Isolated Complete Distal Biceps Femoris Tendon Tears: Case Series and Literature Review

The Biceps femoris is a vital component of the posterolateral corner of the knee. We report two cases of isolated rupture of the biceps femoris, discuss the possible mechanism of injury, and review the literature.

Serum Creatine Kinase Increases after Acute Strength Training in College Athletes with Menstrual Irregularities

Chronic menstrual dysfunction and low female sex hormones adversely affect muscular performance in women but studies in college athletes are scarce. A cohort of 18 Japanese, female college athletes at the University of Tsukuba, Japan, were recruited and studied over 3 weeks under 2 conditions. One group had normal menstrual cycling (CYC, 9 athletes) while the other had irregular cycles (DYS, 9 athletes). Hormones and creatine kinase (CK) were measured from blood under both rest (RE) and exercise (EX) conditions. Biceps femoris tendon stiffness was measured by myometry. No differences in age, height, weight, menarche age, or one-repetition maximum weight existed between the groups. The DYS group had persistently low levels of estrogen and progesterone. In the CYC group, the CK level significantly increased at each point immediately post-exercise and 24 h post-exercise compared to pre-exercise in Weeks 1 and 2, and significantly increased at 24 h post-exercise compared to pre-exercise status in Week 3. The DYS group was significantly different only between pre-exercise and 24 h post-exercise over all 3 weeks. The DYS group also suffered from higher biceps femoris tendon stiffness at 24 h post-exercise. Chronic menstrual irregularities in Japanese college athletes increase muscle damage markers in the bloodstream and muscle stiffness after acute strength training.

Risk factors for common peroneal nerve injury in knee dislocation: a retrospective study

Background Knee dislocation is a serious injury, representing less than 0.2% of all orthopedic injuries, and 16% to 40% of these patients suffer an associated injury to the common peroneal nerve (CPN). However, it is still unclear which structures are most intently associated with CPN injury. This study attempts to analyze the potential risk factors for CPN injury and provide clues for a comprehensive diagnosis of knee dislocation. Methods We retrospectively reviewed 153 cases of knee dislocation related to lateral and/or posterior ligament injury between 2015 and 2018. All 153 patients were divided into the CPN injury group or the no-CPN injury group. The baseline characteristics included age, gender, cause of injury, posterior cruciate ligament (PCL) disruption, anterior cruciate ligament (ACL) disruption, popliteofibular ligament and/or tendon of popliteus injury, biceps femoris tendon injury and fibular head fracture. We identified potential variables for a multivariable logistic regression model to identify the major risk factors for CPN injury. Results Multivariate regression analysis revealed the biceps femoris tendon injury and fibular head fracture to be predictive of CPN injury in knee dislocation. Gender, age, cause of injury, ligamentous classification, popliteofibular ligament and/or tendon of popliteus injury, PCL disruption or ACL disruption do not predict CPN injury. Conclusions Biceps femoris tendon injury and fibular head fracture are risk factors of CPN injury in knee dislocation. A better understanding of the risk factors for CPN injury allows surgeons to achieve more accurate diagnoses.

Arthroscopic Anatomy of the posterolateral structures of the knee

Objectives The purpose of this study was to describe an arthroscopic surgical approach to identify and expose the popliteus tendon (PT), posterior fibular head, Fibular collateral ligament (FCL), popliteal fibular ligament (PFL), biceps femoris tendon, and the peroneal nerve. Methods 10 fresh human cadaveric knees were examined arthroscopically using standard anterior and posterior portals. The use of a transeptal approach with both posteromedial and posterolateral portals was required using a standard 30 degrees arthroscope. Optimal portal placement and specific technique and sequence for appropriate visualization of the PLC structures were tested and documented. Results In all specimens, all the PLC structures that we attempted to identify were successfully visualized. These included the PT, posterior fibular head, the FCL, the PFL, biceps femoris tendon, peroneal nerve, PT and FCL femoral attachments. Conclusion This study demonstrated that the identification and exposure of the PLC structures using an all arthroscopic approach can be successfully performed with precise portal placement. This technique may serve as a basis for arthroscopic treatment of PLC injuries.

Ultrasound of the Knee

Chapter 124 discusses US scanning of the knee, which is commonly performed for assessment of superficial knee structures, such as the extensor mechanism tendons and collateral ligaments, as well as identification of Baker cysts or prepatellar bursae. Dynamic US evaluation, such as flexion/extension of the knee or varus/valgus stress maneuvers, may improve diagnostic performance and further characterize severity of tendon or ligamentous injury and ligament incompetence. US examination may be comprehensive or focused, with constant modification of patient and probe positioning to allow for optimal visualization of the knee structures. Common US artifacts, such as anisotropy of the extensor tendons or heterogeneous appearance of the distal joined attachment of the lateral collateral ligament proper and the distal biceps femoris tendon, should not be mistaken for pathology. Although parameniscal cysts can be readily identified by US, there is ongoing controversy regarding the role of US in evaluation of meniscal tears.

Diagnóstico y tratamiento de la entesopatía distal del bíceps crural en un corredor profesional (Diagnosis and treatment of distal biceps femoris tendon enthesopathy in a professional runner)

RESUMEN Objetivo: describir el diagnóstico y tratamiento de la entesopatía del tendón distal del bíceps crural en un corredor profesional. Método: el diagnóstico se obtuvo mediante datos clínicos y exploraciones complementarias. Describimos la técnica quirúrgica, el manejo post-operatorio y el sistema de valoración empleado en el seguimiento. Resultados: el diagnóstico se confirmó histológicamente. La recuperación funcional fue completa. Conclusión: solo hemos encontrado otro caso publicado de entesopatía del tendón distal del bíceps crural, sin referencia a afectación del nervio ciático poplíteo externo. Si el tratamiento conservador no resuelve la sintomatología, puede estar indicada la cirugía. ABSTRACT Objective: to describe the diagnostic and treatment strategies for distal biceps femoris tendon enthesopathy, in a professional runner. Method: The diagnosis was based on clinical and complementary studies. The surgical technique, postoperative management and assessment, are described. Results: Histological study confirmed the diagnosis and the clinical outcome was satisfactory, with complete recovery after surgical management. Conclusion: there is only one published study assessing distal biceps femoris tendon enthesopathy. The possible involvement of the peroneal nerve has not been previously considered. If conservative treatment only provides temporary relief of symptoms, then surgery can be indicated. RESUMO Objetivo: descrever o diagnóstico e tratamento da entesopatia do tendão crural do bíceps distal em um corredor profissional. Método: o diagnóstico foi obtido por meio de dados clínicos e explorações complementares. Descrevemos a técnica cirúrgica, o manejo pós-operatório e o sistema de avaliação utilizado no acompanhamento. Resultados: o diagnóstico foi confirmado histologicamente. A recuperação funcional foi completa. Conclusão: encontramos apenas outro caso publicado de entesopatia do tendão distal do bíceps crural, sem referência ao envolvimento do nervo ciático poplíteo externo. Se o tratamento conservador não resolver os sintomas, a cirurgia pode ser indicada.