Overuse injuries of the hip and snapping hip syndrome

OVERUSE INJURIES OF THE HIP AND SNAPPING HIP SYNDROME BRUNO NOESBERGER, MD, and ADRIAN R. EICHENBERGER, MD

Repetitive microtrauma is the mechanism of overuse injuries. Stress fractures of the neck of the femur are often diagnosed late when suspected bone scan is mandatory to avoid disastrous displacement. They are classified in transverse unstable fractures, which need internal fixation and compression fractures, which are stable. Pelvic stress fracture occurs mainly in the lower pubic ramus in marathoners during, or a few weeks after, the race. Diagnosis is made by anteroposterior view or bone scan. After having stopped running they normally heal spontaneously. In differential diagnostis we have to consider osteitis pubis which can result from athletic activity. Adductor tendinitis is common in soccer and hockey players. Treatment usually is conservative. At times when groin pain is becoming chronic, surgical tenotomy is indicated. Snapping of the hip may be due to iliotibial snapping or snapping of the iliopsoas muscle. Iliopsoas bursography under fluoroscopy could show a sudden jerking movement in iliopsoas tendon snapping. KEY WORDS: stress fracture, adductor tendinitis, snapping hip syndrome

For the patients or athletes as well as for the physicians w h o prescribe exercise, it is relevant to u n d e r s t a n d the mechanism of overuse injury, namely, repetitive microtrauma. Risk factors include inappropriate progression of the rate, intensity, duration, and complexity of training, as well as anatomic malalignment; muscle-tendon imbalances of strength, endurance, or flexibility; shoewear; surface, and pre-existent disease states. One of ~the most important risk factors in training is training error. We k n o w empirically that athletes should not increase their training more than 10% per week. Muscle-tendon imbalance is perhaps the second most important risk factor. Changes in the relative strength and flexibility of flexor and extensor muscle groups m a y lead to overuse injuries. Predisposing factors for femoral neck stress fractures include strength ratio inbalance b e t w e e n the agonist and antagonist muscle-tendon units of the hip, as well as strength differential b e t w e e n the two legs.

STRESS FRACTURE OF THE FEMORAL NECK Femoral neck stress fracture is a consequence of musclet e n d o n imbalance and the diagnosis must always enter into consideration of any overuse-related symptom. The injury is especially rare in the individual with open epiphysis. The sports that are usually involved with the injury are long distance running, jumping events, and

From the Orthopedic and Trauma Department, Regionalspital Interlaken, Interlaken, Switzerland. Address reprint requests to Bruno Noesberger, MD, Chief, Orthopedic and Trauma Department, Regionalspital Interlaken, Weissenaustrasse, 3800 Interlaken, Switzerland. Copyright © 1997 by W.B. Saunders Company 1060-1872/97/0502-000555.00/0 1 38

hiking. 1 A surprisingly high incidence has been reported in ballet dancers. 2 A stress fracture is a partial or complete fracture of a bone resulting from its inability to withstand nonviolent stress that is applied in a rhythmic, repeated subthreshold manner. • Stress fractures of the pelvis and the hips are relatively u n c o m m o n . Matheson analyzed 320 athletes with stress fractures p r o v e n b y positive bone scans. 3

The following distribution ensued: Tibia 49.1% Tarsal bones 25.3% Metatarsal bones 8.8% F e m u r 7.2% Fibula 6.6% Pelvis 1.6% Sesamoids 0.9% The presence of bilateral stress fractures was f o u n d in 16%. McBryde f o u n d a m o n g 1,000 stress fractures in runners, the pelvis was involved in 6%, the femur in 14% and half of these were bilateral. 4 The entity of stress fractures has been identified in subsequent literature b y a variety of terms including fatigue fracture, insufficiency fracture, pseudofracture and march fracture. It is due to a dysbalance b e t w e e n healthy bone and excessive overload within the limits of elasticity without existence of any metabolic disease or macrotrauma history. Breithaupt described 1,855 stress fractures due to long marches in military. 5 Further studies of stress fractures in soldiers were published. 6,7 They have in comm o n the history of repetitive training or cyclic low level forces. There are different classifications. 7,8 We prefer the classification in two types, after Devas, 8 because this classification has therapeutic consequences. Devas has gone on to classify femoral neck stress fractures into transverse, unstable fractures, and compression fractures, which are stable. Operative Techniques in Sports Medicine, Vol 5, No 3 (July), 1997: pp 138-142

t Fig 1. Dislocated subcapital stress fracture on the right side and undisplaced compression fracture with a haze of condensation in a 21-year-old soldier,

TRANSVERSE (TENSION) FRACTURES Transverse fractures are perpendicular axis to the femoral neck and start as a crack at the superior neck apparent on a standard AP pelvic radiograph, and become complete over days. If left untreated, there is a significant risk of displacement. Almost all stress fractures in patients over the age of 60 are of this type (Figs I through 4).

Fig 3. Bone scan of the pelvis of the same patient as Figs 1 and 2. The bone scan proved the bilateral femoral neck fracture and the calcaneus fatigue fracture,

COMPRESSION FRACTURES Compression fractures show radiographically a haze of condensation at the inferior neck and are stable (Fig 5). M~iller9 stated that in the development of overuse injuries as in fatigue fractures, and in bone remodeling, forces arising from body weight or loading are of less importance than forces induced by muscle action. Muscle forces are not only static but also dynamic. We think that the contrary is also possible, that muscles can get weaker and are no longer able to function as a tension band principle and, therefore, no longer protect the bone. Flexion forces can arise and, by repetitive loading, the bone can lead to stress fracture. Stress fractures develop mainly in persons who sustain a strange and long loading, eg, in athletes who change their

Fig 2, Stress fracture of the right calcaneus in the same patient as Fig 1. OVERUSE INJURIES OF THE HIP

training and, hence, overload muscles and skeletal parts that were infrequently used before. Stress fractures have a higher frequency in the female sex with a ratio of 10:1 in the same training intensity.1° Early diagnosis may be difficult and the physician has to be suspicious in diagnosing this fracture. Patients sometimes are even sent to the psychiatrist because they are thought to be malingerers. The diagnosis often is delayed and patients are treated as having back sprain or a hip muscle strain. 7 The predominant symptom is pain, and clinical examination may be minimal.

Fig 4. Three months after the operation of the dislocated right femoral neck fracture, The radiograph shows solid union of the right hip and healed fatigue fracture on the left side.

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Radiographic findings may be diagnosed 4 to 6 weeks after symptoms begin. In stress fractures of cancellous bone with mainly compression forces the first sign of suspicion is a small band of increasing density perpendicular to the bone trabecula. Later, a thickening of the periphery at the cortical bone develops a sign of periostal callus formation. When a stress fracture is suspected scintigraphy is mandatory to allow early detection and to avoid disastrous displacement and the possibility of avascular necrosis. Prather et a111found a positive bone scan 15 days after onset of symptoms. The need to obtain totalbody scans should be emphasized because patients often have multiple areas of involvement. Athletes with very dynamic activity like jumping or sprinting may show physiologically increased uptake. Myositis, tendinitis, or a chronic compartment syndrome may present increased uptake in the second phase. 1° The physician, nevertheless, should not be critical in the indication of bone scans when he suspects a stress fracture, because the potential morbidity of stress fracture of the femoral neck is high.

Case Report

Fig 5. A 45-year-old woman of 130 kg body weight suffered from knee pain with effusion. The radiograph of the right hip revealed ,by chance a compression type fracture of the femoral neck,

Signs and Symptoms of Femoral Neck Stress Fracture • Load depending deep anterior hip tenderness • Irradiating thigh or knee pain • Pain at the extremes of hip motion • Antalgic gait • Positive hop test The hop test may be helpful. The patient attempting to hop on the injured leg, suffers from pain if an undisplaced stress fracture is present. Differential Diagnosis

It is imperative for the sports physician dealing with athletes presenting with chronic pain to always include the possibility of stress fracture. A careful history, taking into account the details of training and the equipment used, can help determine that an overuse injury is present and which tissue involved is most suspect. One has to remember that infection or tumor may present similar symptoms. We have seen a decathlete with chronic hip pain in whom we suggested a stress fracture but on the bone scan an osteoid osteoma of the femoral neck could be diagnosed. Furthermore, other conditions have to be considered in differential diagnosis like Periostitis, Ewing- and Osteosarcomas, and the chronic sklerosing form of Osteomyelitis.

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A 21-year-old recruit in the Swiss army complained of thigh pain on the right side during a day-long march. The day after he also complained of heel pain on the right side. The physician in charge as well as the army camp physician didn't take it seriously and believed him to be a malingerer, without having performed radiographs and sent the recruit to the psychiatrist who confirmed the statement of the two colleagues. The next weekend he came to the emergency room. Bilateral femoral neck fractures and a calcaneus fatigue fracture could be diagnosed. Bone scan proved the presence of the stress fractures. An emergency operation was needed to correct the dislocated neck fracture on the right side.

Treatment The treatment of a stable compression fracture depends on pain and disability. It usually begins with rest. Approximately 4 to 6 weeks are needed for the stress fracture to heal, therefore no vigorous activities are allowed during this period. Once physical activity is resumed, one should watch for signs of refracturing. The treatment of a transverse fracture, which begins in the superior cortex and progresses across the neck, may displace and therefore needs fixation. We prefer cannulated screws. If the fracture is sustained by a young athlete and a considerable growth can be expected by the open growth line we would consider pins more appropriate than screws. Fortunately in the young athlete stress fracture of the neck or of the femur is often of compression type, and healing can be expected with relative rest and limited weight-bearing.

PELVIS STRESS FRACTURES They frequently occur in long distance runners or marathoners and usually are seen in the ischio-pubic ramus. The presenting symptom is pain in the groin. The fracture NOESBERGER AND EICHENBERGER

usually is nondisplaced. The pelvic stress fracture is more common in women than in men. All fractures in Pavlov's series 12 occurred during or within a 5-week period after a marathon race or an intensification of the training regimen. In two of eleven cases they encountered delayed union whereas all others healed and were asymptomatic after 2 to 5 months after the patients stopped running.

OSTEITIS PUBIS Osteitis pubis is often a cause of unexplained groin pain. Although it can be a complication of urologic operations, there are many reports that osteitis pubis can result from athletic activity. Hanson et a113indicated that the adductor muscles may transmit shear forces to the pubis symphysis during kicking in soccer; often it is misinterpreted as muscle sprain because stretching aggravates the symptoms. Harris and Murray 14 outlined the clinical and radiographical features of this entity. It is characterized by symmetrical bone resorption at the medial ends of the pubic bones. The symphysis is widened, and some patients may show instability that can be seen on films in one-leg stance (Flamingo view). Clinically it is characterized by the gradual onset of localized pain in the pubis region, which may irradiate in the groin or lower portion of the abdomen. Because stretching aggravates the symptoms one might think of a strained muscle or even a hernia. Adductor spasm and antalgic limp may be present. It seems to be a self-limiting disorder but it can last several months. Most patients respond to conservative treatment like NSAIDs, oral use of cortisone, and local injections of steroids.

ADDUCTOR TENDINITIS Groin strain or overuse injuries of the adductors are common in soccer, hockey, and in breast-stroke swimming. Similar symptoms can occur in cross-country skiers and in skaters. These injuries are common because of the dynamic requirements of the skating motion. The athlete adducts the thigh forcibly in push-off to initiate the gliding stroke. In soccer players it is due to repetitive forcible external rotation of the abducted leg. The studs of the shoes and a muddy field may be causative. Pain is elicited on passive adduction. Strengthening and stretching exercises should be taught to prevent the appearance and recurrence of these symptoms. Treatment involves the use of ice, rest, protection, and antiinflammatory agents. Ultrasound or short-wave diathermy may be helpful after the acute period. Consideration of the causative factors and aggressive early diagnosis must be performed to prevent groin pain from becoming chronic. Active resistance exercises against gravity should not begin for approximately 3 to 6 weeks after initial injury because they may aggravate the pain. In chronic cases a surgical release of the gracilis and adductor longus from the bone may be indicated. In the study of Martens et aP 5 of 109 patients with adductor tendinitis, 81 required surgery. In differential diagnosis one has to consider a soft groin, tendopathy of the rectus femoris, or the iliopsoas muscle and urologic affectations OVERUSE INJURIES OF THE HIP

as in prostatitis. Bayens 16 has described a case of vaginal pain in a high-powered sportswomen which proved to be from adductor tendinitis due to long distance running.

PIRIFORMIS SYNDROME A tight piriformis muscle may compress the sciatic nerve. Overuse or hypertrophy may lead to impingement of the nerve. Some may include radicular pain, numbness, or weakness of the lower extremity. Some are just bothered by the contracture of the muscle. Examination reveals point tenderness over the buttocks medial to the greater trochanter. Internal rotation of the hip may exacerbate the pain. Differential diagnosis includes trochanteric bursitis, sacroiliac joint pain. Treatment consists of rest, ice, and stretching of the muscle (toe touching with the legs crossed).

SNAPPING HIP SYNDROME A snapping hip is a common problem in children and young adults. Illiotibial band snapping, the external variety of snapping hip occurs at the greater trochanter and the iliopsoas snapping as the internal form occurs at iliopectinal eminence. Stuart and Epstein 16 report two cases of habitual hip dislocation presenting as snapping hip. A clinical entity that is rarely described but should be rembered.

ILIOTIBIAL BAND SNAPPING The snapping tendon syndrome may be caused by abnormalities of the fascia lata. It is characterized by hip pain and audible snapping. It occurs as the hip goes from flexion to extension. Weyer and T6nnis 18 described an examination method for the identification of the snapping hip by bending 30 ° to 40 °, adduction, and alternative internal and external rotation of the hip. Through the maximal pretension of the iliotibial tract, it is possible to definitely prove the existance of even minor snapping. In view of the fact that examination method is a passive one, it can also be employed intraoperatively for direct control of the result of the operation. The etiology in most cases is unknown and cannot be identified. Brignall and Stainsby19 reported a case of fibrosis of the Glutaeus maximus after an injection in the buttock as cause of snapping hip. It is seen in young adolescents, predominantly in the female with a wide pelvis or prominent trochanters. In our clinic we have seen it quite often after total hip arthroplasty operated by transgluteal approach, and it can get painful from friction between the trochanter and the overlying iliotibial band. 2° In these cases it is often difficult to tell if a trochanteric bursitis releases the snapping or if the snapping generates a trochanteric bursitis. At times snapping may be asymptomatic so can be left alone. Treatment includes rest, iliotibial band stretching, antiinflammatory agents, and, often, one or two steroid injections may be helpful. At times snapping can be resistent to conservative measures and surgery has to be performed to eliminate disabling pain from snapping or bursitis. The technique we have used for over 25 years is Z-plasty and fixation of the iliotibial band to the trochanter. 21

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SNAPPING OF ILIOPSOAS MUSCLE The internal etiology of s n a p p i n g is refered to the s n a p p i n g of the iliopsoas in the d e e p anterior groin. The s n a p p i n g is released b y extension f r o m a flexed a n d externally rotated position. J a c o b s o n a n d Allen 22 d e s c r i b e d the p a t h o a n a t o m y of this p o o r l y u n d e r s t o o d s y m p t o m complex a n d could d e m o n s t r a t e b y iliopsoas b u r s o g r a p h y u n d e r fluoroscopic control, that a s u d d e n jerking m o v e m e n t is elicited of the iliopsoas o v e r the anterior femoral h e a d and capsule as the t e n d o n m o v e d f r o m lateral to m e d i a l w i t h hip extension. This cause of hip p a i n has b e e n reported usually affecting y o u n g a n d active patients, such as dancers. The p a i n m a y occur w i t h o u t the presence of an enlarged iliopsoas bursa, w h i c h is a separate condition. Patients are able to r e p r o d u c e their s y m p t o m s b y extension of the fixed, abducted, a n d externally rotated hip a n d they cannot report a specific incident that h a d initiated their s y m p t o m s . The b u r s a b e t w e e n the t e n d o n a n d the hip capsule can get inflamed w i t h the repetitive s n a p p i n g m a n o e u v r e . A small a m o u n t of contrast injected into the b u r s a d e m o n s t r a t e s the presence of a snapping. A therapeutic injection in the b u r s a m a y delay or obviate surgery. 23-25 C o n s e r v a t i v e t r e a t m e n t consists in modified activity, hip flexor stretching, a n d a n t i - i n f l a m m a t o r y medication. An operative a p p r o a c h involving a partial release or lengthening of the iliopsoas m a y be necessary at times. 21 The t e n d o n release is p e r f o r m e d t h r o u g h a 5-cm horizontal incision a p p r o x i m a t e l y 2.5 c m b e l o w the inguinal skin crease a n d centered over the adductors. Between pectineus a n d adductor brevis, m e d i a l to the femoral artery, the iliopsoas t e n d o n is identified and d i v i d e d u n d e r direct vision using t e n d o n release t h r o u g h this a p p r o a c h rather than a m o r e extensive ilioinguinal exposure, it is cosmetically more acceptable and avoids damage to the lateral cutaneous nerve. Bandi related to m e his experience of a p s o a s m i n o r s y n d r o m e (W. Bandi, personal c o m m u n i c a t i o n , 1995). The patients suffer f r o m a painful tension d e e p in the groin a n d present antalgic scoliosis w h i c h d i s a p p e a r s w h e n they p u t the leg on a step. Clinically one can p a l p a t e p r o x i m a l l y of the inguinal ligament a painful a n d taut rope. Pain increases d u r i n g p a l p a t a t i o n w h e n the patient rises his straight leg. W h e n conservative m e a s u r e s fail, the surgical t e n o t o m y of the p s o a s m i n o r t e n d o n m a y give g o o d results. Bandi prefers an incision 8 cm long parallel to the inguinal ligament. Blunt dissection b e t w e e n rectus a n d obliquus a b d o m i n u s . Extraperitoneally the fascia iliaca is incised and the femoral n e r v e is p u s h e d medially. The

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tendon of the p s o a s m i n o r is cut a n d the taut ends of the t e n d o n separate b y 2 to 3 cm.

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