| Legg–Calvé–Perthes syndrome | |
|---|---|
| Classification and external resources | |
Upper extremity of right femur viewed from behind and above. |
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| ICD-10 | M91.1 |
| ICD-9 | 732.1 |
| OMIM | 150600 |
| DiseasesDB | 9891 |
| MedlinePlus | 001264 |
| eMedicine | radio/387 |
| MeSH | D007873 |
Legg–Calvé–Perthes syndrome is a degenerative disease of the hip joint, where growth/loss of bone mass leads to some degree of collapse of the hip joint and to deformity of the ball of the femur and the surface of the hip socket. The disease is characterized by idiopathic avascular osteonecrosis of the capital femoral epiphysis of the femoral head leading to an interruption of the blood supply of the head of the femur close to the hip joint. The disease is typically found in young children, and it can lead to osteoarthritis in adults. The effects of the disease can sometimes continue into adulthood. It is also known more simply as Perthes disease,[1] ischemic necrosis of the hip, coxa plana, osteochondritis and avascular necrosis of the femoral head, Legg–Perthes Disease or Legg–Calve-Perthes Disease (LCPD).
It is named for Arthur Legg, Jacques Calvé and Georg Perthes[1][2][3][4] and was first described by Karel Maydl.
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Legg believed cause was impairment of blood supply to the femoral epiphysis, Calve ricketts, and Perthes deduced an infection possibly causing degenerative arthritis leads to LCP disease. Presently, a number of factors have been implicated including heredity, trauma, endocrine, inflammatory, nutritional, and altered circulatory hemodynamics. [5] Risk factors are not limited to impaired and disproportionate growth, low birth weight, delayed skeletal maturity, short stature, systemic hormonal changes and low economic index [6] Although no-one has identified the cause of Perthes disease it is known that there is a reduction in blood flow to the joint. The disease is theorized to include the artery of ligmentum teres femoris being constricted or even blocked too early, not allowing for time when the medial circumflex femoral artery takes over. The medial femoral circumflex artery is the principle source of blood supply to the femoral head. LCP disease is a vascular restrictive condition of idiopathic nature. Symptoms like femoral head disfigurement, flattening and collapse occurs typically between ages four to ten, mostly male children of Caucasian descent. Children affected by LCP disease often display uneven gait, limited range of motion and they experience mild to severe pain in groin area. [7] For example, a child may be six years old chronologically but may have grown only four years old in terms of bone maturity. The child may then engage in activities appropriate for six years old child but lacking the bone strength of an older child, these activities may lead to flattening or fracture of the hip joint. Genetics do not appear to be a determining factor, but it has been suggested that a deficiency of blood factors with anticoagulant property used to disperse blood clots may lead to blockages in the vessels supplying the joint, but these have not been proven. It has also been suggested that there is a deficiency of proteins C and S which also act as blood anticoagulants; if that were the case it is possible that their deficiency could cause clot formation in ligamentum teres femoris artery and hinder blood supply to the femoral head. However there is no evidence of this, over the years many theories have been published but none have stood up to professional research.
Common symptoms include hip, knee, or groin pain, exacerbated by hip/leg movement. The pain feels like a tooth ache, possibly severe. There is a reduced range of motion at the hip joint and a painful or antalgic gait. There may be atrophy of thigh muscles from disuse and an inequality of leg length. In some cases, some activity can cause severe irritation or inflammation of the damaged area including standing, walking, running, kneeling, or stooping repeatedly for an extended period of time.
The first signs are complaints of soreness from the child, which are often dismissed as growing pains, and limping or other guarding of the joint, particularly when tired. The pain is usually in the hip, but can also be felt in the knee ('referred pain'). In some cases, pain is felt in the unaffected hip and leg, due to the child favoring the injured side and placing the majority of their weight on the "good" leg. It is predominantly a disease of boys (4:1 ratio). Perthes is generally diagnosed between 5 and 12 years of age, although it has been diagnosed as early 18 months. Typically the disease is only seen in one hip, but bilateral Perthes is seen in about 10% of children diagnosed. (The differential diagnosis for Bi-lateral Perthes disease is Multiple Epiphyseal Dysplasia.} [8]
Onset of pain may be up to 4 hours after inactivity. Knee pain is felt in the back of the knee rather than in the front, not unlike a localized charley horse. This lasts for an hour or so and returns nightly on inactivity.
X-Rays of the hip may suggest and/or verify the diagnosis. X-rays usually demonstrate a flattened, and later fragmented, femoral head. A bone scan or MRI may be useful in making the diagnosis in those cases where x-rays are inconclusive. Neither bone scan nor MRI offer any additional useful information beyond that of x-rays in an established case. If MRI or bone scans are necessary, a positive diagnosis relies upon patchy areas of vascularity to the capital femoral epiphysis (the developing femoral head).
The goal of treatment is to avoid severe degenerative arthritis. Orthopedic assessment is crucial. Younger children have a better prognosis than older children.
Treatment has traditionally centered on removing pressure from the joint until the disease has run its course. Options include traction (to separate the femur from the pelvis and reduce wear) braces (often for several months, with an average of 18 months) to restore range of motion, physiotherapy, and surgical intervention when necessary because of permanent joint damage. To maintain activities of daily living, custom orthotics may be used. Over night traction may be used in lieu of walking devices or in combination. [9] These devices internally rotate the femoral head and abduct the leg(s) at 45 degrees. Orthoses can start as proximal as the lumbar spine (LSO), and extend the length of the limbs to the floor. Most functional bracing is achieved using a waist belt and thigh cuffs derived from the Scottish-Rite Orthosis.[10] These devices are typically prescribed by a physician and implemented by a certified orthotist. For older children, the distraction method has been found to be a successful treatment, using an external fixator which relieves the hip from carrying the body's weight. This allows room for the top of the femur to regrow. Many children need no intervention at all and are simply asked to refrain from contact sports or games which impact the hip. The Perthes Association has a "library" of equipment which can be borrowed to assist with keeping life as normal as possible, newsletters, a helpline, and events for the families to help children and parents to feel less isolated.
Modern treatment focuses on removing pressure from the joint to increase blood flow, in concert with physiotherapy. Pressure is minimized on the hip through use of crutches or a cane, and the avoidance of running-based sports. Swimming is highly recommended, as it allows exercise of the hip muscles with full range of motion while reducing the stress to a minimum. Cycling is another good option as it also keeps stress to a minimum. Physiotherapy generally involves a series of daily exercises, with weekly meetings with a physiotherapist to monitor progress. These exercises focus on improving and maintaining a full range of motion of the femur within the hip socket. Performing these exercises during the healing process is essential to ensure that the femur and hip socket have a perfectly smooth interface. This will minimize the long term effects of the disease. Use of zoledronic acid has also been investigated.[11]
Perthes disease is self limiting, but if the head of femur is left deformed there can be a long-term problem. Treatment is aimed at minimizing damage while the disease runs its course, not at 'curing' the disease. It is recommended not to use steroids or alcohol as these reduce oxygen in the blood which is needed in the joint. As sufferers age, problems in the knee and back can arise secondary to abnormal posture and stride adopted to protect the affected joint. The condition is also linked to arthritis of the hip, though this appears not to be an inevitable consequence. Hip replacements are relatively common as the already damaged hip suffers routine wear; this varies by individual, but generally is required any time after age 50.
Perthes is rare, occurring in approximately 5.5 of 100,000 children per year (and therefore a lifetime risk of developing the disease is about 1 per 1200 individuals). Male to female ratio of occurrence is 5:1. Most cases of Perthes disease have presented themselves by age 14 years old. [12] Caucasians are affected more frequently than other races. Children of sufferers of the disease themselves have a very slightly increased risk; 1 in 100 male children of adults with Legg–Calvé–Perthes syndrome also exhibit the syndrome. It is most commonly seen in persons aged 3–12 years, with a median of 6 years of age. In the US, 1 in 1200 children younger than 15 years will have this condition, while the occurrence in the UK is a slightly more common. Maternal cigarette smoking adds confounding factors beyond biological and environmental. Maternal tobacco smoking appears to be another significant risk which carries a risk five times higher than those not exposed to smoking. Second hand and side stream smoke appear less significant than maternal ingestion during pregnancy. [13]
Children younger than 6 have the best prognosis since they have time for the dead bone to revascularize and remodel, with a good chance that the femoral head will recover and remain spherical after resolution of the disease. [14] Children who have been diagnosed with Perthes' Disease after the age of 10 are at a very high risk of developing osteoarthritis and Coxa Magna. When an LCP disease diagnosis occurs after age eight, a better outcome results with surgery rather than non-operative treatments. [15] Shape of femoral head at the time when Legg-Calve Perthes Disease heals is the most important determinant of risk for degenerative arthritis; hence, the shape of femoral head and congruence of hip are most useful outcome measures.[16]
Osteonecrosis of the femoral head of young, small breed dogs (LCP disease) was first described in veterinary literature by Tutt in 1935 [17]: he described the disease, as did Waldenstromin 1(1909) in humans,[18] Toy and small breeds, particularly Toy Poodles, Yorkshire Terriers, Pugs, Jack Russell Terriers, and Dachshunds can be affected. LCP disease is an osteonecrosis of the femoral head in small breed dogs, usually those weighing less than 12 kg. There seems to be no sex predilection in the dog as contrasted to humans, in whom an 80% male incidence of the disease is evident. As in children, however, the condition is usually unilateral, with only about 10% to 15% incidence of bilateral disease. The age of onset varies between 4 months and 12 months, with a peak incidence at about 7 months. [19] The pathology of avascular necrosis followed by revascularization and bony remodeling of the femoral head in the dog certainly suggests a vascular etiology even though the cause of the condition is not completely understood. [20] Hip pain is usually seen by the age of 6 to 8 months.[21] The disease is bilateral in 12 to 16 percent of cases.[22] X-rays are necessary to make the diagnosis and show increased opacity and focal lysis in the head of the femur, and later in the disease, collapse and fracture of the neck of the femur. The recommended treatment is surgical removal of the head of the femur, but conservative treatment (rest, exercise restriction, and pain medication) may be effective in a limited number of cases (less than 25 percent, according to some studies).[22] The prognosis is excellent with surgery.
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