EELS: Autonomous snake-like robot with task and motion planning capabilities for ice world exploration.

Ice worlds are at the forefront of astrobiological interest because of the evidence of subsurface oceans. Enceladus in particular is unique among the icy moons because there are known vent systems that are likely connected to a subsurface ocean, through which the ocean water is ejected to space. An existing study has shown that sending small robots into the vents and directly sampling the ocean water is likely possible. To enable such a mission, NASA's Jet Propulsion Laboratory is developing a snake-like robot called Exobiology Extant Life Surveyor (EELS) that can navigate Enceladus' extreme surface and descend an erupting vent to capture unaltered liquid samples and potentially reach the ocean. However, navigating to and through Enceladus' environment is challenging: Because of the limitations of existing orbital reconnaissance, there is substantial uncertainty with respect to its geometry and the physical properties of the surface/vents; communication is limited, which requires highly autonomous robots to execute the mission with limited human supervision. Here, we provide an overview of the EELS project and its development effort to create a risk-aware autonomous robot to navigate these extreme ice terrains/environments. We describe the robot's architecture and the technical challenges to navigate and sense the icy environment safely and effectively. We focus on the challenges related to surface mobility, task and motion planning under uncertainty, and risk quantification. We provide initial results on mobility and risk-aware task and motion planning from field tests and simulated scenarios.

The InSight HP3 Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities.

The NASA InSight Lander on Mars includes the Heat Flow and Physical Properties Package HP3 to measure the surface heat flow of the planet. The package uses temperature sensors that would have been brought to the target depth of 3-5 m by a small penetrator, nicknamed the mole. The mole requiring friction on its hull to balance remaining recoil from its hammer mechanism did not penetrate to the targeted depth. Instead, by precessing about a point midway along its hull, it carved a 7 cm deep and 5-6 cm wide pit and reached a depth of initially 31 cm. The root cause of the failure - as was determined through an extensive, almost two years long campaign - was a lack of friction in an unexpectedly thick cohesive duricrust. During the campaign - described in detail in this paper - the mole penetrated further aided by friction applied using the scoop at the end of the robotic Instrument Deployment Arm and by direct support by the latter. The mole tip finally reached a depth of about 37 cm, bringing the mole back-end 1-2 cm below the surface. It reversed its downward motion twice during attempts to provide friction through pressure on the regolith instead of directly with the scoop to the mole hull. The penetration record of the mole was used to infer mechanical soil parameters such as the penetration resistance of the duricrust of 0.3-0.7 MPa and a penetration resistance of a deeper layer ( > 30 cm depth) of 4.9 ± 0.4 MPa . Using the mole's thermal sensors, thermal conductivity and diffusivity were measured. Applying cone penetration theory, the resistance of the duricrust was used to estimate a cohesion of the latter of 2-15 kPa depending on the internal friction angle of the duricrust. Pushing the scoop with its blade into the surface and chopping off a piece of duricrust provided another estimate of the cohesion of 5.8 kPa. The hammerings of the mole were recorded by the seismometer SEIS and the signals were used to derive P-wave and S-wave velocities representative of the topmost tens of cm of the regolith. Together with the density provided by a thermal conductivity and diffusivity measurement using the mole's thermal sensors, the elastic moduli were calculated from the seismic velocities. Using empirical correlations from terrestrial soil studies between the shear modulus and cohesion, the previous cohesion estimates were found to be consistent with the elastic moduli. The combined data were used to derive a model of the regolith that has an about 20 cm thick duricrust underneath a 1 cm thick unconsolidated layer of sand mixed with dust and above another 10 cm of unconsolidated sand. Underneath the latter, a layer more resistant to penetration and possibly containing debris from a small impact crater is inferred. The thermal conductivity increases from 14 mW/m K to 34 mW/m K through the 1 cm sand/dust layer, keeps the latter value in the duricrust and the sand layer underneath and then increases to 64 mW/m K in the sand/gravel layer below. Supplementary Information: The online version contains supplementary material available at 10.1007/s11214-022-00941-z.

Geology of the InSight landing site on Mars.

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed successfully on Mars and imaged the surface to characterize the surficial geology. Here we report on the geology and subsurface structure of the landing site to aid in situ geophysical investigations. InSight landed in a degraded impact crater in Elysium Planitia on a smooth sandy, granule- and pebble-rich surface with few rocks. Superposed impact craters are common and eolian bedforms are sparse. During landing, pulsed retrorockets modified the surface to reveal a near surface stratigraphy of surficial dust, over thin unconsolidated sand, underlain by a variable thickness duricrust, with poorly sorted, unconsolidated sand with rocks beneath. Impact, eolian, and mass wasting processes have dominantly modified the surface. Surface observations are consistent with expectations made from remote sensing data prior to landing indicating a surface composed of an impact-fragmented regolith overlying basaltic lava flows.

Outcomes at 7 and 21 years after surgical treatment of Dupuytren's disease by fasciectomy and open-palm technique.

The goal of this study was to assess the recurrence of Dupuytren's disease and the stability of the functional result after fasciectomy combined with the McCash open-palm technique. From 1989 to 1999, 56 consecutive patients were surgically treated for Dupuytren's disease. In 2003, 40 of these operated patients were reviewed by an independent evaluator; 12 patients were Tubiana stage 1, 16 stage 2, 9 stage 3 and 3 stage 4. Twenty-one of them were reviewed again in 2016 by a second evaluator who was unaware of the clinical results in 2003. The mean follow-up was 7.32 years (range, 4.26 to 12.5 years) at the first review. Recurrence occurred in 7 patients (17.5%) and extension of the disease in 15 (37.5%). Three patients had developed complex regional pain syndrome (CRPS). Mean residual contracture was 19.3°. Average improvement in finger extension was 53°. At the second review, 21 patients were assessed with a mean follow-up of 21.5 years (range, 18.7 to 26.3 years). None of them were re-operated and no extension of the disease was observed. There was no recurrence in patients who had no recurrence in 2003. However, the contracture had worsened in five patients (23.8%), three of whom had a recurrence of the disease in 2003. Mean residual contracture was 31.8°. Recurrence occurs most often in the first few years after surgery. The functional result is stable over time. CRPS and the number of rays operated are the main factors negatively affecting overall improvement of mobility.

Radiocarpal dislocations and fracture-dislocations: Injury types and long-term outcomes.

INTRODUCTION: Radiocarpal dislocation (RCD) and fracture-dislocations (RCFD) are severe but rare injuries for which the treatment and outcomes are not well defined. The aim of this retrospective study was to describe the prevalence of the various injury types and their long-term outcomes. PATIENTS AND METHODS: Between 1992 and 2014, 41 patients with RCFD were seen at our institution. According to the Dumontier classification, there were 4 cases of type 1 and 37 cases of type 2. Thirteen patients were reviewed again after a mean follow-up of 168 months (20-260). RESULTS: Among these 41 patients, 6 required secondary wrist fusion. At the latest follow-up evaluation, flexion-extension amplitude was 100° (25°-152°), grip strength was 86% of the contralateral side (10kgf-112kgf), the mean VAS for pain was 1.3 (0-5), the mean QuickDASH was 23 (0-59) and the mean PWRE was 27 (0-75). Six patients developed osteoarthritis in the radiocarpal and midcarpal joints. DISCUSSION: For cases of RCD, when reduction and stabilization have been confirmed by a dorsal approach, there is no reason to perform volar capsule and ligament suturing. For cases of RCFD, after anatomical reduction, radiostyloid pinning can be performed and an open surgical approach is not always required. Radiolunate fusion is a good solution for treating secondary instability. CONCLUSION: The good functional outcomes and absence of osteoarthritis can be attributed to the effective reduction and radiocarpal stabilization, along with the absence of radial and intracarpal marginal fractures. LEVEL OF EVIDENCE: IV, retrospective.

Results of the Dubert procedure for chronic painful fracture-dislocations of the fifth carpometacarpal joint. A report of 6 cases.

Carpometacarpal (CMC) fracture-dislocations of the fifth ray are common. For chronic injuries, Dubert proposed combining resection arthroplasty of the base of the fifth metacarpal (M5) with synostosis with the fourth metacarpal (M4). Our aim was to evaluate the results of this procedure. Between 1994 and 2014, 7 men and 1 woman with an average age of 36 years (range, 27 to 45) were operated on. The right hand was involved in 6 of the 8 cases. All patients had symptomatic osteoarthritis secondary to isolated articular malunion and subluxation of the 5th CMC joint. Fusion was obtained right away in all 8 cases. Six patients were evaluated with a mean follow-up of 93 months (range, 7 to 249). At the final assessment, all patients reported a significant decrease in pain. The mean pain assessed by a visual analog scale (VAS) was 0.6/10 (range, 0 to 5). Range of motion in flexion-extension of the M4-M5 block ranged from 10° to 20°. Grip strength remained reduced by 15% to 70%. All patients except one were satisfied with the outcome. The technique described by Dubert is an effective method to relieve pain. By fusing together M5 and M4, it preserves the length of the fifth ray and a certain adaptability of the palm when gripping. However, it can be used only when the CMC joint of the 4th ray is healthy. This stabilized arthroplasty is an effective and reliable technique for the treatment of symptomatic osteoarthritis secondary to CMC fracture-dislocation of M5.

Chronic instability of the thumb metacarpo-phalangeal joint: Seven-year outcomes of three surgical techniques.

BACKGROUND: Severe sprain of the thumb metacarpo-phalangeal joint (TMCPJ) is a common injury whose functional outcome is good when repair is performed at the acute stage. The diagnosis is often missed, however, leading to chronic instability. The optimal treatment of chronic TMCPJ instability is controversial. The objective of this study was to compare the clinical outcomes of the three main surgical techniques used to treat chronic TMCPJ instability. HYPOTHESIS: Arthrodesis is the best surgical option when ligament repair is not feasible. MATERIAL AND METHODS: This single-centre retrospective study included all patients managed surgically between 2000 and 2012 for chronic post-traumatic TMCPJ instability using any of the three following techniques: primary repair, ligament reconstruction, and arthrodesis. Subjective and objective outcomes and complication rates at last follow-up were compared across these three techniques. RESULTS: Of 67 included patients, 55 were re-evaluated, after a mean follow-up of 84 months (range: 24-164 months). Among them, 48 (87.3%) were satisfied or very satisfied with the outcome. Pain relief was significantly better in the arthrodesis group. Mean Quick-DASH scores were 17.4 (range: 0.0-89.5) with primary repair, 25.7 (range: 0.0-58.3) with ligament reconstruction, and 17.8 (range: 0.0-50.0) with arthrodesis. Mean pinch-test strength compared to the normal side was 89% with primary repair, 84% with ligament reconstruction, and 94% with arthrodesis. In the ligament reconstruction group, 6 of the 10 patients had instability at last follow-up and the proportion of patients describing themselves as fully recovered was significantly smaller than in the other groups. Four failures were recorded at last follow-up. CONCLUSION: Surgery to treat chronic TMCPJ instability produces good outcomes. Primary repair deserves preference whenever possible. In contrast to previous reports, outcomes after ligament reconstruction were not better compared to arthrodesis. LEVEL OF EVIDENCE: IV, retrospective study.

Volar fracture-dislocation of the proximal interphalangeal joint: Four cases at an average follow-up of 3 years.

Volar dislocation of the proximal interphalangeal joint associated with dorsal fracture of the base of the middle phalanx is a rare injury, with only 38 cases published. We report here four such cases: three treated surgically and one conservatively. Patients had a mean age of 19.5 years. At an average follow-up of 3 years, pulp-to-palm contact was obtained and no pain was reported with regular daily activities. All patients considered themselves cured and were very satisfied with the result. Incomplete reduction of the dorsal fragment or the presence of localized articular impaction warrant surgical treatment.

Surgical treatment of carpal boss by simple resection: Results in 25 cases at a mean of 8 years' follow-up.

Carpal boss is a symptomatic bony protrusion on the dorsal surface of the wrist at the base of the 2nd and/or 3rd metacarpal. The goal of this study was to assess the reliability and safety of simply resecting the exostosis. From 1994 to 2014, 29 cases of carpal boss were treated by simple resection. Twenty-five of these patients were subsequently assessed by telephone questionnaire at a mean of 8 years' follow-up (range 1.1 to 20 years). There were no cases of recurrence; however, 1 patient reported carpometacarpal instability requiring fusion, 5 years after surgery. Eight of the 24 patients without fusion (33%) reported moderate episodic pain (visual analog scale [VAS] pain: mean, 2.3/10, range 1 to 4). Range of motion improved in 8 cases (33%), was unchanged in 11 (46%) and decreased in 5 (21%). Twenty patients (83%) had no functional impairment; 4 reported impairment during unusual hand movements. Fifteen patients considered themselves cured (60%), 9 considered their status improved (36%) and one - the patient who required fusion - considered his status unchanged. Patients were very satisfied with the procedure in 15 cases (60%) and satisfied in 10 (40%). In all cases, features of dysplasia were present and associated with secondary osteoarthritis limited to the area of impingement. The single failure was most likely due to excessive bone resection. Simple exostosis resection is sufficient to effectively treat carpal boss. Fusion should be reserved for the rare cases of secondary metacarpal instability.

[The MEU classification system for distal radius fractures: Prognostic and therapeutic value of an independent assessment of various fracture parameters]. / Le système de classification MEU des fractures de l'extrémité distale du radius. Intérêts pronostique et thérapeutique d'une analyse indépendante des différents paramètres de la fracture.

Distal radius fractures (DRF) are often complex injuries that can impact the radial metaphysis (M), the radial epiphysis (E) and the distal ulna (U). Each of these parameters can influence the outcome. In a given injury, these three DRF components are involved to a varying degree and are variably associated. The MEU classification independently analyzes the three main bone components of the fracture; thus, all possible combinations and each specific injury can be described. It accurately depicts the type and severity of the DRF. Our results show that this classification is useful for both prognosis and treatment. The criteria are simple and easy to determine, making the system reliable and reproducible. The classification system uses rigorous and validated criteria to define fracture instability: any fracture for which M>2 and/or E>2 (severe fracture) is more likely to be associated with secondary displacement, DRUJ pain, and patient dissatisfaction. Furthermore, a metaphyseal fracture entering the DRUJ (M') and the presence of a displaced ulnar fracture (U>1) affect the functional outcome, thus these two features must also be included in the classification system.

Isolated or predominant capitolunate osteoarthritis is the consequence of lunotriquetral dissociation. X-ray analysis of 22 consecutive cases.

Secondary osteoarthritis due to a scapholunate malalignment is well known, but is debatable in cases of lunotriquetral malalignment. It has been shown that lunotriquetral malalignment can lead to midcarpal osteoarthritis. The hypothesis of this retrospective study was that a relationship exists between the presence of midcarpal osteoarthritis and the presence of lunotriquetral malalignment. All patients with midcarpal osteoarthritis, isolated or predominant, treated between 1981 and 2013 were reviewed. Intracarpal angles were measured and the relative position of the carpal bones was analyzed by two examiners. Osteoarthritis of the wrist's joints was quantified in three stages. Diagnosis of static dissociative ligament lesion was made and correlated with the location of osteoarthritis. Twenty-two wrists in 20 patients (13 men and 7 women; mean age of 59 years) were included. The lunocapitate osteoarthritis was moderate in 6 cases and severe in 16 cases. The radioscaphoid osteoarthritis was moderate in 5 cases and severe in 1 case. Lunotriquetral malalignment was present in all cases; it was isolated in 8 cases and associated with scapholunate malalignment in 14 cases. In isolated lunotriquetral malalignment cases, midcarpal osteoarthritis was isolated or associated with degenerative lesions of lunotriquetral interval. Cases of perilunate instability in which the osteoarthritis is more severe in the midcarpal joint than in the radioscaphoid joint likely resulted from an injurying mechanism with ulnar beginning (ulnar-sided perilunate instability).

Surgical treatment of mucous cysts by subcutaneous excision and osteophyte resection: Results in 68 cases at a mean 6.63 years' follow-up.

The goal of this study was to assess the results of treatment of mucous cysts by subcutaneous excision and osteophyte resection without an associated skin procedure. From 1993 to 2013, 81 mucous cysts were operated on. In 27 cases, a nail deformity was present. Obvious osteoarthritis was present in 84% of cases. Among them, 67 patients (68 cysts) were subsequently assessed through a phone questionnaire after a mean follow-up of 6.6 years. Patients who reported a recurrence or suspected one were reassessed in consultation. Among the 68 evaluated cases, two developed an infection and one had delayed skin healing; these complications occurred on cysts with a previous fistula. In one case (1.5%), a recurrence was observed four months after excision of a subungual cyst. All nail deformities had resolved; 53 patients felt no discomfort and 65 were very satisfied or satisfied with the procedure and would undergo surgery again. The recurrence rate of 1.5% is consistent with that of other studies where the same procedure was used, without cutaneous grafting, ranging from 0 to 2%. This result is better than in studies where a graft or a flap was performed without systematic joint debridement. Our procedure is sufficient to effectively treat mucous cysts with less morbidity. Complications are rare and occur only in cysts associated with a fistula, justifying their early surgical treatment.

Lateral elbow ligamentoplasty by autologous tendon graft in posterolateral rotatory instability: Results in 18 cases at a mean 5 years' follow-up.

INTRODUCTION: Posterolateral rotatory instability is the most frequent form of elbow instability. This clinical entity, described by O'Driscoll et al. in 1991, concerns young subjects following elbow trauma. Diagnosis is founded on symptomatology and positive posterolateral rotatory instability test. Treatment is based on reconstruction of the ulnar bundle of the lateral collateral ligament. The present study assessed medium-term clinical and radiological results in lateral ligamentoplasty for posterolateral elbow instability. MATERIALS AND METHODS: A retrospective continuous single-center series included 19 cases: 11 male, 8 female, operated on between 1995 and 2010; mean age was 37.8 years (range, 20-63 years). Surgery consisted in lateral ulnar collateral ligament reconstruction by autologous palmaris longus tendon graft following Nestor et al. (1992). RESULTS: Eighteen patients were assessed at a mean 61 months' follow-up. Mean time off work was 3.2 months (range, 2-7 months); all patients returned to work. No revision surgery was required. Mean range of motion in flexion, extension, pronation and supination was respectively 135°, 8°, 84° and 76°. Instability test was systematically negative at follow-up. Mean Mayo Clinic and Quick-DASH scores were respectively 90 (range, 60-100) and 21 (range, 0-63). All patients were satisfied or very satisfied with their result. CONCLUSION: Lateral ulnar collateral ligament reconstruction by autologous palmaris longus tendon graft provided reliable and lasting results. We consider it to be the reference treatment for chronic instability, and sometimes in acute post-traumatic instability. LEVEL OF EVIDENCE: IV.

Wrist osteoarthritis.

Painful wrist osteoarthritis can result in major functional impairment. Most cases are related to posttraumatic sequel, metabolic arthropathies, or inflammatory joint disease, although wrist osteoarthritis occurs as an idiopathic condition in a small minority of cases. Surgery is indicated only when conservative treatment fails. The main objective is to ensure pain relief while restoring strength. Motion-preserving procedures are usually preferred, although residual wrist mobility is not crucial to good function. The vast array of available surgical techniques includes excisional arthroplasty, limited and total fusion, total wrist denervation, partial and total arthroplasty, and rib-cartilage graft implantation. Surgical decisions rest on the cause and extent of the degenerative wrist lesions, degree of residual mobility, and patient's wishes and functional demand. Proximal row carpectomy and four-corner fusion with scaphoid bone excision are the most widely used surgical procedures for stage II wrist osteoarthritis secondary to scapho-lunate advanced collapse (SLAC) or scaphoid non-union advanced collapse (SNAC) wrist. Proximal row carpectomy is not indicated in patients with stage III disease. Total wrist denervation is a satisfactory treatment option in patients of any age who have good range of motion and low functional demands; furthermore, the low morbidity associated with this procedure makes it a good option for elderly patients regardless of their range of motion. Total wrist fusion can be used not only as a revision procedure, but also as the primary surgical treatment in heavy manual labourers with wrist stiffness or generalised wrist-joint involvement. The role for pyrocarbon implants, rib-cartilage graft implantation, and total wrist arthroplasty remains to be determined, given the short follow-ups in available studies.

Isolated paralysis of the serratus anterior muscle: surgical release of the distal segment of the long thoracic nerve in 52 patients.

INTRODUCTION: Isolated serratus anterior (SA) paralysis is a rare condition that is secondary to direct trauma or overuse. Patients complain of neuropathic pain and/or muscle pain secondary to overexertion of the other shoulder stabilizing muscles. As the long thoracic nerve (LTN) passes along the thorax, it can be compressed by blood vessels and/or fibrotic tissue. The goal of the current study was to evaluate the outcomes of surgical release of the distal segment of the LTN in cases of isolated SA paralysis. PATIENTS AND METHODS: This was a retrospective study of 52 consecutive cases operated on between 1997 and 2012. The average patient age was 32 years (range 13-70). Patients had been suffering from paralysis for an average of 2 years (range 4-259 months); the paralysis was complete in 52% of cases. Every patient underwent a preoperative electroneuromyography (ENMG) assessment to confirm that only the SA was affected and there were no signs of re-innervation. RESULTS: Every patient had abnormal intraoperative findings. There were no complications. All patients showed at least partial improvement following the procedure. The improvement was excellent or good in 45 cases (86.7%), moderate in 4 cases (7.7%) and slight in 3 cases (5.6%). In 32 cases (61.5%), the winged scapula was completely corrected; it was less prominent in 19 cases and was unchanged in one case. The best outcomes following surgical release occurred in patients who presented without preoperative or neuropathic pain and were treated within 18 months of paralysis. DISCUSSION: Isolated SA paralysis due to mechanical injury resembles entrapment neuropathy. We discovered signs of LTN compression or restriction during surgery. Surgical release of the distal segment of the LTN is a simple, effective treatment for pain that provides complete motor recovery when performed within the first 12 months of the paralysis. LEVEL OF EVIDENCE: IV.

Cubital tunnel syndrome: comparative results of a multicenter study of 4 surgical techniques with a mean follow-up of 92 months.

BACKGROUND: Cubital tunnel syndrome is the second most frequent entrapment syndrome. Physiopathology is mixed, and treatment options are multiple, none having yet proved superior efficacy. OBJECTIVES: The present retrospective multicenter study compared results and rates of complications and recurrence between the 4 main cubital tunnel syndrome treatments, to identify trends and optimize outcome. MATERIALAND METHODS: Patients presenting with primary clinical cubital tunnel syndrome diagnosed on electroneuromyography were included and operated on using 1 of the following 4 techniques: open or endoscopic in situ decompression, or subcutaneous or submuscular anterior transposition. Four specialized upper-limb surgery centers participated, each systematically performing 1 of the above procedures. Subjective and objective results and rates of complications and recurrence were compared at end of follow-up. RESULTS: Five hundred and two patients were included and 375 followed up for a mean 92 months (range, 9-144 months); 103 were lost to follow-up and 24 died. Whichever the procedure, more than 90% of patients were cured or showed improvement. There was a single case of scar pain at end of follow-up, managed by endoscopic decompression; there were no other long-term complications. None of the 4 techniques aggravated symptoms. There were 6 recurrences by end of follow-up: 1 associated with open in situ decompression and 5 with submuscular transposition. CONCLUSION: Surgery was effective in treating cubital tunnel syndrome. Submuscular anterior transposition was associated with recurrence. In contrast to literature reports, subcutaneous anterior transposition, which is a reliable and valid technique, was not associated with a higher complication rate than in situ decompression. LEVEL OF EVIDENCE: Level IV. Multicenter retrospective.

[Neonatal suppurative parotidis: a case report and review of the literature]. / Parotidite aiguë néonatale suppurative : revue de la littérature à propos d'une observation.

Suppurative parotidis is an uncommon disease in newborns, with limited information available on its pathogenesis and management: approximately 50 cases have been reported in the literature. Diagnosis is based on clinical signs. The predominant organism is Staphylococcus aureus. The administration of empiric antimicrobial therapy is an essential part of the management in very young patients. Prognosis is good and recurrence of the disease is unusual. We describe a 21-day-old newborn who presented with fever and unilateral swelling of the parotid region, and provide a literature review.

[Posterior interosseous nerve palsy. A series of 18 cases and literature review]. / Les paralysies du nerf interosseux postérieur. À propos de 18 cas et revue de la littérature.

OBJECTIVES: Posterior interosseous nerve palsy is a rare syndrome frequently unrecognized, while the clinical presentation is characteristic: finger extension paresis associated with wrist extension in radially deviated position. Here, we assessed our results of surgical treatment. METHODS: A 20-year retrospective study was carried out in our unit. Analysis of causes and an assessment of postoperative functional outcome were performed. Our study was compared with literature data. RESULTS: Eighteen cases were treated with a predominance in men manual workers. The etiology of the posterior interosseous nerve palsy was tumor in four cases, traumatic in two cases, iatrogenic in two cases and idiopathic in ten cases. In seven of these ten cases, compression under the arch of the extensor carpi radialis brevis was found. The postoperative results were satisfactory with full recovery in nine out of fifteen cases treated by neurolysis, depending on the duration of the paralysis. In the literature, we found 264 cases over 50 years through a variety of clinical cases and five case series. A predominance of tumor etiology was found. CONCLUSION: Ignorance of the clinical presentation of a posterior interosseous nerve palsy frequently leads to misdiagnosis. Early complete neurolysis enables a satisfactory functional recovery.

Gracilis tendon transfer associated with distal alignment for patella alta with recurrent dislocations: an original surgical technique.

Many surgical techniques for the medial patellofemoral ligament have recently been suggested, all of which included problems identifying the femoral anchorage point and determining the proper extent of knee flexion for the transplant. P. Burdin proposed a different and original approach consisting in performing a gracilis muscle transfer to the medial edge of the patella, thus obtaining progressive tension of the transfer during knee flexion by means of the myotatic reflex. We report the results herein. We retrospectively assessed 17 knees treated for patellofemoral instability using this technique. Two cases presented subjective patellofemoral instability and 15 presented objective patellofemoral instability. The patients' mean age was 17.4 years (range, 8-47 years) during the first episode of dislocation. Two cases of instability were secondary to advanced neuromuscular disease. Two knees had already undergone two stabilization attempts. Fifteen knees presented trochlear dysplasia (four stage A, eight stage B, and three stage C). The mean age at surgery was 28.2 years (range, 16-47 years). In 15 cases, the gracilis transfer was associated with lowering the anterior tibial tuberosity (mean, 10mm). No patellar fracture occurred. A persistent sensory deficit of the anterior branch of the internal saphenous nerve was observed in 15 cases. One knee remained painful and retained subjective instability; total knee arthroplasty was performed 3 years after the intervention. The mean follow-up at revision was 5.5 years (range, 1.5-16.5 years). No recurrence of dislocation was reported. Eight cases retained subjective instability. The SF-36 and IKDC scores were good or excellent in 12 cases and the KOOS was good or excellent in 13 cases. Radiologically, patellar tilt persisted in six cases out of 14, translation persisted in two cases out of 14, and secondary patella baja was observed in one. Medial patellofemoral osteoarthritis was observed in five cases: one case IWANO stage I and four cases IWANO stage II. These satisfactory results seem stable over time and were acquired using a simple procedure with reduced morbidity, making it possible to avoid significant displacement of the anterior tibial tuberosity and stabilize the extensor apparatus. It can also be hoped that the onset of secondary patellofemoral osteoarthritis, undoubtedly inevitable, has been delayed.

[A retrospective study of hand and wrist tumors in adults]. / Etude rétrospective d'une série de 623 tumeurs de la main et du poignet chez l'adulte.

OBJECTIVES: Epidemiologic data concerning hand and wrist tumors are still few and sometimes conflicting. In our department, tumor surgeons and hand surgeons manage together those tumors and they have a specific recruitment. This collaboration permitted to make an epidemiologic study of the tumors of the hand operated in the unit. METHODS: We made a retrospective study of all the cases of wrist and hand tumors operated in the unit, from January 1980 to September 2008. Files were collected from diagnostic encoding, letters of consultations and the register of the department of histology. RESULTS: The mean age of the population was 48 years (from 16 to 94 years). The series included 623 tumors treated in 620 patients (372 women and 248 men). Tumors concerned soft tissues in 525 cases (84.1%), bone tissue in 70 cases (11.4%) and skin in 28 cases (4.5%). The prevalence of malign tumors was 1.3% in this study. CONCLUSIONS: This series is the third in number of cases and the data are comparable of those from other studies. The prevalence of bone tumors (11.4%) is higher than in others studies (from 1.6 to 6.6%) and the prevalence of skin tumors is lower. Except for skin tumors which recruitment modalities are more variable, this series seems to be a good reflection of the prevalence of the different types of hand and wrist tumors.