Adam, Elameen A

Background Loss of finger motion after zone II flexor tendon repair remains common and is largely caused by adhesion formation. Although intrinsic vascular and cellular contributions to tendon healing have been examined in canine, avian, and primate models, prior studies have emphasized biochemical or perfusion-based endpoints without comprehensive assessment of functional and mechanical outcomes after clinically relevant repair. Consequently, the influence of intrinsic healing elements on early postoperative function remains unclear. In this study, we employed a novel avian model of intrasynovial (zone II) tendon injury, which enables clinically relevant operative repair, postoperative rehabilitation, and quantitative assessment of tendon function and biomechanics, to investigate the contribution of intrinsic healing elements to tendon repair. Questions/purposes (1) Does operative ablation of intrinsic healing elements worsen early ROM after zone II flexor tendon repair? (2) Does disruption of intrinsic pathways increase adhesion formation, as measured by normalized work of flexion and gross adhesion scores? (3) Does intrinsic tendon component ablation compromise mechanical properties, including ultimate load to failure and stiffness? (4) Does removal of intrinsic elements alter the expression of fibrotic and matrix-related genes during early healing? Methods Using a clinically relevant, large-animal avian ( Meleagris gallopavo ) model of zone II flexor tendon repair, flexor digitorum longus (FDL) tendons underwent sharp transection and primary repair and were assigned to one of four groups: (1) control repair with intact intrinsic elements (3 weeks postinjury, n = 11; 6 weeks postinjury, n = 18), (2) vincular ligation and transection (3 weeks postinjury, n = 12; 6 weeks postinjury, n = 16), (3) tenocyte cryoablation via intraoperative freeze-thaw devitalization (3 weeks postinjury, n = 13; 6 weeks postinjury, n = 13), or (4) complete tendon devitalization (3 weeks postinjury, n = 13; 6 weeks postinjury, n = 16). A total of 112 male and female birds were used for this study. Harvested tendons were evaluated at 3 and 6 weeks postoperatively. Outcomes included interphalangeal ROM, normalized work of flexion, semiquantitative gross adhesion scoring, ultimate load to failure, stiffness, qualitative histologic assessment, qualitative immunofluorescence, and quantitative PCR for fibrotic and matrix-related genes. Results Operative ablation of the intrinsic healing elements did not worsen total ROM and/or increase normalized work of flexion. All experimental groups demonstrated reduced total ROM of the operative digit at 3 weeks postoperatively compared with the contralateral nonoperative digit: mean ± SD control repair with intact intrinsic healing elements (50° ± 10° versus 14° ± 6°, mean difference 36.41° [95% confidence interval (CI) 26.87° to 45.94°]; p < 0.001), vincular disruption group (50° ± 10° versus 14° ± 7°, mean difference 35.97° [95% CI 21.44° to 45.51°]; p < 0.001), tenocyte cryoablation group (50° ± 10° versus 15° ± 8°, mean difference 35.27° [95% CI 25.99° to 44.55°]; p < 0.001), and complete tendon devitalization group (50° ± 10° versus 11° ± 4°, mean difference 38.97° [95% CI 29.44° to 48.50°]; p < 0.001). However, no differences between the groups were detected. Similarly, the total ROM was impaired at 6 weeks postinjury compared with the nonoperative digit in all groups. We did not detect any differences between the groups, and results did not demonstrate time-dependent differences between the two time points. Furthermore, normalized work of flexion, a proxy for peritendinous adhesion severity, was increased in all experimental groups at 3 weeks postinjury: mean ± SD control repair with intact intrinsic healing elements (0 ± 0 N mm/° versus 4 ± 3 N mm/°, mean difference -3.33 [95% CI -5.73 to -0.93]; p = 0.003), vincular disruption group (0 ± 0 N mm/° versus 4 ± 2 N mm/°, mean difference -3.09 [95% CI -5.49 to -0.69]; p = 0.006), tenocyte cryoablation group (0 ± 0 N mm/° versus 3 ± 2 N mm/°, mean difference -2.99 [95% CI -5.33 to -0.66]; p = 0.006), and complete tendon devitalization group (0 ± 0 N mm/° versus 4 ± 2 N mm/°, mean difference -3.31 [95% CI -5.70 to -0.91]; p = 0.003). However, no group differences were detected. At the 6-week follow-up, the normalized work of flexion was also elevated in all groups without any differences between the treatments. Furthermore, the integrity of the tendon intrinsic components has been presumed to be a major determinant of flexor tendon healing strength after zone II tendon repair. However, our results do not support this assumption. At both time points, there were no differences in ultimate load and stiffness between the experimental groups, and there were no group × time interaction effects. Additionally, structural removal of the intrinsic healing elements did not result in meaningful qualitative histologic differences in extrinsic fibrosis, neovascularization, or collagen fiber organization. The profibrotic gene, transforming growth factor beta induced (TGFBI), was upregulated in all experimental groups compared with the normal FDL tendon. Matrix remodeling, measured by matrix metalloproteinase 7 (MMP7) activity, was also activated in all groups relative to the normal FDL tendon. However, no differences were detected between the groups. Conclusion Operative ablation of intrinsic healing elements, including the flexor vincular system and resident tenocytes, did not worsen early ROM, adhesion formation, or mechanical properties after zone II flexor tendon repair in a clinically relevant large-animal model. Early healing was characterized by a robust fibrovascular response across all groups, indicating that extrinsic mechanisms predominate during the early reparative phase. Paradigms that modulate the extrinsic tendon healing mechanisms could represent a more viable approach to flexor tendon healing outcomes than focusing on bolstering the intrinsic components. Clinical Relevance Our findings suggest that early functional recovery in this model may depend more on modulation of the extrinsic fibrotic response than on preservation of intrinsic vascular or cellular elements, supporting the development of antiadhesion therapies. Additional preclinical studies are needed to identify the cellular niches that drive extrinsic fibrosis and adhesion formation, determine whether they can be selectively modulated without impairing tendon healing, and establish the translational relevance of these mechanisms across species before clinical application.

Objective To evaluate cancer risk in individuals with cleft lip and/or cleft palate (CL/P). Design Retrospective chart review of patients with CL/P, including abstraction of information on cancer diagnoses was conducted. Cancer risk was compared with national population-based estimates using standardized incidence ratios (SIRs) and exact binomial tests. Subgroup analyses compared demographic and clinical characteristics between patients with and without cancer. Setting Study was performed at a single tertiary academic center with multidisciplinary surgical, pediatric, and genetic care. Patients/Participants Total of 2121 patients with CL/P from 1970 to 2024 with complete medical documentation were included. Main Outcome Measures Main outcomes included prevalence of cancer diagnoses, childhood cancer incidence, and differences in cancer occurrence by age, cleft type, syndromic status, and family history. Results Total of 144 patients (6.8%) had pathologically confirmed cancer diagnoses. Twelve childhood cancers were identified, with 10 cases presenting before age 15. Children younger than 15 with CL/P had a significantly elevated cancer risk (SIR 4.7; 95% confidence interval: 1.8-7.6; P < .00001). Pediatric cancers occurred mainly in syndromic cases. Cancer prevalence was higher in cleft palate only and cleft lip/palate cases compared with cleft lip only ( P < .05). Cancer occurrence was not higher in adults with CL/P compared to the general population. Conclusions Cancer risk is not uniformly elevated over the lifespan in individuals with CL/P. Increased cancer risk is observed in our pediatric cohort. Clinical care should include careful assessment of childhood cancers, syndromic features, and family history, with consideration for genetic counseling and multidisciplinary follow-up.

ABSTRACT Calcific tendinopathy is a common musculoskeletal disorder marked by calcium deposition within tendons, often accompanied by pain, impaired mobility, and in severe cases, ossification. However, the mechanisms underlying tendon mineralization remain poorly understood. In contrast to pathological human calcification, turkeys naturally develop tendon mineralization during growth without signs of inflammation or ossification. This study had two phases: an observational phase to assess onset and progression of calcification, and an interventional phase to evaluate the role of mechanical loading. In the observational phase, flexor tendons were collected from turkeys aged 1–16 weeks in a serial sacrifice study and analyzed by Von Kossa staining and biomechanical testing. Calcification began at 7 weeks, localized within organized collagen matrices, progressed through Weeks 8–14, and peaked by 16 weeks. In the interventional phase, nine female turkeys were randomized at 4 weeks into a transection group ( n = 3), sham group ( n = 3), and control group ( n = 3). Transection at the muscle–tendon junction eliminated mechanical loading. At 16 weeks, tendons were analyzed by histology, quantitative RT‐PCR, ICP‐MS, and biomechanical testing. Transected tendons showed a near‐complete absence of mineralization, reduced expression of osteogenic markers (osteopontin, osteocalcin, Runx‐2), and significantly lower calcium, magnesium, and phosphorus levels. Biomechanical testing indicated reduced stress relaxation, stiffness, and Young's modulus in the transected group. Tendon calcification in turkeys functioned as a mechanically regulated, nonpathological process. The study established a relevant model for early tendon mineralization and offered a basis for developing load‐dependent therapies for human tendon disease.

Objective This study aimed to identify specific causes, clinical features, and contributing factors associated with early childhood mortality in a vulnerable subset of patients with cleft lip and/or palate (CL/P) who did not survive to undergo surgical repair. Design This was a retrospective chart review study. Setting The study was conducted at a single tertiary medical center. Patients/Participants We identified 26 liveborn CL/P patients who died without cleft repair from 1970 to 2024. Their data was compared to a control group of 2070 surgically repaired CL/P patients from the same institution. Main Outcome Measures Our primary goal was to characterize the clinical profile of patients experiencing prerepair mortality. Secondary outcomes included identifying causes of death, maternal and prenatal risk factors, and comparing these findings with the surgically repaired patients. Results All 26 unrepaired patients (100%) had genetic syndromes or isolated severe congenital anomalies, a significant difference compared to 24% in the surgically repaired group ( P < .0001). Trisomy 13 (30.8%), holoprosencephaly (23.1%), congenital cardiac defects (11.5%), and trisomy 18 (11.5%) were the leading causes of death. The median age at death for unrepaired patients was 25 days (interquartile range 4-125 days), significantly lower than the 61.9 years in the control group ( P < .0001). Multivariable logistic regression showed that genetic syndromes or severe congenital anomalies were strongly associated with early mortality ( P < .0001). Notably, all unrepaired patients who were born in the United States after 2005 had accurate prenatal diagnoses, which allowed clinical planning before the patients were born. Conclusions Prerepair mortality in CL/P is significantly driven by underlying genetic syndromes or congenital anomalies. For surgeons, this highlights the importance of genetic testing and prenatal care to guide appropriate surgical management. Considering a wait in surgical intervention until patients are approximately 4 months old may allow for better survival assessment and informed decisions for these high-risk individuals.