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Tendon injuries positively correlate with patient age, as aging has significant effects on tendon homeostatic maintenance and healing potential after injury. Vascularity is also influenced by age, with both clinical and animal studies demonstrating reduced blood flow in aged tissues. However, it is unknown how aging effects vascularity following tendon injury, and if this vascular response can be modulated through the delivery of angiogenic factors. Therefore, the objective of this study is to evaluate the vascular response following Achilles tendon injury in adult and aged rats, and to define the alterations to tendon healing in an aged model following injection of angiogenic factors. It was determined that aged rat Achilles tendons have a reduced angiogenesis following injury. Further, the delivery of vascular endothelial growth factor, VEGF, caused an increase in vascular response to tendon injury and improved mechanical outcome in this aged population. This work suggests that reduced angiogenic potential with aging may be contributing to impaired tendon healing response and that the delivery of angiogenic factors can rescue this impaired response. This study was also the first to relate changes in vascular response in an aged model using in vivo measures of blood perfusion to alterations in healing properties.

Overuse-induced tendinopathy is highly prevalent in the general population. Percutaneous fenestration, or dry needling, techniques have been increasing in popularity, but despite their current use, there are no controlled laboratory studies to provide fundamental support for this practice. The objective of this study was to establish a model for percutaneous needling of the rat supraspinatus tendon using ultrasound guidance and to evaluate the biological response of needling healthy tendon. A total of 44 male Sprague-Dawley rats (477 ± 39 g) were used to evaluate the effect of dry needling on healthy supraspinatus tendon properties. Ten rats were reserved as un-needled control animals, and the remaining animals underwent either mild or moderate bilateral needling protocols and were sacrificed at 1 or 6 weeks post-needling (n = 8-10/group). Color Doppler ultrasound imaging was performed to analyze blood flow within the tendon. Histological and immunohistochemical analyses were used to determine cellular, inflammatory, and extracellular matrix properties of the tissue. Finally, quasi-static tensile mechanical analysis was performed to obtain viscoelastic, structural, and material properties to evaluate the tendon healing outcome. Data were tested for normality, and then two-way analysis of variance tests were performed followed by post hoc tests for multiple comparisons. Both the mild and moderate needling groups caused a transient healing response at early time points as shown by a statistically significant (p < 0.05) reduction in mechanical properties, and increase in blood flow, inflammation, and production of collagen III and glycosaminoglycans as compared to the control. Furthermore, mild needling properties returned to or exceeded pre-needling values at the 6-week time point. Clinical significance: Needling the rat supraspinatus tendon is a feasible technique that causes a transient healing response followed by a return to, or improvement of, normal tendon properties, indicating potential applicability in understanding the effects of current practices utilizing dry needling of tendons in humans. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2035-2042, 2019.

Purpose Primary hemi-arthroplasty is gaining rising attention to treat unstable intertrochanteric fractures in senile patients with severe osteoporosis. The objective of this study is to evaluate the early clinical and radiographic outcomes using bone conserving revision stem for unstable intertrochanteric fractures in senile osteoporotic population. Methods A retrospective observation of a series of 31 patients with unstable intertrochanteric fractures were conducted. The average age of the patients enrolled was 82.1 years and all patients underwent primary hemi-arthroplasty with the application of bone conserving and fully porous-coated revision stem. Clinical and radiographic evaluations during both the hospital-stay and follow-up were performed. Results The 31 patients were followed up for an average of 23 months postoperatively. The average operation time was 74.2 min while the mean intraoperative blood loss was 200.1 ml, with an average 11.1 g/L decrease of hemoglobulin after the procedure. The mean Harris hip score was 82.1 and visual analog scale was 1.7 at the latest follow-up. No intra-operative or postoperative peri-prosthetic fracture was noted. Postoperative complications included one thrombosis formation in posterior tibial vein and one congestive heart failure, both patients were discharged uneventfully after treatment. Twenty-one (21/31, 67.7%) patients regained their pre-injury walking activities. Radiographically, none of these hips had evident loosening of the stem or osteolysis. With follow-up period of 23 months, the mortality rate was 3.2% (1/31) with no revision required. Conclusion Primary hemi-arthroplasty with application of the bone conserving, cementless revision stem could serve as a reliable alternation in treatment of unstable intertrochanteric fractures in senile population with osteoporosis.

The study was conducted to define the biomechanical response of rat Achilles tendon after a single bout of exercise and a short or long duration of daily exercise. We hypothesized that a single bout or a short duration of exercise would cause a transient decrease in Achilles tendon mechanical properties and a long duration of daily exercise would improve these properties. One hundred and thirty-six Sprague-Dawley rats were divided into cage activity (CA) or exercise (EX) groups for a single bout, short-term, or long-term exercise. Animals in single bout EX groups were euthanized, 3, 12, 24, or 48 h upon completion of a single bout of exercise (10 m/min, 1 h) on a flat treadmill. Animals in short-term EX groups ran on a flat treadmill for 3 days, 1, or 2 weeks while animals in long-term EX groups ran for 8 weeks. Tendon quasi-static and viscoelastic response was evaluated for all Achilles tendons. A single bout of exercise increased tendon stiffness after 48 h of recovery. Short-term exercise up to 1 week decreased cross-sectional area, stiffness, modulus, and dynamic modulus of the Achilles tendon. In contrast, 8 weeks of daily exercise increased stiffness, modulus, and dynamic modulus of the tendon. This study highlights the response of Achilles tendons to single and sustained bouts of exercise. Adequate time intervals are important to allow for tendon adaptations when initiating a new training regimen and overall beneficial effects to the Achilles tendon.

The present study reported early clinical outcomes and perioperative precautions for medical staffs during joint arthroplasty procedures in SARS-CoV-2-infected patients.The medical records of 8 patients with SARS-CoV-2 infection who underwent joint arthroplasty from January 19 to September 24, 2020 were retrospectively reviewed and analyzed. Perioperative precautions and follow-up (time length varies from 6 month to 13 months, 11 months in average) for SARS-CoV-2 infection of medical staffs were reported.All patients recovered well from both the primary disease and SARS-CoV-2 infection. Significant improved Visual analogue scale was observed with no major complications or recurrence of the COVID-19 at discharge. There was no evidence indicating SARS-CoV-2 infection in any health providers.Elective joint arthroplasties for patients in recovery period of SARS-CoV-2 infection could be continued under comprehensive preoperative evaluation and appropriate medical protection. For patients with currently confirmed or highly suspected COVID-19, the operation should be carried out only if it was essential.

Background:Lesions of the long head of the biceps tendon are often associated with massive rotator cuff tears (MRCTs), and biceps tenotomy is frequently performed for pain relief and functional reservation. However, the efficacy and safety of biceps tenotomy regarding the effects on the surrounding tissues in chronic MRCT are unclear.Hypothesis:Biceps tenotomy would result in improved mechanical and histological properties of the intact subscapularis tendon and improved in vivo shoulder function while not compromising glenoid cartilage properties.Study Design:Controlled laboratory study.Methods:Right supraspinatus and infraspinatus tendons were detached in 25 male Sprague-Dawley rats, followed by 4 weeks of cage activity to create a chronic MRCT condition. Animals were randomly divided into 2 groups and received either biceps tenotomy (n = 11) or sham surgery (n = 14) and were sacrificed 4 weeks thereafter. Forelimb gait and ground-reaction forces were recorded 1 day before the tendon detachment (baseline), 1 day before the surgical intervention (biceps tenotomy or sham), and 3, 7, 10, 14, 21, and 28 days after the intervention to assess in vivo shoulder joint function. The subscapularis tendon and glenoid cartilage were randomly allocated for mechanical testing or histologic assessment after the sacrifice.Results:Compared with sham surgery, biceps tenotomy partially restored the in vivo shoulder joint function, with several gait and ground-reaction force parameters returning closer to preinjury baseline values at 4 weeks. With biceps tenotomy, mechanical properties of the subscapularis tendons were improved, while mechanical properties and histological Mankin scores of the glenoid cartilage were not diminished when compared with the sham group.Conclusion:Biceps tenotomy in the presence of chronic MRCT partially preserves overall shoulder function and potentially restores subscapularis tendon health without causing detrimental effects to joint cartilage. This laboratory study adds to the growing literature regarding the protective effects of biceps tenotomy on the shoulder joint in a chronic MRCT model.Clinical Relevance:This study provides important basic science evidence supporting the use of biceps tenotomy in patients with massive rotator cuff tears.

OBJECTIVE The purpose of this study was to present an initial surgical experience in the management of 1- or 2-level degenerative disc disease of the cervical spine using biodegradable anterior cervical plates (bACPs) in anterior cervical discectomy and fusion (ACDF). The authors also aimed to provide insight into this critical and controversial clinical issue by clarifying outcomes for patients receiving bACPs and by comparing their outcomes with those achieved using a traditional metallic anterior cervical plate (mACP) implant. METHODS A retrospective review was conducted for 2 series of patients who had undergone ACDF using either bACP (31 patients, 38 segments) or mACP (47 patients, 57 segments) instrumentation. The patients were followed up for a mean 13.5 ± 0.9 months (range 12–18 months) in the bACP group and 14.8 ± 1.5 months (range 14–22 months) in the mACP group. Clinical outcomes were determined according to scores on the visual analog scale (VAS), the modified Japanese Orthopaedic Association (mJOA) scoring system, and Odom's criteria. Radiological images were used to assess fusion rates, intervertebral height, Cobb's angle, and the width of prevertebral soft tissue. RESULTS Both VAS and mJOA scores were significantly improved at each follow-up in both groups. Excellent or good results according to Odom's criteria were achieved in 93.5% (29/31) of patients in the bACP group and 93.6% (44/47) of patients in the mACP group. At 6 months postoperatively, the fusion rate was 94.7% (36/38) in the bACP group and 96.5% (55/57) in the mACP group, but subsidence of the intervertebral space at the surgical level was more evident in the bACP group. Angulation, as measured by Cobb's angle, demonstrated obvious healing in both groups, while better maintenance was observed in the mACP group. The local inflammatory reaction was uneventful during follow-up. Dysphonia and dysphagia were observed in both groups during the follow-up. CONCLUSIONS The relatively comparable early clinical and radiographic outcomes and the overall acceptable complication rates for bACP and mACP use suggest that bACPs could be used as alternative instruments in ACDF. Mild graft resorption was noted without evidence of symptoms. However, the prospective efficacy of biodegradable instrumentation can only be elucidated with longer-term observation.