Bacterial skin recolonization in the operating room: comparison between various antisepsis protocols.

BACKGROUND: Surgical site infection (SSI) largely implicates the patient's endogenous skin microbiota. Perioperative disinfection protocols do not follow a general agreement. AIM: To compare antisepsis and skin protection protocols on quantitative analysis of recolonization in the operating room at regular time-steps. The study hypothesis was that one protocol would be more effective than others. METHODS: A single-centre prospective interventional study was conducted between January and June 2019. Healthy volunteers were randomized between protocols and served as their own controls. The protocols began ahead of scheduled orthopaedic surgery with a preoperative shower, mechanical cleansing, application of major antiseptics (alcoholic Bétadine™ 5% or alcoholic chlorhexidine 0.5%), sterile draping, then adhesive draping (3M™ Steri-Drape™ or iodine-impregnated 3M™ Ioban2™). Sampling was by swabbing in the operating room at 30 min intervals up to 90 min after draping. Cultures were performed under aerobic and anaerobic conditions. Qualitative and quantitative (cfu/mL) bacteriology was performed in the laboratory by direct reading on the blood agar plates. FINDINGS: Thirty subjects were included; none was lost to follow-up or excluded from analysis. Bacterial load before manipulation (T0) was significantly higher in males (P < 0.0001) despite a significantly shorter shower-to-sampling interval (P = 0.03). Smoking (P = 0.85), body mass index (P = 0.38), and depilation (P = 0.50) did not significantly affect preoperative load. Mean load increased significantly under all protocols up to T90 min, without significant superiority for any one protocol. Associated Bétadine™/Ioban™ showed the lowest T90 load, and chlorhexidine alone the highest, but without significant difference. Isolates at T0 were predominantly healthy skin commensals: coagulase-negative staphylococci, micrococci, and coryneforms. CONCLUSION: No one protocol demonstrated superiority, whether in immediate bactericidal action or in preventing skin recolonization in the operating room. Further studies are needed to define generally agreed protocols for SSI risk management.

Complications with cement spacers in 2-stage treatment of periprosthetic joint infection on total hip replacement.

INTRODUCTION: The aim of the present study was to assess our management of infected total hip replacement in indications for 2-stage surgical treatment according to current guidelines when a cement spacer has been used. The study hypothesis was that the complications rate related to cement spacers is low. MATERIAL AND METHOD: A single-center retrospective study included 26 patients receiving a spacer between the two stages of total hip replacement, over a 5 year period. We analyzed the spacers used, mechanical complications, infectious complications and the second stage of surgery. RESULTS: During the interval between surgeries, in the 26 patients, there were 19 spacer-related mechanical complications (73% of patients): 11 dislocations (42.3%), 5 spacer fractures (19.2%), 5 femoral bone lyses or fractures (19.2%) and 3 acetabular lyses or fractures (11.5%). In 4 cases, complications were associated. The greater the femoral offset of the spacer, the more frequent were femoral bone lyses or fractures (p=0.05), and the smaller the offset the more frequent were acetabular lyses or fractures (p=0.05). The rates of mechanical complications (p=0.003) and spacer fracture (p=0.02) were significantly greater in older patients. There were 4 cases of reinfection (19%): i.e., an 81% treatment success rate. One reinfection implicated a new bacterium: methicillin-susceptible Staphylococcus aureus. The second surgical stage was significantly longer in complex bipolar revision (p=0.009). CONCLUSION: The present results showed a high risk of spacer-related complications, and thus the importance of selection of patients liable to derive real benefit and those for whom a Gilderstone procedure would be preferable. LEVEL OF EVIDENCE: IV, retrospective study.

Usefulness of sonication for diagnosing infection in explanted orthopaedic implants.

BACKGROUND: Orthopaedic implant infection is a rare but serious complication whose optimal treatment requires an accurate microbiological diagnosis. The objective of this study was to determine whether culturing sonicated explants improved sensitivity compared to culturing standard sonicated soft-tissue samples. HYPOTHESIS: Cultures of explant sonication fluid are more sensitive than cultures of soft-tissue sonication fluid in patients with implant infection. METHODS: This single-centre retrospective study included all sonication fluid samples from implants explanted in orthopaedic surgery theatres for any reason. The microbiological results of the implant sonication fluid cultures were compared to those of cultures of sonicated soft-tissue and bone samples taken during the same procedure. The primary evaluation criterion was the difference in microorganisms recovered from explant sonication fluids versus fluid/tissue cultures. RESULTS: The study included 187 explants removed between September 2009 and June 2015. Of the definite infections, 83% were identified by explant sonication, 86% by fluid/tissue cultures, and 91% by both techniques combined. Explant sonication recovered causative organisms in 10 patients with definite infection but negative fluid/soft tissue cultures. Antibiotic therapy prior to explantation was associated with lower sensitivity of explant sonication (57% vs. 67% for fluid/soft tissue cultures). CONCLUSION: Explant sonication improved the diagnosis of infection when combined with fluid/soft tissue cultures. LEVEL OF EVIDENCE: IV, retrospective single-centre study.

Collection and reconstruction after harvesting donor tissues from the musculoskeletal system: Technique specific to the lower limbs.

The lack of available musculoskeletal grafts in France forces us to import a very large quantity of these tissues to use in complex reconstruction procedures. The goal of this article is to describe methods for collecting donor tissues from the musculoskeletal system and for reconstructing the harvested areas. We also provide a summary of the collection procedures performed, harvested grafts and available tissues. While tissue collection requires a significant time investment, the emergence of dedicated teams may be a solution for increasing the number and quality of human musculoskeletal allograft tissues.

Does using a polyethylene RM press-fit cup modify the preparation of the acetabulum and acetabular offset in primary hip arthroplasty?

INTRODUCTION: When performing total hip arthroplasty (THA), it is important to maintain the femoral and acetabular offsets to ensure good joint stability and to restore the function of the hip abductor muscles. In our practice, we mainly use a lateralized stem and hollow out the acetabulum to the quadrilateral plate to accommodate a press-fit polyethylene cup. However, the repercussions of this preparation method, which is driven by the cup's design, are not known. We carried out a retrospective study to assess: (1) the changes in the femoral and acetabular offset; (2) the height of the center of rotation; and (3) the repercussions on wear. HYPOTHESIS: We hypothesized there would be no significant differences between the preoperative and postoperative femoral and acetabular offsets. PATIENTS AND METHODS: We reviewed 88 primary THA cases performed with the RM Pressfit™ cup that had a minimum of 5 years' follow-up. A lateralized self-locking Muller-type cemented femoral stem was used in 92.0% of cases and a standard stem in 8.0%. Measurements were done on plain radiographs with MHP™ and Mesurim Pro™ software. The average follow-up was 6.5 years (5-8). RESULTS: On average, the acetabular offset was reduced by 2.75mm±5.9 mm (range: -17.5 to +10.6 mm) (P<0.001) and the femoral offset was increased by 0.01mm±5.5 mm (range: -17.8 to +11.0 mm) (P=0.99). In terms of total offset, medialization of 2.74mm±7 mm (range: -17.7 to +18.2mm) was found (P=0.001). The acetabular center of rotation was on average 4.77mm±5.1 mm higher (P<0.001). The mean annual wear at the more recent follow-up (min.: 5 years) was 0.068mm (range: 0.01 to 0.25mm) per year. The wear was not impacted by having more than 5mm change in offset. DISCUSSION: Measurements of acetabular offset revealed statistically significant medialization due to the type of implant used and the surgical technique. The anatomical technique consists of positioning the cup in subchondral bone without contacting the quadrilateral plate. This preserves bone stock, which may be useful later on if the cup is revised, particularly in younger patients. Conversely, the femoral offset did not change significantly, despite the use of lateralized stems in 92.0% of cases. We measured an annual wear rate of 0.068mm per year, which is lower than in other published studies, possibly because our patient population was older. LEVEL OF EVIDENCE: IV, retrospective study.

Acetabular bone defects in THA revision: Reconstruction using morsellised virus-inactivated bone allograft and reinforcement ring. Seven-year outcomes in 95 patients.

BACKGROUND: Acetabular cup loosening is among the main reasons for revision total hip arthroplasty (THA). The implantation of a cryopreserved morsellised bone allograft is a reference method for filling bone defects. However, the outcomes of bone grafts treated with viral inactivation and secured into the host bone (notably using a reinforcement device) are unclear. We therefore retrospectively reviewed cases of acetabular revision with morsellised bone allograft implanted into a reinforcement ring for acetabular revision to assess: (1) clinical survival of the acetabular implant (time to new revision with acetabular component removal), (2) radiological implant survival, (3) and bone graft osseointegration evaluated using Oswestry's criteria. HYPOTHESIS: Virus-inactivated bone allografts provide similar outcomes to cryopreserved allografts. MATERIAL AND METHODS: From 2004 to 2009, 95 patients underwent acetabular revision. There were 60 (63%) females and 35 (37%) males with a mean age of 71.7 years (range: 44.2-90 years). Over 90% of patients had bone defects type 2 or higher in the AAOS classification. Each patient was evaluated after at least 5 years, by an examiner who had not been involved in the revision and who determined the Postel-Merle d'Aubigné (PMA) score and patient satisfaction. We assessed the clinical survival of the acetabular implant (time to new revision with acetabular implant removal), radiological implant survival (migration>5mm, active radiolucent line, failure of graft osseointegration, or reinforcement ring failure), and allograft osteointegration evaluated using Oswestry's criteria. RESULTS: After a mean follow-up of 7years (range: 5.2-10years), 7 (7.4%) patients had been lost to follow-up and 3 (3.4%) had required surgical revision, after 3 to 73 months (for aseptic loosening in 2 cases and infection in 1 case). The estimated 10-year survival rate was 96.2% (95% confidence interval [95%CI]: 88.2-98.7). The mean PMA score at last follow-up had increased significantly, by 2.8 points (p<0.05), to 13.8 (95%CI: 78.4-88.1). Of the 88 re-evaluated patients, 78 (89%) were satisfied or very satisfied. The overall radiological survival rate was 84.5% (95%CI: 78.4-88.1) after a mean of 5.9 years (range: 0.5-10). Allograft osseointegration was satisfactory (Oswestry score≥2) in 95.8% of patients. DISCUSSION: In our population, allografts previously subjected to virus inactivation and implanted into a reinforcement ring produced outcomes similar to those reported previously with cryopreserved allografts. LEVEL OF EVIDENCE: IV, retrospective case-series study.

What are the risk factors for dislocation in primary total hip arthroplasty? A multicenter case-control study of 128 unstable and 438 stable hips.

INTRODUCTION: Dislocation after total hip arthroplasty (THA) is a leading reason for surgical revision. The risk factors for dislocation are controversial, particularly those related to the patient and to the surgical procedure itself. The differences in opinion on the impact of these factors stem from the fact they are often evaluated using retrospective studies or in limited patient populations. This led us to carry out a prospective case-control study on a large population to determine: 1) the risk factors for dislocation after THA, 2) the features of these dislocations, and 3) the contribution of patient-related factors and surgery-related factors. HYPOTHESIS: Risk factors for dislocation related to the patient and procedure can be identified using a large case-control study. PATIENTS AND METHODS: A multicenter, prospective case-control study was performed between January 1 and December 31, 2013. Four patients with stable THAs were matched to each patient with a dislocated THA. This led to 566 primary THA cases being included: 128 unstable, 438 stable. The primary matching factors were sex, age, initial diagnosis, surgical approach, implantation date and type of implants (bearing size, standard or dual-mobility cup). RESULTS: The patients with unstable THAs were 67±12 [37-73]years old on average; there were 61 women (48%) and 67 men (52%). Hip osteoarthritis (OA) was the main reason for the THA procedure in 71% (91/128) of the unstable group. The dislocation was posterior in 84 cases and anterior in 44 cases. The dislocation occurred within 3 months of the primary surgery in 48 cases (38%), 3 to 12 months after in 23 cases (18%), 1 to 5years after in 20 cases (16%), 5 to 10years after in 17 cases (13%) and more than 10years later in 20 cases. The dislocation recurred within 6 months of the initial dislocation in 23 of the 128 cases (18%). The risk factors for instability were a high ASA score with an odds ratio (OR) of 1.93 (95% CI: 1.4-2.6), neurological disability (cognitive, motor or psychiatric disorders) with an OR of 3.9 (95% CI: 2.15-7.1), history of spinal disease (lumbar stenosis, spinal fusion, discectomy, scoliosis and injury sequelae) with an OR of 1.89 (95% CI: 1.0-3.6), unrepaired joint capsule (all approaches) with an OR of 4.1 (95% CI: 2.3-7.37), unrepaired joint capsule (posterior approach) with an OR of 6.0 (95% CI: 2.2-15.9), and cup inclination outside Lewinnek's safe zone (30°-50°) with OR of 2.4 (95% CI: 1.4-4.0). DISCUSSION: This large comparative study isolated important patient-related factors for dislocation that surgeons must be aware of. We also found evidence that implanting the cup in 30° to 50° inclination has a major impact on preventing dislocation. LEVEL OF EVIDENCE: Level III; case-control study.

[Early aseptic loosening of cemented cup in metal-on-metal total hip arthroplasties]. / Echec par descellement aseptique précoce de la cupule acétabulaire cimentée de prothèses totales de hanche à couple de frottement métal-métal.

PURPOSE OF THE STUDY: The aim of this study was to report cases of acetabular failure of metal-on-metal total hip arthroplasties using cemented cups with a metal-metal bearing. MATERIAL AND METHODS: From 1997 to 1999, 137 patients underwent total hip arthroplasty with a 28-mm head and a metal-metal (Metasul) bearing. At mean follow-up of three years eight months (range 2-6 years), three patients had died and thirteen were lost to follow-up or had less than 2 years follow-up. The analysis thus included 118 patients (122 hips) 67 women and 51 men (mean age 61 years). The same transgluteal approach with two cemented implants (Palacos gentamycine) was used in all patients. The Postel-Merle-d'Aubigné score was used for clinical assessment with search for lucent lines in the Delee and Charnley zones and cup migration on the standard x-rays. Actuarial survival curves were drawn using revision and failure as the end events. RESULTS: In this series, there were no cases of dislocation or infection but there were five revisions for aseptic cup loosening: one at two years, two at four years, and two at five years. Among the remaining 117 implants, outcome was clinically very good in 101, good in 10 and fair in 6. Radiologically, there were no cases of femoral lucent lines, migration or osteolysis. For the cup, a lucent line measuring less than 1 mm and stable was observed in 81 hips. A progressive lucent line was observed in 18 hips with 11 showing signs of probable loosening. The five-year survival using surgical revision as the endpoint was 94%. Using cup failure (revision and progressive line), it was 80%. Revisions and radiographically probable loosenings were statistically more significant in small cups measuring 44 and 46 mm. DISCUSSION: In this series, cemented metal-on-metal bearings showed a rate of failure greater than observed in metal-polyethylene implants and metal-on-metal implants using a press fit cup. Other series using a metal-on-metal bearing with a cemented cup have found the same trend. CONCLUSION: We have discontinued this type of implant and recommend avoiding direct cementing of the polyethylene-metasul cup on the bone for total hip arthroplasty. The metal-on-metal bearing can still be used, but without cementing the cup.

[The cemented Müller straight stem total hip prosthesis with polyethylene cup and 28 mm head: ten-year results]. / Résultats à 10 ans de la prothèse totale de hanche cimentée autoblocante de Müller avec cupule en polyéthylène en diamètre de 28 mm.

PURPOSE OF THE STUDY: The purpose of this study was to evaluate the 10-year results of the cemented Müller straight stem total hip prosthesis with polyethylene cup and 28 mm head. MATERIAL AND METHOD: From May 1988 to May 1990, 187 cemented prostheses (second-generation technique) were implanted via a transgluteal approach for degenerative hip disease. A Protasul 10 straight stem with a 28 mm modular head and a gamma ray sterilized polyethylene cup was used in all cases. At ten years, the follow-up of the 187 implants was: 60 implants in deceased patients, 24 implants in patients contacted by telephone (all with implants in place), 90 implants in 82 patients seen for review. The series thus included 40 women and 42 men, mean age 65 years. The clinical outcome was assessed with the Postel Merle d'Aubigné (PMA) score. Radiographic assessment noted lucent lines, granulomas, implant migration, polyethylene wear, and ossifications. Survival curves were established with the actuarial method. RESULTS: Among the 187 implants, two patients required revision: one for sepsis and the other for posttraumatic dislocation. Among the 82 patients reviewed at 10 year, the PMA score was 16.8 (92% good and very good results). Radiographically, assessment of the acetabular component demonstrated three probable and one certain loosening, four cases of polyethylene wear greater than 2 mm. At the femoral level, osteolysis was noted in zones 1, 3, and 7 and rarified bone in zone 7 in four patients. Linear penetration of the stem into the cup was 0.09 mm/yr, corresponding to a volumetric wear of 55, 35 mm3/year. Brooker grade 3 ossification was observed in 27% of men and 14% of women. DISCUSSION: The clinical results were comparable to other series of cemented prostheses. At ten years, acetabular loosening was more frequent with active radiolucent lines present from the fifth year. It would thus appear that better results could be achieved by optimizing the bearing. Furthermore, there was no parallelism between the clinical and anatomic observations, cup loosening and femoral osteolysis were well tolerated. The prevention of ossification appears to be an important point, particularly in men.

A comparison of patient-specific and conventional instrumentation for total knee arthroplasty: a multicentre randomised controlled trial.

In this study we randomised 140 patients who were due to undergo primary total knee arthroplasty (TKA) to have the procedure performed using either patient-specific cutting guides (PSCG) or conventional instrumentation (CI). The primary outcome measure was the mechanical axis, as measured at three months on a standing long-leg radiograph by the hip-knee-ankle (HKA) angle. This was undertaken by an independent observer who was blinded to the instrumentation. Secondary outcome measures were component positioning, operating time, Knee Society and Oxford knee scores, blood loss and length of hospital stay. A total of 126 patients (67 in the CI group and 59 in the PSCG group) had complete clinical and radiological data. There were 88 females and 52 males with a mean age of 69.3 years (47 to 84) and a mean BMI of 28.6 kg/m(2) (20.2 to 40.8). The mean HKA angle was 178.9° (172.5 to 183.4) in the CI group and 178.2° (172.4 to 183.4) in the PSCG group (p = 0.34). Outliers were identified in 22 of 67 knees (32.8%) in the CI group and 19 of 59 knees (32.2%) in the PSCG group (p = 0.99). There was no significant difference in the clinical results (p = 0.95 and 0.59, respectively). Operating time, blood loss and length of hospital stay were not significantly reduced (p = 0.09, 0.58 and 0.50, respectively) when using PSCG. The use of PSCG in primary TKA did not reduce the proportion of outliers as measured by post-operative coronal alignment.

Opening-wedge high tibial osteotomy with a secure bone allograft (Osteopure™) and locked plate fixation: Retrospective clinical and radiological evaluation of 69 knees after 7.5years follow-up.

BACKGROUND: Medial opening-wedge high tibial osteotomy (OWHTO) provides reliable and long-lasting benefits, despite the wide range of wedge-filling and internal-fixation techniques used. The purpose of this work was to assess the clinical and radiological outcomes in a case-series of OWHTO performed using a secure bone allograft and locked plate fixation. HYPOTHESIS: The clinical and radiological outcomes of OWHTO with a high-safety bone allograft and locked plate fixation are similar to those reported in previous case-series studies. MATERIALS AND METHODS: A single-centre retrospective design was used to study 69 knees in 64 patients with a mean age of 51.8years (31-53years) and a preoperative hip-knee-ankle (HKA) angle of 173° (165°-180°). The wedge was filled with secure Osteopure™ bone allograft and fixation was achieved using an Integra Surfix(®) locked plate. Mean follow-up was 7.5years (5-9.3years). Clinical and functional outcomes were assessed by determining the IKS and KOOS-PS scores and recording complications related or unrelated to the allograft. The main criterion for assessing OWHTO survival was the time to revision surgery for symptom recurrence. Radiological assessment criteria were the HKA angle, tibial slope, patellar height, and osteoarthritis grade. GESTO criteria were used to evaluate the behaviour of the allograft. RESULTS: Of the 69 knees, 64 (92.8%) were re-evaluated. The survival rate after 9.3years was 95%±2.7% (3 failures managed with arthroplasty). The functional IKS score improved significantly, by 20 points (P<0.001). Mean increases of 7.8° for the HKA angle and 3.5° for tibial slope were recorded. Bone healing without radiological abnormalities was consistently achieved within 6months. There were no complications related to the allograft (infections, allergies; local or systemic toxicity). DISCUSSION: The clinical, radiological, and safety outcomes documented in our study were similar to those reported in earlier work. LEVEL OF EVIDENCE: IV, retrospective case-series study.

Monitoring of polyethylene wear in nonmetal-backed acetubular cups by digitized anteroposterior pelvic radiography.

The aim of this study was to assess polyethylene wear in a total hip prosthesis by digitized radiography of the whole pelvis in the anteroposterior (AP) plane. The three-dimensional (3-D) pose of the nonmetal-backed acetubular cup, materialized by its metal ring and the femoral head made of metal or ceramic, was estimated using iterative algebraic algorithms with inner bias correction and bootstrapping for variance reduction. Points of interest were obtained by maximizing the correlation between sampled density profiles and 3-D geometric models degraded by the modulation transfer function (MTF) of the radiographic system and the film scanner. The error in the maximal correlation estimate were inferred from noise power spectra (NPS) and allowed the calculation of the point covariance matrix. Both NPS and MTF were modeled for each stage and estimated using least-square fitting of the overall NPS model to the autospectral density function calculated in stationary regions. Comparison of the radiographic time series was made possible by the high accuracy level and 3-D matching from the cup orientation. The feasibility of the full 3-D measurement, the assumption of negligible lateral wear and its influence on AP wear are discussed on simulated and real radiographic data.

Intraosseous xanthoma without lipid disorders. Case-report and literature review.

A case of intraosseous xanthoma in a patient with a normal lipid profile is reported. Hyperlipidemia is present in most patients with xanthomas. Intraosseous xanthomas are rare, particularly in normolipidemic patients, in whom the presenting symptom is pain without skin lesions. A lytic lesion with a rim of sclerosis is seen on radiographs. Histology shows foam cells, giant cells, and fibrosis. Intraosseous xanthoma is a benign tumor, and other diagnoses must be ruled out (histiocytosis X, Erdheim Chester disease, clear cell carcinoma metastasis). Surgical excision of the lesion is the elective treatment.

[Comparison of two electrical stimulation protocols on quadriceps muscle after anterior cruciate ligament surgery. Feasability study]. / Etude comparative de deux protocoles d'électrostimulation du quadriceps après chirurgie du ligament croisé antérieur. Etude de faisabilité.

OBJECTIVES: To evaluate the feasibility of a study comparing the effects of two protocols of electrical stimulation of the quadriceps femoris after anterior cruciate ligament surgery. MATERIAL: Seven sportsmen with a mean age of 26 yrs were randomly grouped in two: a 20 Hz stimulated group (4 patients) and a 80 Hz stimulated group (3 patients). After surgery all patients received electrical stimulation of the quadriceps femoris, five days a week, for 12 weeks, and had a standard program of voluntary contractions. The main outcome assessed before and three months after surgery were: quadriceps and hamstring peak torque at 90, 180 and 240 degrees /second, maximal isometric quadriceps at 75 degrees of flexion and muscle and subcutaneous fat volumes of the thigh using MRI. RESULTS: After 12 weeks of rehabilitation, the thigh muscle volume deficit of the operated limb was between 3 and 9% in the 20 Hz stimulated group and between 1 and 2% in the 80 Hz stimulated group. Quadriceps peak torque deficit was less than 30% except for two patients in the 20 Hz stimulated group. Maximal isometric quadriceps deficit of the operated limb was higher than 30% except for two patients in the 20 Hz stimulated group. CONCLUSION: The study showed that comparison of two protocols of electrical stimulation of the quadriceps femoris after anterior cruciate ligament surgery is possible if stimulation period is not more than four weeks.

[Study of the posterior cruciate ligament using a 3D computer model: ligament biometry during flexion, application to surgical replacement of the ligament]. / Etude du ligament croisé postérieur à l'aide d'un modèle 3D informatique: biométrie ligamentaire lors de la flexion, application au remplacement chirurgical du ligament.

We have developed a 3D computed model of the knee joint, constructed from MRI acquisitions in a living individual. We have used this model to perform an anatomic and biometric study of the posterior cruciate ligament (PCL) during flexion, and an assessment of the optimal location for an intraarticular graft. The method used a 3D computed model constructed from MRI acquisitions during knee flexion (0 to 75 degrees). The range of motion was limited by a positioning device. We took 13 acquisitions from 0 to 75 degrees of flexion. Each acquisition consisted of 21 sagittal cross sections of 3 mm slice thickness. We used the Delaunay reconstruction to obtain a 3D geometric model. A matching process to fix one part of the articulation during the movement, allows for the kinematic analysis of the tibia relative to the fixed femur. This model allows to follow the displacement of a bone point during knee flexion. Knowing the relative displacement of the bone insertions of the ligament, it may be possible to determine the length of the PCL and its bands, to evaluate the length variation during movement, and to determine the optimal location for the insertion of an intraarticular graft, that would lead to the least stretch during flexion. It was found that the mean length of the PCL was 30.2 mm, with the posterior band being 30% longer than the anterior band. During flexion the posterior band increases its length by 10% at 50 degrees flexion, and by 20% at 75 degrees flexion. The anterior band stretches more, to reach 40% elongation at 75 degrees flexion. The best position for insertion of a graft seems to be in the posterolateral portion of the anatomic tibial insertion, and posterior to the anatomic femoral insertion. This method confirms the data in the literature, states precisely the length of the different bands of the PCL, and specifies the points of insertion for a graft, which lead to the least variation in length during flexion.

[Xenograft-related complications after filling valgus open wedge tibial osteotomy defects]. / Complications en rapport avec l'utilisation d'une xénogreffe (Lubboc) pour le comblement de l'ouverture médiale dans l'ostéotomie tibiale de valgisation.

PURPOSE OF THE STUDY: The purpose of this study was to assess clinical tolerance and radiological and histological changes observed after using a safe bovine xenograft (Lubboc) to fill open wedge defects after tibial osteotomy for valgisation in patients with medial femoro-tibial degeneration. MATERIAL AND METHODS: Thirty-one valgus open wedge tibial osteotomies were filled with a xenograft (Lubboc) and fixed with an epiphyseal plate in 16 women and 13 men, mean age 55 years two months. All patients had medial femorotibial degeneration with genu varum. Mean varus deviation was 6 degrees. RESULTS: At two years six months follow-up, five patients had developed a local complication: three cases of non-infected discharge and two infections. Among the other 26 cases, the radiographic evolution of the xenograft was similar to that described for autologous grafts but for seven cases, a lucent line persisted, isolating the graft. A biopsy was obtained in fifteen patients during the material removal procedure. Cell infiltration was absent in nine grafts. DISCUSSION: In light of the large number of local complications and the unpredictable nature of the radiological and histological outcome xenografting should be discontinued.

[Failure of the polyethylene cups directly implanted into bone. A study of 32 Freeman cups after 9 years of followup (6-12 years)]. / Echec des cupules en polyéthylène implantées directement sur l'os. Etude de 32 cupules de Freeman à 9 ans de recul (6-12 ans).

PURPOSE OF THE STUDY: A clinical and radiological assessment was performed on 32 Freeman polyethylene uncemented acetabular cups, at an average of 9 years follow up. This study was dedicated to analyze polyethylene bone direct fixation. MATERIAL: Between 1984 and 1988, 30 patients were operated for 32 total hip prostheses. Mean age of the population at the time of surgery was 66 years. In all cases the prosthesis was a cemented Müller femoral stem with a Freeman uncemented cup. The acetabular component was made with polyethylene with three pegs fitted with an offset hemispheric cup. METHOD: All patients were reviewed at 1, 3, 5 years and maximal follow-up. Their functional evaluation was performed using Merle d'Aubigné's hip rating scale: pain score, motion score and walking score. Radiological assessment was performed to identify acetabular cup migration, bone lysis, and radio lucency. Revision for acetabular cup loosening was compiled. RESULTS: Five patients died, 27 THA were evaluated at maximum follow-up. Seven revisions were performed after the fifth years. Merle d'Aubigné's score was 14 at the time of revision. X-rays evidenced more than 5 mm migration of the cup, with massive bone lysis. Merle d'Aubigné's score was 16 for the 20 remaining THA. Radiologically, 10 cups showed migration less than 3 mm, five of which with lysis. Among the 10 cups without migration, 5 showed sclerosis near the acetabulum. The study evidenced that cases of migration exceeding 5 mm induced a revision during the next 3 years. DISCUSSION: Our study confirms failure of bone polyethylene direct fixation, with 25 per cent of revision after a five years period. This seems to be the result of micro movement, wear and bone lysis. A five years follow up is not sufficient to evaluate a component, since all revisions were performed after five years. For many authors, radiological evaluation of acetabular component migration is an important criterion for uncemented prosthesis. The EBRA computerized method is an accurate method for determining early migration, and can be used for pro and retrospective studies. CONCLUSION: Our study confirms a high rate of failures of the Freeman uncemented cup at an average of nine-year period, as previously reported in literature.

[Bone reconstruction, leg length discrepancy, and dislocation rate in 52 Wagner revision total hip arthroplasties at 44-month follow-up]. / Reconstruction osseuse, inégalité de longueur des membres, taux de luxation de 52 prothèses de Wagner, en révision d'arthroplasties totales de hanche au recul moyen de 44 mois.

PURPOSE OF THE STUDY: The primary and secondary stability of a revision implant is highly compromised in cases with important loss of bone stock from the proximal femoral after severe femoral loosening. Several methods using implants with or without cement have been proposed for reconstruction after femoral bone loss. The purpose of this study was to analyze mid-term clinical and radiological outcome with the Wagner prosthesis for revision surgery. MATERIAL AND METHODS: Fifty-two cases of aseptic femoral loosening were treated with this method in 36 women and 14 men, mean age 70 years (range 32-92 years). None of the patients was lost to follow-up; five who died after 18 months were retained for analysis. Mean follow-up was 44 months (range 18-88 months). The mean preoperative Postel Merle d'Aubigné (PMA) score was 10.5 +/- 0.4. These patients had major bone loss (5 grade II, 24 grade III, 23 grade IV in the SOFCOT classification). The transfemoral access was used in 17 cases and bone grafts in 32. Clinical outcome was assessed with the PMA score and leg length discrepancy was measured. Radiographically, stability was assessed by measuring stem impaction and progression of radiolucent lines. RESULTS: The overall functional score was significantly improved from 10.5 +/- 0.4 preoperatively to 14.6 +/- 0.5 (p<0.001). All items on the score improved but pain relief was the most notable. Improvement in the gait score was limited due to persistent limping in 39 patients. Leg length discrepancies were found in 8 patients with 6 shortenings and 2 lengthenings. The clinical situation remained stable after one year. The implant remained stable in 48 patients (92 p. 100) and stem impaction was observed in 4 before 12 months. Two of these cases required a second revision. Metaphyseal reconstruction was observed in 42 patients (81 p. 100), including 24 (46 p. 100) who exhibited homogeneous reconstruction with trabeculation. The reconstruction did not progress further after 18 months postoperatively. Complications included four dislocations and five revision procedures (three for cup loosening, two for femoral pivot instability). DISCUSSION: The functional outcome was similar to results reported in the literature, including the high frequency of limping that was caused by various factors (valgus prosthesis neck, leg length discrepancy, muscle deficits). Leg length discrepancies resulted from defective positioning or impaction at loading. Standard radiographic series allowed an assessment of stem impaction. Our low rate could be due to delayed weight bearing. La reconstruction of bone loss did not progress after 18 months and was independent of bone grafting, route of access, and the initial degree of loosening. The high frequency of dislocations with this type of implant can be prevented by horizontalization of the acetabulum and use of anti-dislocation inserts at the first intention revision. CONCLUSION: Our results with the Wagner prosthesis are satisfactory both clinically and radiographically. The two drawbacks of this implant (limping and dislocation), partly due to the design of the femoral stem, have led us to study a new implant that preserves good distal anchoring and optimizes the proximal biomechanics of the hip joint.

Transcultural validation of the Risk Assessment and Predictor Tool (RAPT) to predict discharge outcomes after total hip replacement.

OBJECTIVE: To assess the relevance of the RAPT (Risk Assessment and Prediction Tool), among a cohort of patients undergoing total hip arthroplasty (THA). METHOD: Prospective study of a cohort of patients evaluated before and after THA. The difference between the postoperative orientation predicted by the RAPT and the real one is assessed. Clinical, environmental and psychosocial criteria that could significantly change the orientation are discussed. RESULTS: One hundred and thirty-four patients (94 women and 40 men) were included. The average age was 71.6 (±10) years. Primary hip osteoarthritis was the indication for surgery in 78% of cases. The average length of stay in the surgery ward was 10 (±3) days. It was significantly higher for patients referred to a rehabilitation ward (P<0.0001). Sixty-six percent of patients were referred to a rehabilitation ward and 34% returned directly home. The average length of stay in rehabilitation ward was 27 (±13) days. The validity of the RAPT as a help decision tool has been confirmed. Thus, a low RAPT score was significantly associated with more frequent referral to a rehabilitation ward, conversely, a high RAPT score is significantly related to more frequent direct return to home. CONCLUSION: This study confirmed the usefulness of the RAPT to help in patient orientation decision after total hip arthroplasty. The patient preference remains the main variable for orientation after THA. By the way, the patient preference must not be integrated into the RAPT, but need to be collected and be discussed with the patient.

Complex primary total hip arthroplasty.

Although total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that can make THA a difficult procedure may be anticipated with proper understanding of the case and thorough preoperative planning.