Ankle syndesmosis biomechanical evaluation by shear-waves elastography in healthy young adults: Assessment of the reliability and accuracy of the measurements and definition of a corridor of normality.

BACKGROUND: Aims of this study were: 1/ to evaluate the shear wave speed (SWS) properties of the anteroinferior tibiofibular ligament (AITFL) and the distal interosseous membrane (DIOM) in neutral, dorsal flexion and plantar flexion positions in a cohort of healthy adult volunteers; 2/ to assess the reliability and reproducibility of these measurements. METHODS: Both ankles were analyzed by shear wave elastography (SWE) in 20 healthy patients (10 females/10 males) standing on a hinge support with their ankles in neutral, 20° dorsal flexion and 30° plantar flexion positions. Stiffness of AITFL and DIOM was evaluated by SWS measurement. RESULTS: The SWS of AITFL and DIOM were minimal in the plantar flexion position (4.28 m/s [2.65-5.11] and 3.35 m/s [1.69-4.55], respectively). It increased significantly for both ligaments in neutral position (4.69 m/s [3.53-5.71] and 3.81 m/s [1.91-4.74], respectively; p < 0.0001), and reached their maximum values in dorsal flexion (6.58 m/s [5.23-8.34] and 4.79 m/s [3.07-6.19], respectively; p < 0.0001). There was no correlation between each ligament regardless the positions. SWS of AITFL was independent of demographic characteristics analyzed. SWS of DIOM was negatively correlated with height in dorsal flexion (ρ = -0.35; p = 0.03) and in plantar flexion (ρ = -0.37; p = 0.02). Female gender was associated with increased DIOM SWS in neutral (p = 0.005), dorsal flexion (p = 0.003), and plantar flexion (p = 0.001) positions. Moreover, foot morphology (foot arch, hind foot frontal deviation) did not impact AITFL nor DIOM SWS. Inter- and intra-observer measurements were all good or excellent. CONCLUSION: The AITFL and DIOM, stabilizers of the distal tibiofibular syndesmosis, increase in stiffness while dorsal flexion increases. This study describes a reliable and reproducible protocol to assess their stiffness by SWE, and defines a corridor of normality.

Comparison of "Bilboquet" device and locking plate for surgical treatment of proximal humerus complex fractures at two years follow-up.

PURPOSE: Surgical treatment of three or four part fractures of the proximal humerus is complex. Different conservative techniques have been described. The main goal of this study was to compare the clinical and radiological outcomes of Bilboquet and locking plate at two year follow-up. METHODS: This is a retrospective, comparative study, with a continuous series of 41 patients. Bony fixation was achieved with a Bilboquet device in 22 patients or a locking plate in 19 patients. Patient evaluation included clinical data: shoulder range of motion, Constant-Murley shoulder score and DASH (Disabilities of the Arm, Shoulder and Hand) score, and imaging using standard shoulder X-rays. RESULTS: Of the 41 patients included, 1 patient was lost to follow-up in the locking plate group. At a mean follow-up of 24 months patients in Bilboquet group showed a Constant score higher than in locking plate (p = 0.02). Range of motion and DASH score were not significantly different between the two groups. avascular necrosis occured in three patients of Bilboquet group (14%) versus in two patients in the locking plate group (11%) (p > 0.5). Complication and reintervention rate were non-significantly higher in the locking plate group than in the Bilboquet group (37 vs 14%). CONCLUSION: Bilboquet and locking plate give good functional outcomes in complex proximal humerus fractures. However, the Bilboquet device appears to provide better functional results than locking plate at mid-term follow-up.

Open reduction and internal fixation of three- and four-part proximal humeral fractures by intrafocal distraction: a clinical and radiographic study of thirty-two cases with five to ten years of follow-up.

PURPOSE: The disadvantage of ORIF of proximal humerus fracture (PHF) by intrafocal distraction is that once the device is inserted, it cannot be removed. This study was designed to evaluate the tolerance of such a titanium alloy device at five years of minimal follow-up (FU) and secondarily to assess the relevance of the osteosynthesis of these fractures. METHOD: Thirty-two patients operated for PHF and implanted with a titanium alloy device between 2009 and 2011 were reviewed: fifteen three-part fracture (3-PF) with mean age 65.2 ± seven years and mean FU at 86 months, and seventeen four-part (4-PF) with mean age 62.9 ± 12 years and mean FU at 88 months. RESULTS: There were no signs of clinical or radiological incompatibility to the metal. The lateral cortex of the humeral shaft at the wedge component level of the device was thinner than pre-operatively in half of the cases. For the fifteen 3-PF, the median raw and weighted constant score (CS) were 75 and 100, respectively. Only one case presented avascular necrosis (AVN). For the seventeen 4-PF, the median raw and weighted CS were 64 and 88, respectively. Seven cases presented AVN and none of them seven had initially a dorsomedial metaphyseal extension of the humeral head. Kaplan-Meier survivorship analysis, with 95% confidence interval, was calculated at 89.7% (79.7-100%) survivorship at 7.18 years of follow-up. CONCLUSIONS: This study shows no incompatibility of the titanium alloy device, radiological signs of localized stress shielding in half of the cases with no functional impact, excellent clinical and radiological evolution of the 3-PF, and AVN in all 4-PF without dorsomedial metaphyseal extension of the humeral head whereas most of cases without AVN had dorsomedial metaphyseal extension.

Isolated open anterior shoulder release in brachial plexus birth palsy.

BACKGROUND: In children with brachial plexus birth palsy (BPBP), a shoulder joint internal contracture is commonly observed, which may result in glenohumeral osseous deformities and posterior joint subluxation. The purpose of this retrospective study was to evaluate the impact of an isolated anterior shoulder release on osteoarticular disorders and assess the subsequent clinical improvements. METHODS: Forty consecutive BPBP patients with glenohumeral dysplasia underwent an open anterior shoulder release. Shoulder scans (ie, magnetic resonance imaging preoperatively and computed tomography postoperatively) were conducted to assess glenoid version and the percentage of the humeral head anterior to the middle of the glenoid fossa. Clinical data including analytical shoulder range of motion and modified Mallet scores were collected. RESULTS: After a mean follow-up period of 23 months, glenoid version and the percentage of the humeral head anterior to the middle of the glenoid fossa significantly improved from -32° and 18%, respectively, to mean postoperative values of -12° (P < .001) and 45% (P < .001), respectively. Passive and active external rotation increased from -2° and -43°, respectively, to 76° (P < .001) and 54° (P < .001), respectively. The mean modified Mallet score significantly improved from 14.2 to 21.4 points (P < .001). In 8 children with satisfactory passive motion, a latissimus dorsi transfer was performed secondarily to obtain satisfactory active motion. CONCLUSION: In BPBP patients with glenohumeral deformities, isolated open anterior release of the shoulder induces significant remodeling of the joint, reducing posterior joint subluxation and improving both passive and active shoulder ranges of motion. Additional latissimus transfer remains mandatory in selected cases to achieve satisfactory function.

Hemiarthroplasty for proximal humerus fractures with conservation of the whole humeral head as autograft: does it improve greater tuberosity healing?

PURPOSE: Hemiarthroplasty (HA) for proximal humerus fracture (PHF) is associated with tuberosity complications like migration, non-union, and resorption. In order to improve the rate of consolidation of the greater tuberosity (GT), we have developed a hollow humeral head prosthesis in which the whole humeral head is inserted and used as autograft. This study is designed to evaluate the consolidation rate of the GT with this device. METHOD: Twenty-two patients at mean age of 68 were treated between 2015 and 2017 for four-part fractures, fracture-dislocations, and head-split fractures with HA including the bony humeral head. The humeral prosthesis device comprises a prosthetic cephalic cup in which the detached humeral head is inserted and a cementless adjustable humeral stem which works like a jack. Mean follow-up was 14 months. The consolidation of GT was followed on X-rays. As comparison, 15 published series were selected and analyzed. RESULTS: There were two mechanical complications related to GT consolidation (9.1%). In the 20 other cases, the GT was radiologically consolidated without displacement. While the raw proportion of complications observed in the present series was lower than that reported in each of the 15 comparative series, the proportion of complications observed in the present series was significantly different from that observed only in seven out of the 15 previous series. CONCLUSION: Whole conservation of the humeral head as an autograft along with proper surgical technique yielded in 20 consolidations of GT without displacement in 22 cases of PHF treated with hemiarthroplasty.

Arthrodesis Versus Carpometacarpal Preservation in Key-Grip Procedures in Tetraplegic Patients: A Comparative Study of 40 Cases.

PURPOSE: Constructing a lateral key pinch (KP) is a universal aim of any functional upper limb surgery program for tetraplegia. Three stages are required: (1) activating the pinch mechanism by flexor pollicis longus tenodesis to the radius or by tendon transfer to the flexor pollicis longus, (2) simplifying the polyarticular chain, and (3) positioning the thumb column. We compared 2 techniques for accomplishing the latter stage, 1 utilizing arthrodesis of the carpometacarpal joint (CMC) and 1 that did not require arthrodesis of the CMC. MATERIALS AND METHODS: We reviewed 40 cases of KP reconstruction at a mean follow-up of 7.4 years: 17 who had undergone CMC arthrodesis and 23 without CMC arthrodesis. In this group, an abductor pollicis longus tenodesis was necessary to properly position the thumb column in 17 patients. RESULTS: Active KP cases with CMC arthrodesis were significantly stronger than those without an arthrodesis. For passive KP cases, the difference between those cases with CMC arthrodesis and those without was not significant. Regarding opening, for active KP cases with CMC preservation alone, the mean distance between the thumb pulp and the index finger was 4.0 cm at rest and 5.8 cm when passively grasping large objects; for active KP cases without arthrodesis, these values were 3.4 and 6.8 cm, respectively, with the wrist in flexion. For passive KP cases, these values were 2.2 and 3.5 cm with CMC arthrodesis compared with 2.4 and 6.9 cm without arthrodesis. Overall, 23.5% of patients with CMC arthrodesis could not maintain contact between the thumb and the index finger compared with 30.4% without arthrodesis. CONCLUSIONS: Active KP is stronger with than without CMC arthrodesis; however, the KP reconstruction does not open as far when grasping large objects. For passive KP, CMC arthrodesis significantly limits passive opening, with no gain in strength. Neither technique is superior in terms of KP stability. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Bipolar transfer of the pectoralis major muscle for restoration of elbow flexion in 29 cases.

BACKGROUND: This study evaluated the functional outcomes of bipolar pedicled pectoralis major (PM) transfer to restore elbow flexion. METHODS: We retrospectively reviewed 29 transfers in 28 patients with a mean age of 31.2 years (range, 5-65 years). The loss of elbow flexion was due to brachial plexus palsy in 24 patients, elbow flexors necrosis in 4, and poliomyelitis in 1. The entire PM muscle was mobilized and fixed proximally to the coracoid process. Intraoperative positioning and postoperative immobilization of the shoulder and the elbow flexed at 60° and 120°, respectively, allowed direct distal fixation of the muscle to the biceps brachii tendon. RESULTS: At the last follow-up (mean, 13 months; range, 4-37 months), 41% of the transfers (n = 12) recovered grade 4 elbow flexion strength and were able to lift 2.2 kg on average (range, 0.5-5 kg), 52% (n = 15) recovered grade 3 strength, and 7% (n = 2) had a poor result (ie, grade 2 elbow flexion). The mean active elbow flexion was 100° (ranging, 30°-150°), and the patients had 0° to 10° elbow flexion contracture. CONCLUSIONS: Our results indicate that bipolar PM transfer is a reliable and effective procedure to restore elbow flexion. Flexion of the shoulder and elbow allowed the transfer to reach the elbow fold and avoided an interposition graft between the distal PM and the biceps brachii tendon.

Pulseless supracondylar humeral fractures in children: vascular complications in a ten year series.

PURPOSE: The management of pulseless supracondylar fractures remains controversial. The aims of this study were to: (1) analyse functional and vascular outcomes of conservative treatment for cases with absent pulse before reduction, whether patients showed limb ischaemia or not; and (2) identify factors associated with vascular complications. METHODS: Twenty-seven children with absent pulses on presentation were treated consecutively between 1999 and 2009. The brachial artery was surgically explored in cases of persistent signs of ischaemia after reduction. Signs of vascular impairment were recorded in the early post-operative period and at a mean final follow-up of 3.5 years. RESULTS: Recurrent ischaemia with a compartment syndrome occurred in a patient with initial ischaemia and a pink, pulseless hand after reduction. Patients with an initially well-perfused hand and those with pre-operative ischaemia and palpable pulses after reduction had satisfactory outcomes, as did patients with early arterial exploration. No patient showed signs of chronic vascular impairment. The need for vascular repair was significantly correlated with open fracture, initial ischaemia and nerve impairment. CONCLUSIONS: Conservative management of supracondylar fractures with absent pulses avoided long-term vascular complications provided that patients with a pulseless, well-perfused hand on presentation were closely monitored after reduction. Further study is necessary to determine whether a forearm Doppler would help identify children with absent pulses after reduction who need surgical revascularisation due to an insufficient collateral circulation.

Comparison of lateral and skyline fluoroscopic views for detection of prominent screws in distal radius fractures plating: results of an ultrasonographic study.

INTRODUCTION: Extensor tendon rupture is a recognized complication of volar plate fixation of distal radius fractures due to screws protruding past the dorsal cortex. The aim of this study was to compare the Skyline view with traditional lateral fluoroscopic views using ultrasonography as a reference standard in the postoperative assessment. MATERIALS AND METHODS: A monocentric prospective study was conducted to identify screws penetrating the dorsal cortex after volar plating of distal radius fractures. PATIENTS AND INTERVENTION: Intraoperative anteroposterior (AP) and lateral views were used for group A (28 patients). AP, lateral and skyline fluoroscopic views were used for Group B (40 patients). Prominent screws were changed. MAIN OUTCOME MEASUREMENTS: Ultrasound was done 6 months postoperatively to evaluate the number and length of prominent dorsal screws and any signs of extensor tenosynovitis. RESULTS: The number of prominent dorsal screws exceeding 1 mm was 14 in group A (14.9%), and 16 screws (11.8%) in group B (p = 0.487). Average length of prominent dorsal screw was 1.9 mm (range 1-2.1 mm) for group A and 2.4 mm (range 1.1-4.8 mm) for group B (p = 0.534). The number of patients with extensor tenosynovitis was 11 for group A and 12 for group B (p = 0.66). CONCLUSIONS: The Skyline view does not provide sensitive and reliable detection of the dorsal screw penetration. Intraoperative ultrasound might be a better tool to detect screw prominence. LEVEL OF EVIDENCE: III, case-control study.

Finger reconstruction using induced membrane technique and ulnar pedicled forearm flap: a case report.

INTRODUCTION: Injuries referred to as "rollover hands" are associated with multiple and complex lesions of the dorsal aspect of the hand. We present a case of a multitissular reconstruction following a severe injury of the dorsum of the fingers in a 45-year-old woman. MATERIALS AND METHODS: The bone loss reconstruction was performed in two stages using the Masquelet induced membrane technique. In the first stage, a cement spacer was inserted into the phalanx bone defects. For the second stage, the membrane induced by the foreign-body reaction was opened, the spacer was removed, and an autologous cancellous bone graft was inserted into the defects. The skin coverage was obtained using a reverse ulnar artery forearm pedicled flap. The digits were covered jointly. Three surgical procedures over the course of a 2-month period were required to desyndactylize the fingers and to defat the flap. RESULTS: At the 2-year follow-up examination, the patient exhibited good integration of their hand use in daily living. The esthetic result was deemed to be satisfactory. Definitive bone consolidation occurred 4 months after the second stage. CONCLUSIONS: Rollover hands are typically a challenge for both the patient and the hand surgeon. The risk of septic complications, as well as the need for several stages of surgical reconstruction, makes the Masquelet technique particularly attractive for the treatment of phalanx bone defects consecutive to rollover injuries.

Anatomical study of the musculocutaneous nerve branching pattern: application for selective neurectomy in the treatment of elbow flexors spasticity.

PURPOSE: Spastic flexion deformity of the elbow is mainly mediated by the biceps brachii and the brachialis muscles, innervated by the musculocutaneous nerve. Selective neurectomy of the musculocutaneous nerve showed promising results to relieve excessive spasticity in the long term but lacks of a consensual surgical strategy. The aim of the study was to describe the distal branching pattern of the motor branches of the musculocutaneous nerve in an attempt to develop guidelines for surgery. METHODS: Sixteen arms of fresh cadaver specimen were dissected. We recorded the site of each primary and terminal motor branch as a percentage of the distance from the coracoid process to the lateral epicondyle. RESULTS: The biceps muscle was innervated by one to five primary motor branches. The first branch emerged from the nerve at an average of 37.1% of the arm length, and the most distal terminal branch at 55.7%. The brachialis muscle received one to three primary branches. The first branch exited the nerve at an average of 51.7% of the arm length and the last terminal branch at 69.3%. The average number of terminal branches dedicated to the biceps and the brachialis muscles were, respectively, 7.9 and 6.5. CONCLUSIONS: According to our findings, we recommend to dissect the musculocutaneous nerve between 18 and 75% of the distance between the coracoid process and the lateral epicondyle to identify the motor terminal branches to the biceps brachii and the brachialis muscle, sparing sensory branches.

Digital vs Conventional OSCE in Orthopedic Surgery: A Feasibility Cross-Sectional Study.

OBJECTIVE: Remote OSCEs (Objective Structured Clinical Examination) are an alternative evaluation method during pandemic periods but they have never been evaluated in orthopedic surgery. We aimed to evaluate whether remote OSCEs would be feasible, and efficient for assessment of undergraduate medical students. METHODS: A cross-sectional study was performed. Thirty-four students were randomly assigned into 2 equal groups, either the conventional OSCE group or the digital OSCE group. Three types of skills were assessed: technical procedure, clinical examination, and radiographic analysis. Students were graded and they filled in a satisfaction questionnaire for both types of OSCEs. RESULTS: The mean score, out of 20, was 14.3 ± 2.5 (range 9.3-19) for the digital sessions, versus 14.4 ± 2.3 (range 10-18.6) for conventional sessions (p = 0.81). Bland Altman Plot showed that 88% of students scored within agreement. The average global feedback was different for item repeatability, relevance, and OSCEs preference (p < 0.0001, p = 0.0001, and p < 0.0001 respectively). However, they did not report differences for the item concerning the organization (p = 0.2). CONCLUSION: The results of this comparative study between digital and conventional OSCEs showed comparable distance learning scores between the 2 groups, whatever the skill assessed. However, the student's evaluation showed some reticence to conduct again OSCEs remotely.

Anatomical variations in the sensory innervation of the dorsal surface of the first digit space, a cadaveric study with clinical consequences.

INTRODUCTION: Radial nerve palsy is a classical complication of a humeral shaft fracture. In clinical practice, motor palsy of the radial nerve is sometimes observed without an abnormality felt in the sensory territory. HYPOTHESIS: We hypothesised that this dissociation between sensory and motor involvement is related to anatomical variations of the sensory innervation of the dorsal surface of the first digit space, thus, we decided to study the nature and frequency of these variations. MATERIAL AND METHOD: A cadaveric study was conducted on 24 upper limbs to analyse the truncal origin of the sensory branches innervating the dorsal surface of the first digit space. RESULTS: The sensory branch of the radial nerve (SBRN) participated in the innervation of the dorsal surface of the first digit space in 22 limbs, an anatomical variation was present in 2 cases with a mixed innervation by the SBRN and the lateral cutaneous nerve of forearm (LCNF) in 1 case and singular innervation by LCNF, with no SBRN involvement, in 1 case. Communications between SBRN and LCNF were found in 7 cases. DISCUSSION: Pure motor radial damage, without a sensory deficit of the dorsal surface of the first digit space, does not preclude a complete traumatic injury of the radial nerve. The sensory innervation of this region can be relayed by a branch of the LCNF. LEVEL OF EVIDENCE: IV; cadaveric study.

Transfer of a C7 Fascicle for the Pectoralis Major to the Suprascapular Nerve: A 3-Year Follow-Up Patient Series.

BACKGROUND: In patients with C5-C6 brachial plexus injury, spinal accessory nerve transfer to the suprascapular nerve is usually performed for the restoration of shoulder abduction. In order to minimize donor deficits, we transferred one fascicle of the ipsilateral C7 root, dedicated to the pectoralis major muscle, to the suprascapular nerve. METHODS: Ten patients with a mean age of 33 years (range, 19 to 51 years) were operated on at a mean delay of 4 months after their trauma (range, 2 to 7 months). Patients had C5-C6 brachial plexus palsy with avulsed roots on spinal magnetic resonance imaging scan. In addition to the partial C7 transfer, patients sustained nerve transfers to the posterior branch of the axillary nerve and to the motor branches of the musculocutaneous nerve for the biceps and brachialis muscles. RESULTS: At a mean follow-up of 36 months (range, 29 to 42 months), mean shoulder abduction and external rotation ranges of motion were, respectively, 99 degrees (range, 60 to 120 degrees; p = 0.001) and 58 degrees (range, 0 to 80 degrees; p = 0.001). In nine patients, shoulder abduction strength was graded M4, according the British Medical Research Council grading scale, against 1.6 kg (range, 1 to 2 kg), and was graded M3 in one patient. External rotation strength was graded M4 in nine patients and M3 in one patient. Residual strength of the pectoralis major muscle was graded M4+ in every patient. CONCLUSIONS: C7 partial transfer to the suprascapular nerve showed satisfactory results at long-term follow-up for active shoulder abduction and external rotation recovery in C5-C6 brachial plexus palsies. This technique replaced spinal accessory nerve transfer in the authors' practice. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

An ultra-thinned groin flap for reconstruction of complete digital ring avulsion injuries.

In complete digital ring avulsions, amputation is usually carried out when replantation of the avulsed tissue is not an option or has failed. The purpose of this study was to report our experience in treating Urbaniak Class III degloved fingers using an ultra-thinned pedicled groin flap. Sixteen patients from ages 11 to 26 years were included. In all cases, the flexor digitorum superficialis tendon, extensor apparatus and proximal interphalangeal joint were intact. Rehabilitation included immediate active mobilization, with flap division at day 21. At a mean follow-up of 15 months, all patients but one were satisfied with the appearance. Two had mild subjective cold intolerance. No flap failure was recorded. The mean total active motion was 183° and the mean QuickDASH score was 8.8/100. Patients recovered S1 sensibility according to the Mackinnon and Dellon classification. The ultra-thinned groin flap has proved to be a reliable technique for non-replantable ring avulsions.Level of evidence: IV.

Sarcomas of the hand: A retrospective series of 26 cases.

BACKGROUND: Hand sarcomas frequently suffer from a delayed diagnosis, and the current guidelines for their management are often not followed. METHODS: The objectives of our study were to determine: (1) the rate of inadequate initial treatments; (2) the rates of mortality, recurrence, and complementary excision in a cohort of patients with a sarcoma of the hand who were treated at our reference center between 2000 and 2015. RESULTS: The series comprised 26 patients (mean age 40 years). Of the 20 patients not initially treated at a reference center, 17 had inadequate initial treatment. Of the six patients treated at our center, one had inadequate initial care. Significantly more patients had inadequate initial care outside a reference center (p=0.0045). The cumulative probabilities of recurrence or metastases at 5 years were 15% and 30%, respectively. Survival by cumulative incidence was 71% at 5 years and 56% at 10 years. CONCLUSIONS: Sarcomas of the hand are a deadly pathology. All diagnostic uncertainty warrants referral of the patient to a reference center. LEVEL OF PROOF: IV.

Deciphering pathological remodelling of the human cartilage extracellular matrix in osteoarthritis at the supramolecular level.

The extracellular matrix (ECM) of articular cartilage is a three-dimensional network mainly constituted of entangled collagen fibrils and interfibrillar aggrecan aggregates. During the development of osteoarthritis (OA), the most common musculoskeletal disorder, the ECM is subjected to a combination of chemical and structural changes that play a pivotal role in the initiation and the progress of the disease. While the molecular mechanisms involved in the pathological remodelling of the ECM are considered as decisive, they remain, however, not completely elucidated. Herein, we report a relevant way for unravelling the role and nature of OA progress on human cartilage tissues, in terms of chemical composition and morphological and mechanical properties at the level of supramolecular assemblies constituting the cartilage ECM. For this purpose, we used X-ray photoelectron spectroscopy (XPS), and developed an innovative methodological approach that provides the molecular composition of the ECM. Moreover, we used atomic force microscopy (AFM) to probe the tissues at the level of individual collagen fibrils, both imaging and force spectroscopy modes being explored to this end. Taken together, these nanoscale characterization studies reveal the existence of two stages in the OA progress. At the early stage, a marked increase in the aggrecan and collagen content is observed, reflecting the homeostatic chondrocyte activity that tends to repair the cartilage ECM. At the late stage, we observe a failed attempt to stabilize and/or restore the tissue, yielding significant degradation of the supramolecular assemblies. This suggests an imbalance in the chondrocyte activity that turns in favor of catabolic events. Chemical changes are also accompanied by ECM structural changes and stiffening. Interestingly, we showed the possibility to mimic the imbalanced activities of chondrocytes by applying enzymatic digestions of healthy cartilage, through the combined action of hyaluronidase and collagenase. This yields damage strictly analogous to that observed at high OA severity. These findings bring mechanistic insights leading to a better understanding of the mechanism by which OA is initiated and progresses in the cartilage ECM. They offer guidelines for the development of curative treatments, such as targeting the homeostatic balance of chondrocyte metabolism through the control of enzymatic reactions involved in catabolic processes.

Ulnar neuropathy at the elbow.

At the elbow, the ulnar nerve (UN) may be the site of a static compression (by the cubital tunnel retinaculum and Osborne's ligament between the two heads of the flexor carpi ulnaris), or a dynamic compression, especially when the nerve is unstable (subluxation/dislocation outside the ulnar groove). The clinical basis for the diagnosis of ulnar neuropathy involves looking for subjective and objective signs of sensory and/or motor deficit in the ulnar nerve's territory in the hand, a pseudo-Tinel's sign, and doing manipulations to provoke UN irritation. The diagnosis is confirmed by electromyography and ultrasonography. In the early stages, patient education and elimination of flexion postures or repeated elbow flexion motions can provide relief. If this fails or signs of sensory and/or motor deficit are present, surgical treatment is proposed. If the nerve is stable, in-situ nerve decompression is typically done as the first-line treatment. If the nerve is unstable, anterior nerve transposition - generally subcutaneous - or more rarely, a medial epicondylectomy can be done. If surgical treatment fails, the patient's history is reviewed, and diagnostic tests can be repeated. Except in cases of a fibrotic scar, the main causes of failure are neuroma of a branch of the medial cutaneous nerve of the forearm, instability of the nerve and persistence of a compression point. In the latter two cases, surgical revision is justified and anterior nerve transposition or epicondylectomy can be proposed.

Induced membrane technique applied to the forearm: Technical refinement, indications and results of 13 cases.

INTRODUCTION: The unique anatomical characteristics of the forearm bones makes their reconstruction challenging. The aim of this study was to report the surgical methods and results of the induced membrane technique applied to traumatic forearm bone defects. MATERIAL AND METHODS: We evaluated retrospectively a case series of 13 patients operated between 2010 and 2017. The first surgical step consisted of debridement of the fracture site and implantation of a cement spacer with appropriate fixation. The anatomy of the forearm skeleton had to be restored. The second step, done 6 weeks later, consisted of removing the cement spacer and applying cancellous bone autograft harvested from the iliac crest. The outcome measures were radiological bone union, need for surgical revision, and postoperative wrist range of motion. RESULTS: All 13 patients were men, with a mean age of 39 years (18-67). The average follow-up was 2.5 years. Eleven patients were suffering from a nonunion and two from a post-traumatic bone defect. Six patients had an identified preoperative infection. Three patients had previously undergone an unsuccessful treatment for their nonunion with bone addition. The maximum length of bone reconstruction was 12 cm. Union was achieved in 12 of 13 patients in a mean of 5 months (3-8). The other patient died during the postoperative course. Two patients needed revision surgery: ulnar shortening osteotomy (1 case) and additional tendon reconstruction (1 case). The mean pronosupination range was 123° on average (55-180°). The mean flexion-extension range was 106° (90-130°). CONCLUSION: The induced membrane technique is a reliable reconstruction technique that is well suited to reconstruction of the forearm skeleton. LEVEL OF EVIDENCE: IV, retrospective study.