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Among people who participate in sports, extra-articular soft tissue injuries around the hip are common. The hamstring, quadriceps, adductor, and abductor muscle groups are often the site of soft tissue injury. Overlapping conditions make it difficult to identify the primary cause of hip pain and dysfunction. A proper evaluation and diagnosis of the impairment are crucial for the selection of interventions and quick return to play. The purpose of the clinical commentary is to present an evidence based stepwise progression in the evaluation and treatment of several common soft tissue injuries of the hip.
Soft tissue injuries around the hip are common, particularly among people who participate in sports. The hip has four sets of strong muscles surrounding the joint: the hamstring muscles in the posterior, quadriceps muscles in the anterior, adductor muscles on the medial side, and abductors on the lateral side. Each of these sets of muscles are often the site of soft tissue injury.1 The hamstring and quadriceps muscle groups are particularly at risk for muscle strains because they cross both the hip and knee joints. These muscles are also used for high-speed activities such as track and field events, football, basketball, ice hockey, and soccer.
The most common mechanism of injury for muscle strains in the hip area occur when a stretched muscle is forced to contract suddenly. A fall or direct blow to the muscle, overstretching, and overuse can tear muscle fibers, resulting in a strain. The risk of muscle strain increases if the patient has had a history of injury to the area, inadequate warm-up before exercising, or attempts to do too much too quickly. Strains may be mild, moderate, or severe depending on the extent of the injury. Pain over the injured muscle is the most common symptom of a hip strain. Contracting the muscle increases the pain level. Swelling may also be present, depending on the severity of the strain. A loss of strength in the muscle may also exist.
Evaluation of hip muscle strains can be challenging. A muscle that is painful during contraction and painful when stretched may be strained. Specific exercises or stretches which stress the involved muscle can help determine which muscle is injured. An X-ray may be used to rule out the possibility of a stress fracture of the hip, which has similar symptoms, including pain in the groin area with weight bearing. In most cases, no additional tests are needed to confirm the diagnosis.
In general, treatment and rehabilitation are designed to relieve pain, restore range of motion, and restore strength - in that order. The use of RICE (rest, ice, compression, elevation) is the standard protocol for mild to moderate muscle strains. Gentle massage of the area with ice may help to decrease swelling. Non-steroidal anti-inflammatory drugs (NSAIDs) can be taken to reduce swelling and ease pain. Compression shorts or a wrap bandage may also be helpful in decreasing swelling and providing support. If walking causes pain, weightbearing should be limited and crutches should be considered for the first day or two after the injury.
The group of muscles along the inner thigh is referred to as the adductor muscle group. This group of six muscles includes the pectineus, adductor longus, adductor brevis, adductor magnus, gracillis, and obturator externus. All of the adductor muscles are innervated by the obturator nerve except for the pectineus, which gets its motor intervention from the femoral nerve. These muscles originate in the inguinal region at various points on the pubis. The muscles travel inferior to insert along the medial femur. The main action of this muscle group is to adduct the thigh in the open kinetic chain and stabilize the lower extremity to perturbation in the closed kinetic chain. Each individual muscle can also provide assistance in femoral flexion and rotation.1,2 The adductor longus is thought to be the most frequently injured adductor muscle.3 The lack of mechanical advantage may make the adductor muscles more susceptible to strain.
Adductor muscle strains can result in missed playing time for athletes in many sports. Adductor muscle strains are encountered more frequently in ice hockey and soccer.4–6 These sports require a strong eccentric contraction of the adductor musculature during competition.7,8 Adductor muscle strength has been linked to the incidence of adductor muscle strains. Specifically, the strength ratio of the adduction to abduction muscles groups has been identified as a risk factor in professional ice hockey players.7 Intervention programs can lower the incidence of adductor muscle strains but not avoid injury altogether. Therefore, proper injury treatment and rehabilitation must be implemented to limit the amount of missed playing time and avoid surgical intervention.8
Symptoms of a groin strain include pain on palpation of the adductor tendons or the insertion on the pubic bone, or both, and groin pain during adduction against resistance.9–11 Groin strains, and muscle strains in general, are graded as a first degree strain if there is pain but minimal loss of strength and minimal restriction of motion. A second-degree strain is defined as tissue damage that compromises the strength of the muscle, but not including complete loss of strength and function. A third degree strain denotes complete disruption of the muscle tendon unit; including complete loss of function of the muscle.11 A thorough history and a physical examination is needed to differentiate groin strains from athletic pubalgia, osteitis pubis, hernia, hip-joint osteoarthrosis, rectal or testicular referred pain, piriformis syndrome, or presence of a coexisting fracture of the pelvis or the lower extremities.9–13 Imaging studies can sometimes be useful to rule out other possible causes of inguinal pain.12
The exact incidence of adductor muscle strains in sport is unknown - due, in part, to athletes playing through minor groin pain and the injury going unreported. In addition, overlapping diagnosis can also skew the exact incidence. Groin strains are among the most common injuries seen in ice hockey players,14–16 accounting for 10% of all injuries in elite Swedish ice hockey players.17 Furthermore, Molsa18 reported that groin strains accounted for 43% of all muscles strains in elite Finish ice hockey players. Tyler et al7 published that the incidence of groin strains in a single National Hockey League team was 3.2 strains per 1000 player-game exposures. In a larger study of 26 National Hockey League teams, Emery et al3 reported the incidence of adductor strains in the National Hockey League has increased over the last six years. The rate of injury was greatest during the preseason compared to regular and postseason play. Prospective soccer studies in Scandinavia have reported a groin strain incidence between 10 and 18 injuries per 100 soccer players.19 Ekstrand and Gillquist4 documented 32 groin strains in 180 male soccer players representing 13% of all injuries over the course of one year. Adductor muscle strains, certainly, are not isolated to these two sports.
Previous studies have shown an association between strength and flexibility and musculoskeletal strains in various athletic populations.4,20,21 Ekstrandt and Gillquist4 found that preseason hip abduction range of motion was decreased in soccer players who subsequently sustained groin strains compared with uninjured players. This study is in contrast to the data published on professional ice hockey players that found no relationship between passive or active abduction range of motion (adductor flexibility) and adductor muscle strains.7,22
Adductor muscle strength has been associated with a subsequent muscle strain. Tyler et al7 found preseason hip adduction strength was 18% lower in NHL players who subsequently sustained groin strains compared with the uninjured players. The hip adduction to abduction strength ratio was also significantly different between the two groups. Adduction strength was 95% of abduction strength in the uninjured players but only 78% of abduction strength in the injured players. Additionally, in the players who sustained a groin strain, preseason adduction to abduction strength ratio was lower on the side which subsequently sustained a groin strain compared with the uninjured side. Adduction strength was 86% of abduction strength on the uninjured side but only 70% of abduction strength on the injured side. Conversely, another study on adductor strains on ice hockey players found no relationship between peak isometric adductor torque and the incidence of adductor strains.22 Unlike the previous study this study had multiple testers using a hand held dynamometer, which would increase the variability and decrease the likelihood of finding strength differences. However, results reported by Emery et al22 demonstrated that players who practiced during the off season were less likely to sustain a groin injury as were rookies in the NHL. The final risk factor was the presence of a previous adductor strain. Tyler et al7 also linked pre-existing injury as a risk factor, in their study four of the nine groin strains (44%) were recurrent injuries. This results is consistent with the results of Seward et al23 who reported a 32% recurrence rate for groin strains in Australian rules football.
Now that researchers can identify players at risk for a future adductor strain, the next step is to design an intervention program to address all risk factors. Tyler et al14 were able to demonstrate that a therapeutic intervention of strengthening the adductor muscle group could be an effective method for preventing adductor strains in professional ice hockey players. Prior to 2000 and 2001 seasons, professional ice hockey players were strength tested. Thirty-three of these 58 players were classified as “at risk” (which was defined as having an adduction to abduction strength ratio of less than 80%) and placed on an intervention program. The intervention program consisted of strengthening and functional exercises aimed at increasing adductor strength. (Table 1) The injuries were tracked over the course of the two seasons. Results indicated three adductor strains which all occurred in game situations. This gives an incidence of 0.71 adductor strains per 1,000 player game exposures. Adductor strains accounted for approximately 2% of all injuries. In contrast, 11 adductor strains and an incidence of 3.2 adductor strains per 1,000 player game exposures occurred in the previous two seasons prior to the intervention. In those prior two seasons adductor strains accounted for approximately 8% of all injuries. Injury rate after intervention was also significantly lower than the incidence reported by Lorentzon et al17 who found adductor strains to be 10% of all injuries. Of the three players who sustained adductor strains, none of the players had sustained a previous adductor strain on the same side. One player had bilateral adductor strains at different times during the first season. This data demonstrated that a therapeutic intervention of strengthening the adductor muscle group can be an effective method for preventing adductor strains in professional ice hockey players.
Despite the identification of risk factors and strengthening intervention for ice hockey players, adductor strains continue to occur in all sports.13 The high incidence of recurrent strains could be due to incomplete rehabilitation or inadequate time for complete tissue repair. Hömlich et al8 demonstrated that a passive physical therapy program of massage, stretching, and modalities was ineffective in treating chronic groin strains. By contrast, an 8-12 week active strengthening program consisting of progressive resistive adduction and abduction exercises, balance training, abdominal strengthening, and skating movements on a slide board proved more effective in treating chronic groin strains. An increased emphasis on strengthening exercises may reduce the recurrence rate of groin strains. An adductor muscle strain injury program, progressing the athlete through the phases of healing has been developed by Tyler et al14 and anecdotally seems to be effective. (Table 2) This type of treatment regime combines modalities and passive treatment immediately, followed by an active training program emphasing eccentric resistive exercise. This method of rehabilitation program has been supported throughout the literature.11,13
A sports hernia occurs when weakening of the muscles or tendons of the lower abdominal wall occur. This part of the abdomen is the same region where an inguinal hernia occurs, called the inguinal canal. When an inguinal hernia occurs, sufficient weakening of the abdominal wall exists to allow a pouch, the hernia, to be felt. In the case of a sports hernia, the problem is due to a weakening or tear in the abdominal wall muscles, but no palpable hernia exist.
The symptoms of a sports hernia are characterized by pain during sports movements, particularly twisting and turning during single limb stance. This pain usually radiates to the adductor muscle region and even the testicles, although it is often difficult for the patient to pin-point. Following sporting activity, the person with a sports hernia will be stiff and sore. The day after competition, mobility and practice will be difficult. Any exertion that increases intra-abdominal pressure, such as coughing or sneezing can cause pain. In the early stages, the patient may be able to continue playing their sport, but the problem usually gets progressively worse.
The diagnosis of a sports hernia is based on the patient's history and clinical signs when all other causes are ruled out. Currently, no clinical special tests exist with a high degree of specificity to diagnose this pathology. In addition, an MRI is usually not helpful in further differentiation. Therefore, this pathology is a diagnosis of exclusion. Non-operative treatment usually involves a short period of rest followed by physical therapy focusing on abdominal strengthening which may temporarily alleviate the pain, but definitive treatment remains surgical repair and rehabilitation.
The hamstrings are actually comprised of three separate muscles: the biceps femoris, semitendinosus and semimembranosus. These muscles originate just underneath the gluteus maximus on the pelvic bone and attach on the tibia. The hamstrings are primarily fast-twitch muscles, responding to low repetitions and powerful movements. The primary functions of the hamstrings are knee flexion and hip extension.
Hamstring muscle strains commonly result from a wide variety of sporting activities, particularly those requiring rapid acceleration and deceleration. An eccentric load to the muscle causes the majority of these injuries. Garrett 24 demonstrated that, in young athletes, hamstring muscle strains typically involve myotendinous disruption of the proximal biceps femoris muscle. Other authors have also shown experimentally that the weak link of the muscle complex is the myotendinous junction.13,25 Although apophyseal fractures of the ischial tuberosity have been reported in young athletes, the majority of hamstring muscle strains are first and second degree strains.26
Hamstring muscle strains are among the most common injuries in sports involving high-speed movement and physical contact. Hamstring strains are by far the most commonly seen muscle strains in Australian rules football with an incidence of 8.05 injuries per 1000 player-game-hours. Soccer players are also susceptible to hamstring strains with an incidence of 3.0 per 1000 player-game-hours for hamstring strains. Overall, any athlete who sprints as part of their sport may contribute to the incidence of hamstring strains.27,28
Factors causing hamstring muscle injury have been studied for many years. Age and previous injury were identified as the main risk factors for hamstring strains injury among elite football players from Iceland.27 It has been suggested that muscle weakness, strength imbalance, lack of flexibility, fatigue, inadequate warm-up, and dyssynergic contraction may predispose an athlete to a hamstring strain.28
Fatigue has been implicated in the pathogenesis of muscle strain injury. Because muscle strains have been observed to occur either late in training or late in competitive matches, muscle fatigue has been indicated as a risk factor. Another study suggests that the injuries occur either early in games or training or late in games or training with inadequate warm-up and muscle fatigue, respectively, being the hypothesized reasons.29 However, little quantitative data exists to support these statements. Croisier30 suggests that the persistence of muscle weakness and imbalance may give rise to recurrent hamstring muscle injuries and pain. These authors feel that when there is insufficient eccentric braking capacity of the hamstring muscles compared with the concentric motor action of the quadriceps muscles, the muscle may be at risk for injury.
Ekstrand and Gillquist31 prospectively studied male Swedish soccer players and found hamstrings to be the muscle group most often injured. The authors noted that minor injuries increased the risk of having a more severe injury within two months. Others have noted a recurrence rate of 25% for hamstring injuries in intercollegiate football players.32
Most clinicians prescribe warm-up and stretching to help reduce the incidence of muscle strains. The evidence supporting this idea is weak and largely based on retrospective studies.33 In fact, following hamstring injury, the affected extremity and muscle group are significantly less flexible than the uninjured side, but no differences in isokinetic strength exists.34 However, Jonhagen et al 35 found decreased flexibility and lower eccentric hamstring torques in runners who sustained a hamstring strain when compared with uninjured subjects matched for age and speed. The role of stretching and warm-up in injury prevention needs to be better understood so that optimal strategies can be developed.
No consensus exists for rehabilitation of the hamstring muscles after strain. However, a rehabilitation program consisting of progressive agility and trunk stabilization exercises has been shown to be more effective than a program emphasizing isolated hamstring stretching and strengthening in promoting return to sports and preventing injury recurrence in athletes suffering an acute hamstring strain.36 The aim of the physical therapy is to restore full pain free range of motion and strength throughout the range of motion. In addition, as a complement to the usual restoration of function, restoration of eccentric muscle strength and correction of agonist/antagonist imbalances in the rehabilitation process. We recommend the inclusion of eccentric exercises at an elongated position of the hamstring muscles, sub maximally, as soon as the patient can tolerate. The rationale is based on basic science animal research37 and imaging studies of human muscle tissue12 that have indicated incomplete healing following muscle strains. Fibrosis at the injury site is thought to be related to the risk of re-injury. Based on these observations, interventions aimed at remodeling the muscle tissue may be effective in reducing the risk associated with a history of a prior muscle strain. Eccentric muscle contractions have been shown to result in muscle-tendon junction remodeling in an animal model38 and more recently have been shown to cause intramuscular collagen remodeling in humans.39 Therefore, an eccentrically based training program for previously injured muscles could theoretically reduce recurrence rates and would be worth studying in future research.
Rehabilitation would start with relative rest and protection of the injured muscle phase lasting from 1 to 3 days. Returning to exercise in this stage can lead to re-injury and disruption of the healing tissue. Multiangle isometrics should be initiated to properly align the regenerating muscle fibers and limit the extent of connective tissue fibrosis. Rest, ice, compression, and elevation, along with anti-inflammatory medication, is helpful during the immediate stages of treatment. Heat, electrical stimulation, and ultrasound modalities can also be used in conjunction with each other during the rehabilitation program to facilitate a return to competition.40,41 Heat is effective at increasing tissue temperature prior to stretching and exercise. Electric stimulation can be used to control edema and pain. Ultrasound is used as a deep-heating agent during the subacute phase to decrease spasm and prevent soft-tissue shortening.
An effective strengthening program should treat the hamstrings as a two-joint muscle and focus on concentric and eccentric contractions. Although lack of flexibility has been identified as a factor leading to hamstring injuries, the effectiveness of pre-exercise muscle stretching in reducing injuries has recently been questioned. In fact, Worrell34 et al sites decreased strength and power up to one hour following passive stretching. In theory, this decrease in force production is thought to result from the relaxation of the muscle tendon unit. Therefore, prior to athletic competition, a general warm-up (jogging, cycling) to increase tissue temperature, followed by dynamic stretching that includes sports-specific movements is recommended. Examples of dynamic stretches for the legs include forward or backward lunges, high-knee marching, and straight-leg kicks. Static stretching should be performed after the athletic activity.
The quadriceps is a group of four muscles that sit on the anterior aspect of the thigh- the vastus medialis, intermedius and lateralis, and rectus femoris. The quadriceps attaches to the front of the tibia via the patella tendon and originate at the top of the femur. The exception is the rectus femoris which actually crosses the hip joint and originates on the pelvis. The function of the quadriceps, as a whole, is to extend the knee. The rectus femoris functions to extend the knee but also acts as a hip flexor because the muscle crosses the hip joint. Any of these muscles can strain (or tear) but probably the most common is the rectus femoris. The grading system is the same as the adductor strains. A grade III tear is felt as an abrupt, sudden, acute pain that occurs during activity (often while sprinting). The injury may be accompanied by swelling or bruises on the thigh. The rehabilitation of quadriceps strains follow the same principles as the rehabilitation process of adductors and hamstring muscle strains.
Bursae are lined with synovium and are synovial fluid filled sacs that exist normally at sites of friction between tendons and bone as well as between these structures and the overlying skin.1 A bursae is analogus to filling a balloon with oil and rubbing it between your fingers. The purpose of the bursae is to dissipate friction caused by two or more structures moving against one another.1 The development of a bursitis is the product of one of two mechanisms. The most common mechanism is inflammation secondary to excessive friction or shear forces as a result of overuse. Post-traumatic bursitis is the other mechanism and stems from direct blows and contusions that cause bleeding in the bursae with resultant inflammation. The three major bursae around the hip joint that are susceptible to bursitis are the iliopsoas bursae, ischial bursae, and the greater throcanteric bursae.
The greater trochanteric bursae lies between the gluteus maximus, tensor fascia lata (TFL), and the surface of the greater trochanter. Its location on the lateral aspect of the hip exposes it to contact injuries in sports such as football, soccer, and ice hockey. More commonly, trocanteric bursitis is seen in the clinic as an overuse injury found in runners, bike riders, and cross-country skiers. The problem may also be found in individuals with an increased Q-angle, prominent trochanters, or a leg-length discrepancy. Repetitive motion of hip flexion and extension on an excessively compressed bursae can give rise to irritation and inflammation. This problem can occur with tightness in tissues around the hip, for example the iliotibial band (ITB) pulling across the hip or hip adductors bringing the thigh into a more midline position. Poor running mechanics or continuous running on banked surfaces that brings the lower extremity into an increased adducted position can also cause undo pressure at the hip.
Signs and symptoms of trochenteric bursitis include warmth and reported pain at the greater trochanter region of the hip. Pain with hip abduction resistance, palpable tenderness at lateral hip, pain with gait, and possible swelling or ecchymosis at the surface of the greater trochanter, as well as pain with lying on affected side may be present.42–44
Intervention begins by taking a thorough history from the patient to determine activity level, length of onset, or mechanism of possible traumatic incident. Examination is then performed to check for range of motion (ROM), tenderness, tightness, and weakness in surrounding soft tissue structures. It is necessary to analyze gait and stair patterns as well as possibly analyzing running mechanics if subjective complaints warrant.
Initial home rehabilitation for the individual will consist of rest, ice, and NSAIDs. Clinical treatment will emphasize modalities for inflammation (i.e ultrasound), stretching of appropriate structures such as the IT band and adductors, as well as slow integration into progressive resistive exercises for encompassing hip musculature. If the underlying cause is due to a leg-length discrepancy, the problem should be corrected with the appropriate device. Upon normalization of ROM and flexibility, a gradual return to sport specific activities should be implemented. Full return to sports should emphasize prevention with a regular stretching program or appropriate padding for traumatic injuries.
While uncommon, ischial bursitis, may occur as a complication of an injury to the hamstring insertion into the ischial tuberosity or as a direct trauma to a fall or hit. The symptoms include pain while sitting and localized tenderness. It is important to distinguish this bursitis from a hamstring tear at the origin. Initial treatment consists of rest, ice, and NSAIDs. A sitting cushion may be utilized as needed. General stretching of the hamstrings and progressive resistant exercises are implemented as pain subsides.
Iliopsoas (iliopectineal) bursitis is most often due to excessive activity, possibly due to irritation by the iliopsaos muscle passing over the iliopectineal eminence. This rubbing may also be associated with a “snapping” hip. Pain is reported in the inguinal area and can radiate into femoral triangle. Associated palpable tenderness can be present by placing the hip in flexion and external rotation. This position can also help relieve symptoms. Treatment includes the rest, NSAIDs, and stretching of the iliopsoas. Strengthening of any muscle imbalances can be initiated in pain-free arcs.
Snapping hip syndrome (Coxa Saltans) can arise from two different sources: intra-articular and extra-articular. Intra-articular causes include loose bodies, osteocartilaginous exotosis, labral tears, synovial chondromatosis, and subluxation of the hip. More common though are the extra-articular causes of a “snapping” hip. This problem occurs primarily when, but not exclusively to, the IT band snapping over the greater trochanter during hip flexion and extension. Hip adduction and knee extension will tighten the IT band and accentuate the snapping sensation. This continuous pathomechanical movement can lead directly to trochenteric bursitis. A second extra-articular source comes from the iliopsoas tendon as it passes just in front of the hip joint. This tendon can catch on the pelvic brim (iliopectineal eminence) and cause a snap when the hip is flexed.45
This syndrome is common in ballet dancers where 44 percent of reported hip pain involved a snapping or clicking.46 Most complaints concerned the sensation with only one-third reporting pain. The condition can present itself with specific flexion movements of the thigh such as sit-ups. Both have signs and symptoms of an audible snap or click either laterally or anterior deep in the groin which may or may not be painful.
Treatment for a patient with snapping hip syndrome begins with a thorough examination. During the subjective evaluation, the clinician must question the patient to determine which actions exacerbate symptoms during daily activities and athletics. The objective examination is designed to determine the severity of pathology and to perform a biomechanical assessment. The information gathered in this portion of the examination can be used to guide specific elements of the treatment program. Muscle-tendon length and strength, joint mobility testing, and palpation of the injured area are key to a proper examination. Biomechanical assessment of the patient includes both static (posture) and dynamic (gait/functional movement) elements. Particular areas of attention during the examination include observation of genu recurvatum, knee flexion contracture, overpronation of the foot, hip flexion contracture, and the amount of internal or external rotation present in the lower extremity during static stance. Also take note of leg length. Gait analysis allows the clinician to confirm the findings of static examination and to observe if a movement dysfunction is present. Functional movements (eg, squatting, stair accent/descent) may further demonstrate to the clinician the severity of the movement dysfunction.45
Once identification of contributing factors has been completed, treatment can be directed toward those factors. Intervention during the acute phase consists of standard anti-inflammatory care and the elimination of activities that exacerbate symptoms. Physical therapy modalities (eg, ice, ultrasound, electrical stimulation, iontophoresis) may be used during this time.40,41 Activity modification depends on the severity of the pathology. Crutches may be used in severe cases, while simply decreasing the time and intensity of the aggravating activity is commonly used in less acute cases. Muscle weakness and tightness in the thigh or pelvis is addressed with a strengthening and stretching program. Overpronation may require a foot orthotic to assist with foot stabilization. Leg length deformities commonly require a lift in the shoe to assist with balancing the entire lower extremity. For those patients with a symptomatic snapping hip and trochanteric bursitis unresponsive to conservative therapy, a surgical procedure has been described as an effective method of treatment in this specific population.47
In conclusion, proper treatment of soft tissue injuries of the hip starts with a thorough evaluation of the entire kinetic chain. Often, overlapping conditions exist around the hip joint making it difficult to identify the primary cause of the hip pain and dysfunction. Once a diagnosis has been made, an evidence based stepwise progression as outlined in this paper is paramount for returning the athlete to the playing field quickly and safely.