Screw Diameter and Use of a Washer Affect Symptomatic Implant Removal Rates in Pediatric Medial Epicondyle Fractures.

OBJECTIVE: Medial epicondyle fractures are a common pediatric injury. When operative, cannulated partially threaded screws, with or without a washer, are commonly utilized. These implants may need to be removed after full healing if symptomatic. There is mixed evidence regarding the influence of a washer on rates of implant removal, and the influence of screw size has not been studied. We aim to determine the rate of symptomatic deep implant removal for each fixation type and identify factors associated with the need for removal. METHODS: This was an IRB-reviewed, retrospective, case-cohort study. Patients treated at our institution between January 1, 2004 and December 31, 2019, age 18 years old or younger, with a medial epicondyle fracture managed operatively with 4.0 or 4.5 mm cannulated screws with or without washers were included. Patients with multiple operative ipsilateral elbow fractures and those who underwent implant removal for reasons other than pain or irritation were excluded. Removal rates were compared between screw sizes (4.0 vs 4.5 mm), as well as with and without a washer using a Cox proportional hazards model. RESULTS: In total, 151 patients met the inclusion criteria, 54 with symptomatic hardware removed and 97 without symptomatic hardware removed. A significantly higher number of patients treated with 4.5 mm screws compared with 4.0 mm screws underwent removal of symptomatic deep implants (50% vs 30%, P = 0.033). In a multivariable Cox regression model adjusting for age and ulnar nerve status, when no washer was used, the hazard ratio (HR) for symptomatic hardware removal for 4.5 mm screws was 2.92 times the HR for 4.0 mm screws (95% CI: 1.35-6.29). When a 4.0 mm screw was used, the HR for symptomatic hardware removal for a washer was 3.24 times the HR without a washer (95% CI: 1.53-6.84). CONCLUSION: Implant removal rates are influenced by screw size and the use of a washer. These results may help guide implant choice and counsel families regarding the rate of symptomatic implant removal. LEVEL OF EVIDENCE: Level III-therapeutic level, case-control study.

Missed positional gluteal compartment syndrome in an obese patient after foot surgery: a case report.

BACKGROUND: Gluteal compartment syndrome is an uncommon condition and can be difficult to diagnose. It has been diagnosed after trauma, vascular injury, infection, surgical positioning, and prolonged immobilization from drug or alcohol intoxication. The diagnosis is based on clinical findings and, in most cases, recognizing these symptoms and making a diagnosis early is critical to a complete recovery. CASE PRESENTATION: A 53-year-old male who underwent left foot surgery had severe pain to his contralateral hip and posterior gluteal compartment radiating to the right lower extremity immediately postoperative. He was positioned supine with a "bump" placed under his right hip to externally rotate his operative leg during the surgery. Due to the patient's complex past medical history, a presumptive diagnosis of a herniated disc and/or compression of the sciatic nerve was made as a cause for the patient's pain. This resulted in a misdiagnosis period of 36 h until the patient was diagnosed with unilateral gluteal compartment syndrome. Performing a fasciotomy was decided against due to the increased risk of complications. The patient was treated with administration of IV fluids and closely monitored. On post-op day 6, the patient was discharged. At three months post-op, the patient was walking without a limp and he had no changes in his peripheral neurologic examination compared to his preoperative baseline. CONCLUSION: Gluteal compartment syndrome is a surgical emergency that must be considered postoperatively especially in obese patients with prolonged operation times who experience acute buttock pain. The use of positional bars or "bumps" in the gluteal area should be used with caution and raise awareness of this complication after orthopedic surgeries.

Anterior Cruciate Ligament Graft Removal Versus Retention in the Setting of Septic Arthritis After Reconstruction: A Systematic Review and Expected Value Decision Analysis.

PURPOSE: To provide further guidance on the optimal decision between anterior cruciate ligament (ACL) graft removal versus retention in the setting of septic arthritis following reconstruction using an expected value decision analysis. METHODS: A systematic review and expected value decision analysis and sensitivity analyses were performed to quantify the clinical decision. A decision tree was created with 5 outcomes of interest: nonoperative complications, revision surgery, early reoperation, late reoperation, and "well." Pooled probabilities of each outcome were generated through a systematic literature review. We included only peer-reviewed studies, published in English, with at least 6 months of follow-up. One hundred randomly selected volunteers were given descriptions of the clinical scenario, the 2 treatment options, and outcomes of interest. Patients younger than 18 and older than 50 years and those previously treated for either ACL injury or septic arthritis, or both, were excluded from the analysis to minimize bias. These hypothetical patients indicated preferences for each outcome on a visual analog scale and responses were averaged to generate overall "utility values." Fold-back analysis summed products of pooled outcomes probabilities with respective averaged utility values. The resulting overall expected values for graft removal and debridement were compared, with the highest expected value considered to be superior. We then performed 1-way sensitivity analyses to mitigate sample bias. RESULTS: Fold-back analysis revealed graft removal to be strongly favored over retention, with overall expected values of 17.2 and 8.64, respectively. The most important contributor to the difference in overall expected values was late reoperation (8.59 vs 2.50 for removal and retention, respectively). Despite adjustments made to the rates of revision and early reoperation during the 1-way sensitivity analyses, graft removal remained the optimal strategy. CONCLUSIONS: This expected value decision analysis revealed that ACL graft removal was strongly favored by patients over graft retention in the setting of postoperative septic arthritis when consideration was given to the probabilities of wellness, nonoperative complications, revision surgery, early reoperation, and late reoperation. Sensitivity analysis revealed that although variation in rates of other outcomes did not impact this preference, the rate of late reoperation had a substantial impact. Only a sizable increase in the probability of late reoperation (from 0% to 60%) after graft removal would cause potential patients to favor graft retention. LEVEL OF EVIDENCE: Level IV, systematic review and decision analysis.

Improved external rotation with concomitant reverse total shoulder arthroplasty and latissimus dorsi tendon transfer: A systematic review.

BACKGROUND: In conjunction with reverse total shoulder arthroplasty (RSA), latissimus dorsi and teres major (LD-TM) transfer has been advocated in the setting of combined loss of elevation and external rotation. The purpose of this systematic review is to summarize the clinical outcomes following RSA with LD-TM transfer. METHODS: A search of PubMed, EMBASE, CINAHL, Medline, and Cochrane databases was performed between January 1, 1990 and March 1, 2016 and included articles related to outcomes following RSA with LD-TM transfer. Primary outcomes of interest were constant score, shoulder range of motion, and patient satisfaction. Secondary outcomes of interest included subjective shoulder value, simple shoulder test, activities of daily living requiring external rotation, and visual analog pain score. Additional outcomes evaluated included complications and reoperations. Frequency-weighted values of outcome data were utilized. RESULTS: Five level IV studies involving 98 shoulders met the inclusion criteria. The mean age of the cohort was 69.1 ± 5.19 years (range 47-85). RSA with LD-TM transfer was performed for rotator cuff arthropathy (94%) or proximal humerus fracture (6%). The average follow-up was 44.5 ± 10.38 months (range 12-105 months). The constant score improved from 28 to 65 ( p < 0.0005). Active external rotation improved from -7.4° to 22.9° ( p < 0.0005). There was a 22.4% overall complication rate, including dislocation (5.1%), infection (5.1%), and transient nerve palsy (3.4%). CONCLUSION: Patients undergoing RSA with LD-TM transfer in the setting of loss of external rotation demonstrate reliable clinical improvements in shoulder function with complication rates which are comparable to RSA alone.

Local manganese chloride treatment accelerates fracture healing in a rat model.

This study investigated the effects of local delivery of manganese chloride (MnCl2), an insulin-mimetic compound, upon fracture healing using a rat femoral fracture model. Mechanical testing, histomorphometry, and immunohistochemistry were performed to assess early and late parameters of fracture healing. At 4 weeks post-fracture, maximum torque to failure was 70% higher (P<0.05) and maximum torsional rigidity increased 133% (P<0.05) in animals treated with 0.125 mg/kg MnCl2 compared to saline controls. Histological analysis of the fracture callus revealed percent new mineralized tissue was 17% higher (P<0.05) at day 10. Immunohistochemical analysis of the 0.125 mg/kg MnCl2 treated group, compared to saline controls, showed a 379% increase in the density of VEGF-C+ cells. In addition, compared to saline controls, the 0.125 mg/kg MnCl2 treated group showed a 233% and 150% increase in blood vessel density in the subperiosteal region at day 10 post-fracture as assessed by detection of PECAM and smooth muscle α actin, respectively. The results suggest that local MnCl2 treatment accelerates fracture healing by increasing mechanical parameters via a potential mechanism of amplified early angiogenesis leading to increased osteogenesis. Therefore, local administration of MnCl2 is a potential therapeutic adjunct for fracture healing.

Local ZnCl2 accelerates fracture healing.

This study evaluated the effect of local zinc chloride (ZnCl2 ), an insulin mimetic agent, upon the early and late parameters of fracture healing in rats using a standard femur fracture model. Mechanical testing, radiographic scoring, histomorphometry, qualitative histological scoring, PCNA immunohistochemistry, and local growth factor analysis were performed. Fractures treated with local ZnCl2 possessed significantly increased mechanical properties compared to controls at 4 weeks post fracture. The radiographic scoring analysis showed increased cortical bridging at 4 weeks in the 1.0 (p=0.0015) and 3.0 (p<0.0001) mg/kg ZnCl2 treated groups. Histomorphometry of the fracture callus at day 7 showed 177% increase (p=0.036) in percent cartilage and 133% increase (p=0.002) in percent mineralized tissue with local ZnCl2 treatment compared to controls. Qualitative histological scoring showed a 2.1× higher value at day 7 in the ZnCl2 treated group compared to control (p = 0.004). Cell proliferation and growth factors, VEGF and IGF-I, within fracture calluses treated with local ZnCl2 were increased at day 7. The results suggest local administration of ZnCl2 increases cell proliferation, causing increased growth factor production which yields improved chondrogenesis and endochondral ossification. Ultimately, these events lead to accelerated fracture healing as early as 4 weeks post fracture.

Local vanadium release from a calcium sulfate carrier accelerates fracture healing.

This study evaluated the efficacy of using calcium sulfate (CaSO4 ) as a carrier for intramedullary delivery of an organic vanadium salt, vanadyl acetylacetonate (VAC) after femoral fracture. VAC can act as an insulin-mimetic and can be used to accelerate fracture healing in rats. A heterogenous mixture of VAC and CaSO4 was delivered to the fracture site of BB Wistar rats, and mechanical testing, histomorphometry, micro-computed tomography (micro-CT) were performed to measure healing. At 4 weeks after fracture, maximum torque to failure, effective shear modulus, and effective shear stress were all significantly higher (p < 0.05) in rats treated with 0.25 mg/kg VAC-CaSO4 as compared to carrier control rats. Histomorphometry found a 71% increase in percent cartilage matrix (p < 0.05) and a 64% decrease in percent mineralized tissue (p < 0.05) at 2 weeks after fracture in rats treated with 0.25 mg/kg of VAC-CaSO4 . Micro-CT analyses at 4 weeks found a more organized callus structure and higher trending maximum connected z-ray. fraction for VAC-CaSO4 groups. Evaluation of radiographs and serial histological sections at 12 weeks did not show any evidence of ectopic bone formation. As compared to previous studies, CaSO4 was an effective carrier for reducing the dose of VAC required to accelerate femoral fracture healing in rats.

Effects of local insulin delivery on subperiosteal angiogenesis and mineralized tissue formation during fracture healing.

Local insulin delivery has been shown to improve osseous healing in diabetic animals. The purpose of this study was to quantify the effects of local intramedullary delivery of saline or Ultralente insulin (UL) on various fracture healing parameters using an in vivo non-diabetic BB Wistar rat model. Quantitation of local insulin levels showed a rapid release of insulin from the fractured femora, demonstrating complete release at 2 days. RT-PCR analysis revealed that the expression of early osteogenic markers (Col1α2, osteopontin) was significantly enhanced with UL treatment when compared with saline controls (p < 0.05). Significant differences in VEGF + cells and vascularity were evident between the treatment and control groups at day 7 (p < 0.05). At day 21, histomorphometric analysis demonstrated a significant increase in percent mineralized tissue in the UL-treated animals compared with controls (p < 0.05), particularly within the subperiosteal region of the fracture callus. Mechanical testing at 4 weeks showed significantly greater mechanical strength for UL-treated animals (p < 0.05), but healing in control animals caught up at 6 weeks post-fracture. These results suggest that the primary osteogenic effect of UL during the early stages of fracture healing (1-3 weeks) is through an increase in osteogenic gene expression, subperiosteal angiogenesis, and mineralized tissue formation.

Right atrial chromaffin paraganglioma in a dog.

Cardiac neoplasia is relatively uncommon in canine patients, with the most common neoplasms including right atrial hemangiosarcoma and paragangliomas occurring at the heart base (i.e. chemodectomas or aortic body tumors). Intracardiac paragangliomas are rare neoplasms in humans and have seldom been documented in the veterinary literature. This report describes the clinical course and histopathological findings in an adult canine patient with an intracardiac chromaffin paraganglioma (non-adrenal pheochromocytoma) of the right atrium.

The effects of local vanadium treatment on angiogenesis and chondrogenesis during fracture healing.

This study quantified the effects of local intramedullary delivery of an organic vanadium salt, which may act as an insulin-mimetic on fracture healing. Using a BB Wistar rat femoral fracture model, local vanadyl acetylacetonate (VAC) was delivered to the fracture site and histomorphometry, mechanical testing, and immunohistochemistry were performed. Callus percent cartilage was 200% higher at day 7 (p < 0.05) and 88% higher at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Callus percent mineralized tissue was 37% higher at day 14 (p < 0.05) and 31% higher at day 21 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Maximum torque to failure was 104% and 154% higher at 4 weeks post-fracture (p < 0.05) for the healing femurs from the VAC-treated (1.5 and 3.0 mg/kg) animals. Animals treated with other VAC doses demonstrated increased mechanical parameters at 4 weeks (p < 0.05). Immunohistochemistry detected 62% more proliferating cells at days 7 (p < 0.05) and 94% more at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg VAC. Results showed 100% more vascular endothelial growth factor-C (VEGF-C) positive cells and 80% more blood vessels at day 7 (p < 0.05) within the callus subperiosteal region of VAC-treated animals (1.5 mg/kg) compared to controls. The results suggest that local VAC treatment affects chondrogenesis and angiogenesis within the first 7-10 days post-fracture, which leads to enhanced mineralized tissue formation and accelerated fracture repair as early as 3-4 weeks post-fracture.

Role of local insulin augmentation upon allograft incorporation in a rat femoral defect model.

Each year, over one million orthopedic operations are performed which a bony defect is presence, requiring the use of further augmentation in addition to bony fixation. Application of autogenous bone graft is the standard of care to promote healing of these defects, but several determents exist in using autogenous bone graft exist including limited supply and donor site morbidity. Prior work has demonstrated that local insulin application to fracture sites promote fracture healing, but no work has been performed to date in its effects upon defect healing/allograft incorporation. The goal of this study was to examine the potential role of local insulin application upon allograft incorporation. Microradiographic, histologic, and histomorphometric analysis outcome parameters showed that local insulin significantly accelerated new bone formation. Histological comparisons using predetermined scoring systems demonstrated significantly greater healing in femora treated with insulin compared to control femora (p < 0.001). Quantitatively more bone production was also observed, specifically in areas of endosteal (p = 0.010) and defect (p = 0.041) bone in femora treated with local insulin, compared to control femora, 6 weeks after implantation. This study demonstrates the potential of local insulin as an adjunct for the treatment of segmental defect and allograft incorporation.

Allometric scaling of M-mode cardiac measurements in normal adult dogs.

Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r2 = .55-.88). Most variables were most closely related to an index of body length, BW(1/3), although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.

Isolation of Bartonella washoensis from a dog with mitral valve endocarditis.

We report the first documented case of Bartonella washoensis bacteremia in a dog with mitral valve endocarditis. B. washoensis was isolated in 1995 from a human patient with cardiac disease. The main reservoir species appears to be ground squirrels (Spermophilus beecheyi) in the western United States. Based on echocardiographic findings, a diagnosis of infective vegetative valvular mitral endocarditis was made in a spayed 12-year-old female Doberman pinscher. A year prior to presentation, the referring veterinarian had detected a heart murmur, which led to progressive dyspnea and a diagnosis of congestive heart failure the week before examination. One month after initial presentation, symptoms worsened. An emergency therapy for congestive heart failure was unsuccessfully implemented, and necropsy evaluation of the dog was not permitted. Indirect immunofluorescence tests showed that the dog was strongly seropositive (titer of 1:4,096) for several Bartonella antigens (B. vinsonii subsp. berkhoffii, B. clarridgeiae, and B. henselae), highly suggestive of Bartonella endocarditis. Standard aerobic and aerobic-anaerobic cultures were negative. However, a specific blood culture for Bartonella isolation grew a fastidious, gram-negative organism 7 days after being plated. Phenotypic and genotypic characterizations of the isolate, including partial sequencing of the citrate synthase (gltA), groEL, and 16S rRNA genes, indicated that this organism was identical to B. washoensis. The dog was seronegative for all tick-borne pathogens tested (Anaplasma phagocytophilum, Ehrlichia canis, and Rickettsia rickettsii), but the sample was highly positive for B. washoensis (titer of 1:8,192) and, according to indirect immunofluorescent-antibody assay, weakly positive for phase II Coxiella burnetii infection.

Fatal case of endocarditis associated with Bartonella henselae type I infection in a domestic cat.

We report the first feline case of Bartonella henselae endocarditis. Despite negative blood cultures, the cat had high Bartonella antibody titers and B. henselae type I DNA was detected in the damaged aortic valve. Microscopic examination of the valve revealed endocarditis with small silver positive coccoid structures in endothelial cells.