Antibiotic Therapy for 6 or 12 Weeks for Prosthetic Joint Infection.

BACKGROUND: The management of prosthetic joint infection usually consists of a combination of surgery and antimicrobial therapy. The appropriate duration of antimicrobial therapy for this indication remains unclear. METHODS: We performed an open-label, randomized, controlled, noninferiority trial to compare 6 weeks with 12 weeks of antibiotic therapy in patients with microbiologically confirmed prosthetic joint infection that had been managed with an appropriate surgical procedure. The primary outcome was persistent infection (defined as the persistence or recurrence of infection with the initial causative bacteria, with an antibiotic susceptibility pattern that was phenotypically indistinguishable from that at enrollment) within 2 years after the completion of antibiotic therapy. Noninferiority of 6 weeks of therapy to 12 weeks of therapy would be shown if the upper boundary of the 95% confidence interval for the absolute between-group difference (the value in the 6-week group minus the value in the 12-week group) in the percentage of patients with persistent infection within 2 years was not greater than 10 percentage points. RESULTS: A total of 410 patients from 28 French centers were randomly assigned to receive antibiotic therapy for 6 weeks (205 patients) or for 12 weeks (205 patients). Six patients who withdrew consent were not included in the analysis. In the main analysis, 20 patients who died during follow-up were excluded, and missing outcomes for 6 patients who were lost to follow-up were considered to be persistent infection. Persistent infection occurred in 35 of 193 patients (18.1%) in the 6-week group and in 18 of 191 patients (9.4%) in the 12-week group (risk difference, 8.7 percentage points; 95% confidence interval, 1.8 to 15.6); thus, noninferiority was not shown. Noninferiority was also not shown in the per-protocol and sensitivity analyses. We found no evidence of between-group differences in the percentage of patients with treatment failure due to a new infection, probable treatment failure, or serious adverse events. CONCLUSIONS: Among patients with microbiologically confirmed prosthetic joint infections that were managed with standard surgical procedures, antibiotic therapy for 6 weeks was not shown to be noninferior to antibiotic therapy for 12 weeks and resulted in a higher percentage of patients with unfavorable outcomes. (Funded by Programme Hospitalier de Recherche Clinique, French Ministry of Health; DATIPO ClinicalTrials.gov number, NCT01816009.).

Periprosthetic joint infection in aseptic total hip arthroplasty revision.

PURPOSE: There is no consensus regarding systematic screening for infection in aseptic revision total hip arthroplasty (THA). The rationale for systematic intra-operative samples is to increase the sensitivity of latent infections detection, which may require specific treatment. However, the incidence of occult infection in revision THAs is not precisely known. As such, the aim of the study was to evaluate the incidence of occult infection in presumed aseptic revision THAs and identify associated risk factors. METHOD: Bacteriological samples from 523 aseptic THA revisions performed for five years were analyzed. Revisions performed for periprosthetic joint infection (PJI) or clinical suspicion of PJI were excluded. Microbiological cultures were performed using tissue samples in 505 cases (97%), synovial fluid in blood culture vials in 158 (30%), and in dry tubes in 263 (50%). Implants were sent for sonication in 12 cases (2.6%). The mean number of microbiological samples per patient was 3.6 (range, 1-15). Histology samples were collected for 300 patients (57%). RESULTS: The incidence of occult infection was 7% (36 cases) and contamination 8% (42 cases). Among occult infections, the primary reasons for revision were dislocation (42%), aseptic loosening (25%), fracture (19%), and others (14%). The infection rate in the dislocation group was significantly higher than that of other reasons for revision (p < 0.001). Among the patients determined with PJI, the revision THA was performed less than a year after primary in 19 (53%). CONCLUSION: The incidence of occult PJI justifies systematic intraoperative sampling. A short time between primary arthroplasty and revision or an early postoperative dislocation is a factor to suspect infections.

A Multicentric, Open-Label, Randomized, Comparative Clinical Trial of Two Different Doses of Expanded hBM-MSCs Plus Biomaterial versus Iliac Crest Autograft, for Bone Healing in Nonunions after Long Bone Fractures: Study Protocol.

ORTHOUNION is a multicentre, open, comparative, three-arm, randomized clinical trial (EudraCT number 2015-000431-32) to compare the efficacy, at one and two years, of autologous human bone marrow-derived expanded mesenchymal stromal cell (hBM-MSC) treatments versus iliac crest autograft (ICA) to enhance bone healing in patients with diaphyseal and/or metaphysodiaphyseal fracture (femur, tibia, and humerus) status of atrophic or oligotrophic nonunion (more than 9 months after the acute fracture, including recalcitrant cases after failed treatments). The primary objective is to determine if the treatment with hBM-MSCs combined with biomaterial is superior to ICA in obtaining bone healing. If confirmed, a secondary objective is set to determine if the dose of 100 × 106 hBM-MSCs is noninferior to that of 200 × 106 hBM-MSCs. The participants (n = 108) will be randomly assigned to either the experimental low dose (n = 36), the experimental high dose (n = 36), or the comparator arm (n = 36) using a central randomization service. The trial will be conducted in 20 clinical centres in Spain, France, Germany, and Italy under the same clinical protocol. The confirmation of superiority for the proposed ATMP in nonunions may foster the future of bone regenerative medicine in this indication. On the contrary, absence of superiority may underline its limitations in clinical use.

Periprosthetic shoulder infection: an overview.

Periprosthetic shoulder infection (PSI) is rare but potentially devastating. The rate of PSI is increased in cases of revision procedures, reverse shoulder implants and co-morbidities. One specific type of PSI is the occurrence of low-grade infections caused by non-suppurative bacteria such as Propionibacterium acnes or Staphylococcus epidemermidis.Success of treatment depends on micro-organism identification, appropriate surgical procedures and antibiotic administration efficiency. Post-operative early PSI can be treated with simple debridement, while chronic PSI requires a one- or two-stage revision procedure. Indication for one-time exchange is based on pre-operative identification of a causative agent. Resection arthroplasty remains an option for low-demand patients or recalcitrant infection. Cite this article: EFORT Open Rev 2017;2:104-109. DOI: 10.1302/2058-5241.2.160023.

Laterality and grip strength influence hand bone micro-architecture in modern humans, an HRpQCT study.

It is widely hypothesized that mechanical loading, specifically repetitive low-intensity tasks, influences the inner structure of cancellous bone. As such, there is likely a relationship between handedness and bone morphology. The aim of this study is to determine patterns in trabecular bone between dominant and non-dominant hands in modern humans. Seventeen healthy patients between 22 and 32 years old were included in the study. Radial carpal bones (lunate, capitate, scaphoid, trapezium, trapezoid, 1st, 2nd and 3rd metacarpals) were analyzed with high-resolution micro-computed tomography. Additionally, crush and pinch grip were recorded. Factorial analysis indicated that bone volume ratio, trabeculae number (Tb.N), bone surface to volume ratio (BS.BV), body weight, stature and crush grip were all positively correlated with principal components 1 and 2 explaining 78.7% of the variance. Volumetric and trabecular endostructural parameters (BV/TV, BS/BV or Tb.Th, Tb.N) explain the observed inter-individual variability better than anthropometric or clinical parameters. Factors analysis regressions showed correlations between these parameters and the dominant side for crush strength for the lunate (r2 = 0.640, P < 0.0001), trapezium (r2 = 0.836, P < 0.0001) and third metacarpal (r2 = 0.763). However, despite a significant lateralization in grip strength for all patients, the endostructural variability between dominant and non-dominant sides was limited in perspective to inter-individual differences. In conclusion, handedness is unlikely to generate trabecular patterns of asymmetry. It appears, however, that crush strength can be considered for endostructural analysis in the modern human wrist.

BMI-related microstructural changes in the tibial subchondral trabecular bone of patients with knee osteoarthritis.

Overweight is a risk factor for osteoarthritis on the knees. Subchondral trabecular bone (SCTB) densification has been shown to be associated with cartilage degeneration. This study analyzed the microarchitectural changes in the SCTB of tibial plateaus to validate the hypothesis that the degree of remodeling is correlated with a patient's body weight. Twenty-one tibial plateaus were collected during total knee arthroplasty from 21 patients (15 women and 6 men). These patients had a mean age of 70.4 years (49-81), mean weight of 74.7 kg (57-93) and mean body mass index (BMI) of 28.4 kg/m2 (21.3-40.8). One cylindrical plug was harvested in the center of each tibial plateau (medial and lateral). Micro-CT parameters (7.4 µm resolution) were determined to describe the SCTB structure. On the medial plateau, there were significant correlations between BMI and bone volume fraction BV/TV (r = 0.595, p = 0.004), structure model index SMI (r = -0.704 p = 0.0002), trabecular space Tb.Sp (r = 0.600, p = 0.04) and trabecular number Tb.N (r = 0.549, p = 0.01). SCTB densification during osteoarthritis is associated with a reduction in its elastic modulus, which could increase cartilage stress, and accelerate cartilage loss. SCTB densification has been shown to precede cartilage degeneration. The correlation of SCTB microarchitecture and body weight may explain why knee osteoarthritis is more common in overweight or obese patients. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1653-1660, 2017.

Cadaveric Study Comparing the Biomechanical Properties of Grafts Used for Knee Anterolateral Ligament Reconstruction.

PURPOSE: To measure the biomechanical properties (maximum load, stiffness, and elongation) of the anterolateral ligament (ALL), gracilis, and iliotibial band (ITB) within the same subject. METHODS: Thirteen unpaired knees were used (7 women, 6 men). The donors had a mean age at death of 54 years (range: 37 to 70 years). The mechanical properties of two types of ALL grafts were evaluated: ITB and two-strand gracilis. The mechanical properties of ALL were also measured. Validated methods were used to perform the tensile tests to failure and to record the results. Student's t-test was used to compare the various samples. RESULTS: The maximum load to failure was 141 N (±40.6) for the ALL, 200.7 N (±48.7) for the gracilis, and 161.1 N (±27.1) for the ITB. Only the gracilis had a significantly higher failure load than ITB and ALL (P = .001 and P = .03). The stiffness was 21 N mm-1 (±8.2) for the ALL, 131.7 N mm-1 (±43.7) for the gracilis, and 39.9 N mm-1 (±6) for the ITB. The elongation at failure was 6.2 mm (±3.2) for the ALL, 19.9 mm (±6.5) for the gracilis, and 20.8 mm (±14.7) for the ITB. CONCLUSIONS: The gracilis had the highest maximum load to failure. The ITB's mechanical properties most closely resemble those of the ALL. CLINICAL RELEVANCE: The biomechanical properties of each potential ALL graft can be factored in when deciding which type of graft to use.

Can the gracilis replace the anterior cruciate ligament in the knee? A biomechanical study.

PURPOSE: The purpose of this study was to determine whether a four-strand gracilis-only construct possesses the biomechanical properties needed to act as an anterior cruciate ligament (ACL) reconstruction graft. METHODS: This was a pilot study with 32 cadaver specimens. The biomechanical properties of three types of grafts were determined using validated tensile testing methods: patellar tendon (BTB), both hamstring tendons together (GST4) and gracilis alone (G4). RESULTS: The maximum load at failure of the G4 was 416.4 N (±187.7). The GST4 and BTB had a maximum load at failure of 473.5 N (±176.9) and 413.3 N (±120.4), respectively. The three groups had similar mean maximum load and stiffness values. The patellar tendon had significantly less elongation at failure than the other two graft types. CONCLUSIONS: The biomechanical properties of a four-strand gracilis construct are comparable to the ones of standard grafts. This type of graft would be useful in the reconstruction of the anteromedial bundle in patients with partial ACL ruptures.

Biomechanical study of ACL reconstruction grafts.

There are no published studies describing the strength quadrupled gracilis tendon alone and quadrupled semitendinosus tendon alone in the configuration used for anterior cruciate ligament (ACL) reconstruction. The primary objective was to compare the mechanical properties of grafts used for ACL reconstruction during a tensile failure test. The secondary objective was to evaluate the effect of uniform suturing on graft strength. Fifteen pairs of knees were used. The mechanical properties of five types of ACL grafts were evaluated: patellar tendon (PT), sutured patellar tendon (sPT), both hamstring tendons (GST4), quadrupled semitendinosus (ST4), and quadrupled gracilis (G4). Validated methods were used to perform the tensile tests to failure and to record the results. Student's t-test was used to compare the various samples. The maximum load to failure was 630.8N (± 239.1) for the ST4, 473.5N (± 176.9) for the GST4, 413.3N (± 120.4) for the sPT, and 416.4N (± 187.7) for the G4 construct. Only the ST4 had a significantly higher failure load than the other grafts. The sPT had a higher failure load than the PT. The ST4 construct had the highest maximum load to failure of all the ACL graft types in the testing performed here. Uniform suturing of the grafts improved their ability to withstand tensile loading.

Evaluation of the accuracy of patient-specific cutting blocks for total knee arthroplasty: a meta-analysis.

PURPOSE: Because published studies on the accuracy achieved with patient-specific guides during total knee arthroplasty (TKA) contradict each other, this systematic review and meta-analysis sought to compare radiological TKA outcomes when patient-specific cutting blocks (PSCB) were used to the outcomes when standard manual instrumentation was used. METHODS: The meta-analysis was implemented according to PRISMA Statement Criteria. The primary endpoint was the hip-knee-ankle (HKA) angle, which represents the leg's mechanical axis. The accuracy of component placement in the coronal and sagittal planes, and the accuracy of femoral component rotation were also compiled. After testing for publication bias and heterogeneity across studies, data were aggregated random-effects modeling when necessary. RESULTS: Fifteen articles were included: 916 total knee arthroplasty cases in the PSCB group and 998 in the MI group. The mechanical axis did not differ between the two groups (weighted mean difference 0.07°; 95 % CI, -0.5° to 0.65°; p = 0.8). Risk ratio analysis revealed no protective effect of using PSCB relative to the appearance of HKA angle outliers (RR = 0.88; 95 % CI, 0.68-1.13; p = 0.3). There was a trend towards a protective effect with PSCB for the risk of femoral component outliers, but the opposite was observed for the tibial component. The implantation procedure was stopped in 30 cases because the surgeon-authors found excessive discrepancies between the intra-operative observations and the pre-operative plan. CONCLUSIONS: This meta-analysis found no evidence that using patient-specific cutting blocks provides superior accuracy to using manual instrumentation during TKA.

Obesity is no longer a risk factor for dislocation after total hip arthroplasty with a double-mobility cup.

PURPOSE: Dislocation is one of the most feared complications after total hip arthroplasty (THA). This risk is greater in obese patients compared with the general population. METHODS: We performed a retrospective cohort study in which the main objective was to compare the dislocation rate between obese patients (BMI > 30 kg/m²) (exposed group) and non-obese patients (BMI ≤ 30 kg/m²) (unexposed group) after primary THA with a double-mobility acetabular cup. The patients had a minimum follow-up of 24 months. RESULTS: The 'obese' group consisted of 77 THA cases and the 'non-obese' group of 425 cases; the two groups were similar in terms of age, gender and ASA score. After a mean follow-up of 58.3 ± 27 months (range 27-159), 43 patients had been lost to follow-up and 56 had died; the two groups had similar mean values. One patient in the 'obese' group had suffered a dislocation due to a fall 16 months after the THA. One patient in the 'non-obese' group had suffered a dislocation after a periprosthetic femur fracture with stem subsidence two months after the THA procedure. Both patients underwent surgical revision where the double-mobility cup was preserved; there were no further dislocation events as of the last follow-up. The dislocation rate in the two groups was similar (1.3 % versus 0.23%, p > 0.05). No cases of loosening were found. Revisions were secondary to deep or superficial infection (n = 22), periprosthetic femur fracture (n = 10) or haematoma (n = 3). CONCLUSION: These findings imply that double-mobility cups are a reliable way of reducing the risk of dislocation in obese patients after primary THA.

Reverse shoulder arthroplasty for malignant tumors of proximal humerus.

BACKGROUND: Reverse shoulder arthroplasty (RSA) provides an alternative for shoulder girdle reconstruction after wide transarticular resection of the proximal humerus for malignant tumor. The aim of this study was to evaluate midterm outcomes of this therapeutic option. METHODS: Ten patients with RSA were included and reviewed with 24 months of minimum follow-up. Proximal resection of malignant tumor included the "V" deltoid insertion in 4 patients. The humeral stem was coated (with an allograft in 2 patients and a cement mantel in 3) or left uncoated (5 patients). RESULTS: At a mean follow-up of 42 months, among 8 prosthesis available for evaluation (2 patients died), the Constant and Murley score averaged 52 points, the 11-item version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) score averaged 29.5 points, the Subjective Shoulder Value averaged 58%, and the Musculoskeletal Tumor Society score averaged 20.25 points. Mean forward active elevation reached 122°, external rotation at side was -2°, and internal rotation was to L4. Three prostheses were unstable. The involvement of "V" deltoid insertion at surgery trended to worsen the clinical outcome. Atrophy of the anterior deltoid occurred in most of patients who had a previous transdeltoid biopsy. Radiographic evaluation found 1 stem loosening, 1 stem at risk, and 3 scapular notches without glenoid loosening. CONCLUSION: Use of RSA after resection of a malignant tumor of the proximal humerus seems to be an acceptable option to preserve function. However, radiographic evolution is worrisome, and long-term study remains necessary to validate this therapeutic option with follow-up.

Osteoblast-derived sphingosine 1-phosphate to induce proliferation and confer resistance to therapeutics to bone metastasis-derived prostate cancer cells.

Sphingosine 1-phosphate (S1P) plays important roles in cell proliferation, differentiation or survival mainly through its surface G-protein-coupled receptors S1P1-5. Bone represents the major site of metastasis for prostate cancer (CaP) cells, which rely on bone-derived factors to support their proliferation and resistance to therapeutics. In the present work we have found that conditioned medium (CM) from the MC3T3 osteoblastic cell line or primary murine and human osteoblast-like cells, as well as co-culture with MC3T3 stimulate proliferation of CaP lines in S1P-dependent manner. In addition, osteoblastic-derived S1P induces resistance of CaP cells to therapeutics including chemotherapy and radiotherapy. When S1P release from osteoblastic cells is decreased (inhibition of SphK1, knock-down of SphK1 or the S1P transporter, Spns2 by siRNA) or secreted S1P neutralized with anti-S1P antibody, the proliferative and survival effects of osteoblasts on CaP cells are abolished. Because of the paracrine nature of the signaling, we studied the role of the S1P receptors expressed on CaP cells in the communication with S1P secreted by osteoblasts. Strategies aimed at down-regulating S1P1, S1P2 or S1P3 (siRNA, antagonists), established the exclusive role of the S1P/S1P1 signaling between osteoblasts and CaP cells. Bone metastases from CaP are associated with osteoblastic differentiation resulting in abnormal bone formation. We show that the autocrine S1P/S1P3 signaling is central during differentiation to mature osteoblasts by regulating Runx2 level, a key transcription factor involved in osteoblastic maturation. Importantly, differentiated osteoblasts exhibited enhanced secretion of S1P and further stimulated CaP cell proliferation in a S1P-dependent manner. By establishing the dual role of osteoblast-borne S1P on both osteoblastic differentiation and CaP cell proliferation and survival, we uncover the importance of S1P in the bone metastatic microenvironment, which may open a novel area of study for the treatment of CaP bone metastasis by targeting S1P.

Traumax screw plate vs. Gamma nail. Blood loss in pertrochanteric fractures treated by minimally invasive osteosynthesis.

PURPOSE: This study is aimed to determine whether the Traumax dynamic hip screw reduces perioperative blood loss and transfusion rate compared to the Gamma nail in the treatment of pertrochanteric fractures. MATERIALS AND METHODS: A series of 331 patients were followed prospectively in a cohort study between February 2008 and October 2011 after a pertrochanteric fracture. Two types of fixation were used, 163 patients were treated with a Gamma nail and 168 patients with a minimally invasive screw plate Traumax. Perioperative blood loss, evaluated by the Mercuriali formula based on pre- and postoperative haemoglobin and transfusion rates were compared in order to assess risk factors. RESULTS: Increased perioperative blood loss was significantly linked with patient-related parameters (age, anticoagulant and platelet aggregation inhibitor treatment). Type of osteosynthesis and type of fracture were also risk factors for blood loss and transfusion. The Traumax group had significantly lower blood loss (347 ml vs. 577 ml) and transfusion rate (33.9% vs. 63.8%) than the Gamma group. Involvement of the greater trochanter increased the risk of blood loss only in the Gamma group. Functional results and bone healing were comparable at six months follow-up. CONCLUSION: Screw plate Traumax significantly reduces perioperative bleeding after pertrochanteric fractures. It avoids fracture gaps that tend to maintain bleeding. Given the morbidity and complications related to acute anaemia and blood transfusion, the surgical management of these elderly patients is aided by this choice of fixation.

Prospective study comparing functional outcomes and revision rates between hip resurfacing and total hip arthroplasty: preliminary results for 2 years.

There is a need of independent prospective studies about modern generation of hip resurfacing implants. The aim of this propective observational study was to compare the functional outcomes and revision rates with hip resurfacing arthroplasty and total hip arthroplasty and to present the preliminary results at 2 years. Patients included were recruited prospectively in the Partial Pelvic Replacement Hip Project by a single surgeon between January 2007 and January 2010. Patients were assessed with the Harris Hip Score (HHS) and Postel-Merle d'Aubigné (MDA) score and Devane Score. The end point of the study was reoperation for any cause related to the prosthesis. At a mean follow up of 38.6 months there were a total of 142 patients with hip resurfacing (group 1) [100 Durom(®) (Zimmer Inc., Warsaw, IN, USA) and 42 Birmingham Hip Resurfacing(®) (Smith & Nephew, Memphis, TN, USA)] and 278 patients with total hip arthroplasty (group 2). The results showed significantly greater gain of HHS, MDA and Devane score with hip resurfacing procedures. However, considering all the complications, the rate was significantly higher in group 16.4% vs 1.79% in group 2 (P<0.0001). In group 1 we observed 6 complications only concerned males with Durom(®) implants. The follow up of this cohort is still on going and may deliver more information on the evolution of these results in time.

Massive Proximal Extravasation as a Complication during Arthroscopic Anterior Cruciate Ligament Reconstruction.

Extra-articular extravasation of irrigation fluid is relatively common around entry incisions and is usually limited to the subcutaneous tissue. Very rarely, extravasation occurs above the knee, in the thigh and even up into the pelvis. We are reporting the second case of irrigation fluid extravasation during a knee arthroscopy, which spread up to the thigh, groin and perineum during anterior cruciate ligament reconstruction, whilst the tourniquet was inflated. In our case, we think that the extravasation was caused by a fault in the pressure sensor due to the fact that the reservoir was over-filled. The irrigation pressure was therefore too high, and the irrigation fluid was able to diffuse, despite the presence of a pneumatic tourniquet, up past the thigh.

Radiological validation of a fluoroscopic guided technique for femoral implant positioning during hip resurfacing.

PURPOSE: The positioning of the femoral cup in hip resurfacing is essential for the survival of the implant. We described a technique in 2005 to position the femoral cup guided by fluoroscopy independent of the approach performed. The main objectives were to study the positioning of the femoral components of the implant and the accuracy of the technique. METHODS: Between 2003 and 2011 we conducted a prospective study of 160 consecutive hip resurfacings all operated with this fluoroscopic-guided technique. Three independent observers performed a radiographic analysis at the pre-operative planning stage and on postoperative radiographs using OsiriX software. The statistical analysis was based on comparison of two groups by Student's t test. RESULTS: The entire implant was positioned in valgus, with an average of 7.816° valgus (p <0.001). All implants were positioned in neutral or anteverted with a mean of 1.98° (p <0.001). The risk of malpositioning on the antero-posterior plane was less than 1.41° with p <0.019. The risk of profile positioning error was lower than 0.80° with p <0.047. CONCLUSION: This study validates a technique of femoral implant positioning for resurfacing. It is simple, precise and independent of the approach performed.

Anatomy of the bands of the hamstring tendon: how can we improve harvest quality?

BACKGROUND: The hamstring tendons, gracilis and semitendinosus are widely used in ligament and reconstructive surgery. Their accessory bands or insertions are technical pitfalls during harvesting. METHODS: Thirty fresh cadaver knees have been studied, in order to 1) determine the anatomy of the bands of the gracilis and semitendinosus tendons, and, 2) to identify risk factors for failure during harvesting. RESULTS: Semitendinosus always had at least one band, sometimes two, strong, tendinous, and generally running to the fascia of gastrocnemius medialis to which they are attached, at an acute angle in a distal direction. Their presence is constant and they are only exceptionally found more than 100 mm from the tendon's tibial insertion. Gracilis shows the greatest anatomical variability, and over one quarter have no bands (although there may be as many as three). Their location, destination and angle of attachment to the tendon vary greatly. These bands are mainly aponeurotic and less strong, but must be carefully and widely dissected. CONCLUSION: Anatomical variability makes harvesting of pes anserinus tendons difficult. Three simple anatomical criteria have been highlighted that can be assessed by the surgeon during harvesting. The criteria are the insertion, the direction and the anatomical type of the bands.

Hip resurfacing: a systematic review of literature.

PURPOSE: We conducted a systematic review of the literature in order to take stock of hip resurfacing according to the principle of "evidence based medicine". Our main objective was to compare the rate of revision of resurfacing implants with survival limits set by the National Institute of Clinical Excellence (NICE). METHODS: A systematic review was undertaken of all published (Medline, Cochrane, EMBASE) literature research databases up to July 2012 as recommended by the PRISMA statement. Data extraction focused on functional outcomes, complications and survival rates. The survival rates of implants were analysed according to the mean of the series in comparison to the NICE criteria. RESULTS: Fifty-three studies were identified and included 26,456 cases with an average of 499.17 ± 856.7 (range, 38-5000) cases per study. The median survival was 95.57 % ± 3.7 % (range, 84-100). The percentage of studies which satisfied the criteria set by NICE was 69.8 %. In terms of cumulative revision rates pondered by the number of implants, BHR®, Conserve Plus® and Cormet® showed the best results. The mean postoperative score was 91.2 ± 7.72 (range, 68.3-98.6). There was no statistically significant difference between implants in terms of functional outcomes. CONCLUSION: On the basis of the current evidence base, this review of the literature emphasises the importance of certain parameters that can improve the results of resurfacing. The type of implant seems to play an important role as does patient selection.