3D MODEL of an anatomically inert human hand: feasibility study.

OBJECTIVES: Surgery for congenital malformation of the hand is complex and protocols are not available. Simulation could help optimize results. The objective of the present study was to design, produce and assess a 3D-printed anatomical support, to improve success in rare and complex surgeries of the hand. MATERIAL AND METHODS: We acquired MRI imaging of the right hand of a 30 year-old subject, then analyzed and split the various skin layers for segmentation. Thus we created the prototype of a healthy hand, using 3D multi-material and silicone printing devices, and drew up a printing protocol suitable for all patients. We printed a base comprising bones, muscles and tendons, with a multi-material 3D printer, then used a 3D silicone printer for skin and subcutaneous fatty cell tissues in a glove-like shape. To evaluate the characteristics of the prototype, we performed a series of dissections on the synthetic hand and on a cadaveric hand in the anatomy lab, comparing realism, ease of handling and the final result of the two supports, and evaluated their respective advantages in surgical and training contexts. A grading form was given to each surgeon to establish a global score. RESULTS: This evaluation highlighted the positive and negative features of the model. The model avoided intrinsic problems of cadavers, such as muscle rigidity or tissue fragility and atrophy, and enables the anatomy of a specific patient to be rigorously respected. On the other hand, vascular and nervous networks, with their potential anatomical variants, are lacking. This preliminary phase highlighted the advantages and inconveniences of the prototype, to optimize the design and printing of future models. It is an indispensable prerequisite before performing studies in eligible pediatric patients with congenital hand malformation. CONCLUSION: The validation of 3D-printed anatomical model of a human hand opens a large field of applications in the area of preoperative surgical planning. The postoperative esthetic and functional benefit of such pre-intervention supports in complex surgery needs assessing.

Retrospective study of functional benefits and satisfaction in multisite upper-limb surgery in children with unilateral cerebral palsy.

OBJECTIVES: To evaluate the functional impact of individualised multisite neuro-orthopedic upper-limb surgery in children with unilateral cerebral palsy, and to assess patient satisfaction. PATIENTS AND METHODS: This retrospective study evaluated the impact of surgery on unilateral functional capacity on the Melbourne Assessment (MA2) and Box and Blocks test, on bimanual performance on the Assisting Hand Assessment, and on achievement of individualised goals. Satisfaction was assessed on a Likert scale between 6 and 14 months after surgery. RESULTS: Twenty-three children were included (mean age, 13.2 ± 3 years). They underwent neuro-orthopedic surgery as part of their care pathway, with botulinum toxin, splints and functional training. After surgery, there was a significant 11.7-point improvement in the MA2 dexterity domain (p = 0.003) and 10.6 points in the MA2 range of motion domain (p = 0.005). Satisfaction was high in 81% of patients. CONCLUSION: Neuro-orthopedic upper-limb surgery included in a global care pathway in children with unilateral cerebral palsy improved unilateral upper-limb function and patient satisfaction. The present cohort should be expanded to further explore the impact of surgery on bimanual performance, focusing on more homogeneous functional levels and surgical procedures.

Treatment of scaphoid nonunion by arthroscopic cancellous bone grafting.

INTRODUCTION: In order to avoid Scaphoid Nonunion Advanced Collapse (SNAC) type osteoarthritis, which progressively affects the radial and midcarpal joints, several vascularized and non-vascularized grafting techniques have been described. Over the past decade, there has been growing interest in arthroscopic cancellous bone grafts for scaphoid nonunion. The aim of this novel prospective study was to assess the healing rate of scaphoid grafts under arthroscopy, and the prognostic factors for healing. MATERIAL AND METHODS: This prospective study was carried out across 10 centers between September 2019 and April 2021, in patients aged 16 to 65. Scaphoid nonunion grafting was performed arthroscopically. Union was assessed on CT scans and displacement correction angles were measured preoperatively and then at 3 and 6months. We assessed mobility, Jamar wrist strength, functional results as per the Patient Related Wrist Score (PRWE) and the Quick Disabilities of the Arm, Shoulder and Hand (Quick DASH) score. Risk factors for nonunion were assessed. RESULTS: We included 77 patients with a mean age of 24years (18 to 55years) with a mean time between trauma and treatment of nonunion of 34.8months (6 to 180months). The population was represented by 46 manual workers and 20 were smokers. In 42 cases, the nonunion was proximal, in Schernberg zone I or II. At the last follow-up of 12.9months on average (Standard Deviation: 8.7months), union was achieved in 72 patients (93.5%). The average duration of union was 3.4months (Standard Deviation 1.6). Among the 5 patients who did not heal, grafting was performed in addition to the fixation. We did not identify any contributory factors for nonunion. CONCLUSION: This study demonstrated the effectiveness of arthroscopic treatment of scaphoid nonunion with a union rate at least equivalent to pedicled vascularized grafts. Smoking and delayed treatment were no longer considered unfavorable prognostic factors in the context of arthroscopic treatment. LEVEL OF EVIDENCE: III.

Outcomes of distal biceps tendon reattachment using the ToggleLoc™ fixation device with ZipLoop™ technology with single mini-open technique.

Anatomical repair of distal biceps tendon ruptures has been shown to restore elbow supination and flexion strength. Here, we report the outcomes of distal biceps tendon reattachment using the ToggleLoc fixation device with ZipLoop technology through a single incision. This was a retrospective study of 38 patients with a mean age of 49.5 years. The mean follow-up time was 15 months (range 4/28). The average time to surgery was 21 days. The fixation button was introduced in a bone tunnel and the tendon passed through a bone window using the ToggleLoc™, which allows the tendon to be tensioned using sutures. The tendon was reattached in 30° elbow flexion. The mean strength deficit in supination was 23.9% in comparison with the contralateral side. We discovered four instances of heterotopic ossification on follow-up radiographs. There were seven cases of persistent lateral antebrachial cutaneous nerve paresthesia, but no damage to the posterior interosseous nerve. This new technique places the tendon in a bone tunnel using a single surgical approach. It provides the surgeon with good feedback on the tension of the repair, which is unique among endobutton-type devices. We recommend using the ToggleLoc™ with ZipLoop™ technology as it is a simple, reliable and reproducible technique for distal biceps tendon reattachment.

Ultrasound Evaluation of the Protector Role of the Pronator Quadratus Suture in Volar Plating.

The main complication of volar locking plates for distal radius fractures is flexor tendon rupture. The flexor pollicis longus (FPL) is the most commonly ruptured. Repair of the pronator quadratus (PQ) is one of the ways to prevent tendon rupture. The main purpose of this series was to evaluate the role of PQ repair after volar plating to prevent flexor tendon rupture using ultrasound (US). This work was a mono-operator prospective series of 20 consecutive patients with volar locking plates for distal radius fracture between September 2014 and May 2015. The PQ was repaired in all patients. A clinical, ultrasound, and perioperative evaluation of the flexor tendon was performed by this same surgeon. There was no flexor tendon rupture or tenosynovitis. There were no type A cases, which are characterized by contact between the plate and the FPL, and mostly type C cases, which are characterized by no contact between the plate and the FPL on US imaging. The suture of the PQ was sustainable over time when we removed the plate. Pronator quadratus repair is one of the ways to prevent flexor tendon rupture after volar plating. The outward-running suture is an effective technique for repairing the PQ. Ultrasound may be helpful during follow-up to detect asymptomatic flexor tendon irritation.

Treatment of partial lacerations in flexor tendons by trimming. A biomechanical in vitro study.

BACKGROUND: Treatment of a partial laceration in zone 2 of a flexor tendon is controversial. The intact part of the tendon can usually sustain forces of normal unresisted motion, and repaired partially lacerated tendons can actually be weaker than unrepaired ones. However, complications such as triggering or entrapment have been reported in association with unrepaired tendons. The purpose of this study was to measure the biomechanical behavior following trimming of the tendon as an alternative to repair. METHODS: Thirty-six flexor digitorum profundus tendons were harvested from sixteen unpaired fresh-frozen cadaveric human hands and were randomly assigned to be subjected to either 50% or 75% partial laceration, which was either lateral or volar, and were then assigned to no repair, repair with a running suture, or trimming. Mean and maximum gliding resistances were measured as the flexor digitorum profundus glided through the bone-A2 pulley complex and the flexor digitorum superficialis. Values were normalized to those measured in the intact tendon. The tendons were then distracted to failure, and maximum load and stiffness were recorded. RESULTS: There was triggering or entrapment of eight unrepaired tendons; two cases were severe, and six were minor. When no severe trigger was obvious, the unrepaired tendons had the lowest tendency for gliding resistance, followed by the tendons treated with trimming and then by those treated with the running suture. Overall, the tendons with a volar laceration had higher mean and maximum gliding resistance than those with a lateral laceration (p < 0.05), those with a 75% partial laceration had higher mean gliding resistance than those with a 50% laceration (p < 0.05), and the tendons that were repaired with running suture had higher mean gliding resistance than those treated with trimming (p < 0.05). Tendon strength was not significantly different among the three types of treatment. CONCLUSIONS: From the perspective of gliding resistance after partial tendon laceration, no repair appears necessary unless triggering is a problem. If triggering occurs, then trimming of a partially lacerated tendon may be a reliable alternative to repair, at least in terms of gliding resistance and strength.

Reproducible volar partial lacerations in flexor tendons: a new device for biomechanical studies.

A device was designed to create clinically relevant, precise partial flexor digitorum profundus tendon lacerations for in vitro studies but can be adapted for in vivo studies. This caliper-based system utilizes a direct measurement of the tendon height and assumes an elliptical cross section to select the depth of the cut. The accuracy was tested on 60 cuts on 12 human tendons lacerated to an expected 50% or 75% of their cross-sectional area, based on the assumption that the cross-section was elliptical in shape. The cuts were made in portions of the tendon that varied in cross-sectional shape and size. The cut surface of the laceration was colored with Methylene blue and then the laceration was completed. The tendon cross-section was digitally imaged and the respective areas of the stained and unstained regions were evaluated using image-processing software. The mean lacerated areas were 52% (SD 5%) and 73% (SD 6%) for targeted lacerations of 50% and 75%, respectively. The device thus appears to be accurate within an acceptable 5% margin of error from the expected area, and adaptable to intra- and inter-tendinous size variations.