Analysis of cellularity in H&E-stained rat bone marrow tissue via deep learning.

Our objective was to develop an automated deep-learning-based method to evaluate cellularity in rat bone marrow hematoxylin and eosin whole slide images for preclinical safety assessment. We trained a shallow CNN for segmenting marrow, 2 Mask R-CNN models for segmenting megakaryocytes (MKCs), and small hematopoietic cells (SHCs), and a SegNet model for segmenting red blood cells. We incorporated the models into a pipeline that identifies and counts MKCs and SHCs in rat bone marrow. We compared cell segmentation and counts that our method generated to those that pathologists generated on 10 slides with a range of cell depletion levels from 10 studies. For SHCs, we compared cell counts that our method generated to counts generated by Cellpose and Stardist. The median Dice and object Dice scores for MKCs using our method vs pathologist consensus and the inter- and intra-pathologist variation were comparable, with overlapping first-third quartile ranges. For SHCs, the median scores were close, with first-third quartile ranges partially overlapping intra-pathologist variation. For SHCs, in comparison to Cellpose and Stardist, counts from our method were closer to pathologist counts, with a smaller 95% limits of agreement range. The performance of the bone marrow analysis pipeline supports its incorporation into routine use as an aid for hematotoxicity assessment by pathologists. The pipeline could help expedite hematotoxicity assessment in preclinical studies and consequently could expedite drug development. The method may enable meta-analysis of rat bone marrow characteristics from future and historical whole slide images and may generate new biological insights from cross-study comparisons.

Outcomes of acute versus delayed total hip arthroplasty following acetabular fracture.

PURPOSE: Post-traumatic arthritis is known complication following acetabular fracture. The aim was to compare mid- to long-term outcomes of acute THA (aTHA) for acetabular fracture and delayed THA (dTHA) following failure of ORIF or conservative management. METHODS: We retrospectively analysed 60 THA (21 aTHA; 39 dTHA) performed for acetabular fracture between 2004 and 2014 in 60 patients with a mean age of 59 years (20-94). Functional and Radiographic outcomes were assessed at a mean follow-up of 5 years (2-13) utilizing Oxford, Harris Hip (HHS), and Postel Merle d'Aubigné (PMA) scores and Brooker classification. RESULTS: The mean HHS (73), Oxford (32) and PMA (12) scores were significantly lower in the aTHA group. Acute THA was significantly associated with lower postoperative Oxford (ß = -4.2), HHS (ß = -7.8), and PMA (ß = -2.2) scores at mean 5 years (2-13). Eleven patients returned to the operating room. There were no significant differences between THA performed in acute or delayed fashion. The two primary reasons for revision were periprosthetic joint infection (n = 5) and aseptic loosening (n = 4). Survivorship free from reoperation at 10 years was 91% and 82% for aTHA and dTHA, respectively (p = 0.24). Increased PMA scores were associated with decreased overall survival of the THA free from reoperation (HR = 0.60). The degree of heterotopic ossification was significantly higher in the aTHA group (p < 0.001). CONCLUSION: Acute THA in the setting of acetabular fracture is a technically challenging procedure. However, in the present series, aTHA provided satisfactory immediate stability and good survivorship at 10 years in a medically vulnerable patient population. LEVEL OF EVIDENCE: Level 3; Therapeutic study.

In vitro Insect Fat Cultivation for Cellular Agriculture Applications.

Cell-cultured fat could provide important elements of flavor, nutrition, and texture to enhance the quality and therefore expand consumer adoption of alternative meat products. In contrast to cells from livestock animals, insect cells have been proposed as a relatively low-cost and scalable platform for tissue engineering and muscle cell-derived cultured meat production. Furthermore, insect fat cells have long been cultured and characterized for basic biology and recombinant protein production but not for food production. To develop a food-relevant approach to insect fat cell cultivation and tissue engineering, Manduca sexta cells were cultured and induced to accumulate lipids in 2D and 3D formats within decellularized mycelium scaffolding. The resultant in vitro fat tissues were characterized and compared to in vivo fat tissue data by imaging, lipidomics, and texture analyses. The cells exhibited robust lipid accumulation when treated with a 0.1 mM soybean oil emulsion and had "healthier" fat profiles, as measured by the ratio of unsaturated to saturated fatty acids. Mycelium scaffolding provided a simple, food-grade approach to support the 3D cell cultures and lipid accumulation. This approach provides a low-cost, scalable, and nutritious method for cultured fat production.

Lumbar fusion involving the sacrum increases dislocation risk in primary total hip arthroplasty.

AIMS: Concurrent hip and spine pathologies can alter the biomechanics of spinopelvic mobility in primary total hip arthroplasty (THA). This study examines how differences in pelvic orientation of patients with spine fusions can increase the risk of dislocation risk after THA. PATIENTS AND METHODS: We identified 84 patients (97 THAs) between 1998 and 2015 who had undergone spinal fusion prior to primary THA. Patients were stratified into three groups depending on the length of lumbar fusion and whether or not the sacrum was involved. Mean age was 71 years (40 to 87) and 54 patients (56%) were female. The mean body mass index (BMI) was 30 kg/m2 (19 to 45). Mean follow-up was six years (2 to 17). Patients were 1:2 matched to patients with primary THAs without spine fusion. Hazard ratios (HR) were calculated. RESULTS: Dislocation in the fusion group was 5.2% at one year versus 1.7% in controls but this did not reach statistical significance (HR 1.9; p = 0.33). Compared with controls, there was no significant difference in rate of dislocation in patients without a sacral fusion. When the sacrum was involved, the rate of dislocation was significantly higher than in controls (HR 4.5; p = 0.03), with a trend to more dislocations in longer lumbosacral fusions. Patient demographics and surgical characteristics of THA (i.e. surgical approach and femoral head diameter) did not significantly impact risk of dislocation (p > 0.05). Significant radiological differences were measured in mean anterior pelvic tilt between the one-level lumbar fusion group (22°), the multiple-level fusion group (27°), and the sacral fusion group (32°; p < 0.01). Ten-year survival was 93% in the fusion group and 95% in controls (HR 1.2; p = 0.8). CONCLUSION: Lumbosacral spinal fusions prior to THA increase the risk of dislocation within the first six months. Fusions involving the sacrum with multiple levels of lumbar involvement notably increased the risk of postoperative dislocation compared with a control group and other lumbar fusions. Surgeons should take care with component positioning and may consider higher stability implants in this high-risk cohort.

The CJOrtho app: A mobile clinical and educational tool for orthopedics.

The need for modern patient evaluation tools continues to grow. A dependable and reproducible assessment provides objective follow-up and increases the validity of collected data. This is where mobile apps come into play, as they provide a link between surgeons and patients. They also open the possibility of interacting with other healthcare staff to exchange common scientific reference systems and databases. The CJOrtho app provides fast access to 65 classification systems in orthopedics or trauma surgery, 20 clinical outcome scores and a digital goniometer. The development of free mobile apps is an opportunity for education and better follow-up, while meeting the demands of patients.

Degenerative subtalar joints complicated by medial plantar intraneural cysts : cutting the cystic articular branch prevents recurrence.

AIMS: The pathogenesis of intraneural ganglion cysts is controversial. Recent reports in the literature described medial plantar intraneural ganglion cysts (mIGC) with articular branches to subtalar joints. The aim of the current study was to provide further support for the principles underlying the articular theory, and to explain the successes and failures of treatment of mICGs. PATIENTS AND METHODS: Between 2006 and 2017, five patients with five mICGs were retrospectively reviewed. There were five men with a mean age of 50.2 years (33 to 68) and a mean follow-up of 3.8 years (0.8 to 6). Case history, physical examination, imaging, and intraoperative findings were reviewed. The outcomes of interest were ultrasound and/or MRI features of mICG, as well as the clinical outcomes. RESULTS: The five intraneural cysts followed the principles of the unifying articular theory. Connection to the posterior subtalar joint (pSTJ) was identified or suspected in four patients. Re-evaluation of preoperative MRI demonstrated a degenerative pSTJ and denervation changes in the abductor hallucis in all patients. Cyst excision with resection of the articular branch (four), cyst incision and drainage (one), and percutaneous aspiration/steroid injection (two) were performed. Removing the connection to the pSTJ prevented recurrence of mIGC, whereas medial plantar nerves remained cystic and symptomatic when resection of the communicating articular branch was not performed. CONCLUSION: Our findings support a standardized treatment algorithm for mIGC in the presence of degenerative disease at the pSTJ. By understanding the pathoanatomic mechanism for every cyst, we can improve treatment that must address the articular branch to avoid the recurrence of intraneural ganglion cysts, as well as the degenerative pSTJ to avoid extraneural cyst formation or recurrence. Cite this article: Bone Joint J 2018;100-B:183-9.

The minimum follow-up required for radial head arthroplasty: a meta-analysis.

AIMS: The primary aim of this study was to define the standard minimum follow-up required to produce a reliable estimate of the rate of re-operation after radial head arthroplasty (RHA). The secondary objective was to define the leading reasons for re-operation. MATERIALS AND METHODS: Four electronic databases, between January 2000 and March 2017 were searched. Articles reporting reasons for re-operation (Group I) and results (Group II) after RHA were included. In Group I, a meta-analysis was performed to obtain the standard minimum follow-up, the mean time to re-operation and the reason for failure. In Group II, the minimum follow-up for each study was compared with the standard minimum follow-up. RESULTS: A total of 40 studies were analysed: three were Group I and included 80 implants and 37 were Group II and included 1192 implants. In Group I, the mean time to re-operation was 1.37 years (0 to 11.25), the standard minimum follow-up was 3.25 years; painful loosening was the main indication for re-operation. In Group II, 33 Group II articles (89.2%) reported a minimum follow-up of < 3.25 years. CONCLUSION: The literature does not provide a reliable estimate of the rate of re-operation after RHA. The reproducibility of results would be improved by using a minimum follow-up of three years combined with a consensus of the definition of the reasons for failure after RHA. Cite this article: Bone Joint J 2017;99-B:1561-70.

Radiation dose and magnification in pelvic X-ray: EOS™ imaging system versus plain radiographs.

BACKGROUND: In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: (1) image magnification and (2) radiation dose between the EOS imaging system and plain X-ray. HYPOTHESIS: The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray. MATERIAL AND METHOD: A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3±13.7years (range, 24-87years). Magnification and radiation dose (dose-area product [DAP]) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1±5.3kg/m2 (range, 17.6-42.3kg/m2), including 7 with morbid obesity. RESULTS: Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15±0.05 (range, 1-1.32) on plain X-ray (P<10-5). In patients with BMI<25, mean magnification on plain X-ray was 1.15±0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22±0.06 (range, 1.18-1.32). The mean radiation dose was 8.19±2.63dGy/cm2 (range, 1.77-14.24) with the EOS system, versus 19.38±12.37dGy/cm2 (range, 4.77-81.75) with plain X-ray (P<10-4). For BMI >40, mean radiation dose was 9.36±2.57dGy/cm2 (range, 7.4-14.2) with the EOS system, versus 44.76±22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20dGy with each extra BMI point for the EOS system, versus 0.74dGy for plain X-ray. CONCLUSION: Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower. LEVEL OF EVIDENCE: 3, prospective case-control study.

Mid-term outcomes of 77 modular radial head prostheses.

AIMS: Radial head arthroplasty (RHA) may be used in the treatment of non-reconstructable radial head fractures. The aim of this study was to evaluate the mid-term clinical and radiographic results of RHA. PATIENTS AND METHODS: Between 2002 and 2014, 77 RHAs were implanted in 54 men and 23 women with either acute injuries (54) or with traumatic sequelae (23) of a fracture of the radial head. Four designs of RHA were used, including the Guepar (Small Bone Innovations (SBi)/Stryker; 36), Evolutive (Aston Medical; 24), rHead RECON (SBi/Stryker; ten) or rHead STANDARD (SBi/Stryker; 7) prostheses. The mean follow-up was 74.0 months (standard deviation (sd) 38.6; 24 to 141). The indication for further surgery, range of movement, mean Mayo Elbow Performance (MEP) score, quick Disabilities of the Arm, Shoulder and Hand (quickDASH) score, osteolysis and positioning of the implant were also assessed according to the design, and acute or delayed use. RESULTS: The mean MEP and quickDASH scores were 90.2 (sd 14; 45 to 100), and 14.0 points (sd 12; 1.2 to 52.5), respectively. There were no significant differences between RHA performed in acute or delayed fashion. There were 30 re-operations (19 with, and 11 without removal of the implant) during the first three post-operative years. Painful loosening was the primary indication for removal in 14 patients. Short-stemmed prostheses (16 mm to 22 mm in length) were also associated with an increased risk of painful loosening (odds ratio 3.54 (1.02 to 12.2), p = 0.045). Radiocapitellar instability was the primary indication for re-operation with retention of the implant (5). The overall survival of the RHA, free from re-operation, was 60.8% (sd 5.7%) at ten years. CONCLUSION: Bipolar and press-fit RHA gives unsatisfactory mid-term outcomes in the treatment of acute fractures of the radial head or their sequelae. The outcome may vary according to the design of the implant. The rate of re-operation during the first three years is predictive of the long-term survival in tight-fitting RHAs. Cite this article: Bone Joint J 2017;99-B1197-1203.

Can a target zone safer than Lewinnek's safe zone be defined to prevent instability of total hip arthroplasties? Case-control study of 56 dislocated THA and 93 matched controls.

BACKGROUND: Various factors contribute to instability of total hip arthroplasty (THA), with implant orientation being a major contributor. We performed a case-control study with computed tomography (CT) data to determine whether: 1) orientation contributes to THA instability and 2) a safer target zone for stability than Lewinnek's classic safe zone can be defined. MATERIAL AND METHODS: We included prospectively 363 cases of THA dislocation that occurred during the calendar 2013 year in 24 participating hospitals. Of the 128 dislocations that occurred in patients who underwent THA at these centers, 56 (24 anterior, 32 posterior) had CT scans, thus were included in the analysis. The control group was matched 4:1 based on implant type, year of implantation, age, sex, bearing types and THA indication. Of the 428 matched control THA cases, 93 had CT scans. In all, the CT scans from 149 cases (56 unstable, 93 stable) were analyzed to determine the acetabular cup's inclination and anteversion, and the femoral stem's anteversion. RESULTS: In the unstable THA group, cup inclination was 46.9°±7.4°, cup anteversion was 20.4°±10.8° and stem anteversion was 14.2°±9.9°. In the stable THA group, cup inclination was 44.9°±5.3° (P=0.057), cup anteversion was 22.1°±5.1° (P=0.009) and stem anteversion was 13.4°±4.4° (P=0.362). The optimal total anteversion (cup+stem) of 40-60° was achieved in 16.5% of unstable THA cases and 13.9% of stable THA cases, thus this parameter does not predict stability (odds ratio [OR] of 0.40, P=0.144). The cup was positioned in Lewinnek's safe zone in 44.6% of patients in the unstable group and 68.2% of those in the stable group (OR 3.74, P=0.003). A target zone defined as 40-50° inclination and 15-30° anteversion was better able to distinguish between unstable cases (23.2%) and stable cases (71.6%) resulting in an OR of 13.91 (P<0.001). DISCUSSION: Implant positioning was the only risk factor for instability found in this study. Moreover, our findings reinforce the theory put forward by other authors that Lewinnek's safe zone is not specific enough to differentiate between stable and unstable THA implantations. The target zone for acetabular cups proposed here (40-50° inclination and 15°-30° anteversion) is related to a lower risk of instability. This orientation can be used as a guide, but must be combined with other technical elements to optimize stability. By balancing stability and biomechanics, the 40-50° inclination and 15°-30° anteversion target zone redefines the optimal positioning window. LEVEL OF EVIDENCE: III case-control study.

Internal fixation of intra-capsular proximal femoral fractures in patients older than 80 years: Still relevant? Multivariate analysis of a prospective multicentre cohort.

BACKGROUND: Arthroplasty is now widely used to treat intra-capsular proximal femoral fractures (PFFs) in older patients, even when there is little or no displacement. However, whether arthroplasty is associated with lower mortality and complication rates in non-displaced or mildly displaced PFFs is unknown. The objectives of this prospective study were: (1) to evaluate early mortality rates with the two treatment methods, (2) to identify risk factors for complications, (3) and to identify predictors of functional decline. HYPOTHESIS: Arthroplasty and internal fixation produce similar outcomes in non-displaced fractures of patients older than 80 years with PFFs. MATERIAL AND METHODS: This multicentre prospective study included consecutive patients older than 80 years who were managed for intra-capsular PFFs at eight centres in 2014. Biometric data and geriatric assessment scores (Parker Mobility Score, Katz Index of Independence, and Mini-Nutritional Assessment [MNA] score) were collected before and 6 months after surgery. Independent risk factors were sought by multivariate analysis. We included 418 females and 124 males with a mean age of 87±4years. The distribution of Garden stages was stage I, n=56; stage II, n=33; stage III, n=130; and stage IV, n=323. Arthroplasty was performed in 494 patients and internal fixation in 48 patients with non-displaced intra-capsular PFFs. RESULTS: Mortality after 6 months was 16.4% overall, with no significant difference between the two groups. By multivariate analysis, two factors were significantly associated with higher mortality, namely, male gender (odds ratio [OR], 3.24; 95% confidence interval [95% CI], 2.0-5.84; P<0.0001) and high ASA score (OR, 1.56; 95% CI, 1.07-2.26; P=0.019). Two factors were independently associated with lower mortality, with 75% predictive value, namely, high haematocrit (OR, 0.8; 95% CI, 0.7-0.9; P=0.001) and better Parker score (OR, 0.5; 95% CI, 0.3-0.8; P=0.01). The cut-off values associated with a significant risk increase were 2 for the Parker score (OR, 1.8; 95% CI, 1.1-2.3; P=0.001) and 37% for the haematocrit (OR, 3.3; 95% CI, 1.9-5.5; P=0.02). Complications occurred in 5.5% of patients. Surgical site infections were seen in 1.4% of patients, all of whom had had arthroplasty. Blood loss was significantly greater with arthroplasty (311±197mL versus 201±165mL, P<0.0002). Dependency worsened in 39% of patients, and 31% of patients lost self-sufficiency. A higher preoperative Parker score was associated with a lower risk of high postoperative dependency (OR, 0.86; 95% CI, 0.76-0.97; P=0.014). DISCUSSION: Neither treatment method was associated with decreased mortality or better function after intra-capsular PFFs in patients older than 80 years. Early mortality rates were consistent with previous reports. Among the risk factors identified in this study, age, preoperative self-sufficiency, and gender are not amenable to modification, in contrast to haematocrit and blood loss. CONCLUSION: Internal fixation remains warranted in patients older than 80 years with non-displaced intra-capsular PFFs. LEVEL OF EVIDENCE: III, prospective case-control study.

Proximal femoral fractures in centenarians. A retrospective analysis of 39 patients.

BACKGROUND: A corollary of the current population ageing in France is an increase in proximal femoral fractures (PFFs), particularly among centenarians. The outcomes of PFFs in centenarians in France are unknown. We therefore conducted a retrospective study of centenarians with PFFs both to assess: (1) assess clinical outcomes according to geriatric and trauma scores, (2) and to determine whether routine surgery is warranted. HYPOTHESIS: Morbidity and mortality in a single-centre cohort of centenarians with surgically treated PFFs are consistent with previous reports. MATERIAL AND METHOD: We retrospectively reviewed the data of 33 women and 6 men aged 100 years or over who were treated surgically for PFFs at a single-centre between 2008 and 2014. Of the 39 patients, 15 were living at home and 24 in an institution at the time of the injury. Mean (range) values were 3.30 (0-7) for the Parker Mobility Score, 5.84 (0-12) for the Katz index, and 7.46 (2-12) for the Mini Nutritional Assessment (MNA). Mean time from injury to surgery was 1.7 days (0-12). The 26 extra-capsular fractures were managed by internal fixation and the 13 intra-capsular fractures by hip arthroplasty (n=12) or screw fixation (n=1). RESULTS: After a mean follow-up of 23±14 months (6-60 months), 29 patients had died, including 3 within 48h, 10 within 3 months, and 15 within 1 year. Sequential mortality rates were 33.3% within the first 3 months, 26.9% from months 4 to 9, and 42.2% within the first year. Early dislocation occurred in 3 patients and surgical-site infection in 2 patients. Other complications were heart failure (n=1), confusional state (n=2), pneumonia (n=2), and pyelonephritis (n=2). DISCUSSION: A PubMed search identified five studies of PFFs in more than 10 centenarians, of which only 2 provided detailed information on postoperative general and local morbidity related to the surgical treatment. Our hypothesis was confirmed for 3-month and 1-year mortality rates, which were at the lower ends of previously reported ranges. Local complications related directly to surgery were considerably more common in our study. PFFs in centenarians carry a high risk of death. Despite the absence of a control group, our data support surgery as the best treatment option. LEVEL OF EVIDENCE: IV, retrospective study.

Total hip arthroplasty survival in femoral head avascular necrosis versus primary hip osteoarthritis: Case-control study with a mean 10-year follow-up after anatomical cementless metal-on-metal 28-mm replacement.

BACKGROUND: Total hip arthroplasty is the most widely used procedure to treat avascular necrosis (AVN) of the femoral head. Few studies have compared the outcomes of THA in femoral head AVN and primary hip osteoarthritis. Therefore we performed a case-control study to compare THA for femoral head AVN vs. primary hip osteoarthritis in terms of: (1) prosthesis survival, (2) complication rates, (3) functional outcomes and radiographic outcomes, (4) and to determine whether specific risk factors for THA failure exist in femoral head AVN. HYPOTHESIS: THA survival is similar in femoral head AVN and primary hip osteoarthritis. MATERIAL AND METHODS: We compared two prospective cohorts of patients who underwent THA before 65 years of age, one composed of cases with femoral head AVN and the other of controls with primary hip osteoarthritis. In both cohorts, a cementless metal-on-metal prosthesis with a 28-mm cup and an anatomical stem was used. Exclusion criteria were THA with other types of prosthesis, posttraumatic AVN, and secondary osteoarthritis. With α set at 5%, to obtain 80% power, 246 patients were required in all. Prosthesis survival was assessed based on time to major revision (defined as replacement of at least one implant fixed to bone) and time to aseptic loosening. The other evaluation criteria were complications, Postel-Merle d'Aubigné (PMA) score, and the Engh and Agora Radiographic Assessment (ARA) scores for implant osseointegration. RESULTS: The study included 282 patients, 149 with AVN and 133 with osteoarthritis. Mean age was 47.8±10.2 years (range, 18.5-65) and mean follow-up was 11.4±2.8 years (range, 4.5-18.3 years). The 10-year survival rates were similar in the two groups: for major revision, AVN group, 92.5% (95% confidence interval [95% CI], 90.2-94.8) and osteoarthritis group, 95.3% (95% CI, 92.9-97.7); for aseptic loosening, AVN group, 98.6% (95% CI, 97.6-98.6) and osteoarthritis, 99.2% (95% CI, 98.4-100). The AVN group had higher numbers of revision for any reason (19 vs. 6, P=0.018) and for dislocation (8 vs. 1, P=0.031). Mean PMA scores at last follow-up were comparable in the AVN group (17.65±1.27 [range, 10-18]) and osteoarthritis group (17.59±1.32 [range, 14-18]) (P=0.139). Osseointegration was also similar in the two groups: global Engh score, 26.51±1.81 (range, 14-27) for AVN and 26.84±0.91 (range, 19.5-27) for osteoarthritis (P=0.065); femoral ARA score, 5.83±0.46 (range, 3-6) for AVN and 5.90±0.42 (range, 3-6) for osteoarthritis (P=0.064); and cup ARA score, 5.74±0.67 (range, 3-6) for AVN and 5.78±0.66 (range, 3-6) for osteoarthritis (P=0.344). DISCUSSION: Survival in this study was good and consistent with recent data on AVN, with no difference between AVN and osteoarthritis. Revisions for any cause or for dislocation were more common after THA for AVN. Functional outcomes were similar in the AVN and osteoarthritis groups. An anatomical cementless prosthesis combined with metal-on-metal 28-mm bearing provides durable good outcomes. LEVEL OF EVIDENCE: III, non-randomized comparison of two prospective cohorts.

Recurring intraprosthetic dislocation of rotating-hinge total knee prosthesis. Effect of implant design on intrinsic stability.

During total knee replacement, hinged total knee implants are used in cases where ligament balancing cannot be achieved with less-constrained implants. The case of a patient who experienced two episodes of intraprosthetic dislocation of his rotating-hinge total knee prosthesis is described. There are very few reports of this type of dislocation with these implants. The implant's design, particularly of the hinge, plays an important role in stability. The balance between the flexion and extension spaces is very important even when using a hinged total knee implant. The role of the extensor mechanism in anteroposterior stability is reviewed, along with simple ways to augment it.

Minimally invasive medial hip approach.

The medial approach to the hip via the adductors, as described by Ludloff or Ferguson, provides restricted visualization and incurs a risk of neurovascular lesion. We describe a minimally invasive medial hip approach providing broader exposure of extra- and intra-articular elements in a space free of neurovascular structures. With the lower limb in a "frog-leg" position, the skin incision follows the adductor longus for 6cm and then the aponeurosis is incised. A slide plane between all the adductors and the aponeurosis is easily released by blunt dissection, with no interposed neurovascular elements. This gives access to the lesser trochanter, psoas tendon and inferior sides of the femoral neck and head, anterior wall of the acetabulum and labrum. We report a series of 56 cases, with no major complications: this approach allows treatment of iliopsoas muscle lesions and resection or filling of benign tumors of the cervical region and enables intra-articular surgery (arthrolysis, resection of osteophytes or foreign bodies, labral suture).

The frequency of sequelae of slipped upper femoral epiphysis in cam-type femoroacetabular impingement.

Slipped upper femoral epiphysis (SUFE) is one of the known causes of cam-type femoroacetabular impingement (FAI). The aim of this study was to determine the proportion of FAI cases considered to be secondary to SUFE-like deformities. We performed a case-control study on 96 hips (75 patients: mean age 38 years (15.4 to 63.5)) that had been surgically treated for FAI between July 2005 and May 2011. Three independent observers measured the lateral view head-neck index (LVHNI) to detect any SUFE-like deformity on lateral hip radiographs taken in 45° flexion, 45° abduction and 30° external rotation. A control group of 108 healthy hips in 54 patients was included for comparison (mean age 36.5 years (24.3 to 53.9). The impingement group had a mean LVHNI of 7.6% (16.7% to -2%) versus 3.2% in the control group (10.8% to -3%) (p < 0.001). A total of 42 hips (43.7%) had an index value > 9% in the impingement group versus only six hips (5.5%) in the control group (p < 0.001). The impingement group had a mean α angle of 73.9° (96.2° to 53.4°) versus 48.2° (65° to 37°) in the control group (p < 0.001). Our results suggest that SUFE is one of the primary aetiological factors for cam-type FAI.

Reduced blood loss with ligation of medial circumflex pedicle during total hip arthroplasty with minimally invasive posterior approach.

A total hip arthroplasty procedure can lead to significant perioperative blood loss due to bleeding from the medial circumflex pedicle. When either the anterior or posterior approach is used, haemostasis of this pedicle, which is typically performed with electrocautery without dissection, can be inadequate. The purpose of this study was to evaluate the efficacy of a novel surgical technique in which the pedicleis is directly ligated. A single-centre, single-surgeon prospective study was performed to compare pedicle ligation to electrocautery (control group). In the ligation group, the pedicle was identified in front of the upper-third of the quadratus femoris and ligated. The mean postoperative blood loss in the ligation group (293.4±34.8 mL) was significantly less than in the control group (419.0±36.8 mL) (P<0.05). Pedicle ligation is a simple procedure that reduces blood loss during total hip arthroplasty.

Pudendal nerve neuralgia after hip arthroscopy: retrospective study and literature review.

INTRODUCTION: Pudendal nerve neurapraxia is a classic complication after traction on the fracture table. Diagnosis, however, is difficult and often overlooked, especially after arthroscopy in traction on fracture table; incidence is therefore not known exactly. HYPOTHESIS: The study hypothesis was that incidence of pudendal nerve neuropathy exceeds 1% after hip arthroscopy. MATERIALS AND METHODS: Results for 150 patients (79 female, 71 male) undergoing hip arthroscopy between 2000 and 2010 were analyzed retrospectively. The principal assessment criterion was onset of pudendal neuralgia. Secondary criteria were risk factors (history, surgery time, type of anesthesia), associated complications, onset to diagnosis interval and pattern of evolution. RESULTS: At a mean 93 months' follow-up, there were 3 cases (2 women, 1 man) (2%) of pure sensory pudendal neuralgia; 2 concerned labral lesion resection and 1 osteochondromatosis. Surgery time ranged from 60 to 120min, under general anesthesia with curarization. Time to diagnosis was 3 weeks. No complementary examinations were performed. Spontaneous resolution occurred at 3 weeks to 6 months. No significant risk factors emerged. CONCLUSION: The present study found 2% incidence of pudendal neuralgia, with no risk factors emerging from analysis. Prevention involves limiting traction force and duration by using a large pelvic support (diameter>8-10cm). Patient information and postoperative screening should be systematic. LEVEL OF EVIDENCE: Level IV. Retrospective study.

Obesity has no adverse effect on the outcome of unicompartmental knee replacement at a minimum follow-up of seven years.

The significance of weight in the indications for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was that weight does not affect the long-term rate of survival of UKRs. We undertook a retrospective study of 212 UKRs at a mean follow-up of 12 years (7 to 22). The patients were distributed according to body mass index (BMI; < vs ≥ 30 kg/m(2)) and weight (< vs ≥ 82 kg). Kaplan-Meier survivorship analysis was performed and ten-year survival rates were compared between the sub-groups. Multimodal regression analysis determined the impact of the various theoretical contraindications on the long-term rate of survival of UKR. The ten-year rates of survival were similar in the two weight subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to 96.3); < 82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the two BMI subgroups (≥ 30 kg/m(2): 92% (95% CI 82.5 to 95.3); < 30 kg/m(2): 94% (95% CI 78.4 to 95.9)). Multimodal regression analysis revealed that weight plays a part in reducing the risk of revision with a relative risk of 0.387, although this did not reach statistical significance (p = 0.662). The results relating weight and BMI to the clinical outcome were not statistically significant. Thus, this study confirms that weight does not influence the long-term rate of survival of UKR.

Posterior tibial tendon transfer in the spastic brain-damaged adult does not lead to valgus flatfoot.

BACKGROUND: We studied the possible development of valgus flat foot after transfer of the posterior tibial tendon to the lateral cuneiform, used for surgical restoration of dorsiflexion in brain-damaged adult patients with spastic equinovarus foot. METHODS: Twenty hemiplegic patients were reviewed with a mean postoperative follow-up of 57.9 months. Weightbearing radiographs, static baropodometry analysis and functional evaluation were used to assess postoperatively outcomes. RESULTS: On the operated side, weightbearing radiographs showed an absence of medial arch collapse and a symmetrical and physiological hindfoot valgus; static baropodometric analysis showed a reduced plantar contact surface with a pes cavus appearance. The surgical procedure yielded good functional results. Nineteen patients were satisfied with the outcome of their surgery. CONCLUSIONS: Our findings support that transfer of the posterior tibial tendon does not lead to valgus flat foot in the spastic brain-damaged adult, and is still a current surgical alternative for management of spastic equinovarus foot.