Practice Essentials
Hip overuse injuries such as tendinitis and bursitis occur commonly in active individuals who participate in running, cycling, and cutting sports such as football, hockey, soccer, etc. [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] These injuries can occur after an acute injury, such as an adductor strain from soccer, or present as a chronic pain, such as a hamstring tendinopathy from repetitive activities such as running. Training errors, biomechanical issues, and sudden increases in activity levels are also risk factors. In the adolescent age group, traction injuries such as avulsion fracture and apophysitis can occur and cause difficulties with training and performance. [11, 12]
The investigation into the cause and treatment of hip overuse injuries can often be frustrating for clinicians and patients alike. Many musculoskeletal injuries can cause referred pain into the hip area, but so can intra-abdominal, gynecologic, urologic, and spinal disorders. [1, 3, 4, 5, 6, 7, 8, 13]
Etiology
Rectus Femoris/Quadriceps
The rectus femoris originates at the ASIS (direct head) and AIIS (nondirect head) and crosses the hip and knee joint, making it the only quadriceps muscle to do so. It functions as a hip flexor and knee extender, and it receives innervation from the femoral nerve (L2-L4).
Strains of the rectus, which usually occur in the middle third of the thigh, may result in complete ruptures of the muscle belly, presenting as an acute enlargement of the affected thigh or a pseudotumorous growth. These deformities are out of proportion to their significance, however, because even complete ruptures of the rectus femoris result in little or no functional disability. The site of the strain is often tender to palpation and may be ecchymotic. An obvious defect can be palpated at times.
Chronic proximal rectus femoris or quadriceps pain can occur with apophysitis in the skeletally immature patient. Continued activity will weaken the growth plate, putting this area at risk for an avulsion after an acute stress of the muscle-tendon unit. This injury is accompanied by a pop or snap, with immediate pain and disability.
Iliopsoas Bursitis/Tendinitis
The iliopsoas is the primary hip flexor, and it is also an external hip rotator. [6, 14, 15] This muscle is a combination of the psoas major muscle (originating at the lateral surface of the T12-L4 vertebral bodies) and the iliacus muscle (iliac fossa origin) below the inguinal ligament which insert on the lesser trochanter of the femur. The iliopsoas muscle receives its innervations from the femoral nerve and lumbar plexus (L1-L3). The trochanteric bursa lies beneath the muscle and is the largest synovial bursa in humans. This bursa can be from 5-7 cm x 2-4 cm in size and can communicate directly with the hip joint. Pain from the bursa or tendon is usually caused by an overuse injury, acute trauma, or rheumatoid arthritis.
The mechanism of injury for an acute iliopsoas trauma is usually a sudden hyperextension, which is commonly seen in athletes who are involved in rowing, uphill running, track and field, and strength training. This type of injury is usually seen in young adults and is more common in women. Patients present with pain over the anterior thigh with a palpable and/or audible snap. A shortened stride on the affected side may be present, and this is usually due to guarding against hyperextension of the hip.
Chronic anterior hip pain may result from iliopsoas or rectus femoris tendinitis. An audible or palpable snap may be felt with flexion or extension of the hip. As in all tendinitis and tendinosis, this is a result of repetitious weight-bearing activities, such as running and jumping. These conditions will often occur after abrupt changes in levels of activity, such as during preseason training or when an individual is first training for a race. Because tendinosis is a degenerative process, less obvious changes in activity can lead to symptoms in older patients and will have a more insidious onset.
The symptoms of pain and tightness will initially start after an activity but will progress to occur during the workout over time. Eventually, the individuals will stop the workouts because of the pain, and their activities of daily living may be affected.
The patient will complain of anterior hip and groin pain that is worsened with extension of the hip or active flexion of the hip or active extension of the knee against resistance. Getting out of a car or walking up the steps will lead to increased pain.
A palpable mass may also be noted under the inguinal ligament, at which time a consideration of aspiration or a steroid injection may be considered if ultrasound guidance is available.
Gluteus Medius Syndrome and Trochanteric Bursitis
The gluteus medius functions as a primary hip abductor. [1, 8, 16, 17] It originates at the external surface of the ilium and inserts onto the posterior lateral surface of the greater trochanter. This muscle is innervated by the superior gluteal nerve (L4-S1).
The greater trochanteric bursa lies directly lateral to the greater trochanter. This lateral growth of the femur abuts the tensor fasciae latae and lateral quadriceps muscles. The bursa provides lubrication and cushioning to allow the muscles to flex and extend over the trochanter without damaging the muscles. It also cushions the tendon before the attachment of the gluteus medius and minimus. Bursitis in this area can be secondary to changes in activity or training, biomechanical problems lower down the leg, or from direct trauma. These conditions lead to increased pressure of the muscles against the bursa and trochanter—with resultant inflammation.
Pain will occur with hip flexion such as walking, climbing stairs, or getting out of a car or a chair. Nocturnal pain while lying on the affected side is common. A snap is occasionally felt or heard in the lateral hip with flexion or extension.
Gluteus medius syndrome involves tenderness to palpation of the gluteus medius muscle, which can be triggered by sudden falls, prolonged weight bearing on one extremity for long periods, activity overuse, or sporting injuries. Most commonly, this situation is observed in middle-aged women who have embarked upon a vigorous walking program or who have started working out at a health club. Patients may present with pain that is transient and worsening over a time period, a Trendelenburg gait, and weakness. These symptoms specifically affect runners, as there is tilting of the pelvis with running. It is important for the clinician to examine the patient for a leg-length discrepancy.
Hip-abduction strengthening should be avoided in the initial stages of gluteus medius syndrome because it only provokes tendinitis. As the acute stage resolves, hip-abductor strengthening is important and is best achieved in the aquatic environment.
It can be difficult to distinguish between trochanteric bursitis and gluteus medius tendinitis due to their proximity at the insertion site. Resistance to abduction or internal rotation of the hip may help distinguish these 2 entities, as trochanteric bursitis will not elicit pain with resisted hip abduction, and gluteus medius tendinitis will present with more posterior tenderness to palpation at the insertion site. Diagnostic ultrasound can be performed to determine if fluid is present in the bursa or to look for echogenic changes that are consistent with tendinopathy. Ultrasound-guided injections into the greater trochanteric bursa will be more effective if fluid and distention of the bursa can be demonstrated. [18, 19]
Long et al conducted a study to test the hypothesis that sonographic evaluation of sources for greater trochanteric pain syndrome would show that bursitis was not the most commonly encountered abnormality. [20] The study population consisted of 877 unique patients: 602 women, 275 men; average age, 54 years; and age range, 15-87 years. Of the 877 patients with greater trochanteric pain, 700 (79.8%) did not have bursitis on ultrasound. A minority of patients (177, 20.2%) had trochanteric bursitis. Of the 877 patients with greater trochanteric pain, 438 (49.9%) had gluteal tendinosis, four (0.5%) had gluteal tendon tears, and 250 (28.5%) had a thickened iliotibial band. The authors concluded that the cause of greater trochanteric pain syndrome is usually some combination of pathology involving the gluteus medius and gluteus minimus tendons as well as the iliotibial band. Bursitis is present in only the minority of patients. These findings have implications for treatment of this common condition. [20]
An MRI study suggested that there is an association between increased acetabular anteversion and gluteal tendinopathy, which supports a growing body of evidence implicating abnormal biomechanics in the development of this condition. [21]
Groin/Adductor Strain
Adduction of the hip is performed by the gracilis, pectineus, obturator externus, adductor longus, adductor brevis, and adductor magnus muscles. The main origin is along the pubic ramus, and the insertions range from the trochanteric fossa to the tibial tuberosity. The obturator nerve (L2-L4) provides the main innervations for the adductor muscle group.
Adductor or groin strains are commonly seen in ice hockey and soccer players. [9] These injuries are usually the result of strong eccentric contractions and rapid decelerations that occur during these sports activities, and they are often accompanied by a pop, with immediate resultant pain and disability. Often, weight bearing will be difficult, and the athlete may need to use crutches. The adductor longus is most commonly injured, and athletes classically present with pain with the following: (1) palpation of the muscle belly and insertion, (2) passive stretching, and (3) resistance to contraction.
Adductor strains are also common in football, figure skating, and track and field. Athletes at risk are those with decreased adductor strength, lack of off-season conditioning, inadequate warm-up and stretching, and a history of previous strains. Adductor strains are graded from first degree to third degree, ranging from a minimal loss of strength and ROM (first degree) to a complete loss of muscle function (third degree). If these injuries are not properly rehabilitated after the acute stage, they may become chronic, leading to a more frustrating situation for the athlete.
Hamstring
The hamstrings function as hip extensors and consist of the semitendinosus muscle, semimembranosus muscle, and the biceps femoris. These muscles originate from the ischial tuberosity, with the short head of the biceps femoris coming off the middle third of the femur. They insert onto the medial tibia (semimembranosus and semitendinosus) and lateral fibula (biceps femoris). [22, 23]
Acute hamstring injuries occur with the acceleration associated with sprinting and court or field sports. A snap or pop is felt, and immediate pain will limit further participation. Risk factors for these injuries are similar to other acute injuries mentioned above, such as poor warm-ups, poor flexibility, or decreased strength from previous hamstring strains. Acute hamstring injuries most often occur within the mid belly of the muscle, but myotendinous rupture can occur.
Chronic hamstring pain can result from a poorly rehabilitated acute injury in which the strength was not completely restored. Proximal hamstring tendinitis is less common than chronic muscle-based pain. Apophysitis and acute avulsions from the ischial tuberosity occur in skeletally immature athletes, such as gymnasts and dancers.
Epidemiology
United States statistics
Hip overuse syndrome is a relatively common condition, particularly in people who are physically active.
Snapping hip syndrome is the third most common hip pathology in young women and is most frequently observed among gymnasts and ballet dancers. The syndrome has been reported as an incidental finding in approximately 5-10% of the general population. [24]
International statistics
Among soccer players, 10-18% of all injuries are hip or groin injuries, and 62% of these are adductor strains. [9]
An Australian study showed that hamstring injury accounts for 10% of all injuries in field-based team sports (soccer, rugby union, field hockey, Gaelic football, hurling, and Australian football). [25]
Functional Anatomy
The hip joint can be imagined as a ball and socket. The ball, called the femoral head, is seated within the acetabulum of the pelvic bone (the socket). Both of these bones are covered by articular cartilage, a lubricating and cushioning layer that helps to prevent damage to the underlying bones. Likewise, the labrum is a cushion of fibrocartilage deep within the socket that helps to aid articulation and provide further cushioning.
The hip joint is subject to strong forces (which can be multiple times the body weight) with all weight-bearing activities, from walking to running, as well as jumping and cutting sports. This is due to the long, lever-arm mechanism of the lower extremity, with the hip joint being the fulcrum. Thus, the hip joint is often the location of degenerative arthritis as people age.
The capsular ligaments of the hip joint, which act like ropes, are formed from thickened portions of the joint capsule, helping to keep the 2 bones together and aid in articulation. These ligaments provide stability and tension to the joint with movement.
Anteriorly, the rectus femoris, iliopsoas, gracilis, and sartorius muscles connect the pelvic bone to the femur and help aid in flexion of the femur, bringing the leg up toward the body. These muscles, along with the rest of the quadriceps muscles, which extend the knee, are the largest and most powerful muscles in the body, responsible for producing large concentric, isometric, and eccentric forces. Because of this, these muscles are subject to traumatic injuries and tears from sudden starts (concentric contraction), stops (eccentric contractions), and direct trauma, as well as overuse injuries from repetitive activities (microtrauma).
Medially, the set of 3 adductor muscles and the pectineus connect the inner aspect of the femur to the front and inferior aspect of the pelvis; contracting these muscles adducts the femur back to midline and across the body (ie, crossing the legs). From the outside, the tensor fasciae latae and biceps femoris (toward the back) aid in abduction, moving the legs outward from the body. Posteriorly, the semitendinous and semimembranous muscles (the hamstrings), the biceps femoris, and the large gluteus maximus extend the leg backward from the body.
The gluteus medius, another posterior muscle of the hip and buttocks, aids in internal rotation and abduction of the thigh. The piriformis, quadratus, and superior and inferior gemelli work in tandem to perform external rotation of the hip.
Sport-Specific Biomechanics
All of the previously mentioned muscle groups are subject to increased loads in athletic and recreational activity (see Functional Anatomy). Tendons, which attach muscle directly into bone, are structures that are subject to high tensile strength, meaning they must stretch as the muscles shortens, but they do not provide strength. Inflammation of a tendon from injury or repetitive stress is called tendinitis.
Several tendons are cushioned from the underlying bone by a lubricating and cushioning sac called a bursa. The largest bursa in the hip joint is between the iliopsoas muscle and the pelvic brim and is called the iliopsoas bursa. Between the tensor fasciae latae and gluteus medius muscles and the greater trochanter of the femur, a portion of bone that juts out laterally from the proximal femur, lies the greater trochanteric bursa. Any bursa within the body can be inflamed from repetitive stress of the overlying muscles, direct trauma, or a spreading infection.
The tendinous portion of the muscle has poor blood flow, so injury or stress at the attachment of the tendon onto the bone can lead to degeneration of the area. This degeneration is associated with the disorientation of collagen fibers, increased cellularity, and angiofibroblastic degeneration. Pathology examination of these tendons fails to reveal inflammatory cells or increased blood supply to the area. These "scars" within the tendon are difficult to treat because of decreased blood flow into the injured area.
In the pelvic bones of children, adolescents, and young adults, the tendons attach onto a secondary growing portion of bone. This connection between the larger pelvic bone and smaller secondary growth area is called the apophysis, and in this age group it is the weakest link from the musculature to the bone. Consequently, the apophysis can be the direct source of pain from irritation (apophysitis), or it can be broken apart by a strong force on the tendon and pulled away from the larger pelvic bone (avulsion fracture).
Avulsion fractures around the pelvis occur in prepubertal athletes as the result of an actively contracting muscle encountering abrupt resistance such as a misstep, rapid acceleration, or eccentric movements. The treatment of most smaller avulsion fractures is similar to the treatment of strains of the muscle-tendon unit.
Prognosis
Adolescents who present with pain around the hip joint by traction apophysis are expected to recover within a matter of months. Recurrence can be avoided if the intensity and volume of the sports activity is limited modestly until skeletal maturity occurs.
Aggressive athletes in their 20s or 30s may need ongoing physical therapy so that they can ascend the ladder of progressive exercise and return to their sports. Recurrence in this group is high, given the innate desire of these individuals to return to play too quickly. Fortunately, the tendinous structures in this group are pliable, and the chance for repetitive microtearing is lower than that in an older group.
Active athletes older than 40 years have the added burden of a decreasing tendinous pliability and a lower threshold of tendinitis recurrence. Their return to sports must be calculated with great care to slowly ramp up the level and intensity of their activity. A good rule of thumb is to not increase activity more than 10% per week until the patient has progressed back to reasonable exercise levels. In this active group, the reality of abandoning long-distance running or jumping sports may need to be addressed. The treatment team is encouraged to promote the patient's participation in new activities that provoke less hip pain, such as cycling.
Complications
Other than worsening or returning pain, few complications of the overuse injury exist. Educating the athletes will remind them of the long-term nature of these injuries. As we age, our tendons age and degenerate, making recovery from these injuries more difficult.
If the patient's injury is not responding to treatment as quickly as expected, the physician should reconsider the diagnosis (see Differentials). Of paramount importance is reconsidering whether intra-abdominal, intrapelvic, or spinal pathology is responsible for the patient’s symptoms. Further imaging may be necessary to help rule out more worrisome diagnoses.
