The Patient Acceptable Symptom State (PASS) after proximal and distal femoral replacement.

INTRODUCTION: Femoral megaprostheses are used for bone reconstruction surgery in patients with local tumors or who require multiple revisions. Patient reported outcome measures (PROMs) provide a subjective result and, like patient satisfaction, have become an integral part of the outcomes in orthopedics. However, the threshold of satisfaction (PASS: Patient Acceptable Symptom State) has not yet been defined in a French population after this type of arthroplasty. This led us to carry out a retrospective study on a population of patients who received a femoral reconstruction megaprosthesis in order to 1) define the PASS for the Harris Hip Score (HHS), Knee Society Score (KSS) and the Musculoskeletal Tumor Society score (MSTS), 2) study the complications. HYPOTHESIS: The PASS threshold for proximal femur and distal femur reconstruction prothesis for the HHS and the KSS, respectively, will be lower than the threshold for these same scores for primary arthroplasty. MATERIALS AND METHODS: Forty-four patients who were operated on between 2009 and 2020 were included: 23 received a proximal femur prosthesis and 21 received a distal femur prosthesis. The PASS threshold was defined using an anchoring strategy by analyzing ROC curves for the HSS for the proximal femur, KSS for the distal femur and the MSTS for all the prostheses. Complications were classified according to Henderson. RESULTS: The mean follow-up was 4.5 ± 3.6 (1-12.5) years. The PASS threshold was 47.5 (area under curve (AUC) 0.71 (0.45-0.97)) for the HHS, 69.5 (AUC 0.97 (0.92-1.0)) for the KSS knee and 62.5 (AUC 0.81 (0.61-0.99)) for the KSS function. Thirteen patients (29%) had complications, nine of whom required another surgery (20%). The most frequent were Henderson type 1 (soft tissue lesions, n = 5/44 [11%]) and type 2 (loosening, n = 5/44 [11%]) There was no relationship between satisfaction and postoperative complications (p = 0.071). DISCUSSION: Most of the patients who undergo femoral resection and reconstruction (59%) are satisfied with their function, albeit reduced, despite a high complication rate (29%). Our hypothesis is confirmed for the PASS threshold for the HHS (47.5 versus 93) and the KSS knee and function (69.5 and 62.5 versus 85.5 and 72.5). LEVEL OF EVIDENCE: IV; retrospective observational single-center study.

Osteotomies for genu varum: Should we always correct at the tibia? A multicenter analysis of practices in France.

INTRODUCTION: Tibial correction is often performed during a valgus-producing osteotomy for genu varum. However, overcorrection and the creation of a joint line obliquity (JLO) have been associated with unfavorable functional outcomes after high tibial osteotomy (HTO). The aims of this study were to analyze: 1) the corrections obtained after HTO; 2) the rationale behind the indication per the European Society for Sports Traumatology Surgery and Arthroscopy (ESSKA) recommendations; and 3) the correlation between the postoperative corrections obtained and functional outcomes. HYPOTHESIS: A significant number of patients who underwent an isolated HTO did not present an "ideal" theoretical indication based on the preoperative angles and correction targets to be performed. MATERIALS AND METHODS: This multicenter study included 289 isolated HTOs. Demographic and morphometric data were anonymized and compiled in a database. Preoperative radiographic parameters were compared with the ESSKA consensus recommendations on osteotomies for genu varum. The consensus defined the "ideal" indication for performing an HTO as medial tibiofemoral compartment pain with significant tibial varus deformity (medial proximal tibial angle [MPTA]<85°), no significant femoral varus deformity (lateral distal femoral angle [LDFA]<90°), an expected postoperative obliquity of less than 5°, and a correction resulting in moderate tibial valgus (postoperative MPTA<94°). The incidence of patients with an "ideal" theoretical indication for isolated HTO and those with a theoretical indication not perfectly justified by the radiographic data and preoperative planning were recorded. RESULTS: Under the ESSKA consensus criteria, 25.3% (n=73) of isolated HTOs, 15.6% (n=45) of isolated femoral osteotomies, 9.3% (n=27) of double-level osteotomies, and 49.9% (n=144) of cases where no osteotomy was performed due to the lack of significant extra-articular tibial and/or femoral deformity were deemed justified. The presence of a preoperative femoral deformity and the absence of an "ideal" indication for HTO did not affect the postoperative Tegner Activity Scale or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (p>0.05). A high preoperative hip-knee-ankle (HKA) angle and MPTA, which indicated less varus, were associated with a greater risk of there being no "ideal" theoretical indication for an HTO (coefficient of determination [R2]=0.19 and R2=1, respectively; p<0.001). CONCLUSION: This study showed that isolated HTOs in current practice were not justified in a significant number of patients, even though they could lead to tibial overcorrection and excessive JLO. This did not impact the functional results of this series, but it might complicate the performance of a secondary knee arthroplasty. Nevertheless, some young patients in this series underwent a salvage osteotomy outside the "ideal" indications of the European recommendations. LEVEL OF EVIDENCE: IV; case series.

Results of third generation dual mobility total hip arthroplasties with non-cross-linked polyethylene in patients under 60 years of age: comparative study of full pressfit vs. tripod cups after 8.6 years.

BACKGROUND: The concept of dual mobility of total hip arthroplasties (THA) is a revolution in the prevention of dislocations and in the treatment of instability. Its use remains controversial in patients under 60 years old, providing poorer results with first generation cups coated with alumina. This study, carried out on modern dual mobility (DM) cups with a porous bilayer coating, in active patients under 60 years of age aimed to evaluate: (1) the mechanical survival of two latest generation DM THA, with failure defined as revision of acetabular or femoral implants for mechanical loosening, by comparing a tripod cup to a full pressfit cup, (2) to evaluate the complications, (3) to compare the rate of radiographic peri-prosthetic osteolysis between the 2 implants. HYPOTHESIS: The hypothesis was that the medium-term survival of modern DM cups placed in young patients was the same regardless of the type of acetabular fixation used. MATERIALS AND METHODS: This was a retrospective study of 119 latest generation DM THA with standard polyethylene, composed of 66 full pressfit cups and 53 tripod fixation cups, used in primary arthroplasty in 111 patients between 2005 and 2016. The survival study was carried out using medical records. The clinical evaluation was carried out using the modified Harris Hip Score (mHHS) as well as the self-administered Hip and Osteoarthritis Outcome Score (HOOS) and Oxford-12 questionnaires. Radiological analysis was carried out on radiographs looking for bone demineralization and acetabular and femoral lines. RESULTS: At 8.6 years (5-16), no revision for mechanical loosening was observed regardless of the type of cup. The prosthesis dislocation rate (large joint) was 1.7%: 1 case in each group (p = 1), including one revision required in the full pressfit group. Three revisions for mechanical complications were recorded: a recurrent dislocating hip on a full pressfit cup that was not sufficiently anteverted, an acetabular peri-prosthetic fracture on a full pressfit cup and a case of iliopsoas impingement with a retroverted tripod cup. The survival rate for all-cause revision was 93.8% for pressfit (95% CI: 88.2%-99.9%) vs. 96.2% for tripod (95% CI: 91.1%-100%) (p = 0.63) and for revision due to any cause excluding infection, 96.9% for pressfit (95% CI: 92.8%-100%) vs. 98.1% for tripod (95% CI: 94.4%-100%) (p = 0.7). The rate of periacetabular osteolysis was 11%, significantly more present amongst tripod cups (24%, 9 cases) compared to full pressfit cups (2%, 1 case) (p < 0.01). CONCLUSION: This series demonstrates good performance of 3rd generation DM cups with porous bilayer coating in patients under 60 years of age regardless of the type of acetabular fixation, at 8.6 years of follow-up. The rate of osteolysis around full pressfit cups remains very low, unlike that of tripod cups. The use of Double Mobility prostheses for primary hip osteoarthritis is possible in young patients, preferably with full pressfit cups (i.e., without any pegs or additional screws that may promote diffusion of polyethylene debris and osteolysis). LEVEL OF EVIDENCE: III; comparative retrospective study.

Better clinical outcomes and faster weight bearing after medial opening-wedge high tibial osteotomy using allogeneic than synthetic graft: A secondary analysis of a Francophone Arthroscopy Society Symposium.

INTRODUCTION: Although an autogenous graft has the highest rate of bone union to fill the void created in medial opening wedge high tibial osteotomy (MOWHTO), it also has some disadvantages, such as prolonged surgical time, donor site pain and morbidity. Two possible candidates for ideal grafts to replace autogenous grafts are allogeneic and synthetic graft, which are free from donor site pain and morbidity. However, previous reports comparing the clinical results of allogeneic to synthetic graft have been limited and controversial. The purpose of this study is to compare radiological findings and clinical outcomes of using synthetic versus allogenic graft to fill the void created in MOWHTO. HYPOTHESIS: The present clinical study hypothesized that allogenic graft to fill the void would allow the higher rate of bone union and better clinical outcomes. MATERIAL AND METHODS: This study compared the clinical and radiological outcomes of 95 patients who received MOWHTO to fill the void with either synthetic or allogenic graft (44 in Syn group, 51 in Allo group). Preoperatively and postoperatively, all patients were clinically evaluated; Return to work, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including Hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were also reported. RESULTS: Mean follow-up (months) were 24.0±1.3 in Syn group and 26.8±1.2 in Allo group (p=0.13). The postoperative improvement of pain and global WOMAC scores in Allo group were significantly better than in Syn group (ΔPain of WOMAC: Syn group 27.8±4.4, Allo group 49.3±3.8, p value <0.001*) (ΔGlobal score of WOMAC: Syn group 16.7±3.2, Allo group 37.4±4.9, p value=0.002*). The risk of hinge fracture in Syn group was significantly higher than in Allo group (Hinge fracture by Takeuchi grade (0/1/2/3): Syn group 37/3/3/1, Allo group 43/8/0/0, p value=0.04*). The timing of full weight bearing in Allo group was significantly earlier than in Syn group (Weight Bearing (1=FWB, 2=PWB 3wk, 3=PWB 6wk): Syn group 2.7±0.1, Allo group 2.3±0.1, p value=0.01*). DISCUSSION: The use of allogenic graft to fill the void in MOWHTO does not show superiority in bone union compared to synthetic graft, however it improves pain, function, decreases the risk of hinge fracture and allows faster weight bearing than synthetic graft. LEVEL OF PROOF: III; Case-control study.

High tibial osteotomy is equally effective for varus malaligned knees with either virgin or wrecked medial meniscus: An age and gender-matched secondary analysis of a Francophone Arthroscopy Society Symposium.

INTRODUCTION: Despite the growing concept of meniscal preservation, partial meniscectomy could be the definitive procedure in specific scenarios. And total meniscectomy was once before a frequent procedure, with current sequelae of degenerate knees. High tibial osteotomy (HTO) is an effective treatment for patients suffering from unicompartmental degenerative changes, and substantial deformities. However, it is yet to be answered, whether HTO is similarly effective in both post-meniscectomy knees and knees with not previously operated meniscus. HYPOTHESIS: Outcomes of HTO is similar with or without previous history of total or subtotal meniscectomy. METHODS: This study compared the clinical and radiological outcomes of 41 patients who received HTO and had no previous history of surgery in the ipsilateral knee (group I), and 41 age, and gender-matched patients who had meniscectomy surgery in the ipsilateral knee (group II). Preoperatively and postoperatively, all patients were clinically evaluated; the visual analogue scale scores, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including hip-knee-ankle angle, femoral mechanical angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were reported. RESULTS: A total of 82 patients were included; group I (n=41) and group II (n=41). The mean age was 51.18±8.64 (27-68) and 90.24% were male. The duration since the onset of symptoms was longer in group II vs. group I, 43.34±41.03 versus 38.07±36.11months respectively. No significant differences in the clinical evaluation between the two groups with a greater proportion of patients demonstrating moderate degenerative changes. Similar preoperative and postoperative radiographic parameters were reported, in group I, Δ HKA was 7.19±4.14 versus 7.65±3.16 in group II. Preoperative pain VAS scores were slightly higher in group II vs. group I, 79.23±26.35 vs. 76.31±24.45, respectively. However, postoperatively, the pain scores significantly improved in group I vs. group II, 22.84±3.65 vs. 41.69±17.33, respectively. Tegner activity scores and WOMAC scores were comparable between both groups preoperatively and postoperatively. Only the WOMAC function scores were better in group I when compared to group II, 26.13±25.84 versus 20.01±17.98. All patients returned to work at an average of 0.82±0.38months. CONCLUSION: Knee preservation with high tibial osteotomy is equally effective in managing unicompartmental degenerative changes in varus malaligned knees with either no previous history of meniscal surgeries or where a meniscal sacrifice was inevitable, either with subtotal or total meniscectomy. LEVEL OF EVIDENCE: III, retrospective case-control study.

Interest in the combination of antimicrobial therapy for orthopaedic device-related infections due to Enterococcus spp.

INTRODUCTION: The objective of this study was to evaluate the management of orthopaedic device-related infections (ODRIs) due to Enterococcus spp. MATERIALS AND METHODS: We performed a retrospective cohort study in a French tertiary university hospital. Patients with prosthetic joint- or osteosynthesis-associated infections caused by enterococci from 2013 to 2020 were included. Patients who died within 5 days after surgery; who were in palliative care; or who had osteosynthesis of the hand, foot or vertebra were excluded. RESULTS: Thirty-six patients were included, with 24 in the arthroplasty group and 12 in the osteosynthesis material group. Most infections were polymicrobial (63.9%, n = 23). Debridement, antibiotics and implant retention (DAIR) was performed in 30.6% (n = 11), withdrawal of material in 16.7% (n = 6), one-stage exchange in 30.6% (n = 11) and two-stage exchange in 22.2% of cases (n = 8). The antibiotic regimen was amoxicillin in 41.6% (n = 15), rifampicin in 27.8% (n = 10), linezolid in 25% (n = 9) and/or fluoroquinolones in 30.6% (n = 11). Clinical success at 1 year was 67% (18/27). The only variable statistically associated with a decreased risk of clinical failure was a duration of antibiotic therapy of 12 weeks (p = 0.04). Patients with a lower body mass index and age tended to decrease the risk of clinical failure (p = 0.05 and 0.06 respectively). CONCLUSIONS: The management of enterococcal ODRIs is complex, and ODRI patients are at high risk for relapse. In our small study, a better outcome was not demonstrated for patients with combination therapy and rifampicin use. Further studies are needed to improve the medico-surgical strategy for treating these infections.

A predictive score of high tibial osteotomy survivorship to help in surgical decision-making: the SKOOP score.

INTRODUCTION: The high tibial osteotomy (HTO) survival rate is strongly correlated with surgical indications and predictive factors. This study aims to assess HTO survival in the long term, to determine the main predictive factors of this survival, to propose a predictive score for HTO based on those factors. METHODS: This multicentric study included 481 HTO between 2004 and 2015. The inclusion criteria were all primary HTO in patients 70 years old and younger, without previous anterior cruciate ligament injury, and without the limitation of body mass index (BMI). The assessed data were preoperative clinical and radiological parameters, the surgical technique, the complications, the HKA (hip knee ankle angle) correction postoperatively, and the surgical revision at the last follow-up. RESULTS: The mean follow-up was 7.8 ± 2.9 years. The HTO survival was 93.1% at 5 years and 74.1% at 10 years. Age < 55, female sex, BMI < 25 kg/m2 and incomplete narrowing were preoperative factors that positively impacted HTO survival. A postoperative HKA angle greater than 180° was a positive factor for HTO survival. The SKOOP (Sfa Knee OsteOtomy Predictive) score, including age (threshold value of 55 years), BMI (threshold values of 25 and 35 kg/m2), and the presence or absence of complete joint line narrowing, have been described. If the scale was greater than 3, the survival probability was significantly lower (p < 0.001) than if the scale was less than 3. CONCLUSION: A predictive score including age, BMI, and the presence or absence of joint line narrowing can be a helpful in making decisions about HTO, particularly in borderline cases. LEVEL OF EVIDENCE: Retrospective cohort study.

Value of the synovial C-reactive protein test in the diagnosis of total hip and knee periprosthetic joint infections: A case-control study.

INTRODUCTION: The diagnosis of periprosthetic joint infection (PJI) can be challenging and rests on several principles. The use of diagnostic biomarkers, such as the synovial C-Reactive Protein (CRP), seems promising. The purpose of this study was to determine whether synovial CRP was a more discriminating test than serum CRP for the diagnosis of hip and knee PJI. MATERIALS AND METHODS: In total, 194 patients were included in this single center prospective study: 42 primary arthroplasties (control group [CG]), 111 revisions for aseptic prosthesis (aseptic revision group [ARG]), and 41 revisions for septic prosthesis (septic revision group [SRG]) based on the Musculoskeletal Infection Society (MSIS) criteria. RESULTS: The serum and synovial CRP levels were significantly higher in the SRG than the other two groups (SRG serum CRP=75.6mg/L vs. ARG serum CRP=6mg/L and CG serum CRP=2.7mg/L, p<0.001; SRG synovial CRP=31.5mg/L vs. CG synovial CRP=2.6mg/L and ARG synovial CRP=1.7mg/L, p<0.001). The positive likelihood ratios (LR+) were very similar for both the synovial CRP cut-off value of 4.4mg/L (LR+=7.04; sensitivity [Se] 82.5%, specificity [Sp] 88.3%) and the serum CRP cut-off value of 9mg/L (LR+=6.3; Se 87.5%, Sp 86.1%). CONCLUSION: This study showed that synovial CRP testing was not more discriminating than serum CRP in the diagnosis of hip and knee PJI. A serum CRP level greater than 9mg/L was a sign of PJI. LEVEL OF EVIDENCE: III; case-control study.

Implementation and results of an enhanced recovery (fast-track) program in total knee replacement patients at a French university hospital.

INTRODUCTION: In total knee replacement (TKR) surgeries, "fast-track" or enhanced recovery after surgery (ERAS) programs are being developed, but their impact on care pathway quality and safety has not been fully explored in the French literature. The present study aimed to compare results in TKR between fast-track and conventional pathways, addressing the following questions: (1) Are 90-day rates of complications, readmission and surgical revision higher with fast-track? (2) Is mean length of stay (LoS) shorter with fast-track? (3) Are postoperative pain and clinical results improved by fast-track? And, (4) are patients and care staff satisfied with these new programs? HYPOTHESIS: Implementing fast-track for TKR in a university hospital center is beneficial for the patient and does not impair the quality and safety of care. PATIENTS AND METHOD: A case-control study was performed using a retrospective analysis of prospectively collected data. A fast-track program was implemented for TKR by modifying the care pathway. This involved instituting a therapeutic education consultation, optimizing blood sparing, modifying surgical practices, and hastening early mobilization thus actively involving patients in their own management. Between January 2017 and January 2019, 216 patients with a mean age of 69.23±7.80years and mean BMI of 30.15±4.79kg/m2 were included in the fast-track group, with 335 matched patients included in the conventional group. RESULTS: At 90days, there were no significant inter-group differences in rates of infection (fast-track=1.39%, conventional=0.90%; p=0.34), readmission (fast-track=3.24%, conventional=3.58%; p=0.49), or surgical revision (fast-track=2.78%, conventional=2.69%; p=0.298). The visual analog scale (VAS) pain rating was 1.56±1.36 in the fast-track group versus 5±2.41 in the conventional group; p<0.001. LoS was 3.17±1.59days in fast-track versus 7.25±1.85days in the conventional group; p<0.001. Ninety-five percent of patients and 96% of care staff were satisfied with the fast-track program. DISCUSSION: Fast-track implementation ensured quality and safety of care; it did not increase the rate of complications in primary TKR. Mean length of stay was drastically reduced. Both patients and care staff were very satisfied with these new procedures. LEVEL OF EVIDENCE: III; case-control study.

Medium-term survival and clinical and radiological results in high tibial osteotomy: Factors for failure and comparison with unicompartmental arthroplasty.

INTRODUCTION: High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are two surgical solutions for isolated medial tibiofemoral osteoarthritis. Results depend on preoperative criteria and patient selection, but also on postoperative factors: implant positioning, limb alignment. Factors for HTO survival need identifying to reduce risk of failure requiring total knee arthroplasty (TKA). HYPOTHESIS: Age, gender, weight, osteoarthritis grade, degree of correction, type of osteotomy, technique and intraoperative complications impact HTO survival. MATERIAL AND METHOD: As part of a symposium of the French Society of Arthroscopy (SFA), a multicenter retrospective study compared 2 series. The HTO series comprised 488 patients: 153 female (31.4%); mean age, 55.1 years; mean weight, 83.1kg; mean body-mass index (BMI), 28.6. The UKA series comprised 284 patients: 172 female (60.6%); mean age, 64.1 years; mean weight, 75.3kg; mean BMI, 27.6. The main endpoint was comparative survival at 5, 8 and 10 years; secondary endpoints comprised pre- and post-operative hip-knee-ankle (HKA) angle, mechanical femoral angle (mFA) and mechanical tibial angle (mTA), surgical technique, satisfaction, time to and level of return to work, WOMAC and Tegner scores and complications rates. The significance threshold was set at p<0.05; 95% confidence intervals were calculated. RESULTS: Age>54 years, male gender, BMI>25, medial tibiofemoral wear severity Ahlback ≥3, ≥0.9° varus joint component, HKA correction<8°, postoperative HKA<180° and hinge fracture were significantly associated with poorer survival. There was no impact of type of osteotomy, navigation assistance or postoperative HKA 183-186°. Ten-year survival was 74.3% for HTO and 71% for UKA (non-significant); however, survival curves crossed at 6 years. CONCLUSION: HTO showed survival and functional results comparable to those of UKA in selected patients when target limb alignment correction was achieved. The present study determined selection criteria. A predictive score for results of either procedure would facilitate decision-making. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Is patient-specific instrumentation more precise than conventional techniques and navigation in achieving planned correction in high tibial osteotomy?

INTRODUCTION: Preoperative planning in high tibial osteotomy (HTO) is a critical step for achieving the desired correction and a clinically satisfactory outcome. Conventional radiography, navigation assistance and patient-specific instrumentation (PSI) are the 3 means of planning, but no prospective studies have compared precision between the 3. The aims of the present study were: (1) to analyze and compare correction precision between the 3 planning approaches at 1 year's follow-up; (2) to compare results to those reported in the literature; and (3) to analyze factors influencing the achievement of planned correction. HYPOTHESIS: The study hypothesis was that PSI provides more precise and reproducible planned correction than conventional methods or navigation. MATERIAL AND METHOD: Between June 2017 and June 2018, a multicenter non-randomized prospective observational study was conducted in 11 centers. One hundred and twenty-six patients with Ahlbäck grade I, II or III idiopathic medial tibiofemoral osteoarthritis with stable knee were included and allocated to 3 preoperative planning groups: conventional (group 1), navigation (group 2) and PSI (group 3). Mean age at surgery was 51.2 years (range, 19-69 years; median, 53.2 years); 100 male, 26 female. Complete weight-bearing radiographic work-up was performed preoperatively and at 1 year's follow-up. The PSI group also underwent CT as part of guide production. Target angular correction and mechanical Hip-Knee-Ankle (HKA) axis were set preoperatively. The main endpoint was the difference between planned HKA and HKA at a minimum 12 months. RESULTS: Mean HKA difference was 1.1±3 in group 1, 2.1±2.6 in group 2 and 0.3±3.1 in group 3. Precision was better with PSI, but not significantly when comparing all 3 groups together. On pairwise intergroup comparison, there was a significant difference only between groups 2 and 3, in favor of PSI (P=0.011). DISCUSSION: None of the 3 techniques demonstrated superiority in achieving target correction at 1 year. The study hypothesis was thus not confirmed. All 3 techniques proved reliable and precise in HTO planning. LEVEL OF EVIDENCE: III, prospective non-randomized comparative study.

Postoperative Radiation Therapy in Patients with Extracranial Chondrosarcoma: A Joint Study of the French Sarcoma Group and Rare Cancer Network.

PURPOSE: Postoperative radiation therapy (poRT) of intracranial/skull base chondrosarcomas (CHSs) is standard treatment. However, consensus is lacking for poRT in extracranial CHS (eCHS) owing to their easier resectability and intrinsic radioresistance. We assessed the practice and efficacy of poRT in eCHS. METHODS AND MATERIALS: This multicentric retrospective study of the French Sarcoma Group/Rare Cancer Network included patients with eCHS who were operated on between 1985 and 2015. Inverse propensity score weighting (IPTW) was used to minimize poRT allocation biases. RESULTS: Of 182 patients, 60.4% had bone and 39.6% had soft-tissue eCHS. eCHS were of conventional (31.9%), myxoid (28.6%; 41 extraskeletal, 11 skeletal), mesenchymal (9.9%), or other subtypes. En-bloc surgery with complete resection was performed in 52.6% and poRT in 36.8% of patients (median dose, 54 Gy). Irradiated patients had unfavorable initial characteristics, with higher grade and incomplete resection. Median follow-up time was 61 months. Five-year incidence of local relapse was 10% with poRT versus 21.6% without (P = .050). Using the IPTW method, poRT reduced the local relapse risk (hazard ratio, 0.27; 95% confidence interval, 0.14-0.52; P < .001). Five-year disease-free survival (DFS) was 71.8% with poRT and 64.2% without (P = .680). Using the IPTW method, poRT improved DFS (hazard ratio, 0.51; 95% confidence interval, 0.30-0.85; P = .010). The benefit of poRT on local relapse and DFS was confirmed after exclusion of the extraskeletal subtype. There was no difference in overall survival. Prognostic factors of poorer DFS in multivariate analysis were deeper location, higher grade, incomplete resection, and no poRT. CONCLUSIONS: poRT should be offered in patients with eCHS and high-grade or incomplete resection, regardless of the histologic subtype.

Measure of horizontal and vertical displacement of the acromioclavicular joint after cutting ligament using X-ray and opto-electronic system.

INTRODUCTION: Surgical versus orthopedic treatments of acromioclavicular disjunction are still debated. The aim of this study was to measure horizontal and vertical acromion's displacement after cutting the ligament using standard X-ray and an opto-electronic system on cadaver. MATERIALS AND METHODS: Ten cadaveric shoulders were studied. A sequential ligament's section was operated by arthroscopy. The sequence of cutting was chosen to fit with Rockwood's grade. The displacement of the acromion was measured on standard X-ray and with an opto-electronic system allowing measuring of the horizontal displacement. Statistical comparisons were performed using a paired Student's t test with significance set at p < 0.05. RESULTS: Cutting the coracoclavicular ligament and delto-trapezius muscles cause a statistical downer displacement of the acromion, but not after sectioning the acromioclavicular ligament. The contact surface between the acromion and the clavicle decreases statistically after sectioning the acromioclavicular ligament and the coracoclavicular ligament with no effect of sectioning the delto-trapezius muscles. Those results are superposing with those dealing with the anterior translation. DISCUSSION: The measure concerning the acromioclavicular distance and the coracoclavicular distance are superposing with those of Rockwood. However, there is a significant horizontal translation after cutting the acromioclavicular ligament. Taking into account this displacement, it may be interesting to choose either surgical or orthopedic treatment. CONCLUSION: There is a correlation between anatomical damage and importance of instability. Horizontal instability is misevaluated in clinical practice.