The "Metaizeau trick" to facilitate medullary pubic ramus screw insertion: A technical note.

Minimally invasive procedures have recently seen an increase in the treatment of pelvic ring disruptions and select acetabular fractures. Similar to ilio-sacral screws, the superior pubic ramus screw is becoming a preferred method for treating unstable pelvic ring fractures. While the osteology of the superior pubic ramus is well understood and has inherent variability, standard screw insertion techniques work effectively in most cases. If the anatomy prevents the standard approach, there are alternative methods that can be employed for successful screw placement, or there might be a need for an open reduction and internal fixation with plates. Such techniques can be material-intensive and time-consuming. In this paper, we introduce a straightforward method that utilizes the Metaizeau nail as a guide wire to facilitate screw insertion in most instances, termed the "Metaizeau trick". Metaizeau nails, commonly found in trauma centers, are designed to locate a pathway effortlessly using this method. LEVEL OF EVIDENCE: IV.

Laparoscopic treatment of fourteen cases of pelvic ring disruption: a case series.

PURPOSE: Open surgical approaches for the treatment of anterior pelvic arc lesions are associated with several complications. We present the first retrospective descriptive case series on the use of laparoscopy as an alternative. METHODS: This descriptive, retrospective, single-centre study enrolled all patients who underwent laparoscopy for the treatment of pelvic ring disruption between May 2020 and March 2022. The primary outcome was the procedure failure rate based on conversion to open surgery. Secondary outcomes were the duration of the surgical procedure, x-ray exposure, length of hospitalisation, postoperative pain assessment, and functional scores at the last follow-up. RESULTS: The study included two females and 12 males. The mean age of the study participants was 44.2 (23-67) years. In total, nine (64.3%) patients had pubic symphysis disjunction, four (28.6%) had bilateral fractures of the obturator frames, and one (7%) had both. None of the patients required conversion to open surgery. The median operating times for symphysis pubis disruption, obturator frame fracture, and patients with both injuries were 90.0 (60-120), 135 (105-180), and 240 min, respectively. The median overall operating time was 102.5 (60-240) min. The median Iowa Pelvic Score and Majeed Functional Score at the last follow-up were 87 (70-99) and 84 (70-100), respectively. CONCLUSION: Laparoscopic internal fixation is a reliable treatment for pelvic ring disruption. The clinical and radiological outcomes of our patients suggest the usefulness of this technique as an alternative to open approaches.

Consolidation rate in ulnar shortening osteotomy with the APTUS Wrist plate.

INTRODUCTION: Ulnocarpal impaction syndrome causes pain on the ulnar side of the wrist. Various surgical techniques have been described. Ulnar shortening osteotomy is now a standard treatment. However, it is associated with complications such as non-union of the osteotomy site. The main study objective was to report the rate of radiographic consolidation after ulnar shortening osteotomy with a cutting guide. MATERIAL AND METHODS: This multicenter retrospective study of 30 cases reported clinical and radiographic criteria at a minimum 6 month's follow-up. RESULTS: The non-union rate was 3.4%. One case presented non-union of the osteotomy site. 87% of patients were satisfied or very satisfied with the procedure. Mean VAS pain rating was 2.7 ± 2.4. Mean QuickDASH and PRWE scores were 24.7 ± 19.2 and 28.6 ± 25. Mean strength on Jamar dynamometer was 27.4 ± 8.9 kg. One patient developed complex regional pain syndrome. Five patients required plate removal for hardware-related discomfort. DISCUSSION: Ulna shortening osteotomy with the Aptus Wrist plate provides a standardized approach to the surgical treatment of ulnocarpal impaction syndrome. Compared with other series in the literature, the procedure provided satisfactory consolidation and clinical results.

Variations in pelvic tilt during day-to-day activities after total hip arthroplasty measured with an ultrasound system.

INTRODUCTION: The pelvis plays a major role in the orientation of total hip arthroplasty (THA) implants and consequently, on the postoperative stability of the new hip joint. The relationship between the spine and pelvis affects the functional orientation of the acetabular cup, although this relationship differs between individuals and the positions encountered in everyday life. We believe this should be factored in when planning the THA procedure. This led us to conduct an in vivo ultrasound study to document the values of pelvic tilt in standing, sitting and lying positions in patients who have advanced hip osteoarthritis, before and after they undergo THA. HYPOTHESIS: The pelvic tilt when standing, sitting and lying supine does not change significantly after THA. MATERIALS AND METHODS: The pelvic tilt, defined as the angle between the anterior pelvic plane and a vertical line was measured using an ultrasound device in 30 patients before the THA procedure and again 6 months later in standing, sitting and lying positions. The measurements were done during an office visit with the patient on an examination table for the lying position, on a chair for the sitting position and with the heels and occiput against the wall for the standing position. RESULTS: The preoperative and 6-month postoperative pelvic tilt were -5.6̊±10.4̊ [-30.6̊; 11.7̊] and -5.8̊±7.9̊ [-20.6̊; 10.4̊] (p=0.4129) when standing, -44.5̊±6.10 [-53.8̊; -23.9̊] and -43.5̊±6.9̊ [-54.4̊; -17.3̊] (p=0.5760) when sitting, -88.3̊±5.1̊ [-99.3̊; -78.7̊] and -87.9̊±5.9̊ [-97.6̊; -72.4̊] (p=0.6106) when lying supine, respectively. There was no significant difference in the pelvic tilt before and 6 months after THA procedure. Variations of±5̊; ±5-10̊; ±10-15̊ and 15-20̊ were found in 72% (18); 20% (5); 4% (1) and 4% (1) of patients when lying supine, 56% (14); 36% (9); 8% (2); 0% (0) of patients when standing and 76% (19); 24% (6); 0% (0); 0% (0) when sitting. The mean variation for each patient between the preoperative and 6 months postoperative measurement was 4.8±3.4̊ [0.8̊; 10.4̊] (p=0.4129), 3.5±2.3̊ [0.2̊; 9.1̊] (p=0.5760), and 4.6̊±3.2̊ [1.2̊; 15.4̊] (p=0.6106) for the standing, sitting and lying positions respectively. CONCLUSION: The pelvic tilt does not significantly change 6 months after THA. Taking into account the various positions used in everyday life may help to optimize the implant position. We have described the use of an affordable, accurate and non-irradiating device that provides fast and easy measurements of pelvic tilt in various positions. LEVEL OF EVIDENCE: IV.

Augmented versus non-augmented Trochanteric Fixation Nail-Advanced (TFNA) nails for treating trochanteric fractures in patients over sixty-five years of age.

PURPOSE: Intramedullary nailing is a common treatment for pertrochanteric fractures. However, implant-related mechanical failures, such as cut-out and cut-through, lead to higher rates of revision surgery, loss of autonomy, and mortality. Cemented augmentation enhances the bone-implant interface. This study compared the frequency of mechanical failures between augmented and non-augmented Trochanteric Fixation Nail-Advanced (TFNA) nails. METHODS: This descriptive, retrospective study at a level 1 trauma centre included patients aged > 65 years with pertrochanteric fractures treated by a short augmented or non-augmented TFNA nail. The primary outcome was the comparison of cut-out or cut-through rates between groups at three and six months postoperatively. RESULTS: Of the 181 patients analysed, 103 had augmented TFNA nails and 78 had non-augmented TFNA nails. There were no statistically significant differences between groups in terms of demographic characteristics, AO/OTA classification, or quality of reduction. The failure rate was significantly lower in the augmented group than in the non-augmented group: 1 (0.97%) versus 9 (11.54%) (p = 0.005). At six months postoperatively, there was no significant difference between the two groups concerning functional recovery, as measured by the Parker and EuroQoL 5-Dimensions scores. CONCLUSIONS: For patients aged over 65 years, the use of the augmented TFNA nail may reduce the risk of fixation failures such as cut-out.

Study of the position of six volar locking plates for distal radius fracture relative to the watershed line.

INTRODUCTION: Volar plate malpositioning in the treatment of distal radial fracture can lead to tendinitis or even tendon tear, especially when the plate position is very distal. We studied the impact of design on plate position in the distal radius. The primary aim was to compare the position of six volar wrist plates relative to the watershed line using the Soong classification. The secondary objectives were to assess the epidemiology of volar locking plate fixation within the administrative Département of Finistère (northwestern France) and to study whether the type of fracture played a role in plate position. HYPOTHESIS: The plate design itself influences positioning relative to the watershed line on the Soong classification. MATERIALS AND METHODS: A total of 2723 volar locking plate fixation cases were analyzed and categorized according to the Soong classification. Plates used were divided into six groups based on design: Zimmer Biomet®, Newclip Technics®, Stryker®, Synthes®, Medartis® and Medartis® Footprint. The number of Soong 0 + 1 plates (i.e., plates graded 0 and 1 taken together) was determined for each design, then compared using the Marascuilo procedure with a significance level of α = 0.05. RESULTS: On the Marascuilo procedure, we found significant differences in the number of Soong grade 0 + 1 plates. The Zimmer Biomet and Newclip Technics® plates were significantly more often proximal to the watershed line than the Synthes and Medartis Footprint plates. Plate position with the Medartis® design was significantly more proximal to the watershed line than for its companion design, the Medartis® Footprint plate. The rate of volar locking plate fixation of distal radial fractures over the past 10 years increased in Finistère. Also, the type of fracture affected the choice of plate when different designs were available within a hospital center (Medartis® Footprint plate used in 2R3A fractures). CONCLUSION: Our study highlights a significant difference in volar locking plate position relative to the watershed line between the various models available. Plate design is a deciding factor when treating distal radial fracture, to avoid impingement when implant removal is not routinely planned.

Total shoulder arthroplasty in France: An analysis of trends between 2009 and 2019 and projections to the year 2070.

BACKGROUND: Over the past decades, total shoulder arthroplasty (TSA) procedures have steadily increased in the United States and Europe. In France, the number of shoulder surgeries rose by 24.5% between 2012 and 2018, but no study has yet analyzed TSA trends based on patient characteristics. Therefore, the aim of our study was to use the French healthcare database to (1) analyze growth trends based on the patient's sex, age, and comorbidity profile and (2) estimate the most appropriate incidence rate (IR) projections to the year 2070. HYPOTHESIS: We hypothesize that in France, the upward trends are different for each sex and age group. MATERIALS AND METHODS: This study was conducted in France from 2009 to 2019 based on the French healthcare database (SNDS), which contains all nationwide procedures. Patients were analyzed by sex, age group (<65 years, 65-74 years, ≥75 years), and comorbidity profile (4 levels). IR trends per 100,000 population were inferred by patient age, sex, and comorbidity using data from the French hospital discharge database (PMSI) and population forecasts and censuses from the French National Institute of Statistics and Economic Studies (INSEE). Linear, Poisson, logistic, and Gompertz projection models were created to forecast IRs to the year 2070. RESULTS: Between 2009 and 2019, there was a sharper increase in IR in males (+155%; from 6.0 to 15.3) than in females (+118%; from 16.2 to 35.3) across all age groups. This increase was most significant in those younger than 65 years (+112%; from 2.3 to 4.9), in both males (+129%; from 2.1 to 4.8) and females (+99%; from 2.5 to 5.0). From 2012 to 2019, the proportion of patients with mild comorbidities increased by +92% (from 5,435 to 10,410 TSAs, i.e., from 56% to 61% of total procedures), unlike the other comorbidity profiles. All the projections modeled the data from 2009 to 2019 with minor deviations. However, the logistic projection was the most likely, with a 45% increase in the IR for the overall population by 2070 (from 17,175 to 25,338 TSAs), which will start to plateau in 2050. CONCLUSION: The IR has risen sharply in the overall population, as in all age, sex, and comorbidity categories, with the most significant growth seen in the<65 and 65-74 age groups and a shift toward patients with milder comorbidities. According to our projections, the IR will continue to be more significant in older patients, except for males, for whom the IR for those 65 to 74 years old will exceed that of those 75 and older around 2030. In the longer term, the IRs follow a logistic trend, reaching a plateau around 2050. Therefore, an increase in healthcare burden is to be expected to meet the growing demand for TSAs. LEVEL OF EVIDENCE: IV; Descriptive epidemiological study.

Transfer of the palmaris brevis motor branch to the thenar motor branch: A cadaveric preliminary study.

OBJECTIVE: High median nerve injuries can lead to poor distal recovery, especially poor functioning of median innervated thenar muscles involved in thumb opposition and palmar abduction. The palmaris brevis (PB) is a small subcutaneous muscle innervated by ulnar nerve. Innervation of the PB is in most of cases provided by the ulnar digital nerve to the little finger. The purpose of this study is to assess the feasibility of transferring the PB motor branch (PBMB) to the median nerve thenar motor branch (TMB), in order to allow for early restoration of thumb palmar abduction and opposition, through a preliminary cadaveric study. METHODS: Twenty-five cadaver upper limbs were dissected under magnification. The length of the PBMB and TMB, and their origin were recorded. Nerve transfer from PBMB to TMB was conducted, and evaluated on 2 parameters: surgical feasibility, and distance from the coaptation site to the recipient nerve muscle entry point. The PBMB and TMB were harvested, fixated in formalin, then embedded in paraffin. They were sectioned transversely, and stained with a combination of hematoxylin-eosin and Luxol fast blue. Myelinated axons were counted in each specimen and the donor-to-recipient axon ratio was recorded. RESULTS: The PBMB was constant and originated from the ulnar digital nerve of the little finger in all cases. The transfer from PBMB to TMB was feasible in all cases. Mean myelinated axon counts of PBMB and TMB were 253±142 and 356±198, respectively (p=0.06). The donor-to-recipient axon ratio was 1:1.41. The mean distance from coaptation of the PBMB to the recipient thenar muscles was 23.1±3.0mm. CONCLUSIONS: Based on our results, PBMB to TMB transfer is feasible. The PBMB has the advantage over other distal nerve transfer donors to be constant and superficial, allowing for an easier harvest. Moreover, this procedure does not sacrifice any intrinsic function of the hand, and the proximity of the PBMB with the carpal tunnel allows for a single incision procedure. Therefore, early restoration of the median innervated thenar muscles may be feasible by the PBMB to TMB transfer in cases of high median nerve lesions. LEVEL OF EVIDENCE: IV.

ACTIfit™: 38% full resorption at 8 years in a cohort of 18 cases.

BACKGROUND: Preserving meniscal tissue is a major priority in young, physically active patients. Extensive meniscal defects may result in exercise pain and premature osteoarthritis. ACTIfit™ is a synthetic meniscal substitute that may improve short-term functional scores via biological integration with meniscal tissue regeneration. However, long-term data on the lifespan and chondroprotective effect of this newly formed tissue are lacking. The primary objective of this study was to assess the biological integration of ACTIfit™ based on magnetic resonance imaging (MRI) findings. The secondary objective was to evaluate long-term clinical outcomes. HYPOTHESIS: The ACTIfit™ meniscal substitute undergoes biological integration over time, suggesting chondroprotective potential. MATERIALS AND METHODS: A 2014 report by Baynat et al. described the 2-year clinical and radiological outcomes of 18 patients after ACTIfit™ implantation at the Clermont-Tonnerre military teaching hospital (Brest, France). The patients had chronic knee pain of at least 6 months' duration after failure of primary meniscal surgery with segmental meniscal defects. Mean age was 34.0±7.9 years. A concomitant procedure was performed in 13 (60%) patients, including osteotomy in 8 and ligament reconstruction in 5. For the current study, the clinical and radiological follow-up was at least 8 years. Assessments were with the Genovese grading scale for substitute morphology on MRI scans, International Cartilage Research Society (ICRS) score for osteoarthritis progression, and Lysholm score for clinical outcome. Failure was defined as total substitute resorption (Genovese morphology grade 1) or revision surgery with implant removal, conversion to meniscus allografting, or arthroplasty. RESULTS: MRI scans were available for 12 (66%) patients. The reason for not having long-term MRI scans was surgery for substitute removal or arthroplasty in 3 of the remaining 6 patients. Complete implant resorption (Genovese grade 1) was noted in 7/12 (58%) patients and osteoarthritis progression to ICRS grade 3 in 4/12 (33%) patients. At last follow-up, the mean Lysholm score was significantly improved vs. baseline (79±15 vs. 55±13, P=0.005). CONCLUSION: The frequency of complete ACTIfit™ resorption 8 years after implantation was high. This finding argues against ability of this substitute to induce the regeneration of durable meniscal tissue with a chondroprotective effect. The clinical outcome score was significantly improved at last follow-up. However, no conclusions can be drawn regarding the effectiveness of ACTIfit™ given the high frequency of concomitant surgical procedures. LEVEL OF EVIDENCE: IV, retrospective observational cohort.

WALANT for hand wound exploration in isolated conditions: Feasibility study.

INTRODUCTION: Military doctors usually deal with hand wound management. Their practice sometimes takes them far from any specialized surgical center. The WALANT could be a powerful tool for doctors operating in nuclear submarines or as part of special forces. This is a comparative, prospective and multicenter study. The hypothesis was that the management of hand wounds by military doctors specifically trained in WALANT and in the surgical exploration of hand wounds allowed a diagnosis as effective as in the FESUM center. PATIENTS AND METHODS: Military doctors, usually operating in isolated conditions, were trained at WALANT. Then, this method was used for the exploration of hand wounds in the emergency room, in a center outside FESUM. At the end, two different questionnaires were completed respectively by the patient and the operator. They aimed to assess various criteria such as the overall satisfaction of the patient and the operator, the level of pain felt or the ability of the operator to establish a precise lesion assessment. The results were compared with those obtained under the same conditions by hand surgeons in the FESUM centre. RESULTS: No significant difference was found between the two centers in terms of diagnostic capacity, satisfaction, comfort and perceived pain intensity. DISCUSSION: Under cover of prior training, the WALANT is effective for the exploration of hand wounds by submariner doctors and members of the special forces. Its use makes it possible to establish a precise injury report and this in material and human conditions approaching as closely as possible those of the armed forces on mission. The comfort of the patient remains preserved. CONCLUSION: The WALANT represents an effective tool for the exploration and lesion assessment of hand wounds outside the FESUM centre. Since emergency conditions are similar to those encountered in operational conditions, its use is also possible in situations specific to military doctors: nuclear submarines, special forces on mission. LEVEL OF EVIDENCE: III; comparative study, retrospective, multicentre.

Post-traumatic total wrist arthrodesis: Satisfaction study of 42 cases at a mean 97months' follow-up.

INTRODUCTION: Total wrist arthrodesis is effective in reducing pain in osteoarthritic wrist, but at the cost of range of motion. The aim of the present study was to assess patient satisfaction after post-traumatic total wrist arthrodesis, complications and risk factors. HYPOTHESIS: Post-traumatic total wrist arthrodesis provides a high rate of satisfaction. PATIENTS AND METHODS: A single-center retrospective observational satisfaction survey was carried out for the period 2005-2020 by telephone interview. RESULTS: Forty-two post-traumatic dorsal plate total wrist arthrodeses were included. Mean follow-up was 97 months. Total arthrodesis achieved a mean 75% reduction in pain, with good functional results (QuickDASH: 23±9.1 [11-42]) and satisfaction (83% of patients very satisfied or satisfied). Seventy-two percent of patients continued in their previous work. The complications rate was 48%. Twenty patients had complications, including 14 (33%) requiring surgical revision. Thirteen patients (31%) had hardware removed due to plaque discomfort and 1 due to bone and joint infection. Seven patients showed CRPS. CONCLUSION: Total wrist arthrodesis provided good results in terms of pain relief and satisfaction, at the cost of loss of motion. It is a reliable surgical technique, with an essential place in the therapeutic algorithm for post-traumatic osteoarthritic wrist, particularly in manual workers. LEVEL OF EVIDENCE: IV, single-center retrospective observational study.

Functional safe zone for THA considering the patient-specific pelvic tilts: An ultrasound-based approach.

The usual Lewinnek orientation for cup positioning in total hip arthroplasty is not suitable for all patients as it does not consider the patient mobility. We propose an ultrasound-based approach to compute a Functional Safe Zone (FSZ) considering daily positions. Our goal was to validate it, and to evaluate how the input parameters impact the FSZ size and barycentre. The accuracy of the FSZ was first assessed by comparing the FSZ computed by the proposed approach and the true FSZ determined by 3D modelling. Then, the input parameters' impact on the FSZ was studied using a principal component analysis. The FSZ was estimated with errors below 0.5° for mean anteversion, mean inclination, and at edges. The pelvic tilts and the neck orientation were found correlated to the FSZ mean orientation, and the target ROM and the prosthesis dimensions to the FSZ size. Integrated into the clinical workflow, this non-ionising approach can be used to easily determine an optimal patient-specific cup orientation minimising the risks of dislocation.

Anterior pelvic plane estimation for total hip arthroplasty using a joint ultrasound and statistical shape model based approach.

Orienting properly the prosthetic cup in total hip arthroplasty is key to ensure the postoperative stability. Several navigation solutions have been developed to assist surgeons in orienting the cup regarding the anterior pelvic plane (APP), defined by both anterior superior iliac spines (ASIS) and the pubic symphysis. However acquiring the APP when the patient is ready for surgery, i.e., mainly in lateral decubitus, is difficult due to the contralateral ASIS being against the operating table. We propose a method to determine the APP from both (1) alternative anatomical landmarks which are easy to acquire with a navigated ultrasound probe and (2) a Statistical Shape Model (SSM) of the pelvis. After creating a pelvic SSM from 40 data, a SSM-based morphometric analysis has been carried out to identify the best anatomical landmarks allowing the easy determination of the APP. The proposed method has then been assessed with both in silico and in vivo experiments on respectively forty synthetic data, and five healthy volunteers. The in silico experiment shows the feasibility to determine the APP with an average error of 4.7∘ by only acquiring the iliac crest, the anterior superior iliac spine, the anterior inferior iliac spine, and the pubic symphysis. The average in vivo error using the ultrasound modality was 7.3∘ with an estimated impact on both the cup anteversion and inclination of 4.0∘ and 1.7∘ respectively. The proposed method shows promising results that could allow the determination of the APP in lateral decubitus with a clinically acceptable impact on the computation of the cup orientation.

Long-term outcomes of trapeziectomy with Gore-Tex® ligament reconstruction for trapezio-metacarpal osteoarthritis.

BACKGROUND: Trapezio-metacarpal osteoarthritis is a common condition for which the reference standard treatment after failure of non-operative measures is trapeziectomy. Several techniques have been devised to avoid proximal migration of the first metacarpal bone (M1) with impingement on the scaphoid bone. We have developed a Gore-Tex® ligament reconstruction technique that avoids potential complications of tendon harvesting. The objective of this study was to assess the long-term outcomes of this technique. HYPOTHESIS: Trapeziectomy with Gore-Tex® ligament reconstruction is a reliable option for providing lasting pain relief in patients with trapezio-metacarpal osteoarthritis. MATERIALS AND METHODS: We conducted an observational, single-centre, single-surgeon, retrospective cohort study in consecutive patients managed by primary trapeziectomy. We excluded patients with revision trapeziectomy or less than 10 years' follow-up. The primary outcome was event-free survival, defined as absence of revision surgery and of a numerical rating scale score for pain above 3/10. The secondary criteria were clinical tolerance of the Gore-Tex® implant and radiological changes. The patients were assessed at last follow-up either in person or during a teleconsultation. RESULTS: Of 78 included joints, 64 were assessed during patient visits and 24 by teleconsultation. At 10 years, the event-free survival rate was 91.3%, and 60.3% of patients were free of pain. Evidence of osteolysis was visible in 24% of patients. No patient experienced clinical intolerance of the Gore-Tex® implant. The mean Disabilities of Arm, Shoulder and Hand score was 25.5. Metacarpo-phalangeal hyperextension was significantly increased, to 30.6°, and the mean trapezial space ratio was significantly decreased, to 39.1% of the baseline value. CONCLUSION: Long-term event-free survival was high. Functional outcomes and pain were similar to previous reports. Trapeziectomy with Gore-Tex® ligament reconstruction obviates the need for tendon harvesting. Osteolysis developed in some patients but did not correlate with clinical intolerance. Long-term clinical and radiological monitoring is in order after Gore-Tex® implantation. LEVEL OF EVIDENCE: IV, Observational, single-centre, single-surgeon, retrospective cohort study.

Optimal definitions for computing HKA angle in caos: an in-vitro comparison study.

The goal of this study was to assess and compare the precision and accuracy of nine and seven methods usually used in Computer Assisted Orthopedic Surgery (CAOS) to estimate respectively the Knee Center (KC) and the Frontal Plane (FP) for the determination of the HKA angle (HKAA). An in-vitro experiment has been realized on thirteen cadaveric lower limbs. A CAOS software application was developed and allowed the computation of the HKAA according to these nine KC and seven FP methods. The precision and the accuracy of the HKAA measurements were measured. The HKAA precision was highest when the FP is determined using the helical method. The HKAA accuracy was highest using the helical approach to determine the FP and either the notch or the tibial spines to determine the KC. This study shows that the helical approach to determine the FP and either the notch or the middle of tibia spines are the combinations that provide both a good enough accuracy and precision to estimate the HKA.

Relationship between surgeons' position and the duration of the procedure during minimally invasive osteosynthesis of distal radius fractures.

This study aimed to assess the influence of the surgeon's position on procedure time in MIPO (Minimally Invasive Plate Osteosynthesis) for distal radius fracture. The hypothesis was that there was a correlation between procedure time and the surgeon's position in relation to the operated side. Thirteen surgeons (12 right-handed, 1 left-handed) operated on 421 distal radius fractures: 208 right-sided (R) and 213 left-sided (L). Surgeons stood either at the patient's head (H) or the feet (F). Procedure time and scar size were measured. Regardless of operated side (right or left), mean surgery time was 35.5 min (range, 14-71) with the surgeon at the head and 40.5 min (range, 11-119) with the surgeon at the feet. The difference (5 min) was statistically significant. When the right side was operated on, surgery time was 34.2 min (range, 14-66) with surgeon at the head and 41.1 min (range, 11-86) at the feet. The difference (6 min) was statistically significant. No other comparisons were significant. There was no correlation with surgeon's experience. Given that 1 min of operating room time costs between €10.80 and €29, savings of €54 to €145 per procedure can be achieved. The study hypothesis was confirmed, with a correlation between the surgeon's position in relation to the operated side and the duration of the operation. In conclusion, we recommend that surgeons position themselves at the patient's head for of distal radius fracture MIPO.

Long-term survival of the Lefèvre retentive cup: 12-year follow-up analysis of 466 consecutive cases.

INTRODUCTION: The Lefèvre retentive cup is a salvage solution for total hip replacement at high risk of dislocation. Only a few studies have reported the medium or long-term survival; most often, only a small number of patients were included in these studies. This led us to conduct a retrospective analysis of a large population to determine: 1) the 10-year survival rate after primary or revision arthroplasty, 2) the complication rate. HYPOTHESIS: The dislocation rate is<5% for revision arthroplasty and<2% for primary arthroplasty. MATERIAL AND METHODS: This single-center retrospective study included 466 consecutive total hip replacements performed with the Lefèvre retentive cup with a 12-year theoretical minimum follow-up (1/1/1998 to 31/8/2006). There were 257 indications for primary arthroplasty and 209 for revision arthroplasty. The cohort had 316 women and the mean age at surgery was 72.9years (30.2-89.9). The mean follow-up was 10.2±5 years (0.1-19.3). A statistical analysis was done based on the Kaplan-Meier survival curves in two subsets of patients: primary and revision surgery. RESULTS: At the final review, 264 patients had died because of reasons unrelated to the procedures (mean 7.8±4.7years after the procedure), 48 were lost to follow-up (mean 3.0±3.3years after the procedure), and 39 patients (8%) had undergone acetabular revision of which 12 were for infection (2.5%), 25 were for loosening (5.4%) (5 femoral loosening only) and 2 were for dislocation (0.4%). In all, there were 10/466 dislocations (2.1%) of which 5/257 (1.9%) were in the primary group and 5/209 (2.4%) were in the revision group: 2 had a cup exchange and 8 were reduced by closed procedures. The probability of survival free of mechanical complications at 10years was estimated at 94.8%±1.6% (95% CI: 91.6%-98.0%) for the primary group and 87.8%±2.7% (95% CI: 82.4%-93.2%) for the revision groups (p=0.0017). There were 39 re-operations in the overall cohort: 1/257 (0.4%) for dislocation, 7/257 (2.7%) for aseptic loosening and 3/257 (1.2%) for infection in the primary group, while in the revision group, 1/209 (0.5%) was for dislocation, 18/209 (8.6%) for aseptic loosening and 9/209 (4.3%) for infection. CONCLUSION: The Lefèvre retentive cup has good long-term survival with a low mechanical complication rate, both in primary and revision surgery. To us, this implant appears to be a reliable salvage procedure for total hip replacement in patients at high risk for dislocation. LEVEL OF EVIDENCE: IV; retrospective study without control group.

Towards markerless computer assisted surgery: Application to total knee arthroplasty.

PURPOSE: A new approach is proposed to localise surgical instruments for Computer Assisted Orthopaedic Surgery (CAOS) that aims at overpassing the limitations of conventional CAOS solutions. This approach relies on both a depth sensor and a 6D pose estimation algorithm. METHODS: The Point-Pair Features (PPF) algorithm was used to estimate the pose of a Patient-Specific Instrument (PSI) for Total Knee Arthroplasty (TKA). Four depth sensors have been compared. Three scores have been computed to assess the performances: The Depth Fitting Error (DFE), the Pose Errors, and the Success Rate. RESULTS: The obtained results demonstrate higher performances for the Microsoft Kinect Azure in terms of DFE. The Occipital Structure core shows better behavior in terms of Pose Errors and Success Rate. CONCLUSION: This comparative study presents the first depth-sensor based solution allowing the intraoperative markerless localization of surgical instruments in orthopedics.