Legg-Calvé-Perthes Disease

Overview

Definition

Legg-Calvé-Perthes disease (LCPD), also called coxa plana, is a disorder of the hip in which blood supply to the proximal femoral epiphysis Epiphysis The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united. Bones: Structure and Types is temporarily interrupted, resulting in avascular necrosis Avascular Necrosis Hip Fractures and permanent deformity Deformity Examination of the Upper Limbs of the femoral head and acetabulum.

Epidemiology

• Population statistics:
  • Affects 1 in 1,200 people in the United States
  • Male-to-female ratio: 4:1
  • Peak incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency between 4 and 8 years of age
  • 85–90% of cases are unilateral (up to 15% may present with bilateral or sequential Sequential Computed Tomography (CT) involvement)
  • Highest incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: White populations
  • Lowest incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: East Asian populations
  • More prevalent in urban areas in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with lower socioeconomic status
• Risk factors:
  • Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics (10% of cases are familial)
  • HIV HIV Anti-HIV Drugs (up to 5% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with HIV HIV Anti-HIV Drugs have avascular necrosis Avascular Necrosis Hip Fractures of the hip)
  • Clotting disorders
  • Trauma
  • Steroid use
  • Developmental hip dysplasia 
  • Low birth weight
  • Short stature
  • Exposure to tobacco

Etiology

Legg-Calvé-Perthes disease is a multifactorial disease caused by a combination of genetic, environmental, and vascular factors. The interruption of blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to the capital femoral epiphysis Epiphysis The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united. Bones: Structure and Types is the inciting cause. The following have been implicated as potential contributors to vascular compromise:

• Trauma
• Synovitis Synovitis Inflammation of the synovial membrane. Rheumatoid Arthritis
• Coagulopathies Coagulopathies Hemothorax (such as Factor V Leiden Factor V Leiden Hypercoagulable States mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations)
• Steroid use
• Microvascular endothelial dysfunction
• Genetic associations include COL2A1 mutations and abnormalities in insulin-like growth factor-1 Insulin-like growth factor-1 A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on growth hormone. It is believed to be mainly active in adults in contrast to insulin-like growth factor II, which is a major fetal growth factor. Hypertrophic and Keloid Scars (IGF-1)

Pathophysiology

There are 4 stages of LCPD:

1. Necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage: Disruption of blood supply leads to necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage of subchondral cortical bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types or infarction of femoral capital epiphysis Epiphysis The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united. Bones: Structure and Types.
2. Fragmentation Fragmentation Chronic Apophyseal Injury: infarcted bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types reabsorbed
3. Reossification: Osteoblastic activity becomes prominent.
4. Remodeling: Femoral head reshapes during patient growth.

Complications

• Deformities of femoral head with disease progression:
  • Coxa magna: widening of femoral head
  • Coxa plana: flattening of femoral head
• Resultant hip incongruence can lead to:
  • Labral tears
  • Osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis of hip with age

Clinical Presentation

History

• Chief complaint: limp or altered gait Gait Manner or style of walking. Neurological Examination
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways may present early or late in the disease course (after 3 months), usually worsens with activity: pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways is usually mild (limp may be painless) and may be referred to anteromedial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy or knee
• May be associated with delayed bone age Bone Age Short Stature in Children and growth
• Usually lacks systemic symptoms

Clinical findings

• Examination of gait Gait Manner or style of walking. Neurological Examination:
  • Antalgic gait Gait Manner or style of walking. Neurological Examination: short stance phase due to pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways when loading affected hip 
  • Trendelenburg gait Gait Manner or style of walking. Neurological Examination: downward tilt of pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy contralateral to affected hip during swing phase of walking
  • Abductor lurch or intermittent limp, especially after exertion
• Lower extremity exam:
  • Leg-length discrepancy (affected leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy is shorter)
  • Atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation of quadriceps/buttocks muscles from disuse
  • Reduced range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs of hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy

Diagnosis

The diagnosis of LCPD is clinical and confirmed through targeted imaging, so a high degree of suspicion is required in the approach to the limping child.

• Labs may be used to exclude other diagnoses: complete blood count (CBC) and erythrocyte sedimentation rate Erythrocyte Sedimentation Rate Soft Tissue Abscess ( ESR ESR Soft Tissue Abscess) to rule out infectious causes of limp
• X-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays looking for pathological deformation of hip: anteroposterior (AP) and frog-leg lateral views
  • Early radiographs may appear normal.
  • Early findings: widening of joint space
  • Caffey’s sign or crescent sign Crescent sign Intussusception: 
    • Subchondral radiolucent Radiolucent An object of low density that is permeable to X-rays (looks black) X-rays fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures line parallel to articular surface of femoral head
    • May be visible prior to fragmentation Fragmentation Chronic Apophyseal Injury
  • Later findings:
    • Fragmentation Fragmentation Chronic Apophyseal Injury of femoral ossification Ossification The process of bone formation. Histogenesis of bone including ossification. Bones: Development and Ossification center
    • Lateral subluxation Subluxation Radial Head Subluxation (Nursemaid’s Elbow) and flattening of femoral head
• Magnetic resonance imaging (MRI) and bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types scans: may be part of evaluation if diagnosis is in question
  • MRI reveals marrow changes.
  • Bone scan Bone Scan Osteosarcoma reveals decreased perfusion to femoral head.
  • Dynamic contrast-enhanced MRI Contrast-enhanced MRI Imaging of the Head and Brain is now preferred for early detection and monitoring.

Management

Goals of medical therapy

• Eliminating hip irritability and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• Maintaining adequate range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs
• Prevention of femoral epiphysis Epiphysis The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united. Bones: Structure and Types collapse, containment of femoral head

Conservative management

• Minimal weight bearing and protection of joint until ossification Ossification The process of bone formation. Histogenesis of bone including ossification. Bones: Development and Ossification is complete:
  • Hip may be held in abduction Abduction Examination of the Upper Limbs by abduction Abduction Examination of the Upper Limbs casts or ambulatory braces. 
  • Goal is to promote containment of femoral head within acetabulum.
• Physical therapy Physical Therapy Becker Muscular Dystrophy and stretching exercises to maintain range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs and muscle tone Muscle tone The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. Skeletal Muscle Contraction
• Nonsteroidal anti-inflammatory drugs ( NSAIDs NSAIDS Primary vs Secondary Headaches) if needed for pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways management
• Children ＜ 6–8 years old have more favorable outcomes to conservative therapy.

Surgical therapy

• Operative procedures include varus femoral osteotomy and Salter osteotomy (goal is containment of femoral head).
• More commonly used in patient > 8 years of age
• Triple pelvic osteotomy (TPO) is an option for severe cases with significant femoral head deformity Deformity Examination of the Upper Limbs.
• Lack of consensus on best treatment

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

• Generally self-limited (2–4 years)
• Long-term outcomes depend on patient age, extent of femoral head involvement, and treatment.
• Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship left with propensity to degenerative changes Degenerative Changes Spinal Stenosis: 
  • Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship function well until their 40s.
  • Hip replacement may be indicated due to chronic osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis.

Clinical Relevance

Differential diagnosis

• Sickle cell disease Sickle cell disease Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease ( SCD SCD Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease): hemoglobinopathy caused by point mutation Point Mutation A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair. Types of Mutations in 6th codon Codon A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal. Most codons are universal, but some organisms do not produce the transfer RNAs complementary to all codons. These codons are referred to as unassigned codons. Basic Terms of Genetics of β-globin gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics on chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 11, which ultimately leads erythrocytes Erythrocytes Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology to adopt characteristic “sickle” appearance. Can impair blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to femoral head, causing avascular necrosis Avascular Necrosis Hip Fractures of femoral head in young children with SCD SCD Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease. May be referred to as osteonecrosis of femoral head (ONFH).
• Developmental hip dysplasia (DHD): congenital disorder of hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy characterized by hip instability, displayed as subluxation Subluxation Radial Head Subluxation (Nursemaid’s Elbow) or dislocation, frequently recognized in infants.

Within clinical spectrum of LCPD

Short stature: due to genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics, developmental disorders, and leg-length discrepancy, child may be shorter in stature.

Complication of LCPD

Osteoarthritis (OA): most common form of arthritis, often referred to as “wear and tear” arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Principally a disease of aging, characterized by hyaline articular cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology loss, but also involving changes to subchondral bone Subchondral Bone Osteochondritis Dissecans, synovium, and surrounding joint structures. Anatomical abnormalities produced by LCPD increase the risk for degenerative changes Degenerative Changes Spinal Stenosis of the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy and the need for surgical replacement of the hip.