Contributions of the Abductor Muscles to Rotational and Distractive Stability of the Hip in a Biomechanical Cadaveric Model.

Background: The gluteus minimus (GMin) and gluteus medius (GMed) are important dynamic stabilizers of the hip, but quantitative data on their biomechanical roles in stabilizing the hip are currently lacking. Purpose: To (1) establish a reproducible biomechanical cadaveric model of the hip abductor complex and (2) characterize the effects of loading the GMin and GMed on extraneous femoral rotation and distraction. Study Design: Controlled laboratory study. Methods: A total of 10 hemipelvises were tested in 4 muscle loading states: (1) unloaded, (2) the GMin loaded, (3) the GMed loaded, and (4) both the GMin and GMed loaded. Muscle loads were applied via cables, pulleys, and weights attached to the tendons to replicate the anatomic lines of action. Specimens were tested under internal rotation; external rotation; and axial traction forces at 0°, 15°, 30°, 60°, and 90° of hip flexion. Results: When loaded together, the GMin and GMed reduced internal rotation motion at all hip flexion angles (P < .05) except 60° and reduced external rotation motion at all hip flexion angles (P < .05) except 0°. Likewise, when both the GMin and GMed were loaded, femoral distraction was decreased at all angles of hip flexion (P < .05). Conclusion: The results of this study demonstrated that the GMin and GMed provide stability against rotational torques and distractive forces and that the amount of contribution depends on the degree of hip flexion. Clinical Relevance: Improved understanding of the roles of the GMin and GMed in preventing rotational and distractive instability of the hip will better guide treatment of hip pathologies and optimize nonoperative and operative therapies.

Interobserver reliability of biplanar radiography is unaffected by clinical factors relevant to individuals at risk of pathological lower limb torsion.

BACKGROUND: Assessments of lower limb torsion are ubiquitous in clinical gait analysis practice as pathologic lower limb rotational deformity may contribute to gait abnormalities, anterior knee pain, as well as other debilitating conditions. Understandably, the overall utility of any torsional assessment is dependent on the measurement method's intrinsic accuracy, precision, and robustness to clinical interference factors. Recently, biplanar radiography (BPR) measurements of torsion have been shown to be both accurate and precise, but the robustness of BPR to potential interference factors is unknown. RESEARCH QUESTION: How robust are BPR lower limb torsional assessments to six potential interference factors: amount of torsion, skeletal maturity, radiograph quality, prior osteotomy, presence of implants, and observer training background and experience? METHODS: In this retrospective cohort study, four observers of diverse backgrounds and experience generated digital 3D reconstructions of 44 lower limbs using BPR images obtained during standard of care visits (age range 7-35 years). From each reconstruction, four lower limb torsional parameters were computed: femoral torsion, femorotibial rotation, tibial torsion, and transmalleolar axis equivalent. The mean absolute deviation (MAD) of each torsional parameter - calculated across the four observers - was used as the measure of reliability and tested against all interference factors. RESULTS: Results demonstrated that the average MAD was 2.1 degrees for femoral torsion, 3.0 degrees for transmalleolar axis equivalent, 3.8 degrees for femorotibial rotation, and 4.7 degrees for tibial torsion. None of the six potential interference factors were found to systematically influence BPR reliability across all four torsional parameters. Of the factors found to statistically influence one or more torsional parameter, none affected MAD values to a clinically meaningful extent. SIGNIFICANCE: In addition to being accurate and precise, BPR appears to be robust to several clinical factors relevant to children and young adults with or at risk for pathological lower limb torsion.

Osteochondritis Dissecans of the Knee in Young Athletes.

Osteochondritis dissecans of the knee is a relatively rare disorder in young athletes that can lead to premature osteoarthritis. It may be caused by multiple factors, including repetitive stress, local ischemia, aberrant endochondral ossification of the subarticular physis, and hereditary disposition. Nonoperative treatment is typically attempted for patients with open physes, stable lesions, and minimal symptoms. Operative treatment is offered to patients with closed physes, unstable lesions, mechanical symptoms, and failure of nonoperative treatment. Customized rehabilitation and return to sport programs are important for successful outcomes regardless of treatment type.

Osteochondritis Dissecans: Current Understanding of Epidemiology, Etiology, Management, and Outcomes.

➤: Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis. ➤: While generally considered an idiopathic phenomenon, various etiopathogenetic theories are being investigated, including local ischemia, aberrant endochondral ossification of the secondary subarticular physis, repetitive microtrauma, and genetic predisposition. ➤: Diagnosis is based on the history, physical examination, radiography, and advanced imaging, with elbow ultrasonography and novel magnetic resonance imaging protocols potentially enabling early detection and in-depth staging. ➤: Treatment largely depends on skeletal maturity and lesion stability, defined by the presence or absence of articular cartilage fracture and subchondral bone separation, as determined by imaging and arthroscopy, and is typically nonoperative for stable lesions in skeletally immature patients and operative for those who have had failure of conservative management or have unstable lesions. ➤: Clinical practice guidelines have been limited by a paucity of high-level evidence, but a multicenter effort is ongoing to develop accurate and reliable classification systems and multimodal decision-making algorithms with prognostic value.

Open Supracondylar Humerus Fractures in Children.

PURPOSE: Supracondylar humerus (SCH) fractures are the most common elbow fracture in children; however, they rarely occur as open injuries. Open fractures are associated with higher rates of infection, neurovascular injury, compartment syndrome, and nonunion. The purpose of this study was to evaluate the treatment and outcomes of open SCH fractures in children. METHODS: Between 2008 and 2015, four children (1%) had open injuries among 420 treated for SCH fractures at a single center. The mean patient age was six years (range, four to eight years). Two patients had Gustilo-Anderson grade 1 open fractures and two had grade 2 fractures. Tetanus immunization was up-to-date in all. First dose of intravenous antibiotics was given on average 3hr 7min after onset of injury (range, 1hr 38min to 8hr 15min). Time from injury to irrigation and debridement (I&D) and closed reduction and percutaneous pinning (CRPP) was on average 8hr 16min (range, 4hr 19min to 13hr 15min). All patients received 24-hour intravenous antibiotics. Pins were removed at four weeks and bony union occurred by six weeks. RESULTS: After an average follow-up period of 12 months (range, 6 to 22 months), there were no infections, neurovascular deficits, compartment syndromes, cubitus varus deformities, or range of motion losses. All outcomes were excellent according to the Flynn criteria. Due to the unstable nature of open SCH fractures, a medial pin was used in all four cases. No loss of reduction or ulnar nerve injury occurred. CONCLUSION:  Open injuries occur in approximately 1% of all SCH fractures in children. The authors recommend urgent intravenous antibiotics, I&D, and CRPP involving a medial pin to treat open SCH fractures. Excellent outcomes based on the Flynn criteria were obtained in four cases.

The Vacuum-Assisted Closure Device Increases Value in the Treatment of Gustilo Grade IIIb Open Tibia Fractures in Children.

Background Wound management associated with Gustilo grade IIIb open tibia fractures in children often requires muscle flaps, skin grafts, and amputations. The purpose of this study is to report the outcomes and complications of vacuum-assisted closure (VAC) treatment, as well as discuss its role in optimizing value when treating these injuries. Methods A retrospective review of medical records and imaging studies was performed from 2008-2015. Six pediatric patients with Gustilo grade IIIb fractures managed with the VAC were identified. The time to treatment, frequency of VAC changes, VAC size, and closure attempts, including muscle flaps and skin grafts, were documented. Fracture fixation methods, the incidence of delayed union or nonunion, as well as the occurrence of deep tissue infection and compartment syndrome were detailed. Results Five patients were male and one was female with an average age of 12 years (range 8-15 years). All patients sustained a Gustilo IIIb open tibia fracture and were treated with irrigation, debridement, intravenous (IV) antibiotics, fixation, and a VAC as a wound care adjunct. Three patients required both a muscle flap and a skin graft. One patient required a skin graft. There was one case of deep tissue infection. Three patients were treated successfully with the VAC alone and did not require any flap procedures. Conclusions Wound care for Gustilo grade IIIb open tibia fractures in children traditionally involved potentially painful twice-daily dressing changes with solutions such as dilute bleach or iodine. The implementation of VAC markedly reduced the frequency of dressing changes every three days. In the current study, the open wound gradually closed with only a VAC in 50% of Gustilo grade IIIb open pediatric tibia fractures. In summary, the VAC is an adjunct that increases value in the care of pediatric patients with Gustilo grade IIIb open tibia fractures (Value = Outcomes/Cost). Level of evidence Therapeutic level IV.

Traumatic Glenosphere Dissociation Following Reverse Total Shoulder Endoprosthetic Reconstruction for Proximal Humerus Periosteal Chondrosarcoma: A Case Report.

INTRODUCTION: Reverse total shoulder endoprosthetic reconstruction after margin-negative tumor resection of the proximal humerus is becoming more conventional in orthopeadic oncology practices. Mid-term survival and functional outcomes have been satisfactory. This case report corroborates with current literature and further describes a rare traumatic complication. CASE PRESENTATION: We report a case of a 70-year-old male with periosteal chondrosarcoma of the proximal humerus who underwent margin-negative resection and reverse total shoulder endoprosthetic reconstruction that was complicated by glenosphere dissociation sustained from falling onto a hyperflexed arm. Successful revision arthroplasty was performed. CONCLUSION: Enhancing glenohumeral joint stability after wide resection of the proximal humerus is important to address rotator cuff insufficiency. The greater levering effect of a longer humeral prosthesis used to increase soft tissue tension may also increase the risk of glenosphere dissociation secondary to trauma. Proper soft-tissue tensioning and surgical technique are critical.