Trapeziometacarpal joint loading during key pinch grip: A cadaver study.

To our knowledge, no study has directly measured the loads in the trapeziometacarpal joint during an isometric key pinch. The aim of this study was to measure the load acting on the trapeziometacarpal joint for increasingly greater key pinch forces (0.5 kg-1.5 kg). We performed a cadaver study using 10 fresh-frozen, unembalmed adult forearms and hands (5 right and 5 left). Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch grip (i.e., adductor pollicis, flexor pollicis longus, extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus tendons). Measurements were made inside the joint using a force-sensing resistor sensor (Tekscan® FlexiForce™ force sensor). All specimens were tested twice in a row in the same condition. The median load values recorded in the trapeziometacarpal joint were 1.9 kg (IQR 2.2-1.5), 3 kg (IQR 3.4-2.7) and 4.1 kg (IQR 4.4-3.9) during 0.5 kg, 1 kg, and 1.5 kg key pinch, respectively. For each specimen, similar load values were observed during both loading trials. Our findings indicate that the loads measured directly in the trapeziometacarpal joint during a simple key pinch are materially lower than those estimated in biomechanical models of the thumb (generally greater than 10 kg for 1 kg of applied force) probably due to intersubject variability. This pilot study will serve as a basis for further studies, for example, comparing biomechanical thumb models and experimental measurements under the same set-up conditions.

Anatomical and radiological description of ligament insertions on the radial aspect of the scaphoid bone.

Anatomical studies on the radial side of the scaphoid mention inter-ligamentous connections, but without detailed description of their relations to one another. The purpose of this study was to provide an anatomical and radiological description of the ligamentous structure on the radial side of the scaphoid. High-field 3-Tesla 3D MRI scans of 7 cadaveric formaldehyde-fixed wrists were performed to assess the presence and location of each ligament. Dissection was performed in 10 wrists under microscopy on the radial side to assess the dimensions, anatomical variations and angles between ligaments in various wrist positions during in intracarpal pronation/supination, flexion/extension and ulnar/radial deviation. This study confirmed that the same ligament configuration was found on MRI and on dissection. The scaphotrapezial ligament, dorsal intercarpal ligament and radial collateral ligament fibers merge along the dorsal ridge of the scaphoid. The fibers of the radial collateral and radioscaphocapitate ligaments could be distinguished in only 4/10 specimens. Wrist position changes from intracarpal pronation to supination produced major changes in angle between the scaphotrapezial and dorsal intercarpal ligaments, while other position changes affected this angle only slightly. 3D MRI sequences allow these structures to be systematically analyzed in case of scapholunate instability. Further studies should be conducted to assess the biomechanical properties of these ligaments and the clinical consequences of isolated injury in this region.

Comparison of two radiographic landmarks for centering the trapezial component in total trapeziometacarpal arthroplasty.

We performed a retrospective review of standard anteroposterior and lateral radiographs of the thumb in 80 patients, to compare two radiographic landmarks, in terms of mediolateral bone support, for centering the trapezial component in total joint arthroplasty. On anteroposterior view, we identified the distal articular surface of the trapezium and trapezium width, and defined the two midpoints as radiographic landmarks for positioning a 9-mm trapezial cup. Mean trapezium width was significantly greater than the distal articular surface of the trapezium, and the midpoints did not match. Thus, after positioning simulated 9-mm prosthetic cups centered on each landmark, the residual radial bone distance was significantly greater using the landmark based on trapezium width. The mean value was 33% greater with this landmark, and the minimum value was 2.1 mm, compared to 0.2 mm using the landmark based on the distal articular surface. Our study thus suggested that the midpoint of the trapezium width is the more relevant radiographic landmark for centering the trapezial prosthetic cup in total joint arthroplasty, by preserving better bone stock on the radial side without depleting the ulnar side. On an intraoperative anteroposterior fluoroscopic view, this landmark could be used to check cup positioning.

Costal cartilage graft for an unstable post-traumatic trapeziometacarpal intra-articular malunion in a pediatric patient: A case report.

Trapeziometacarpal dislocation is a rare traumatic lesion, especially in the pediatric population. Various treatments have been described for acute cases. We report the case of a 15-year-old boy who was admitted in the emergency department with chronic post-traumatic trapeziometacarpal dislocation due to an untreated first metacarpal base fracture (Bennett), with complete articular destruction. The patient was treated by open reduction, interposition of a costal cartilage graft, and intermetacarpal K-wire fixation. Follow-up at 2 years after the surgery showed excellent clinical and radiological results. This surgical technique had not been described previously in the pediatric population.

Assessment of trapezial prosthetic cup migration: A biomechanical study.

We performed a biomechanical study using 60 Sawbones® rigid foam blocks of two simulated densities (osteoporotic, n = 30 and non-osteoporotic, n = 30) and 10 cadaveric trapezium bones from fresh-frozen, unembalmed adult cadaver hands to assess the trapezial prosthetic cup migration with progressively greater compression loads (10-40 kg). Two cups from the Touch® prosthesis were compared: 9-mm conical cup and 9-mm spherical cup. Uniaxial compression tests were carried out using an MTS Criterion® Series 40 Electromechanical Testing System. Cup migration was measured in millimeters (mm) at 10, 20, and 40 kg of compression load. Median cup migration values were similar in the cadaveric trapezium bones and Sawbones® non-osteoporotic blocks, and higher in the Sawbones® osteoporotic blocks. In the cadaveric trapezium bones and the Sawbones® non-osteoporotic blocks, migration values were less than or equal to 0.1 mm for 10 and 20 kg loads; it was 0.2 mm for 40 kg load. In the Sawbones® osteoporotic blocks, migration values were less than or equal to 0.3 mm for 10 and 20 kg loads; it was 0.4-0.5 mm for 40 kg load. There was no significant difference between the two cup shapes in both cadaveric trapezium bones and Sawbones® non-osteoporotic blocks. In Sawbones® osteoporotic blocks, the largest difference between the two cup shapes was 0.1 mm for loads up to 40 kg, which corresponded to our measurement accuracy. Our findings indicate that the trapezial component of total trapeziometacarpal joint arthroplasty undergoes very weak migration for axial compression loads up to 40 kg, presumably below the threshold of clinical relevance. The cup shape did not have an obvious influence; however, low bone mineral density may result in greater cup migration.

COVID-19: Initial experience of an international group of hand surgeons.

The emergence of the COVID-19 pandemic has severely affected medical treatment protocols throughout the world. While the pandemic does not affect hand surgeons at first glance, they have a role to play. The purpose of this study was to describe the different measures that have been put in place in response to the COVID-19 pandemic by hand surgeons throughout the world. The survey comprised 47 surgeons working in 34 countries who responded to an online questionnaire. We found that the protocols varied in terms of visitors, health professionals in the operating room, patient waiting areas, wards and emergency rooms. Based on these preliminary findings, an international consensus on hand surgery practices for the current viral pandemic, and future ones, needs to be built rapidly.

[Hand wounds]. / Les plaies de la main.

Hand wounds represent a major problem in regard of the number of patients as well as the economic burden associated with it. The close relationship of the different anatomical structures increase the probability of involvement of multiple structures, which require a multidisciplinary approach. Paucity of clinical signs of certain lesions render surgical exploration necessary. Regarding replantation, multiple factors need to be taken into consideration, principally the condition of the amputated part, which is influenced by the trauma but also by the initial care applied to the severed part. Transfer delay to a specialized center should be minimize.

High rate of complications associated with extrafocal kirschner wire pinning for distal radius fractures.

Kirschner wire (K-wire) fixation is a common technique aimed at treating unstable distal radius fractures. We report our experience with extrafocal K-wire fixation in the treatment of unstable distal radius fractures in 34 patients (AO classification: 10 A2, 5 A3, 14 C1, and 5 C2). The patients' median age was 63 years (range, 16-87 years). K-wires remained in place for a median duration period of 42 days, and a splint was applied during 44 days in median. The median follow-up was 2.5 years (range, 1.3-5 years). At the final follow-up examination, all patients were assessed clinically and bilateral radiographs were taken. The median final range of motion was 69 degrees /64 degrees for extension/flexion, 88 degrees/82 degrees for pronation/supination and 36 degrees/21 degrees for ulnar/radial deviation. Grip strength was 81% of the contralateral side. Using the Gartland-Werley score, 12 patients (35%) had excellent results, 17 (50%) good, and five patients (15%) had fair results. The median final radiographic dorsal tilt was 4.5 degrees (range, 0-14 degrees) and 79% of patients had a loss of volar reduction (median 8 degrees). Radial inclination was in median 20 degrees (range, 10-32 degrees) with 82% of the patients with loss of reduction (median 5 degrees). Radial shortening was in median 0.9 mm (range, -2 to +5 mm) and 62% of patients had median loss of radial length of 1.1mm. Radial shortening was the major source of pain due to ulnar impingement. We found a high complication rate, with 15 patients (44%) suffering from at least one of the 30 reported complications. We did not find any direct correlation between radiographic results and mobility. Although good clinical outcome may be obtained, K-wire fixation cannot be routinely recommended.

Aneurysms of the hand: Imaging and surgical technique.

Hand aneurysms are a rare entity only described as case reports in the literature. The aim of our study was to describe a series of four cases and the surgical technique using an arterial bypass. We also wanted to define an algorithm for the imaging of this pathology. We have operated on four patients with hand aneurysms in the past decade or so. One patient had an aneurysm in the thumb proper palmar digital artery, one in the superficial palmar arch and the two others in the ulnar artery. All patients had an excision surgery with direct arterial bypass; no patient had a venous graft. All patients were seen a few years after the surgery and underwent an ultrasonography to check the anastomosis permeability. All anastomoses were permeable 2 to 8 years after surgery. Through a review of the literature we discuss the best algorithm for imaging a hand aneurysm. Direct arterial suture by proximal and distal mobilization allows for long-term permeability. If a graft is necessary, a graft of arterial origin should be preferred. The additional first-line examination is ultrasonography, followed by arteriography if acute ischemia is present; otherwise, CT angiography or MR angiography is performed.

Unipolar ulnar head replacement for treatment of post-Darrach procedure instability.

The aim of this study was to assess distal radioulnar joint stability after unipolar ulnar head replacement for post-Darrach instability. All the patients who underwent ulnar head replacement between1999 and 2015 for post-Darrach procedure instability at our clinic were reviewed. Seven Hebert-type and two uHead (SBI/Stryker) prostheses were implanted. None of the implants were cemented. We assessed stability, pain, range of motion and strength pre- and postoperatively. The changes in the radiographic appearance between immediate postoperative and the last follow-up were determined. All patients (8 patients and 9 joint replacements) had a stable distal ulnar stump at the mean follow-up of 69 months. No complications occurred and no revisions were needed. Pain on a visual analog scale (VAS) was 0 at rest and 6 during maximum effort at the last follow-up; it was 1.5 at rest and 8.5 during effort preoperatively. Wrist flexion and extension, supination and grip strength were unchanged. Pronation increased from 45° to 70°. An area of bone resorption proximal to the ulnar head implant was found in 5 cases but no secondary displacement of the implant or increased pain was reported. Ulnar head replacement stabilizes the ulnar stump. The implant acts as a spacer to place the soft tissues under tension. Distal ulnar stump instability after the Darrach procedure can be solved by a unipolar ulnar head replacement procedure.

In vivo selection of a multidrug-resistant Aeromonas salmonicida during medicinal leech therapy.

We report the selection in a 15-year-old boy of a multidrug-resistant, extended-spectrum ß-lactamase (ESBL)-producing Aeromonas salmonicida after medicinal leech therapy that required an antibiotic prophylaxis based on piperacillin/tazobactam and cotrimoxazole. Whole genome sequencing of the strain indeed revealed 13 antibiotic resistance genes, including the ESBL CTX-M-3 and the unusual ß-lactamase SCO-1.

Dorsal approach and internal fixation of impacted intra-articular distal radius fractures with 2.4 mm locking plates.

The treatment of impacted distal radius fractures is complex. Internal fixation by a dorsal approach with arthrotomy should be considered, particularly when the fractures are dorsally comminuted. This was a retrospective, observational study of 26 patients operated between 2008 and 2012 who were reviewed in September 2013. In the surgical procedure, a single dorsal incision was made over the distal radius and arthrotomy performed; the fracture site was stabilized with two 2.4mm locking plates. The average follow-up was 39months. All fractures were type 23C in the AO classification. All patients were assessed with the QuickDASH and Mayo Wrist scores. Total range of motion was 82% of the contralateral side. Grip strength was 30kg in average. The mean radial sagittal tilt was +6° postoperatively. No plate movement or intra-articular screws were present. Four patients developed symptomatic early osteoarthritis. Thirteen patients had the plate removed due to discomfort. No tendon ruptures were observed. The dorsal approach remains a treatment option for specific intra-articular fractures. It offers direct intra-articular congruency control, along with a stable buttress and locking fixation for early mobilization. Our results are comparable to those using other surgical techniques for this type of high-energy fracture.

Unacceptable failure of the PI2® implant.

The PI2® spacer is designed for treatment of trapeziometacarpal (TM) osteoarthritis. However, the shape of this implant has raised concerns about its stability. We retrospectively investigated 45 implants in 41 patients treated for trapeziometacarpal osteoarthritis in our hospital between 2004 and 2009 who underwent trapeziectomy and insertion of a PI2® spacer. Outcome parameters included revision rates and clinical outcomes correlated with implant position and scaphometacarpal distance, assessed using standard radiographs. A total of 12 implants (27%) were removed at a median time of 10 months (interquartile range (IQR), 7-22 months). These included five dislocations and one early infection. Additionally, a further six patients underwent revision due to persistent pain. Three of these had scapho-trapezoid osteoarthritis, two had developed subluxation of the implant, and one did not show any radiographic abnormalities. A review of patient records revealed that 33 implants remained in place at a median time of 29 months (IQR, 20-57). However, of those, only 21 implants (64%) in 17 patients were available for clinical evaluation at a median follow-up of 29 months (IQR, 19-62 months). No significant differences in clinical outcomes including functional results were observed between in-place ( n = 8) and subluxated ( n = 13) implants. Due to the high revision rate (12/45), consistent with other reports in the literature, we have abandoned the use of the PI2® spacer. We recommend the establishment of a registry for evaluation of future implants. TYPE OF STUDY/LEVEL OF EVIDENCE: Case-series study/level IV.

Non-tuberculous mycobacterial infections of the hand.

UNLABELLED: Non-tuberculous mycobacterial infections of the hand are difficult to treat and require a long time before remission. But how long should we wait to see an improvement? To answer this question, the published scientific literature was reviewed in English, French and German. Tuberculosis, arthritis and osteomyelitis cases were excluded. A total of 241 non-tuberculous mycobacterial hand infections in 38 scientific publications were retrieved. Most were case reports or series. The median age of the patients was 58years and one third was female. Patients were immunocompromised in 17 episodes. The most common species were Mycobacterium marinum in 198 episodes (82%), followed by M. chelonae in 13 cases (5%). There were no cases of mixed infection. Most infections were aquatic in origin and community-acquired, and were treated with a combination of surgical debridement and long-duration systemic combination antibiotic therapy (14 different regimens; no local antibiotics) for a median duration of 6months. The median number of surgical procedures was 2.5 (range 1-5). Clinical success was not immediate: a median period of 3months (range 2-6) was necessary before the first signs of improvement were observed. The majority (173 cases; 76%) remained entirely cured after a median follow-up time of 1.7years (range, 1-6). Only two microbiological recurrences occurred (1%). However, 49 patients (21%) had long-term sequelae such as pain, stiffness and swelling. The approach of long-duration antibiotic treatment in combination with repeated surgery for mycobacterial soft tissue infections of the hand leads to few recurrences. However, clinical success is not immediate and may take up to 3months. TYPE OF STUDY: Therapeutic study: systematic review of level III studies. LEVEL OF EVIDENCE: III.

A comparison of diaphyseal and metaphyseal techniques of ulna shortening.

The aim of this retrospective study was to compare two techniques of ulna shortening for ulnocarpal abutment. The technique performed initially was diaphyseal osteotomy. Subsequently, a metaphyseal osteotomy was performed to avoid the drawbacks related to the plate. The study group consisted of 29 patients: 13 with diaphyseal and 16 with metaphyseal osteotomies. The pre-operative diagnosis was ulnocarpal abutment in all cases. The results were graded according to the scoring system of Chun and Palmer and patients' self-assessment. Both rankings were related to indications, age, gender, occupation, and surgery. Final follow-up occurred at a median of 54 (range 15-144) months after surgery. There was no delayed union or non-union, necrosis of the ulnar head, or infection. Pain relief was the main benefit. Both techniques gave similar outcomes for pain relief, satisfaction, and objective results. The shortening was significantly greater in the metaphyseal group without any apparent consequence on function or pain. No screw removal was needed after metaphyseal osteotomy; in contrast, plate removal was required in all patients. We conclude that both techniques are valuable alternatives for treating ulnocarpal abutment.

[Proliferating trichilemmal tumor of the pulp of a finger: case report and review of the literature]. / Localisation inhabituelle pulpaire d'un kyste trichilemmal proliférant.

Trichilemmal cyst is a benign tumor, developed from hair follicle, located mainly at the scalp. We report a clinical case of unusual location at the finger pulp confirmed by histology. The main differential diagnosis in this reported case was a whitlow. The origin of this cyst is probably the nail matrix whose keratinization is trichilemmal. Surgical excision biopsy allowed a good clinical outcome.

Review of the principal extra spinal pathologies causing sciatica and new MRI approaches.

In this paper we illustrate the principal extraspinal pathologies causing sciatica and new approaches for the study of structures such as the lumbosacral plexus (LSP). Visualisation of the LSP in its entirety is difficult with conventional two-dimensional MRI sequences owing to its oblique orientation. In our institution, we have found that the utilisation of three-dimensional short tau inversion-recovery sampling perfection with application-optimised contrasts using different flip angle evolutions sequence is helpful, allowing multiplanar and maximum intensity projection reconstructions in the coronal oblique plane and curvilinear reformats through the plexus. Diffusion tensor imaging enables the observation of microstructural changes and can be useful in surgical planning. The normal anatomy of the LSP, its different extraspinal pathologies and differential diagnoses are thoroughly presented.

New approaches in imaging of the brachial plexus.

Imaging plays an essential role for the detection and analysis of pathologic conditions of the brachial plexus. Currently, several new techniques are used in addition to conventional 2D MR sequences to study the brachial plexus: the 3D STIR SPACE sequence, 3D heavily T2w MR myelography sequences (balanced SSFP=CISS 3D, True FISP 3D, bFFE and FIESTA), and the diffusion-weighted (DW) neurography sequence with fiber tracking reconstruction (tractography). The 3D STIR sequence offers complete anatomical coverage of the brachial plexus and the ability to slice through the volume helps to analyze fiber course modification and structure alteration. It allows precise assessment of distortion, compression and interruption of postganglionic nerve fibers thanks to the capability of performing maximum intensity projections (MIP) and multiplanar reconstructions (MPRs). The CISS 3D, b-SSFP sequences allow good visualization of nerve roots within the spinal canal and may be used for MR myelography in traumatic plexus injuries. The DW neurography sequence with tractography is still a work in progress, able to demonstrate nerves tracts, their structure alteration or deformation due to pathologic processes surrounding or located along the postganglionic brachial plexus. It may become a precious tool for the understanding of the underlying molecular pathophysiologic mechanisms in diseases affecting the brachial plexus and may play a role for surgical planning procedures in the near future.

Proximal row carpectomy in emergency.

Proximal row carpectomy (PRC) is a well-accepted procedure for the treatment of early post-traumatic degenerative disease of the wrist. Much less frequently, PRC has been advocated as an emergency procedure for irreparable fracture-dislocation of the wrist. Our objective was to compare the results of PRC in patients having undergone this procedure in the two contexts. We conducted a retrospective analysis of the clinical and radiographic results of six patients treated by emergency PRC as compared to six patients who underwent elective PRC. The mean follow-up was 36 months. Both the patient's satisfaction and the grasp of the wrist joint were significantly better in patients who underwent PRC emergency as compared to those having undergone elective PRC. Quick DASH score, radiographic results, and return to work were also more favourable in these patients, but the difference between the two groups was not significant. This study confirms that PRC is a valuable salvage technique indicated in early posttraumatic wrist collapse. Moreover, when performed in emergency, the procedure shows even better subjective and objective results, allowing a majority of patients to return to their previous job.