Meniscal injuries in skeletally immature children with tibial eminence fractures. Systematic review of literature.

PURPOSE: Although the mechanisms of injury are similar to ACL rupture in adults, publications dealing with meniscal lesions resulting from fractures of the intercondylar eminence in children are much rarer. The main objective was to measure the frequency of meniscal lesions associated with tibial eminence fractures in children. The second question was to determine whether there is any available evidence on association between meniscal tears diagnostic method, and frequencies of total lesions, total meniscal lesions, and total entrapments. METHODS: A comprehensive literature search was performed using PubMed and Scopus. Articles were eligible for inclusion if they reported data on intercondylar tibial fracture, or tibial spine fracture, or tibial eminence fracture, or intercondylar eminence fracture. Article selection was performed in accordance with the PRISMA guidelines. RESULTS: In total, 789 studies were identified by the literature search. At the end of the process, 26 studies were included in the final review. This systematic review identified 18.1% rate of meniscal tears and 20.1% rate of meniscal or IML entrapments during intercondylar eminence fractures. Proportion of total entrapments was significantly different between groups (17.8% in the arthroscopy group vs. 6.2% in the MRI group; p < .0001). Also, we found 20.9% of total associated lesions in the arthroscopy group vs. 26.1% in the MRI group (p = .06). CONCLUSION: Although incidence of meniscal injuries in children tibial eminence fractures is lower than that in adults ACL rupture, pediatric meniscal tears and entrapments need to be systematically searched. MRI does not appear to provide additional information about the entrapment risk if arthroscopy treatment is performed. However, pretreatment MRI provides important informations about concomitant injuries, such as meniscal tears, and should be mandatory if orthopaedic treatment is retained. MRI modalities have yet to be specified to improve the diagnosis of soft tissues entrapments. STUDY DESIGN: Systematic review of the literature REGISTRATION: PROSPERO N° CRD42021258384.

Litigation in arthroscopic surgery: a 20-year analysis of legal actions in France.

PURPOSE: The main objective of this study was to identify the epidemiological characteristics of litigation following arthroscopic procedures, performed in private practice and public hospitals in France. The secondary objective was to establish a risk profile for medical malpractice lawsuits after arthroscopic surgery. METHODS: All court decisions related to arthroscopic surgery between 1994 and 2020 were collected and reviewed cases from the two main French legal databases (Legifrance and Doctrine). Data were retrospectively collected and included: gender, joint and defendant's specialty involved, reason behind the lawsuit, initial indication and the type of arthroscopic procedure performed. The final verdicts as well as the indemnity awarded to the plaintiff (if any) were recorded. RESULTS: One-hundred eighty cases met the inclusion criteria of the study and were analyzed: 58 cases were before administrative courts and 122 were before civil courts. An orthopaedic surgeon was involved alone or in solidum in 45.6% of cases (82/180), followed by anesthesiologists in 5.6% (10/180). The private surgery center or public hospital were implicated in 63.9% (115/180) of cases. The 2 most common joints involved in litigation following arthroscopic surgery were the knee (82.2%, n = 148) and the shoulder (11.1%, n = 20). The main reasons behind the lawsuit were related to postoperative infection in 78/180 cases and to a musculoskeletal complication in 45/180 cases (25%). A failure to inform was also reported in 34/180 cases (18.9%). Of the 180 cases, 122 cases (67.8%) resulted in a verdict for the plaintiff. The average indemnity award for the plaintiff was 77.984 euros [2.282-1.117.667]. A verdict for the plaintiff was significantly associated with postoperative infection or a wrong-side surgery, while technical error and musculoskeletal complications were more significantly likely to result in a verdict in favor of the defendant (p = 0.003). CONCLUSION: This study evaluated and mapped lawsuits following after arthroscopic surgery in France over a period of more than 20 years. The main joint involved in lawsuits was knee. The main causes of lawsuits following arthroscopic surgery were related to postoperative infection, musculoskeletal complications and failure to inform. LEVEL OF EVIDENCE: Level IV.

Talar Dislocation: Is Reimplantation a Safe Procedure?

Total or complete dislocation of the talus is a triple dislocation of the tibiotalar, talocalcaneal, and talonavicular joints. It is a rare injury and is considered to be 1 of the most disabling ankle injuries. In light of the literature, there is a lack of consensus on their surgical treatment. The primary objective of this retrospective case series was to assess the long-term clinical and radiological outcomes of 5 patients who underwent talar reimplantation for total talar dislocation. From 2005 to 2011, 5 patients were admitted in emergency care unit with a total talar dislocation. The talar dislocation was surgically reduced and stabilized by a temporary internal fixation. Patients were reviewed with a mean follow-up of 60 months (48-70 months). Clinical and radiological evaluations were performed at the last follow-up. Despite 3 opened-dislocation (60%), none had infection. Three patients obtained subnormal biomechanical function with an American Orthopedic Foot and Ankle Score of 60 to 70/100. Two others patients (40%) underwent a secondary ankle arthrodesis because of avascular necrosis of the talus. Signs of necrosis appeared at 15 months and 24 months. Talar reimplantation should be attempted despite the risk of avascular necrosis: restoration of the talus in the ankle maintains normal hindfoot anatomy and preserves bone stock for future function or a subsequent surgical procedure. Patients should be informed of the risk of secondary surgery. Opened-dislocation seems to be a major risk factor of avascular necrosis, and surgeon must take care to keep soft tissues attached.

Pyoderma gangrenosum after orthopaedic or traumatologic surgery: a systematic revue of the literature.

INTRODUCTION: Pyoderma gangrenosum (PG) is a neutrophilic dermatosis characterised by a painful ulceration mimicking infection of the operative site. To this day, there is still no general agreement on the medical and surgical treatment of PG. This systematic review of the literature aims to summarise recent studies about post-operative PG in orthopaedic surgery to improve its medical and surgical management. METHOD: In April 2017, we carried out an exhaustive review of the literature in MEDLINE, PubMed and Cochrane databases. Key words were pyoderma gangrenosum, orthopaedic surgery, and surgical wound infection. We identified 183 articles. After excluding articles reporting idiopathic PG, cases secondary to non-orthopaedic surgery, and cases about other subtypes of dermatosis, 30 studies were identified. We only included articles reporting PG after orthopaedic or trauma surgery. RESULTS: Thirty-one cases of PG have been reported, 58% (18) of which were in women, whose mean age was 56.5 years. Clinical signs were constant, the most frequently affected site was lower limbs [77.4% (24)] and delay of symptom onset was two to 17 days. Systemic corticosteroid therapy was systematic, polyvalent immunoglobulins were used in two cases and immunosuppressive drugs in one. Negative pressure therapy was used in seven cases and hyperbaric oxygen in three. DISCUSSION: Delayed diagnosis leads to one or more surgical revisions, which could have been avoided by using early and adapted medical treatment. Early onset of a painful and infected ulcer at the operating site in a patient at risk of PG is an indicator that dermatologist advice is recommended before surgical debridement. Surgical revision, outside the inflammatory phase and/or covered by a systemic corticosteroid therapy, does not lead to PG relapse. LEVEL OF EVIDENCE: IV: Systematic revue of the literature.

Extra-articular hip resection with maintenance of pelvic continuity in malignant tumours of the proximal femur with articular invasion.

INTRODUCTION: Extra-articular hip resection may be necessary in cases of malignant tumour of the pelvic bone or of the proximal femur invading the hip joint. When the tumour is in the proximal femur, it is possible to resect the acetabulum en bloc by performing a periacetabular osteotomy, but this creates a discontinuity in the pelvic ring with difficult reconstruction and diminished function. Several techniques described recently seek to be as sparing as possible on the pelvic bone by preserving the posterior column or both columns in order to facilitate reconstruction and improve function. However, these still require complex reconstructions and can necessitate intra-pelvic dissection. TECHNIQUE: We describe here an extra-articular hip resection technique for tumours of the proximal femur invading the joint, with maintenance of pelvic continuity by preserving both columns and the quadrilateral plate of the acetabulum, without intra-pelvic dissection, that can be performed on patients in whom the medial wall of the acetabulum is thick enough. Our preliminary assessments have included studies on dry bone and imaging analyses. The technique was first tested on a single cadaver pelvis (encompassing 2 hips) and subsequently performed on a patient with a pathological fracture of the femoral neck due to osteosarcoma secondary to Paget's disease. CONCLUSIONS: Further clinical applications are essential to evaluate the overall effectiveness, safety and impact on patient functionality of this experimental technique.

Detecting generative artificial intelligence in scientific articles: Evasion techniques and implications for scientific integrity.

BACKGROUND: Artificial intelligence (AI) tools, although beneficial for data collection and analysis, can also facilitate scientific fraud. AI detectors can help resolve this problem, but their effectiveness depends on their ability to track AI progress. In addition, many methods of evading AI detection exist and their constantly evolving sophistication can make the task more difficult. Thus, from an AI-generated text, we wanted to: (1) evaluate the AI detection sites on a text generated entirely by the AI, (2) test the methods described for evading AI detection, and (3) evaluate the effectiveness of these methods to evade AI detection on the sites tested previously. HYPOTHESIS: Not all AI detection tools are equally effective in detecting AI-generated text and some techniques used to evade АI detection can make an AI-produced text almost undetectable. MATERIALS AND METHODS: We created a text with ChatGPT-4 (Chat Gеnеrаtivе Prе-trained Transformer) and submitted it to 11 АI detection web tools (Оriginаlity, ZеrоGPT, Writеr, Cоpylеаks, Crоssplag, GPTZеrо, Sapling, Cоntеnt аt scаlе, Cоrrеctоr, Writеfull еt Quill), bеfоrе аnd аftеr applying strategies to minimise AI detection. The strategies used to minimize AI detection were the improvement of command messages in ChatPGT, the introduction of minor grammatical errors such as comma deletion, paraphrasing, and the substitution of Latin letters with similar Cyrillic letters (a and о) which is also a method used elsewhere to evade the detection of plagiarism. We have also tested the effectiveness of these tools in correctly identifying a scientific text written by a human in 1960. RESULTS: From the initial text generated by the AI, 7 of the 11 detectors concluded that the text was mainly written by humans. Subsequently, the introduction of simple modifications, such as the removal of commas or paraphrasing can effectively reduce AI detection and make the text appear human for all detectors. In addition, replacing certain Latin letters with Cyrillic letters can make an AI text completely undetectable. Finally, we observe that in a paradoxical way, certain sites detect a significant proportion of AI in a text written by a human in 1960. DISCUSSION: AI detectors have low efficiency, and simple modifications can allow even the most robust detectors to be easily bypassed. The rapid development of generative AI raises questions about the future of scientific writing but also about the detection of scientific fraud, such as data fabrication. LEVEL OF EVIDENCE: III Control case study.

A New Classification of the Morphology of Complete Ponticulus Posticus on Cone Beam Computed Tomography.

The objectives of this retrospective study were to measure the prevalence of complete ponticulus posticus (CPP), to propose a new classification based on two different shapes of CPP, to compare these shapes with age and gender, and to test two different methods of measurements of the diameters of CPP on cone beam computed tomography (CBCT). MATERIAL AND METHODS: We used 2012 CBCT scans from Planmeca Promax 3D Mid and Romexis 5.1 software tools to measure the height and width of the CPP, and we measured the surface of the CPP using an ellipse tool. We classified the CPP into "thin" and "thick" shape. RESULTS: the prevalence of CPP was 9.49% with 97 male and 94 female patients. The unilateral type was found in 131 patients, while the bilateral type was found in 60 patients. Intra-observer reliability was evaluated using the intraclass correlation coefficient (ICC). The ICC was 0.875 for height, 0.872 for width, and 0.885 for the ellipse area. Both methods present very good intra-observer reproducibility. The "thin" group tended to be older and significantly more related to female patients. The "thick" group was associated with younger male patients. CONCLUSIONS: the proposed classification of CPP may be used when reporting the CBCT large field of view. There is still a need to increase the knowledge on the atlas and on its main variant, such as complete PP.

Risk of simultaneous and delayed breakage of total hip replacement ceramic implants in patients with trauma induced periprosthetic fracture and acetabular shell loosening.

BACKGROUND: Ceramic implant breakage (CIB) in total hip replacement (THR) is a rare incident. A confusion exists between the fragile mechanical behaviour of ceramic materials (brittleness) and fragility in the common sense (easy to break), leading to the misconception that trauma is to blame for these breakages. Trauma has been reported as a cause of breakage by several authors and it is debated whether the burst force can be reached in one single trauma in-vivo. We did a retrospective investigation aiming to determine the risk of CIB associated with a major trauma defined as a periprosthetic femoral fracture (PPFF) or a traumatic loosening of the acetabular shell (TLAS) in ceramic-on-ceramic (CoC) THR. HYPOTHESIS: The impact forces responsible of PPFF and TLAS, which are probably the most important impact forces sustained by patients, are not sufficient to induce immediate or delayed CIB. MATERIAL AND METHODS: We conducted a retrospective study on 31 patients (62 ceramic implants, 31 acetabular liners and 31 femoral heads) with a PPFF or TLAS between January 2010 and January 2022. We reviewed the records and X-rays at the time of the major trauma and at the last follow-up. We searched for simultaneous CIB, and those occurring on the non-explanted ceramic implants at last follow up (delayed CIB). These major traumas occurred in 9 men and 22 women. Median age was 75 years old [20-97years old]. There were 28 PPFF and 3 TLAS. Mean time from THR to trauma was 91.2±67months [2.4-240months]. RESULTS: On X-rays and after intraoperative confirmation, we do not report any simultaneous CIB on the 62 ceramic implants. Treatment consisted of internal fixation for 20 patients with preservation of both ceramic implants for Vancouver A, B1 and C fractures, 8 stem revisions with preservation of acetabular liner for Vancouver B2 and B3 fractures and 3 acetabular shell revisions to dual mobility and ceramic head change for TLAS. Thus, a total of 48 ceramic implants remained implanted (28 acetabular liners and 20 femoral heads). At last follow-up after the index revision (median=36 months [6-100months]), no patient had a delayed CIB. DISCUSSION: Major trauma resulting in a PPFF or TLAS in patient withs a CoC THR did not result in simultaneous CIB. The impact forces during these traumas are not sufficient to induce immediate breakage of the ceramic implants. At a median 3years follow-up we found no delayed CIB. Because CIB is a rare event, longer follow up and larger cohort study is needed to determine if a single high impact trauma can initiate and favour the spread of a crack in the ceramic material leading to a breakage. Considering the high mechanical resistance of the ceramic implants and the absence of CIB during or after a major trauma in our study, patients with CoC bearings should not be restricted in their daily activity to prevent CIB. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Preoperative Planning for Reverse Shoulder Arthroplasty: Does the Clinical Range of Motion Match the Planned 3D Humeral Displacement?

INTRODUCTION: The functional outcome after reverse shoulder arthroplasty (RSA) is closely linked to how much the humerus shifts because of the implants. While two-dimensional (2D) angle measurements have been used to capture this shift, it can be measured in three dimensions (3D) as the arm change position (ACP). In a previous study, the ACP was measured using 3D preoperative planning software with the passive virtual shoulder range of motion obtained after RSA. The main objective of this study was to evaluate the relationship between the ACP and the actual active shoulder range of motion measured after RSA. The hypothesis was that the ACP and the active clinical range of motion are related such that the ACP is a reliable parameter to guide the preoperative planning of an RSA. The secondary objective was to assess the relationship between 2D and 3D humeral displacement measurements. MATERIALS AND METHODS: This prospective observational study enrolled 12 patients who underwent RSA and had a minimum follow-up of 2 years. The active range of motion in shoulder flexion, abduction, and internal and external rotation was measured. At the same time, ACP measurements were taken from a reconstructed postoperative CT scan, in addition to the radiographic measurements of humeral lateralization and distalization angles on AP views in neutral rotation. RESULTS: The mean humeral distalization induced by RSA was 33.3 mm (±3.8 mm). A non-statistically significant increase in shoulder flexion was observed for humeral distalization beyond 38 mm (R2 = 0.29, p = 0.07). This "threshold" effect of humeral distalization was also observed for the gains in abduction, as well as internal and external rotations, which seemed better with less than 38 mm or even 35 mm distalization. No statistical correlation was found between the 3D ACP measurements and 2D angle measurements. CONCLUSION: Excessive humeral distalization seems to be detrimental to joint mobility, especially shoulder flexion. Humeral lateralization and humeral anteriorization measured using the ACP seem to promote better shoulder range of motion, with no threshold effect. These findings could be evidence of tension in the soft tissues around the shoulder joint, which should be taken into consideration during preoperative planning.

Stability of Le Fort 1 osteotomy in patients with bilateral cleft lip and palate: A retrospective study of 71 patients.

The aim of this study was to evaluate the sagittal and vertical relapses after Le Fort 1 osteotomy in bilateral cleft lip and palate (BCLP) patients. Lateral cephalograms before surgery, immediately after the procedure, at one year, and at least two years (when available) after surgery were superimposed. The positions of five landmarks were studied in a coordinate system. Uni- and multivariate analyses investigated the effect of various factors on the relapse. Of the 71 patients included for a BCLP, 54 presented complete data at one year, and 30 patients were included for the long follow-up study (mean of 55 months). The mean maxillary advancement was 6.2 mm on the sub-spinal point (A). Sagittal relapse occurred at one year (mean of 1.1 mm on point A, 0.7 mm on point prosthion (P); p < 0.0001) and progressed by 0.5 mm and 1.0 mm, respectively, on the same points at the last follow-up. The mean vertical relapse was 0.5 mm on point A (p = 0.044), 0.6 mm on point P (p = 0.16) and 0.5 mm on incisor (I) (p = 0.056). The vertical relapse was correlated to the degree of vertical movement. Three factors were associated to the recurrence including a prior pharyngeal flap, an associated mandibular osteotomy and smoking habits.

Effects of graft pretensioning in anterior cruciate ligament reconstruction.

PURPOSE: Graft pretensioning is used in anterior cruciate ligament (ACL) reconstruction to prevent secondary slackening. Its effects on collagen fibrillar ultrastructure are not known. In this study, we hypothesized that graft pretensioning in ACL reconstruction creates ultrastructural changes detectable in scanning electron microscopy (SEM). METHODS: A prospective comparative study was carried out on 38 ACL reconstructions using a 4-strand semitendinosus graft. Samples were harvested intra-operatively before and after pretensioning for 30 s, 2 or 5 min. The images produced in SEM were analyzed using an original semi-quantitative «CIP¼ score taking into account collagen cohesion, integrity, and parallelism. Intra- and inter-tester reliability for the CIP score were tested. RESULTS: The CIP scores decreased by 3.5 (1.6) points after pretensioning (P < 0.05). Significant differences were found in the 5, 2 min and 30 s subgroups for the global CIP score. Relative decrease (Delta CIP) was significantly higher in the 2 and 5 min subgroups after pretensioning in comparison with the 30 s subgroups. Intra- and inter-tester reliability for the CIP score were 0.85 and 0.92 (P < 0.05). CONCLUSION: Pretensioning ACL grafts resulted in alteration of the collagen fibrillar ultrastructure, detectable using SEM. These results confirm the existence of collagen ultrastructural changes after pretensioning that may be related to its duration. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Metastatic Progression of Osteosarcomas: A Review of Current Knowledge of Environmental versus Oncogenic Drivers.

Metastases of osteosarcomas are heterogeneous. They may grow simultaneously with the primary tumor, during treatment or shortly after, or a long time after the end of the treatment. They occur mainly in lungs but also in bone and various soft tissues. They can have the same histology as the primary tumor or show a shift towards a different differentiation path. However, the metastatic capacities of osteosarcoma cells can be predicted by gene and microRNA signatures. Despite the identification of numerous metastasis-promoting/predicting factors, there is no efficient therapeutic strategy to reduce the number of patients developing a metastatic disease or to cure these metastatic patients, except surgery. Indeed, these patients are generally resistant to the classical chemo- and to immuno-therapy. Hence, the knowledge of specific mechanisms should be extended to reveal novel therapeutic approaches. Recent studies that used DNA and RNA sequencing technologies highlighted complex relations between primary and secondary tumors. The reported results also supported a hierarchical organization of the tumor cell clones, suggesting that cancer stem cells are involved. Because of their chemoresistance, their plasticity, and their ability to modulate the immune environment, the osteosarcoma stem cells could be important players in the metastatic process.

Secondary intramedullary nailing for open tibial shaft fractures. Comparison of a one-stage versus two-stage surgical procedure.

INTRODUCTION: The objective of this study was to compare the rates of radiological and clinical complications after sequential treatment of a tibial shaft fracture by external fixation followed by secondary nailing with an early-stage conversion (C1S) versus a two-stage late conversion (C2S). The hypothesis of this work was that treatment with C1S does not increase the risk of surgical site infections compared to C2S, and allows faster healing with a lower malunion rate. MATERIAL AND METHODS: We carried out a retrospective and comparative study based on the files of the traumatology department of the Édouard Herriot University Hospital in Lyon. We reviewed the records of patients who presented with a Gustilo grade 1, 2 or 3a open tibial fracture treated with external fixation with conversion by intramedullary nailing within 6 months from January 2010 to December 2020. We assessed the occurrence of Surgical Site Infections (SSI), consolidation time, time until resumption of weight bearing and the malunion rate. RESULTS: Of the 55 patients included, a C1S procedure was performed in 25 cases (45.5%) versus 30 cases (54.5%) for C2S. No significant difference was found concerning the occurrence of SSI after intramedullary nailing between the two groups (p=0.81). A significant difference was observed in terms of bone healing (p=0.036) and the malunion rate (0.0013) in favor of nailing in one stage. DISCUSSION: The strategy of converting an open leg fracture early, in one stage (C1S), after initial external fixator placement allows for faster healing and weight bearing, while ensuring a lower malunion rate compared to that of a late two-stage conversion. In the absence of a scar at the time of intramedullary nailing, C1S does not increase the risk of surgical site infections. While the choice of a late and sequential two-stage operation is likely related to the surgeon's apprehension around conversion of an open leg fracture by intramedullary nailing, this study could promote the use of C1S in a greater number of situations. LEVEL OF EVIDENCE: IV.

Correlation of Isokinetic Testing and ACL Failure With the Short Graft Tape Suspension Technique at Six Months.

Purpose: The objective of this study was to correlate the data of the 6-month postoperative isokinetic muscle evaluation before resuming sports activities with the occurrence of ACL reconstruction rerupture after semitendinosus short graft. Methods: From 2015 to 2018, all patients who were operated for an ACL reconstruction with a short semitendinosus autograft (TLS System) and who performed isokinetic tests on dynamometer at their 6th postoperative month were included in this study. The follow-up was prospective with the measurement of epidemiological, radiographic, and isokinetic parameters at 6 months of the ACL reconstruction. The cohort was divided into 2 groups: one group without an ACL reconstruction rerupture (Group 1) and the second group with a rerupture (Group 2). Results: One hundred and four patients were analyzed with an average follow-up of 42.3 months (Minimum: 24; Maximum: 63.5), of which 11 patients (10.6%) had an ACL reconstruction rerupture. Group 1 consisted of 93 patients with an average age of 26.5 ± 9.0 years old who did not have an ACL reconstruction rerupture with an average follow-up of 41.6 ± 12.1 months. Group 2 consisted of 11 patients with an average age of 22.7 ± 6.1 years old, who had an ACL reconstruction rerupture with an average follow-up of 44.8 ± 11.3 months. Concerning extension force recovery, the ratio between operated and healthy knee was 81.8% ± 32.0 for Group 1, and 53.4% ± 20.6 for Group 2 (P = .035). A statistically significant difference was also found (P = .0017) during 60°/s flexion isokinetic test between the two groups. Conclusions: This study revealed a significant link between muscle weakness in flexion and extension during 60°/s isokinetic test at 6 months of ACL reconstruction and semitendinosus autograft rerupture. Patients with an ACL reconstruction retear had inferior muscle dynamometric recovery results at 6 months before resuming sports activities. Level of Evidence: Level III, prognostic, retrospective cohort study.

A calpain-6/YAP axis in sarcoma stem cells that drives the outgrowth of tumors and metastases.

Sarcomas include cancer stem cells, but how these cells contribute to local and metastatic relapse is largely unknown. We previously showed the pro-tumor functions of calpain-6 in sarcoma stem cells. Here, we use an osteosarcoma cell model, osteosarcoma tissues and transcriptomic data from human tumors to study gene patterns associated with calpain-6 expression or suppression. Calpain-6 modulates the expression of Hippo pathway genes and stabilizes the hippo effector YAP. It also modulates the vesicular trafficking of ß-catenin degradation complexes. Calpain-6 expression is associated with genes of the G2M phase of the cell cycle, supports G2M-related YAP activities and up-regulated genes controlling mitosis in sarcoma stem cells and tissues. In mouse models of bone sarcoma, most tumor cells expressed calpain-6 during the early steps of tumor out-growth. YAP inhibition prevented the neoformation of primary tumors and metastases but had no effect on already developed tumors. It could even accelerate lung metastasis associated with large bone tumors by affecting tumor-associated inflammation in the host tissues. Our results highlight a specific mechanism involving YAP transcriptional activity in cancer stem cells that is crucial during the early steps of tumor and metastasis outgrowth and that could be targeted to prevent sarcoma relapse.

Does the Surgical Approach Influence the Canal Fill of the Proximal Femur for Hip Arthroplasty?

BACKGROUND: Choosing the right size of the stem is crucial for uncemented hip arthroplasty. Undersizing can lead to early loosening, peri-prosthetic fracture due to femoral implant insertion, and/or osteointegration failure. The main objective of this study was to find a correlation between the surgical approach and the intramedullary prosthetic canal fill ratio (CFR) of the uncemented femoral implant. The hypothesis of this work was that the surgical approach does not influence the stem sizing during hip arthroplasty. METHODS: In this consecutive series, we analyzed the radiological images of 183 patients who underwent primary hip arthroplasty with 4 different surgical approaches. Dimensions of the implant were evaluated by radiographic measurement of the CFR. In order to assess the shape of the femur, we measured the canal flare index on the preoperative radiographs, and the canal calcar ratio was also measured to establish the shape of the femur according to Dorr's classification. RESULTS: No significant difference was found between the surgical approach and the CFR measured at 4 different levels (CFR 1, 2, 3, and 4) on the postoperative radiograph. When the shape of the femur was assessed by canal flare index, there was no significant difference in implant, whether the femur had a stovepipe canal shape or a champagne-fluted canal shape. CONCLUSION: This study showed that the surgical approach in hip arthroplasty does not influence the canal fill. Therefore, the surgical approach does not factor in undersizing the femoral implant. Despite some difficulties in the exposure of the medullary shaft described by some authors, the anterior approach is not a risk factor for undersizing an anatomical femoral stem. LEVEL OF EVIDENCE: 4.

Does load-bearing materials influence hip capsule thickness in total hip replacement? An MRI case-matched study.

BACKGROUND: Ceramic-on-ceramic (COC) total hip replacements (THR) have exhibited less instability and late dislocation. Hip capsule plays an important role in hip stability. Different surrounding soft tissue reactions have been observed according to the bearing material used but no study compared these data using MRI investigation. Therefore, we performed a retrospective case control study to compare hip capsule thicknesses according to the bearing materials in THR and in native hips. HYPOTHESIS: Hip capsule is thicker after COC THR compared to ceramic- or metal-on-polyethylene (PE) bearings, or native hips. MATERIALS AND METHOD: Magnetic resonance imaging (MRI) images, combined with a multi acquisition variable resonance image combination (MAVRIC) sequence, was used to measure the hip capsule thickness in 16 patients (29 hips) who had either COC (13 hips, median age at surgery: 64.8 years old, median follow-up at imaging: 2482 days), PE bearings (11 hips, median age at surgery: 48.4 years old (significantly different from COC THR), median follow-up at imaging: 1860 days (NS)), or a native hip with no implant (5 hips). Two independent radiologists measured capsular thicknesses in 4 different zones and were blinded regarding the bearing components. The imaged hips were classified into three groups: native, COC and PE. RESULTS: The COC THR group had the thickest capsules (median 7.0mm, range 2.9-15.5mm). This result was statistically significant (p<0.0001) when compared to PE THR (median 4.9mm, range 2.2-10.5mm), and to native hips (median 4.1mm, range 2.7-6.9mm) measurements, respectively. Furthermore, painful hips had thinner capsules (4.6mm, range 2-10.5) compared to not painful hips (6.8mm, range 2.3-15.5) (p=0.0006). DISCUSSION: This is the first in-vivo study measuring capsular thickness in THR with the objective of measuring variations according to the hip implant materials used. The results revealed a significantly thicker capsule for the COC bearing compared to either PE or native hips, and a thinner capsule in painful hips. LEVEL OF EVIDENCE: III, retrospective non-consecutive cohort study.

Contribution of the remaining attachment index in the management of Vancouver B1 periprosthetic hip fracture.

INTRODUCTION: Implant fixation assessment following Vancouver B1 periprosthetic hip fracture is a major decision factor for internal fixation and/or implant revision. The main aim of the present study was to assess the correlation between radiographic Remaining Attachment Index (RAI) and risk of implant loosening at last follow-up following internal fixation of Vancouver B1 periprosthetic hip fracture. MATERIAL AND METHOD: A multicentre retrospective study included 50 patients with Vancouver B1 periprosthetic hip fracture with uncemented femoral stem between 2013 and 2019. Preoperative radiographs were analysed independently by 2 senior orthopedic surgeons, distinguishing 2 groups: RAI>2/3 versus<2/3. Postoperative and last follow-up radiographs were then screened for signs of complete femoral component loosening. RESULTS: Median age was 89 years (range: 36-99 years). Two RAI>2/3 patients showed implant loosening (8%) versus 9 RAI<2/3 patients (36%), disclosing a significant correlation between early loosening and RAI<2/3 (p=0.005). Interobserver agreement for both radiographic RAI and radiographic loosening assessment at last follow-up was 98% with kappa correlation coefficient 0.96 [range: 0.88-1]. CONCLUSION: Remaining Attachment Index<2/3 in Vancouver B1 periprosthetic hip fracture was a risk factor for early implant loosening after isolated internal fixation. In these often frail elderly patients, first-line implant exchange is to be considered in the light of the risk/benefit ratio. The present results confirm the need for rigorous preoperative radiographic work-up of the remaining attachment area in Vancouver B1 fracture. LEVEL OF EVIDENCE: IV.

Three-Dimensional Navigation (O-arm) for Minimally Invasive Shelf Acetabuloplasty.

Hip dysplasia is an important cause of osteoarthritis in young adults. For these patients, conservative treatment is an interesting alternative to arthroplasty. The current literature suggests better clinical and functional outcomes when shelf acetabuloplasty is performed for a moderate joint pinch (<50%) associated with an important external coverage defect of the acetabular cup (<25°). Compared with open surgical procedures, minimally invasive surgical techniques or arthroscopy tend to reduce morbidity. To date, the major intraoperative difficulty remains the positioning of the graft. This Technical Note aims to outline a minimally invasive shelf acetabuloplasty, with optimization of the position of the autologous iliac crest bone graft using 3-dimensional navigation.

Posterior drawer after olecranization of the patella in posterior cruciate-injured knees: A cadaver study.

INTRODUCTION: Olecranization of the patella (OP) is a surgical technique that anchors the patella to the tibia using a Steinmann pin to reduce the posterior drawer in cases of acute posterior cruciate ligament (PCL) tears. The advantage of this procedure is that rehabilitation can start early with passive and active mobilization, all the while maintaining the reduced position. The primary objective of this cadaver study was to evaluate the reduction in the posterior drawer induced by OP. The hypothesis was that OP significantly reduces the posterior drawer at 0°, 45° and 90° flexion after isolated PCL transection. MATERIAL AND METHODS: A Steinman pin was inserted in 70° flexion on seven fresh cadaver knees. Changes in the posterior drawer were measured on radiographs at 0°, 45° and 90° flexion before and after adding a posterior load (150N) in the following sequence: intact knee, after PCL transection, after OP. Posterior translation was measured in millimetres. RESULTS: In unloaded knees, the posterior drawer was significantly reduced after OP in 45° flexion (4.1mm to-1.2mm, p<0.05) and 90° flexion (7.9mm to 3.8mm, p<0.05). When a posterior load was applied, the posterior drawer was significantly reduced in 0° flexion (4.9mm to 0.2mm, p<0.05), 45° flexion (6.7mm to 0.6mm, p<0.05) and 90° flexion (11.8mm to 7.6mm, p<0.05). DISCUSSION: Anchoring the patella to the tibia in 70° flexion led to a significant reduction in the posterior drawer after PCL transection in cadaver knees. Olecranization of the patella may help optimize the healing of an injured PCL treated conservatively. LEVEL OF EVIDENCE: III, controlled laboratory study.