wing, and shaped to accommodate for the patellar remnant. Its cancellous surface is opposed to the roughened patellar bone to which it is fixed by four 1.5 mm cortical screws (the heads of which are countersunk). Any defect will be filled with cancellous chips. The patellar button can then be cemented. Two cases with a long follow-up (5 years) are shown: one is a "typical" indication of isolated patellar loosening 16 years after implantation of a GSB total knee prosthesis, in a 91 year old woman. The other one illustrates the salvage of a "patellectomized" multi-operated knee, in which a trochlear implant was used as a first step, then 4 years later the patellar pseudarthrosed remnant was reconstructed. DISCUSSION: Indications of this technique are obviously rare: the patellar remnant should be thinner than 10 mm, in one piece (or easy to rebuild with the graft), the bone should allow a good purchase of the screws and the extensor apparatus should be in continuity. The first cases seem encouraging, as no secondary fracture or non-union has been seen at five years follow-up. The bone-cement lucency seems to be due to cementing on a cortical surface, but did not increased. Autologous bone has been favoured to increase the chances of union in a poor quality bed. It has the drawback of a second approach to harvest the bone at the iliac wing, where it is not always flat. The surgeon must "cheat" to get as flat a surface as possible for cementing. The loss of quadriceps is so troublesome that Buechel has proposed autologous grafting inside the patellar tendon and Bakay has used a mushroom-shaped allograft. Finally, we should like to advise against too much thinning of the patella to try and gain a few more degrees of flexion in total knee replacement: think of revision! CONCLUSION: We think this technique may be helpful in patellar loosening, as an other way of solving this problem.

[Prosthetic replacement of the anterior cruciate ligament in dogs by carbon fibres (author's transl)]. / Prothèse ligamentaire en fibres de carbone. Etude expérimentale en situation intra-articulaire chez le chien.

Division of the anterior cruciate ligament in dogs usually leads to degenerative arthrosis of the knee after a few weeks. The authors have replaced the anterior cruciate ligament in 7 dogs by an artificial ligament made of carbon fibre. The results were analysed after seven months. In all cases the artificial ligaments had been affected in spite of good clinical behaviour. The fibrous invasion of the carbon fibres was poor. Most of the knees had cartilaginous lesions of the arthrotic type, the synovium was the site of foreign body reaction surrounding deposits of carbon and some carbon deposits were found in lymph glands in the inguinal region.