Anterior hip or groin pain is a common complaint for which people are referred for physical therapy, with the hip region being involved in approximately 5% to 9% of injuries in high school athletes.1 Although anterior hip pain is known to result from a number of musculoskeletal and systemic pathologies, a tear of the acetabular labrum is a recent addition to the list that is of particular interest to physical therapists. This mechanically induced pathology is thought to result from excessive forces at the hip joint2,3 and has been proposed as part of a continuum of hip joint disease that may result in articular cartilage degeneration.2 Although the number of recent articles in the orthopedic literature identifying acetabular labral tears as a source of hip pain is increasing, labral tears often evade detection, resulting in a long duration of symptoms, greater than 2 years on average, before diagnosis.4–8 Studies have shown that 22% of athletes with groin pain9 and 55% of patients with mechanical hip pain of unknown etiology2 were found to have a labral tear upon further evaluation. In order to provide the most appropriate intervention for patients with anterior hip or groin pain, physical therapists should be knowledgeable about all of the possible sources and causes of this pain, including a tear of the acetabular labrum and the possible factors contributing to these tears. Therefore, the purpose of this article is to review the anatomy and function of the acetabular labrum and present current concepts on the etiology, clinical characteristics, diagnosis, and treatment of labral tears.

A large portion of the mechanical work required for walking comes from muscles and tendons crossing the ankle joint. By storing and releasing elastic energy in the Achilles tendon during each step, humans greatly enhance the efficiency of ankle joint work far beyond what is possible for work performed at the knee and hip joints. Summary Humans produce mechanical work at the ankle joint during walking with an efficiency two to six times greater than isolated muscle efficiency.

To guide development of robotic lower limb exoskeletons, it is necessary to understand how humans adapt to powered assistance. The purposes of this study were to quantify joint moments while healthy subjects adapted to a robotic ankle exoskeleton and to determine if the period of motor adaptation is dependent on the magnitude of robotic assistance. The pneumatically-powered ankle exoskeleton provided plantar flexor torque controlled by the wearer's soleus electromyography (EMG). Eleven naïve individuals completed two 30-min sessions walking on a split-belt instrumented treadmill at 1.25 m/s while wearing the ankle exoskeleton. After two sessions of practice, subjects reduced their soleus EMG activation by ~36% and walked with total ankle moment patterns similar to their unassisted gait (r 2 = 0.98±0.02, THSD, p>0.05). They had substantially different ankle kinematic patterns compared to their unassisted gait (r 2 = 0.79±0.12, THSD, p<0.05). Not all of the subjects reached a steady state gait pattern within the two sessions, in contrast to a previous study using a weaker robotic ankle exoskeleton . Our results strongly suggest that humans aim for similar joint moment patterns when walking with robotic assistance rather than similar kinematic patterns. In addition, greater robotic assistance provided during initial use results in a longer adaptation process than lesser robotic assistance.

No abstract

In a simple bipedal walking model, an impulsive push along the trailing limb (similar to ankle plantar flexion) or a torque at the hip can power level walking. This suggests a tradeoff between ankle and hip muscle requirements during human gait. People with anterior hip pain may benefit from walking with increased ankle pushoff if it reduces hip muscle forces. The purpose of our study was to determine if simple instructions to alter ankle pushoff can modify gait dynamics and if resulting changes in ankle pushoff have an effect on hip muscle requirements during gait. We hypothesized that changes in ankle kinetics would be inversely related to hip muscle kinetics. Ten healthy subjects walked on a custom split-belt force-measuring treadmill at 1.25 m/s. We recorded ground reaction forces and lower extremity kinematic data to calculate joint angles and internal muscle moments, powers and angular impulses. Subjects walked under three conditions: Natural Pushoff, Decreased Pushoff and Increased Pushoff. For the Decreased Pushoff condition, subjects were instructed to push less with their feet as they walked. Conversely, for the Increased Pushoff condition, subjects were instructed to push more with their feet. As predicted, walking with increased ankle pushoff resulted in lower peak hip flexion moment, power, and angular impulse as well as lower peak hip extension moment and angular impulse (p<0.05). Our results emphasize the interchange between hip and ankle kinetics in human walking and suggest that increased ankle pushoff during gait may help compensate for hip muscle weakness or injury and reduce hip joint forces.

Abnormal or excessive force on the anterior hip joint may cause anterior hip pain, subtle hip instability and a tear of the acetabular labrum. We propose that both the pattern of muscle force and hip joint position can affect the magnitude of anterior joint force and thus possibly lead to excessive force and injury. The purpose of this study was to determine the effect of hip joint position and of weakness of the gluteal and iliopsoas muscles on anterior hip joint force. We used a musculoskeletal model to estimate hip joint forces during simulated prone hip extension and supine hip flexion under four different muscle force conditions and across a range of hip extension and flexion positions. Weakness of specified muscles was simulated by decreasing the modeled maximum force value for the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion. We found that decreased force contribution from the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion resulted in an increase in the anterior hip joint force. The anterior hip joint force was greater when the hip was in extension than when the hip was in flexion. Further studies are warranted to determine if increased utilization of the gluteal muscles during hip extension and of the iliopsoas muscle during hip flexion, and avoidance of hip extension beyond neutral would be beneficial for people with anterior hip pain, subtle hip instability, or an anterior acetabular labral tear.

Context:Snapping hip, or coxa saltans, is a vague term used to describe palpable or auditory snapping with hip movements. As increasing attention is paid to intra-articular hip pathologies such as acetabular labral tears, it is important to be able to identify and understand the extra-articular causes of snapping hip.Evidence Acquisition:The search terms snapping hip and coxa sultans were used in PubMed to locate suitable studies of any publication date (ending date, November 2008).Results:Extra-articular snapping may be caused laterally by the iliotibial band or anteriorly by the iliopsoas tendon. Snapping of the iliopsoas tendon usually requires contraction of the hip flexors and may be difficult to differentiate from intra-articular causes of snapping. Dynamic ultrasound can help detect abrupt tendon translation during movement, noninvasively supporting the diagnosis of extra-articular snapping hip. The majority of cases of snapping hip resolve with conservative treatment, which includes avoidance of aggravating activities, stretching, and anti-inflammatory medication. In recalcitrant cases, surgery to lengthen the iliotibial band or the iliopsoas tendon has produced symptom relief but may result in prolonged weakness.Conclusions:In treating active patients with snapping soft tissues around the hip, clinicians should recognize that the majority of cases resolve without surgical intervention, while being mindful of the potential for concomitant intra-articular and internal snapping hips.

There is no agreement on how to classify, define or diagnose hip-related pain—a common cause of hip and groin pain in young and middle-aged active adults. This complicates the work of clinicians and researchers. The International Hip-related Pain Research Network consensus group met in November 2018 in Zurich aiming to make recommendations on how to classify, define and diagnose hip disease in young and middle-aged active adults with hip-related pain as the main symptom. Prior to the meeting we performed a scoping review of electronic databases in June 2018 to determine the definition, epidemiology and diagnosis of hip conditions in young and middle-aged active adults presenting with hip-related pain. We developed and presented evidence-based statements for these to a panel of 37 experts for discussion and consensus agreement. Both non-musculoskeletal and serious hip pathological conditions (eg, tumours, infections, stress fractures, slipped capital femoral epiphysis), as well as competing musculoskeletal conditions (eg, lumbar spine) should be excluded when diagnosing hip-related pain in young and middle-aged active adults. The most common hip conditions in young and middle-aged active adults presenting with hip-related pain are: (1) femoroacetabular impingement (FAI) syndrome, (2) acetabular dysplasia and/or hip instability and (3) other conditions without a distinct osseous morphology (labral, chondral and/or ligamentum teres conditions), and that these terms are used in research and clinical practice. Clinical examination and diagnostic imaging have limited diagnostic utility; a comprehensive approach is therefore essential. A negative flexion–adduction–internal rotation test helps rule out hip-related pain although its clinical utility is limited. Anteroposterior pelvis and lateral femoral head–neck radiographs are the initial diagnostic imaging of choice—advanced imaging should be performed only when requiring additional detail of bony or soft-tissue morphology (eg, for definitive diagnosis, research setting or when planning surgery). We recommend clear, detailed and consistent methodology of bony morphology outcome measures (definition, measurement and statistical reporting) in research. Future research on conditions with hip-related pain as the main symptom should include high-quality prospective studies on aetiology and prognosis. The most common hip conditions in active adults presenting with hip-related pain are: (1) FAI syndrome, (2) acetabular dysplasia and/or hip instability and (3) other conditions without distinct osseous morphology including labral, chondral and/or ligamentum teres conditions. The last category should not be confused with the incidental imaging findings of labral, chondral and/or ligamentum teres pathology in asymptomatic people. Future research should refine our current recommendations by determining the clinical utility of clinical examination and diagnostic imaging in prospective studies.