Journal of Manipulative and Physiological Therapeutics
Volume 26, Issue 2 , Page 11, February 2003

The stubborn hip: Idiopathic avascular necrosis of the hip☆

aSports Sciences Resident II, Department of Graduate Studies and Research, Canadian Memorial Chiropractic College, Toronto, Canada

Received 2 November 2001

Article Outline

Abstract 

Objective: To highlight the unusually indolent course of avascular necrosis in this patient, the risk factors of which chiropractors should be aware, the necessity of and means to an early diagnosis, the limitations of plain film radiographs, as well as the current medical treatments. Clinical Features: A 27-year-old male professional soccer player had a tight and achy right hip for approximately 6 years, a condition that increased with physical activity. His active range of motion was limited by 25% in extension and abduction, and all resisted ranges of motion produced pain. After an equivocal radiograph and bone scan, magnetic resonance imaging revealed a subchondral defect located on the superior aspect of the right femoral head, consistent with avascular necrosis of the femoral head. Intervention and Outcome: Presurgical management included Cybex testing, massage, myofascial release, interferential current, muscle strengthening, and muscle balancing exercises 3-5 times per week for 5 months. The patient underwent a curette procedure. Six weeks later, he returned to the chiropractic office for postsurgical rehabilitation, in which he is still involved today. He has made progress with respect to flexibility, strength, and muscle coordination. Conclusions: Idiopathic avascular necrosis of the hip is a clinical entity characterized by pain in the hip made worse with activity and at night, which may radiate to the groin, back, or thigh. Often, physical exam and radiographic findings are equivocal, at which point advanced imaging such as magnetic resonance imaging should be ordered to identify the disease in its earliest stages. (J Manipulative Physiol Ther 2003;26:e11)

Keywords:  Femur Head, Avascular Necrosis, Soccer

 

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Introduction 

It is estimated that 10,000 to 20,000 new cases of avascular necrosis (AVN) of the hip occur each year in the United States, an approximation tempered by the difficulty in actual incidence determination because many cases are clinically silent or misdiagnosed as degenerative joint disease.1 Many chiropractors have been taught that AVN is purely a roentographic diagnosis. This is in juxtaposition to the current tools for staging that have incorporated both advanced imaging, and subjective and objective findings in the absence of plain film evidence.2, 3, 4, 5 It is of vital importance to be cognizant of the numerous etiologic factors and varied clinical presentations associated with AVN (including hip, knee, back, and groin pain) when formulating a list of differentials. This is especially true for the patient with pain in the wake of a normal radiographic study. The educated, timely management and triage of patients suspected of having AVN of the hip could minimize advanced surgical procedures and maintain the viability of the femoral head—an issue of prime importance, especially in younger patients.1, 6, 7

This article highlights the unusually indolent course of AVN in this patient, the risk factors of which chiropractors should be aware, the necessity of and means to an early diagnosis, as well as the current medical treatments.

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Case report 

A 27-year-old male professional soccer player had right anterior hip pain of approximately 6 years' duration. He stated that his hip felt tight and achy in association with playing soccer. His pain was a constant 2/10 on a visual analogue scale (VAS) when he was not active; however, it increased to 8/10 on a VAS scale after practice or a game, at which time it also radiated into the medial thigh. The patient also indicated that his pain was worse at night and aggravated by twisting his torso around the involved limb while it was planted on the ground. He had been treated by various physiotherapists with soft tissue massage and interferential current periodically over the past 6 years, which produced transient relief. The patient also experienced some benefit from over-the-counter nonsteroidal anti-inflammatory drugs. Both his past medical and family histories were unremarkable. He denied any previous trauma or surgery to the hip or low back.

The physical examination revealed a normal posture and gait, with mild swelling of the right anterior hip and thigh. His active range of motion was limited by 25% in extension and abduction, and all resisted ranges of motion produced pain. A lumbar spine screen, which included a baseline neurologic exam, static palpation, active and passive range of motion, standing Kemps, Valsalva, and straight leg raise (SLR) proved unremarkable. Gaenslen's and Yeoman's tests caused right hip pain, whereas Ober's test and a modified Thomas test were both positive for tightness in their respective musculatures. Trendelenburg's test was painful with the right limb planted but yielded a negative result. Palpation of soft tissues revealed tender areas in the gluteus maximus, gluteus medius, iliotibial band, and psoas muscles surrounding the right hip.

Plain film studies of the right hip demonstrated mild sclerosis on both the femoral and acetabular sides of the joint, along with joint space narrowing and a lucency on the inferior aspect of the right femoral head. The radiologist's report stated that the findings were consistent with degenerative joint disease. A bone scan showed no indication of any abnormality in either hip. Magentic resonance imaging (MRI) was then performed, revealing a subchondral defect located on the superior aspect of the right femoral head, consistent with avascular necrosis of the femoral head.

Presurgical management included Cybex testing of both hips, massage and myofascial release, interferential current, muscle strengthening, and muscle balancing exercises 3 to 5 times per week for 5 months. The patient underwent a curette procedure and 6 weeks later returned to the chiropractic office for postsurgical rehabilitation. His current rehabilitation protocol is aimed at restoration of the internal and external rotation, and strength and endurance that he lost after surgery, with a protocol similar to his presurgical regimen.

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Discussion 

Misdiagnoses and clinical silence are the two main reasons that the annual incidence of AVN of the hip is hard to quantify.1, 2 With that in mind, chiropractors possess the ability to identify susceptible patients on the basis of certain risk factors and to aid in the early diagnosis or perhaps avoidance of osteonecrosis.

The numerous purported etiologies concerning the development of AVN substantially broaden the list of potential risk factors. The incidence of AVN ranges from 5% to 25% of patients on prolonged corticosteroid treatment.8, 9, 10 This population of individuals most certainly will seek chiropractic help for conditions such as asthma, systemic lupus erythematosus, and rheumatoid arthritis. Inflammatory arthridities also carry an additional risk in that many are associated with vasculitis that may affect the deep branch of the medial femoral circumflex artery, which is the predominant blood supply to the femoral head.1, 8, 9, 11 Other risk factors include alcoholism, sickle-cell anemia, coagulation deficiencies, Gaucher's disease, Caisson's disease, radiation therapy, and various myeloproliferative disorders, all of which can result in blockage of the aforementioned artery by means of an embolic-type mechanism.1, 3, 12 Trauma, which is the leading cause of AVN to date, can be the result of posterior dislocations of the hip during activity or surgical procedures and obterator externus muscle injuries.12, 13

From a pathogenetic standpoint, these etiologic factors are thought to result in AVN by means of the following mechanisms: (1) direct cellular insult to osteocytes (cytotoxicity); (2) venous stasis, which results in increased intraluminal pressure, thus retarding arterial blood flow; and (3) decreased arterial blood flow as a result of intra- or extravascular blockage of the vessels in question.1, 3, 12

Clinically, the most common symptom is pain in the hip upon weight bearing, which is consistent with the finding that the most common site of pain is the anterior superior aspect of the femoral head.3, 13 Referred pain may also be present in the back, groin, or buttock.3, 13 Many patients report having pain at night, which may be a product of increased intraosseous pressure as a result of venous stasis. As the disease progresses, the patient's pain increases, with a concomitant decrease in range of motion—first as a result of pain, then of the associated degenerative changes, especially on forced internal rotation. A positive Trendelenburg's test can be seen in 50% of patients, and most exhibit a loss of strength in the gluteus medius muscle in comparison to the uninvolved extremity.13

The 2 most prevalent tools for staging the disease are the Ficat and Arlet, and the Steinberg staging systems (Table 1).1, 2, 3, 4, 14

Table 1. Comparison of the Ficat and Arlet, and the Steinberg staging systems
Ficat and Arlet StagingSteinberg Staging
Stage 0 Normal/nondiagnostic radiography, bone scan, and MRI
Stage 1NormalNormal radiograph, abnormal bone scan, or MRI
Stage 2Cystic and/or sclerotic lesions, normal femoral headAbnormal radiograph showing cystic and sclerotic changes in the femoral head
Stage 3Crescent sign producing subchondral collapseCrescent sign producing subchondral collapse
Stage 4Joint space narrowing, secondary acetabular changes (cysts and marginal osteophytes)Flattening of the femoral head
Stage 5 Joint space narrowing with or without acetabular involvement
Stage 6 Advanced degenerative changes
The latter method, based on the sequence of pathologic events known to take place, has the advantage of incorporating findings from MRI and bone scan into its classification.1, 4 In my opinion, it is superior in that it allows for early detection and therefore intervention with negative plain film studies. A study performed by Smith et al14 confirmed that the Ficat classification system has poor interobserver and fair intraobserver reliability, necessitating the need for a more reliable and reproducible classification system. Biopsy demonstrating trabecular bone with empty lacunae is the most definitive method of diagnosis, whereas MRI is the most accurate noninvasive method.1, 7, 15, 16, 17, 18 Classically, AVN appears as a single-density, dark line on a T1-weighted image, signifying the border of viable and necrotic bone at the femoral head. On a T2-weighted image, the “Double Line Sign,” which consists of a white band of granulation tissue interposed between 2 dark bands of necrotic bone, is typical of AVN in the femoral head.1, 19

As yet, there is no generally accepted intervention for prevention of AVN, due in large part to the poor understanding of the disease's natural history. It is common knowledge, however, that early intervention yields the best results.1, 3, 4 AVN progresses rapidly once symptoms and radiographic changes are present. If the disease is left untreated, 80% of femoral heads will collapse within 4 years.1

Conservative treatment involves medications aimed at combating the physiologic processes responsible for disease initiation and includes vasodilators, lipid-lowering agents, and anticoagulants.1 Use of a pulsed electromagnetic direct current at the site of necrotic bone is thought to stimulate osteogenesis, though it has not yet approved by the Food and Drug Administration.1, 3 Protective weight bearing has been shown to provide results similar to core decompression; however, long-term studies indicate that the results are unsatisfactory.1

Surgical procedures are organized in accordance with disease staging, because preservation of the femoral head, especially in young patients, is of paramount importance. More radical procedures, which involve varying degrees of arthroplasty, are reserved for advanced cases.

Core decompression is most effective in Ficat stages I and II, before femoral head collapse, and offers immediate relief of symptoms by decreasing the intraosseous pressure due to venous congestion.1, 3 Bone grafting performed with the aforementioned procedure offers its best results between stages II and IV, and is of 2 varieties—vascularized and nonvascularized, the latter of which yields the best results.1, 3 Cortical or cancellous bone removed from the ilium, fibula, and tibia is inserted into the core. Delloye and Cornu20found this technique to be simple and possess the ability to substantially delay arthroplasty in the active patient. In addition, the article published by Scully et al21revealed an 89% and 81% survival rate for vascularized bone grafts performed on Ficat stage II and III patients, respectively, a result substantially higher than those from core decompression (65% and 21% for stages II and III, respectively).

Osteotomy is usually performed between Ficat stages I and III when a small-to-medium- size lesion is present. It involves altering the varus or valgus inclination of the femoral shaft to redirect weight-bearing forces from the necrotic area of the femoral head to one that is more amenable to support. Inao et al,22 in a 10-year follow-up of patients who had osteotomies, found that 11 out of 14 hips were highly satisfactory to acceptable in terms of disease progression. Mont et al23 also found that 76% of patients had good or excellent results after a mean follow-up duration of 11.5 years.

The use of limited resurfacing is limited to stages III and IV, and involves placing a cap, often made of ceramic, over the involved area in an attempt to prolong the life of the acetabulum.1, 3 Both Scott et al24and Hungerford et al25 report good or excellent results in 88% and 91% of limited femoral resurfacings, respectively.

Finally, total hip replacements are reserved for large lesions that involve greater than 30% of the femoral head, generally in stages IV and V.1, 3 This procedure is also used when the efficacy of one of the previous surgical interventions has run its course.1, 26 Garino and Steinberg26 state that after a 2- to 10-year follow-up of patients with total hip replacements, the revision rate for hybrid hips alone was 2.5% in the entire series, and 2% for hips with a minimum follow-up of 5 years. With the use of modern cement techniques and components, total hip arthroplasty can produce excellent results in the young patient with avascular necrosis and may be the treatment of choice when reconstructive surgery is required.26

Current chiropractic treatment includes identification of risk factors, appropriate referrals for advanced imaging and orthopedic surgical assessment, and both pre- and postoperative rehabilitation. As yet, no definitive information exists with respect to exercise choice and frequency. Convention would suggest that tempering objective findings (flexibility, endurance, strength, and muscle coordination) with the patient's subjective reports each visit will allow for the formation of exercises aimed at restoring functional deficits. In addition, exercises directed at the maintenance of cardiovascular fitness and existing muscular form, as well as those that are sport-specific, are essential for the athlete to reenter competition.

A baseline set of outcome measures was performed in this patient to track his progress and identify deficient areas that needed to be addressed, including range of motion (hip abduction and extension patterns) and Cybex muscle testing, isokinetic strength testing, and a VAS. The same tests were repeated every month, both before and after surgery. The results indicated a strength decrease in hip flexion, extension, and abduction. The patient was given forward and lateral stair-hopping exercises; hip flexion, extension, and abduction resistance exercises with tubing; proprioceptive drills on a wobble board; leg extensions; hamstring curls; and calf raises, which he performed bilaterally both for the crossover effect and for maintenance of existing muscle mass. The patient was also instructed to use a stationary or upper extremity bike for 25 min a day to maintain his cardiovascular fitness. Three times a week, after workouts, he received interferential current (IFC) and myofascial release.

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Conclusions 

Idiopathic AVN of the hip is a clinical entity characterized by pain in the hip made worse with activity and at night, which may radiate to the groin, back, or thigh. Often, physical exam and radiographic findings are equivocal, at which point advanced imaging such as an MRI should be ordered to identify the disease in its earliest stages. Patients with AVN of the hip should be referred for surgical consultation but not discharged, because pre- and postoperative care can maximize the patient's operative success. Routine testing of strength, flexibility, and muscular coordination must be performed to assess the effectiveness of the rehabilitation protocol.

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Acknowledgements 

My thanks to Dr Scott Howitt for his assistance with both the literature and manuscript reviews.

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References 

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☆ Submit requests for reprints to: Jason A. Pajaczkowski, Department of Graduate Studies and Research, Canadian Memorial Chiropractic College, 1931 Bayview Avenue, Toronto, Ontario M4G 3E6, Canada (e-mail: jpajaczkowski@cmcc.ca).

PII: S0161-4754(02)54126-9

doi:10.1067/mmt.2003.13

Journal of Manipulative and Physiological Therapeutics
Volume 26, Issue 2 , Page 11, February 2003

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