Background

The goal of this study was to compare the biomechanical stability of a 2.4-mm dorsal spanning bridge plate with a volar locking plate (VLP) in a distal radius fracture model, during simulated crutch weight-bearing.

Methods

Five paired cadaveric forearms were tested. A 1-cm dorsal wedge osteotomy was created to simulate an unstable distal radius fracture with dorsal comminution. Fractures were fixed with a VLP or a dorsal bridge plate (DBP). Specimens were mounted to a crutch handle, and optical motion-tracking sensors were attached to the proximal and distal segments. Specimens were loaded in compression at 1 mm/s on a servohydraulic test frame until failure, defined as 2 mm of gap site displacement.

Results

The VLP construct was significantly more stable to axial load in a crutch weight-bearing model compared with the DBP plate (VLP: 493 N vs DBP: 332 N). Stiffness was higher in the VLP constructs, but this was not statistically significant (VLP: 51.4 N/mm vs DBP: 32.4 N/mm). With the crutch weight-bearing model, DBP failed consistently with wrist flexion and plate bending, whereas VLP failed with axial compression at the fracture site and dorsal collapse.

Conclusions

Dorsal spanning bridge plating is effective as an internal spanning fixator in treating highly comminuted intra-articular distal radius fracture and prevents axial collapse at the radiocarpal joint. However, bridge plating may not offer advantages in early weight-bearing or transfer in polytrauma patients, with less axial stability in our crutch weight-bearing model compared with volar plating. A stiffer 3.5-mm DBP or use of a DBP construct without the central holes may be considered for distal radius fractures if the goal is early crutch weight-bearing through the injured extremity.

Purpose

The purpose of this systematic review was to summarize the available data on how surgical management of injuries to the thumb ulnar collateral ligament (UCL) complex affects athletes and their return-to-play (RTP) and postinjury performance metrics in addition to evaluating rehabilitation guidelines.

Methods

A systematic search was performed on PubMed and Embase databases for articles on outcomes of surgical treatment of thumb UCL injuries in athletes. Articles with expert recommendations on postoperative management and RTP guidelines were also included separately. Study characteristics were recorded, including sport, RTP rates, and data on performance. Recommendations were summarized by sport. The Methodological Index for Non-Randomized Studies (MINORS) criteria was used to assess methodological quality. The authors also present their recommended return-to-sport algorithm.

Results

Twenty-three articles were included, including 11 with reports on patients and 12 expert opinions on guiding RTP. The mean MINORS score for the applicable studies was 9.4. In the 311 patients included, RTP was 98.1% in aggregate. No performance detriments were noted in athletes after surgery. Thirty-two (10.3%) patients had postoperative complications. The recommendations on timing to RTP vary by sport and author, but all recommended initial thumb protection when returning to sport. Newer techniques, such as suture tape augmentation, suggest the permission for earlier motion.

Conclusions

Return-to-play rates after surgical treatment of thumb UCL injuries are high, with reassuring return to preinjury level of play with few complications. Recommendations for surgical technique have trended toward suture anchors and, now, suture tape augmentation with earlier motion protocols, although rehabilitation guidelines vary by sport and author. Current information on thumb UCL surgery in athletes is limited by the low quality of evidence and expert recommendations.

Type of study/level of evidence

Prognostic IV.

Background

The time dedicated to the study of human anatomy within medical school curriculums has been substantially reduced. The effect of this on the knowledge of incoming orthopaedic trainees is unknown. The current study aimed to evaluate both the subjective perceptions and objective anatomic knowledge of fourth-year medical students applying for orthopaedic residency.

Methods

A multicenter prospective study was performed that assessed 224 students during the course of their interview day for an orthopaedic residency. Participants provided demographic data and a subjective assessment of the quality of their anatomic education, and completed either an upper or lower extremity anatomic examination. Mean total scores and subscores for various anatomic regions and concepts were calculated.

Results

Students on average rated the adequacy of their anatomic education as 6.5 on a 10-point scale. Similarly, they rated the level of importance their medical school placed on anatomic education as 6.2 on a 10-point scale. Almost 90% rated the time dedicated to anatomy as good or fair. Of six possible methods for learning anatomy, dissection was rated the highest.On objective examinations, the mean score for correct answers was 44.2%. This improved to 56.4% when correct and acceptable answers were considered. Regardless of anatomic regions or concepts evaluated, percent correct scores did not reach 50%. There were no significant correlations between performance on the anatomic examinations and either prior academic performance measures or the student's subjective assessment of their anatomic education.

Conclusions

Current students applying into orthopaedic residency do not appear to be adequately prepared with the prerequisite anatomic knowledge. These deficits must be explicitly addressed during residency training to produce competent, safe orthopaedic surgeons.

Background: The aim of this study was to quantify the stabilizing properties of a 3-dimensional (3D)-printed short-arm cast and compare those properties with traditional fiberglass casts in a cadaveric subacute distal radius fracture model. Methods: A cadaveric subacute fracture model was created in 8 pairs of forearms. The specimens were equally allocated to a fiberglass cast or 3D-printed cast group. All specimens were subjected to 3 biomechanical testing modalities simulating daily life use: flexion and extension of digits, pronation and supination of the hand, and 3-point bending. Between each loading modality, radiological evaluation of the specimens was performed to evaluate possible interval displacement. Interfragmentary motion was quantified using a 3D motion-tracking system. Results: Radiographic assessment did not reveal statistically significant differences in radiographic parameters between the 2 groups before and after biomechanical testing. A statistically significant difference in interfragmentary motion was calculated with the 3-point bending test, with a mean difference of 0.44 (±0.48) mm of motion. Conclusions: A statistically significant difference in interfragmentary motion between the 2 casting groups was only identified in 3-point bending. However, the clinical relevance of this motion remains unclear as the absolute motion is less than 1 mm. The results of this study show noninferiority of the 3D-printed casts compared with the traditional fiberglass casts in immobilizing a subacute distal radius fracture model. These results support the execution of a prospective randomized clinical trial comparing both casting techniques.

Pluripotent stem cell-derived organoid technologies have opened avenues to preclinical basic science research, drug discovery, and transplantation therapy in organ systems. Stem cell-derived organoids follow a time course similar to species-specific organ gestation in vivo. However, heterogeneous tissue yields, and subjective tissue selection reduce the repeatability of organoid-based scientific experiments and clinical studies. To improve the quality control of organoids, we introduced a live imaging technique based on two-photon microscopy to non-invasively monitor and characterize retinal organoids' (RtOgs') long-term development. Fluorescence lifetime imaging microscopy (FLIM) was used to monitor the metabolic trajectory, and hyperspectral imaging was applied to characterize structural and molecular changes. We further validated the live imaging experimental results with endpoint biological tests, including quantitative polymerase chain reaction (qPCR), single-cell RNA sequencing, and immunohistochemistry. With FLIM results, we analyzed the free/bound nicotinamide adenine dinucleotide (f/b NADH) ratio of the imaged regions and found that there was a metabolic shift from glycolysis to oxidative phosphorylation. This shift occurred between the second and third months of differentiation. The total metabolic activity shifted slightly back toward glycolysis between the third and fourth months and stayed relatively stable between the fourth and sixth months. Consistency in organoid development among cell lines and production lots was examined. Molecular analysis showed that retinal progenitor genes were expressed in all groups between days 51 and 159. Photoreceptor gene expression emerged around the second month of differentiation, which corresponded to the shift in the f/b NADH ratio. RtOgs between 3 and 6 months of differentiation exhibited photoreceptor gene expression levels that were between the native human fetal and adult retina gene expression levels. The occurrence of cone opsin expression (OPN1 SW and OPN1 LW) indicated the maturation of photoreceptors in the fourth month of differentiation, which was consistent with the stabilized level of f/b NADH ratio starting from 4 months. Endpoint single-cell RNA and immunohistology data showed that the cellular compositions and lamination of RtOgs at different developmental stages followed those in vivo.