Rehabilitation and return to sport criteria following surgical treatment of osteochondritis dissecans of the capitellum: a systematic review.

Background: Osteochondritis dissecans (OCD) of the capitellum is a well-described condition that most commonly affects adolescent throwing athletes and gymnasts. There is no gold standard rehabilitation protocol or timing for return to sport (RTS) after surgical management of OCD of the capitellum. Hypothesis/Purpose: The purpose of the study was to identify in the existing literature any criteria used for RTS following surgical treatment of OCD of the capitellum. The hypothesis was that surgeons would utilize length of time rather than functional criteria or performance benchmarks for RTS. Methods: Level 1 to 4 studies evaluating athletes who underwent surgery for OCD of the capitellum with a minimum follow-up of 1-year were included. Studies not describing RTS criteria, including less than 1-year follow-up, non-operative management only, and revision procedures were excluded. Each study was analyzed for RTS criteria, RTS rate, RTS timeline, sport played, level of competition, graft source (if utilized), and postoperative rehabilitation parameters. Assessment of bias and methodological quality was performed using the Coleman methodology score and RTS value assessment. Results: All studies reported a rehabilitation protocol with immobilization followed by bracing with progressive range of motion. RTS rate was 80.9% (233/288). The majority of studies reported using time-based criteria for RTS (11/15). The most commonly reported timeline was 6 months (range: 3-12 months). Conclusion: The overall RTS rate after surgical treatment of capitellar OCD is high with no consensus on RTS criteria. The two most consistent RTS criteria reported in the literature are return of elbow range of motion and healing demonstrated on postoperative imaging. There is a wide range of time to RTS in the literature, which may be sport dependent. Further research is needed to develop functional and performance-based metrics to better standardize RTS criteria and rehabilitation protocols.

Return to Sport and Performance After Thumb Metacarpophalangeal Joint Collateral Ligament Surgery in the National Basketball Association.

Introduction Basketball players are at increased risk of thumb collateral ligament injury (ulnar collateral ligament (UCL) and radial collateral ligament (RCL)). Methods The National Basketball Association (NBA) players with thumb collateral ligament surgery were identified using publicly available data. Performance statistics, ligament injuries (UCL or RCL), return to sport (RTS) time, laterality, and injury dates were recorded. Cases were matched 1:1 with controls based on age (±1 year), body mass index (BMI), NBA experience (±1 year), and performance statistics prior to the index date. RTS was defined as playing in one NBA game postoperatively. Career longevity was evaluated. Summary statistics were calculated, and Student's t-tests (ɑ = 0.001) were performed. Results All 47 players identified with thumb collateral ligament surgeries returned to sport. Thirty-three players (age: 26.9 ± 3.0) had one year of postoperative NBA experience for performance analysis. Career length (case: 9.6 ± 4.1, control: 9.4 ± 4.3, p > 0.001) was not significantly different from controls (p > 0.001). The same season time to RTS (n = 20) was 7.1 ± 2.4 weeks. Off-season or season-ending surgery (n = 13) RTS time was 28.4 ± 18.7 weeks. Neither thumb collateral ligament (UCL, n = 7; RCL, n = 10; unknown, n = 16) had an identifiable difference between the groups when evaluating career length. Career length, games/season, and performance were not different for players who underwent surgery on their dominant thumb (63.6%, 21/33) compared to controls (p > 0.001). Conclusion RTS rate is high in NBA athletes undergoing thumb collateral ligament surgery. Players do not experience decreased performance or career length due to thumb collateral ligament surgery, regardless of a dominant or non-dominant thumb injury.

S2 alar-iliac screw versus traditional iliac screw for spinopelvic fixation: a systematic review of comparative biomechanical studies.

PURPOSE: To review and compare biomechanical properties between S2 alar-iliac (S2AI) screws and traditional iliac screws for spinopelvic fixation. METHODS: A systematic review was performed according to PRISMA guidelines. All clinical, cadaveric, and finite-element model (FEM) studies that compared the biomechanical properties between S2AI screws and traditional iliac screws were included. Study methodological quality for cadaveric studies were analyzed using the Quality Appraisal for Cadaveric Studies (QUACS) scale. RESULTS: Eight studies (4 cadaveric, 4 FEM) analyzing 58 S2AI screws and 48 traditional iliac screws were included. According to QUACS, the overall methodological quality was "moderate to good" for all four cadaveric studies. All four cadaveric studies found no difference in biomechanical stiffness, screw toggle, rod strain, and/or load-to-failure between the S2AI screws and traditional iliac screws for spinopelvic fixation. All four FEM studies found that S2AI screws were associated with lower implant stresses compared to traditional iliac screws. CONCLUSIONS: There is moderate biomechanical evidence to suggest that there is no significant difference in stability and stiffness between S2AI screws and traditional iliac screws for spinopelvic fixation. However, there is some evidence to support that the placement of S2AI screws may have lower implant stresses on the overall lumbosacral instrumentation compared to traditional iliac screws.

Musculoskeletal pathology as an early warning sign of systemic amyloidosis: a systematic review of amyloid deposition and orthopedic surgery.

BACKGROUND: Transthyretin and immunoglobulin light-chain amyloidoses cause amyloid deposition throughout various organ systems. Recent evidence suggests that soft tissue amyloid deposits may lead to orthopedic conditions before cardiac manifestations occur. Pharmacologic treatments reduce further amyloid deposits in these patients. Thus, early diagnosis improves long term survival. QUESTIONS/PURPOSES: The primary purpose of this systematic review was to characterize the association between amyloid deposition and musculoskeletal pathology in patients with common orthopedic conditions. A secondary purpose was to determine the relationship between amyloid positive biopsy in musculoskeletal tissue and the eventual diagnosis of systemic amyloidosis. METHODS: We performed a systematic review using PRISMA guidelines. Inclusion criteria were level I-IV evidence articles that analyzed light-chain or transthyretin amyloid deposits in common orthopedic surgeries. Study methodological quality, risk of bias, and recommendation strength were assessed using MINORS, ROBINS-I, and SORT. RESULTS: This systematic review included 24 studies for final analysis (3606 subjects). Amyloid deposition was reported in five musculoskeletal pathologies, including carpal tunnel syndrome (transverse carpal ligament and flexor tenosynovium), hip and knee osteoarthritis (synovium and articular cartilage), lumbar spinal stenosis (ligamentum flavum), and rotator cuff tears (tendon). A majority of studies reported a mean age greater than 70 for patients with TTR or AL positive amyloid. CONCLUSIONS: This systematic review has shown the presence of amyloid deposition detected at the time of common orthopedic surgeries, especially in patients ≥70 years old. Subtyping of the amyloid has been shown to enable diagnosis of systemic light-chain or transthyretin amyloidosis prior to cardiac manifestations. LEVEL OF EVIDENCE: Level IV.

Snail synchronizes endocycling in a TOR-dependent manner to coordinate entry and escape from endoreplication pausing during the Drosophila critical weight checkpoint.

The final body size of any given individual underlies both genetic and environmental constraints. Both mammals and insects use target of rapamycin (TOR) and insulin signaling pathways to coordinate growth with nutrition. In holometabolous insects, the growth period is terminated through a cascade of peptide and steroid hormones that end larval feeding behavior and trigger metamorphosis, a nonfeeding stage during which the larval body plan is remodeled to produce an adult. This irreversible decision, termed the critical weight (CW) checkpoint, ensures that larvae have acquired sufficient nutrients to complete and survive development to adulthood. How insects assess body size via the CW checkpoint is still poorly understood on the molecular level. We show here that the Drosophila transcription factor Snail plays a key role in this process. Before and during the CW checkpoint, snail is highly expressed in the larval prothoracic gland (PG), an endocrine tissue undergoing endoreplication and primarily dedicated to the production of the steroid hormone ecdysone. We observed two Snail peaks in the PG, one before and one after the molt from the second to the third instar. Remarkably, these Snail peaks coincide with two peaks of PG cells entering S phase and a slowing of DNA synthesis between the peaks. Interestingly, the second Snail peak occurs at the exit of the CW checkpoint. Snail levels then decline continuously, and endoreplication becomes nonsynchronized in the PG after the CW checkpoint. This suggests that the synchronization of PG cells into S phase via Snail represents the mechanistic link used to terminate the CW checkpoint. Indeed, PG-specific loss of snail function prior to the CW checkpoint causes larval arrest due to a cessation of endoreplication in PG cells, whereas impairing snail after the CW checkpoint no longer affected endoreplication and further development. During the CW window, starvation or loss of TOR signaling disrupted the formation of Snail peaks and endocycle synchronization, whereas later starvation had no effect on snail expression. Taken together, our data demonstrate that insects use the TOR pathway to assess nutrient status during larval development to regulate Snail in ecdysone-producing cells as an effector protein to coordinate endoreplication and CW attainment.

Connecting pancreatic islet lipid metabolism with insulin secretion and the development of type 2 diabetes.

Obesity is the major contributing factor for the increased prevalence of type 2 diabetes (T2D) in recent years. Sustained positive influx of lipids is considered to be a precipitating factor for beta cell dysfunction and serves as a connection between obesity and T2D. Importantly, fatty acids (FA), a key building block of lipids, are a double-edged sword for beta cells. FA acutely increase glucose-stimulated insulin secretion through cell-surface receptor and intracellular pathways. However, chronic exposure to FA, combined with elevated glucose, impair the viability and function of beta cells in vitro and in animal models of obesity (glucolipotoxicity), providing an experimental basis for the propensity of beta cell demise under obesity in humans. To better understand the two-sided relationship between lipids and beta cells, we present a current view of acute and chronic handling of lipids by beta cells and implications for beta cell function and health. We also discuss an emerging role for lipid droplets (LD) in the dynamic regulation of lipid metabolism in beta cells and insulin secretion, along with a potential role for LD under nutritional stress in beta cells, and incorporate recent advancement in the field of lipid droplet biology.

Molecular characterization and juvenile hormone-regulated transcription of the vitellogenin receptor in the cabbage beetle Colaphellus bowringi.

The vitellogenin receptor (VgR) is highly expressed in the ovaries where it is responsible for vitellogenin (Vg) deposition during oogenesis in insects. Therefore, identifying the VgR of insect pests, and understanding the mechanism regulating its expression, could lead to the development of pest management strategies based on disrupting reproduction. We cloned and identified VgR in the cabbage beetle, Colaphellus bowringi, which is a serious pest of cruciferous vegetables in Asia. The regulation of VgR transcription by juvenile hormone (JH) was also investigated. The results show that C. bowringi VgR cDNA contains an open reading frame of 5310 bp encoding 1769 amino acid residues. Protein domain prediction indicates that C. bowringi VgR belongs to the LDLR gene superfamily, having the same group of structural domains that has been well characterized in other insects. VgR mRNA was highly expressed in the ovaries of reproductive female cabbage beetles. Knockdown of VgR reduced yolk deposition in the ovaries, increased the accumulation of Vg proteins in the hemolymph and decreased the transcription of Vg1 and Vg2 in the fat body. RNA interference and hormone challenge experiments showed that JH induced VgR transcription via the JH intracellular receptor methoprene-tolerant (Met) and the JH-responsive transcription factor Krüppel homolog 1 (Kr-h1). Our results suggest that there is a feedback loop between VgR transcription in the ovaries and Vg transcription in the fat body. JH acting through Met-Kr-h1 pathway induces the transcription of the VgR that is essential for Vg uptake and reproductive development. These findings not only reveal the potential JH signaling mechanism regulating VgR transcription, but may also contribute to the development of pest control strategies based on disrupting endocrine-regulated reproduction.

A Contact Pressure Analysis Comparing an All-Inside and Inside-Out Surgical Repair Technique for Bucket-Handle Medial Meniscus Tears.

PURPOSE: To directly compare effectiveness of the inside-out and all-inside medial meniscal repair techniques in restoring native contact area and contact pressure across the medial tibial plateau at multiple knee flexion angles. METHODS: Twelve male, nonpaired (n = 12), fresh-frozen human cadaveric knees underwent a series of 5 consecutive states: (1) intact medial meniscus, (2) MCL tear and repair, (3) simulated bucket-handle longitudinal tear of the medial meniscus, (4) inside-out meniscal repair, and (5) all-inside meniscal repair. Knees were loaded with a 1,000-N axial compressive force at 5 knee flexion angles (0°, 30°, 45°, 60°, 90°), and contact area, mean contact pressure, and peak contact pressure were calculated using thin film pressure sensors. RESULTS: No significant differences were observed between the inside-out and all-inside repair techniques at any flexion angle for contact area, mean contact pressure, and peak contact pressure (all P > .791). Compared with the torn meniscus state, inside-out and all-inside repair techniques resulted in increased contact area at all flexion angles (all P < .005 and all P < .037, respectively), decreased mean contact pressure at all flexion angles (all P < .007 and all P < .001, respectively) except for 0° (P = .097 and P = .39, respectively), and decreased peak contact pressure at all flexion angles (all P < .001, all P < .001, respectively) except for 0° (P = .080 and P = .544, respectively). However, there were significant differences in contact area and peak contact pressure between the intact state and inside-out technique at angles ≥45° (all P < .014 and all P < .032, respectively). Additionally, there were significant differences between the intact state and all-inside technique in contact area at 60° and 90° and peak contact pressure at 90° (both P < .005 and P = .004, respectively). Median values of intact contact area, mean contact pressure, and peak contact pressure over the tested flexion angles ranged from 498 to 561 mm2, 786 to 997 N/mm2, and 1,990 to 2,215 N/mm2, respectively. CONCLUSIONS: Contact area, mean contact pressure, and peak contact pressure were not significantly different between the all-inside and inside-out repair techniques at any tested flexion angle. Both techniques adequately restored native meniscus biomechanics near an intact level. CLINICAL RELEVANCE: An all-inside repair technique provided similar, native-state-restoring contact mechanics compared with an inside-out repair technique for the treatment of displaced bucket-handle tears of the medial meniscus. Thus, both techniques may adequately decrease the likelihood of cartilage degeneration.

The Proximal Tibiofibular Joint: A Biomechanical Analysis of the Anterior and Posterior Ligamentous Complexes.

BACKGROUND: Dislocation of the proximal tibiofibular joint is a complex injury that is often overlooked or misdiagnosed. Surgical management is recommended for severe acute or for chronic symptomatic instability of the proximal tibiofibular joint. Although the anterior ligamentous complex has been reported to be stronger than the posterior complex, biomechanical data are lacking. PURPOSE: To determine the ultimate load of the anterior and posterior ligamentous complexes of the proximal tibiofibular joint to determine optimal graft selection. STUDY DESIGN: Controlled laboratory study. METHODS: Ten nonpaired, fresh-frozen knee specimens were dissected to expose the anterior and posterior proximal tibiofibular ligamentous complexes. The tibia was split in the coronal plane to separate the anterior and posterior ligamentous complexes, and the fibula was left intact. Specimens were secured in a dynamic testing machine and preconditioned for 10 cycles between 2 and 10 N at 0.1 Hz followed by loading to failure at a rate of 25 mm/min. RESULTS: The mean (±SD) ultimate load of the anterior complex (517 ± 144 N) was significantly greater than the mean ultimate load of the posterior complex (322 ± 160 N) ( P = .012). The mean surface areas of the anterior and posterior complexes were 761 ± 174 mm2 and 565 ± 103 mm2, respectively ( P = .008). The mean values for stiffness of the anterior (133 N/mm) and posterior (109 N/mm) complexes were similar ( P = .250). CONCLUSION: The ligaments of the human proximal tibiofibular joint were able to withstand a mean ultimate failure load of 517 ± 144 N for the anterior complex and 322 ± 160 N for the posterior complex. In this regard, it is recommended that the strengths of grafts chosen for proximal tibiofibular reconstructions meet or exceed these values. CLINICAL RELEVANCE: The optimal surgical treatment for addressing residual proximal tibiofibular instability is not well defined. Before an anatomic reconstruction of the proximal tibiofibular ligament is developed, the individual biomechanical properties of the anterior and posterior ligamentous structures of the proximal tibiofibular joint need to be considered to facilitate an optimal reconstruction design.

A Drosophila Genome-Wide Screen Identifies Regulators of Steroid Hormone Production and Developmental Timing.

Steroid hormones control important developmental processes and are linked to many diseases. To systematically identify genes and pathways required for steroid production, we performed a Drosophila genome-wide in vivo RNAi screen and identified 1,906 genes with potential roles in steroidogenesis and developmental timing. Here, we use our screen as a resource to identify mechanisms regulating intracellular levels of cholesterol, a substrate for steroidogenesis. We identify a conserved fatty acid elongase that underlies a mechanism that adjusts cholesterol trafficking and steroidogenesis with nutrition and developmental programs. In addition, we demonstrate the existence of an autophagosomal cholesterol mobilization mechanism and show that activation of this system rescues Niemann-Pick type C1 deficiency that causes a disorder characterized by cholesterol accumulation. These cholesterol-trafficking mechanisms are regulated by TOR and feedback signaling that couples steroidogenesis with growth and ensures proper maturation timing. These results reveal genes regulating steroidogenesis during development that likely modulate disease mechanisms.