Impacts of external rotators and the ischiofemoral ligament on preventing excessive internal hip rotation: a cadaveric study

Background This study examined the biomechanics of preventing excessive internal hip joint rotation related to the hip flexion angle. Method An intramedullary nail with a circular plate equipped with a protractor was installed in the femur of nine normal hips. The circular plate was pulled by 3.15 Nm of force in the internal rotation direction. The external rotators were individually resected, finally cutting the ischiofemoral ligament. The cutting order of the external rotators differed on each side to individually determine the internal rotation resistance. The external rotators were resected from the piriformis to the obturator externus in the right hips and the reverse order in the left hips. Traction was performed after excising each muscle and ischiofemoral ligament. Measurements were taken at 0°, 30°, and 60° of hip flexion, and the differences from baseline were calculated. Results For the right hip measurements, the piriformis and ischiofemoral ligament resection significantly differed at 0° of flexion (p = 0.02), each external rotator and the ischiofemoral ligament resections significantly differed at 30° of flexion (p < 0.01), and the ischiofemoral ligament and piriformis and inferior gemellus resections significantly differed at 60° of flexion (p = 0.04 and p = 0.02, respectively). In the left hips, the ischiofemoral ligament and obturator externus, inferior gemellus, and obturator internus resections significantly differed at 0° of flexion (p < 0.01, p < 0.01, and p = 0.01, respectively), as did each external rotator and the ischiofemoral ligament resections at 30° of flexion (p < 0.01). Conclusion The ischiofemoral ligament primarily restricted the internal rotation of the hip joint. The piriformis and obturator internus may restrict internal rotation at 0° and 60° of flexion.

Obturator internus and externus muscle abscess caused by methicillin-resistant Staphylococcus aureus in a 6-year-old boy: A case report

Obturator abscess is a rare condition in children which usually occurs commonly in tropical countries. Because of its rarity, vague symptomatology and a lack of focus about this condition, the diagnosis of obturator abscess is commonly delayed or missed. Hence, physicians should be familiar with this condition and have a high index of suspicion when a patient presents with fever, pain in the thigh, hip or abdomen and a limp on the affected side which are considered as the classic clinical triad of obturator abscess. Herein, we present a 6-year-old previously healthy Russian boy who was on holiday in Sri Lanka. He presented on the third day of the fever associated with pain in the right thigh and abdomen. This is the first reported case of an obturator externus muscle abscess due to methicillin-resistant Staphylococcus aureus in a European boy visiting a tropical country.

Preventing postoperative prosthetic joint dislocation by repairing obturator externus in total hip arthroplasty performed via the posterior approach

Background In total hip arthroplasty performed via the posterior approach, repairing the posterior soft tissues is a conventional method for preventing postoperative prosthetic joint dislocation. The aim of this study was to verify whether obturator externus repair played the main role and what was the mechanism of the repair preventing the dislocation. Methods Included were 188 patients who underwent primary cementless total hip arthroplasty via the posterior approach. The patients were divided into a repair group (n = 94) and a non-repair group (n = 94). Patients of repair group received additional obturator externus repair while patients of non-repair group did not. The range of motion of hip joint was assessed before and after operation. Data were compared between the two groups. A p value < 0.05 was considered statistically significant. Results Before operation and under anesthesia, with regard to internal rotation of hip joint, the mean values of repair and non-repair groups were 24° ± 16/28° ± 15 (p = 0.2933). The mean values of the groups were 13° ± 8/15° ± 9 immediately after repair (p = 0.5672). Range of internal rotation 1 year after operation were 15° ± 8/19° ± 9 (p = 0.0139). Specifically, the values in repair group were lower than those in non-repair group. During a 5-year period of postoperative follow-up, hip joint dislocation occurred in one patient of non-repair group. No dislocation was observed in repair group. Conclusion When THA is performed via the posterior approach, repairing the obturator externus may decrease the risk of postoperative prosthetic joint dislocation by reinforcing the posterior soft tissues of the hip joint. Level of evidence Therapeutic study, Level IVa.

Contact-Related Strain of Quadratus Femoris, Obturator Externus, and Inferior Gemellus in an Australian Football Player: A Case Report

Context: Muscle injuries of the hip stabilizers are considered rare in sport. Objective: This report presents a previously unreported case of a contact injury resulting in acute strain of quadratus femoris, obturator externus, and inferior gemellus in an amateur Australian rules football player. Design: Level 4—case report. Case Presentation: A player was tackled ipsilateral to the injured leg, while in hip flexion in a lunged position. The case describes the diagnostic process, initial management, and return to play for this athlete. Results: Following rehabilitation, the player was able to return to sport at 8 weeks without ongoing issues. Conclusions: A literature search for sports-related contact injuries to either muscle returned only one result. All other documented cases of injury to these muscle groups are confined to noncontact mechanisms or delayed presentations. Despite conventional teaching, the action of the deep external rotators of the hip appears to be positionally dependent. Knowledge of this type of injury and mechanism may be useful for future clinical reasoning and differential diagnosis in patients with this type of presentation.

Pyomyositis: A Complicated and Curious Case Report

Introduction: In the elderly (over the age of 50), the risk of urinary tract infections is estimated at 8% per year in men. Anatomic abnormalities such as prostatic hypertrophy, leading to urinary retention is considered as the main reason. Pyomyositis is an uncommon condition of optical urethrotomy, especially in patients who have received local radiation therapy in the past. Till date no cases of pectineus muscle abscess and only two cases of obturator externus muscle abscess have been reported in the literature, with only one developing as a result of genitourinary intervention such as urethrotomy. Case presentation: Here we are presenting a case of a very unusual and serious complication in an elderly man presenting with urosepsis several months after undergoing urethrotomy. Conclusion: Elderly men have an increased risk of sepsis, higher than that in women with UTI.

Muscle Spindle Density of Lateral Rotators of the Thigh in Japanese Macaques and a Gibbon

We examined the six small lateral rotators of the hip joint, which is one of the most flexible joints and allows kinematically complex motions of the hindlimb, to elucidate the functional differentiation among these muscles and to test the hypothesis that species-specific characteristics in hindlimb use during locomotion are reflected in the muscle spindle density and in other parameters of the deep small hip joint rotators. For these purposes, we estimated the number of muscle spindles of the superior gemellus muscle (SG), inferior gemellus muscle, quadratus femoris muscle, obturator internus muscle (OI), obturator externus muscle, and piriformis muscle in three Japanese macaques and a gibbon, using 30-µm-thick serial sections throughout each muscle length after azan staining. The numbers of muscle spindles per 10,000 muscle fibers were determined to compare inter-muscle variation. The spindle density was highest in the SG and lowest in the OI in the Japanese macaques, suggesting that the SG, which is attached to the tendon of the OI, functions as a kinesiological monitor of the OI. On the other hand, SG the was missing in the gibbon, and the OI in the gibbon contained more spindles than that in the Japanese macaques. This suggests that the SG and the OI fused into one muscle in the gibbon. We postulate that the relative importance of the deep small hip rotator muscles differs between the Japanese macaques and gibbon and that the gibbon’s muscles are less differentiated in terms of the spindle density, probably because this brachiating species uses its hindlimbs less frequently.