Six-Strand Flexor Pollicis Longus Tendon Repairs With and Without Circumferential Sutures: A Multicenter Study

Background: The purpose of this study is to assess outcomes in flexor pollicis longus tendon repairs with 6-strand core sutures with and without circumferential sutures. Methods: A 6-strand core suture technique with and without circumferential sutures was used. Thirty-three patients were summarized in the C group (circumferential group) and 16 patients in the NC group (non-circumferential group). After the surgery, the wrist was stabilized with a dorsal blocking splint and a controlled early active motion protocol was applied. At weeks 6, 13, and 26 data on demographics, type of injury, surgery, postoperative rehabilitation, complications such as re-rupture and the following outcome measurements were collected: range of motion and its recovery according to the Tang criteria, Kapandji score, thumb and hand strengths, Disabilities of the Arm, Shoulder and Hand score, and satisfaction. Results: There were no significant differences in range of motion and strength between the 2 treatment groups. In both groups, the outcome measurements increased over time and they expressed similar satisfaction with the surgical treatment. In 4 patients of the C group tendon repair ruptured and in 1 patient of the NC group. Conclusions: Six-strand repair technique is an effective procedure to assure early active motion after flexor pollicis longus tendon injuries and good results can also be achieved by omitting the circumferential suture.

Modeling Cell Biological Features of Meiotic Chromosome Pairing

During meiosis, homologous chromosomes become associated side by side in a process known as homologous chromosome pairing. Pairing requires long range chromosome motion through a nucleus that is full of other chromosomes. It remains unclear how the cell manages to align each pair of chromosomes quickly while mitigating and resolving interlocks. Here, we use a coarse-grained molecular dynamics model to investigate how specific features of meiosis, including motor-driven telomere motion, nuclear envelope interactions, and increased nuclear size, affect the rate of pairing and the mitigation/resolution of interlocks. By creating in silico versions of three yeast strains and comparing the results of our model to experimental data, we find that a more distributed placement of pairing sites along the chromosome is necessary to replicate experimental findings. Active motion of the telomeric ends speeds up pairing only if binding sites are spread along the chromosome length. Adding a meiotic bouquet significantly speeds up pairing but does not significantly change the number of interlocks. An increase in nuclear size slows down pairing while greatly reducing the number of interlocks. Interestingly, active forces increase the number of interlocks, which raises the question: How do these interlocks resolve? Our model gives us detailed movies of interlock resolution events which we then analyze to build a step-by-step recipe for interlock resolution. In our model, interlocks must first translocate to the ends, where they are held in a quasi-stable state by a large number of paired sites on one side. To completely resolve an interlock, the telomeres of the involved chromosomes must come in close proximity so that the cooperativity of pairing coupled with random motion causes the telomeres to unwind. Together our results indicate that computational modeling of homolog pairing provides insight into the specific cell biological changes that occur during meiosis.

The Transosseous Internal Four Strand Technique: A New All-Inside Technique for Zone 1 Flexor Tendon Repairs

Background: Multiple techniques for the repair of flexor tendon injuries in zone 1 have been proposed over time. While pull-out suture techniques and bone anchor seem to be stronger than internal suture techniques, they are associated with a higher complication rate. We therefore developed an alternative internal suture repair with similar biomechanical stability to those of pull-out sutures and bone anchors. Methods: Twenty porcine distal phalanges and deep flexor tendons were randomized to 2 groups of 10 each. The tendons were transsected at the level of the distal interphalangeal joint. In group 1, repairs were performed with a well-established intraosseous suture repair and in group 2 with our new multistrand technique. The repairs were biomechanically tested with linear distraction until failure. Results: We recorded a significantly higher 2-mm gap force (2GF)—and thus higher stability—of the repairs in group 1 in comparison to group 2. With a 2GF of more than 50 N, our suture technique allows for a modern early active motion rehabilitation protocol. Breakage of the suture construct occurred at random places in the repair in both groups. No pull-outs were noted. Conclusions: This study presents a strong transosseous multistrand repair technique for flexor tendon repair in zone 1 that is simple and fast to perform and should have enough strength to withstand early active motion rehabilitation.

Evaluation of Rehabilitation of Surgically Repaired Flexor Hand Tendons and Ultrasonographic Follow up of Their Healing

Objectives: To evaluate the role of early rehabilitation of surgically repaired flexor hand tendons in improvement of clinical outcome and the role of musculoskeletal ultrasound in follow up of their healing. Patients and methods: Thirty patients with 31 repaired flexor tendons. Assessment was done after 2nd, 4th,8th and 12th weeks of rehabilitation by visual analogue scale (VAS), total active motion of injured fingers (TAM), grip strength, hand assessment tool (HAT) score and ultrasound (US). Results: There was a significant development in pain assessed by VAS, TAM, grip strength and HAT score of the affected hand (p<0.001). Ultrasonographic assessment of healing flexor tendons showed significant improvement in defect size, thickness, vascularity, echogenicity and margination. There was positive correlation between margination of healing flexor tendon with VAS, hand grip and HAT score. Conclusions: Application of proper rehabilitation programs has a great impact on improving the functional outcome after surgical repair of flexor hand tendons. High-frequency ultrasound is used to follow up tendon healing after surgical repair and to assess the state of tendon repair in relation to clinical result.

Autonomous treatment of bacterial infections in vivo using antimicrobial micro- and nanomachines

The increasing resistance of bacteria to existing antibiotics constitutes a major public health threat globally. Most current antibiotic treatments are hindered by poor delivery to the infection site, leading to undesired off-target effects and drug resistance development and spread. Here, we describe micro- and nanomachines that effectively and autonomously deliver antibiotic payloads to the target area. The active motion and antimicrobial activity of the silica-based robots are driven by catalysis of the enzyme urease and antimicrobial peptides, respectively. These antimicrobial machines show micromolar bactericidal activity in vitro against different Gram-positive and Gram-negative pathogenic bacterial strains and act by rapidly depolarizing their membrane. Finally, they demonstrated autonomous anti-infective efficacy in vivo in a clinically relevant abscess infection mouse model. In summary, our machines combine navigation, catalytic conversion, and bactericidal capacity to deliver antimicrobial payloads to specific infection sites. This technology represents a much-needed tool to direct therapeutics to their target to help combat drug-resistant infections.

Preventing postoperative adhesions after hand tendon repair using acellular dermal matrix

Aims: Postoperative tendon adhesions contribute to functional disability and reconstructive failure. In this study, we present the long-term outcomes of a prospective study in which acellular dermal matrix (ADM) was used to prevent postoperative adhesion after tendon injury. Methods: The study was conducted between March 2014 and February 2017. Patients, aged 19–65 years, with an acute single flexor tendon injury in zones 1 or 2, distal to the palmar digital crease were candidates for the study. Patients were allocated to either an ADM treatment group or a control group without ADM treatment. Results: A total of 37 patients were enrolled in the study: 21 patients in the ADM group and 16 patients in the control group. At six months after surgery, the range of motion in the proximal interphalangeal joint was 81.0±5.1 degrees in the ADM group and 75.8±6.9 degrees in the control group. The range of motion in the distal interphalangeal joint was 79.9±7.1 in the ADM group and 71.2±5.7 degrees in the control group, with significant difference (p=0.03 and p<0.05, respectively). In addition, the total active motion was higher in the ADM group than in the control group. The patients' scores on the Patient Satisfaction Questionnaire were also significantly different, with higher satisfaction scores in the ADM group (p=0.02). The minimal follow-up period was six months. Conclusion: The use of ADM after tendon repair has the potential to significantly improve the outcome of tendon surgery in terms of range of motion. Declaration of interest: None of the authors has any financial interest in the products, devices, or drugs mentioned in this article.