Perthes disease: What is it, Causes, Symptoms and Physiotherapy Management

Legg-Calvé-Perthes disease (LCPD) is an idiopathic juvenile avascular necrosis of the femoral head in a skeletally immature patient, i.e. children. Legg-Calvé and Perthes discovered this disease approximately 100 years ago. The disease affects children from ages of two to fourteen. The disease can lead to permanent deformity and premature osteoarthritis.

LCPD is a hip disorder which is caused by an interruption of blood supply to the femoral head.

As the blood vessels around the femoral head disappear and cells die, the bone also dies and stops growing. When the healing process begins, new blood vessels begin to remove the dead bone. This leads to a decrease in bone mass and a weaker femoral head. It can also lead to deformity of the bone due to new tissue and bone replacing the necrotic bone.


The bone death appears in the femoral head due to an interruption in blood supply. As bone death appears, the ball develops a fracture of the supporting bone. This fracture indicates the outset of bone reabsorption by the body. As bone is slowly absorbed, it is replaced by new tissue and bone.


Other names are: ischaemic necrosis of the hip, coxa plana, osteochondritis and avascular necrosis of the femoral head.


Many aspects of the disease remain unknown or are unclear, including etiology but many factors may be involved including gender, genetics, socioeconomic status and environment. Also the pathophysiology of best methods for treatment of patients in different age groups affected with the disease is unclear.

Perthes disease

Clinically Relevant Anatomy

The femoral head is supplied with blood from the medial circumflex femoral and lateral circumflex femoral arteries, which are branches of the profunda femoris artery.


The medial femoral circumflex artery extends posteriorly and ascends proximally deep to the quadratus femorus muscle. At the level of the hip it joins an arterial ring at the base of the femoral neck.

The lateral femoral circumflex artery extends anteriorly and gives off an ascending branch, which also joins the arterial ring at the base of the femoral neck.

This vascular ring gives rise to a group of vessels which run in the retinacular tissue inside the capsule to enter the femoral head at the base of the articular surface.

There is also a small contribution from a small artery in the ligamentum teres to the top of the femoral head which is a branch of the posterior division of the obturator artery.

Epidemiology /Etiology

LCPD is an idiopathic disease, but a variety of theories about the underlying cause have been proposed since its discovery over a century ago, ranging from congenital to environmental and from traumatic to socio-economic causes. LCPD has been associated with thrombosis, fibrinolysis, and abnormal growth patterns of the bone.

It has also been associated with an abnormality in the Insulin-like Growth Factor-1 Pathway, repeated mircotrauma or mechanical overloading related to hyperactivity of the child or a very low birth weight or short body length at birth.


Some studies suggest a genetic factor, i.e. a type II collagen mutation, and other studies report maternal smoking during pregnancy as well as other prenatal and perinatal risk factors.

It may be be that LCPD requires a set or subset of the aforementioned causes. As of yet it is hard to discern which are determining or merely contributing factors to the onset of the disease.

Pathogenesis

The pathogenesis of osteonecrosis is becoming better understood. Most research suggests either a single infarction event with subsequent mechanical loading that further injures and/or compresses the vessels during the repair process or multiple episodes of infarction are required to produce LCPD.


The key pathological event associated with the initiation of the development of LCPD is disruption of the blood supply to the capital femoral epiphysis.

Subsequently ischaemic necrosis occurs in the bone, marrow and cartilage of the femoral head which results in a cessation of endochondral ossification and decreased mechanical strength.

When mechanical loading surpasses the weakened head’s capacity, deformity is initiated and progresses due to resorption of the necrotic bone and asymmetric restoration of endochondral ossification.

Classification

LCPD classification may be divided into three categories: those defining the stage of the disease, those attempting to prognosticate outcome, and those defining outcome.

Legg calve perthes disease classification

Clinical Presentation

LCPD is present in children 2-13 years of age and there is a four times greater incidence in males compared to females. The average age of occurrence is six years.

Limp: A psoatic limp is typically present in these children secondary to weakness of the psoas major. The limp is worse after physical activities and improves following periods of rest. The limp becomes more noticeable late in the day, after prolonged walking.

Pain: The child is often in pain during the acute stages. The pain is usually worse late in the day and with greater activity. Night pains are frequent.

ROM: The child will show a decrease in extension and abduction active ranges of motion. There is also a limited internal rotation in both flexion and extension in the early phase of the disease.

Unusual high activity level: Children with LCPD are usually physically very active, and a significant percentage has true hyperactivity or attention deficit disorder.

Abnormal growth patterns: General pattern: The forearms and hands are relatively short compared to the upper arm. The feet are relatively short compared to the tibia.

Differential Diagnosis

• Septic arthritis or infectious arthritis
• Sickle cell-Osteonecrosis of the hip
• Spondyloepiphyseal Dysplasia Tarda
• Gaucher Disease
• Transient Synovitis of the hip
• Hip Labral Disorders
• Chondroblastoma
• Juvenile Rheumatoid Arthritis
• Multiple epiphyseal dysplasia

Diagnostic Procedures

A MRI is usually obtained to confirm the diagnosis; however x-rays can also be of use to determine femoral head positioning.

Since LCPD has a variable end result, an imaging modality that can predict outcome at the initial stage of the disease before significant deformity has occurred is ideal.

The extent of femoral head involvement depicted by non-contrast and contrast MRI showed no correlation at the initial stage of LCPD, indicating that they are assessing two different components of the disease process. In the initial stage of LCPD, contrast MRI provided a clearer depiction of the area of involvement.

To quantify femoral head deformity in patients with LCPD novel three dimensional (3D) magnetic resonance imaging (MRI) reconstruction and volume based analysis can be used. The 3D MRI volume ratio method allows accurate quantification and demonstrated small changes (less than 10 percent) of the femoral head deformity in LCPD. This method may serve as a useful tool to evaluate the effects of treatment on femoral head shape.

Outcome Measures

Examination

Gait

Is usually antalgic. It is possible that the child has a Trendelenburg gait (a positive Trendelenburg sign on the affected side).

The child can also have a Duchenne gait, which is marked by a trunk lean toward the stance limb with the pelvis level or elevated on the unloaded side.

There is insufficient evidence and lack of reliability and validity to support use of the observational gait assessment tools with this population.

Range of movement

The restriction of hip motion is variable in the early stages of the disease. Many patients, may only have a minimal loss of motion at the extremes of internal rotation and abduction. At this stage there usually is no flexion contracture. Loss of hip ROM in patients with early LCPD without intra-articular incongruity is due to pain and muscle spasm. [38] This is why, if the child is examined for instance after a night of bed rest, the range will be much better then later in the day.

Further into the disease process, children with mild disease may maintain a minimal loss of motion at the extremes only and thereafter regain full mobility. Those with more severe disease will progressively lose motion, in particular abduction and internal rotation. Late cases may have adduction contractures and very limited rotation, but the range of flexion and extension is only seldom compromised.

Pain

Pain occurs during the acute disease. The pain may be located in the groin, anterior hip area, or around the greater trochanter. Referral of pain to the knee is common.

It’s recommended that pain is assessed using the Numerical Rating Scale (NRS)

 

Atrophy

In most cases there is atrophy of the gluteus, quadriceps and hamstring muscles, depending upon the severity and duration of the disorder.



Medical Management

The approach to treatment is controversial. Prior to evaluating if a surgical intervention is necessary, there has to be a clear understanding of the disease prognosis.

Approaches to treatment can be divided in conservative or operative treatments.

Medications include non-steroidal anti-inflammatories (NSAIDs) for pain and/or inflammation.

Psychological factors are also considered. Persons with a history of LCPD are 1.5 times more likely to develop attention deficit disorders compared to their peers. They also have a higher risk of developing depression.

Physical Therapy Management

PT

There is no consensus concerning the possible benefits of physiotherapy in LCPD, or in which phase of the development of the health problem it should be used.

Physical therapy interventions have been shown to improve ROM and strength in this patient population.

Individuals who participate in supervised clinic visits demonstrate greater improvement in muscle strength, functional mobility, gait speed, and quality of exercise performance than those who receive a home exercise program alone or no instruction at all.

Individuals who receive regular positive feedback from a physical therapist are more likely to be compliant with a supplemental home exercise program.

It is recommended that supervised physical therapy is supplemented with a customized written home exercise program in all phases of rehabilitation.

Improve ROM

• Static stretch for lower extremity musculature
• Dynamic ROM
• Perform AROM and AAROM (active assistive range of motion) following passive stretching to maintain newly gained ROM

Improve strength

• Begin with isometric exercise and progress to isotonic exercises in a gravity lessened position with further progression to isotonic exercises against gravity. It is appropriate to include concentric and eccentric contractions.
• Begin with 2 sets of 10 to 15 repetitions of each exercise, with progression to 3 sets of each exercise to be used
• Local consensus would also do exercises to improve balance and gait and interventions to reduce pain.
• The hip overloading pattern should be avoided in children with LCPD. Gait training to unload the hip might become an integral component of conservative treatment in children with LCPD.

Non-surgical treatment with a brace is a reliable alternative to surgical treatment in LCPD between 6 and 8 years of age at onset with Herring B involvement. However, they could not know whether the good results were influenced by the brace or stemmed from having good prognosis of these patients.

Post-operative management

The rehabilitation is described with reference to the various stages of rehabilitation.

Initial Phase (0-2 weeks post-cast removal)

Goals of the Initial Phase

Minimize pain

• Hot pack for relaxation and pain management with stretchin
• Cryotherapy
• Medication for pain
• Optimize ROM of hip, knee and ankle (see appendix 1 for exercises)
• Passive static stretch (A hot pack may be used, based on patient preference and comfort
• Dynamic ROM
• Perform AROM and AAROM following passive stretching to maintain newly gained ROM
• Increase strength for hip flexion, abduction, and extension and knee and ankle
• Begin with isometric exercises at the hip and progress to isotonic exercises in a gravity lessened position
• Begin with isometric exercises at the knee and ankle, progressing to isotonic exercises in a gravity lessened position with further progression to isotonic exercises against gravity
• Begin with 2 sets of 10 to 15 repetitions of each exercise with progression to 3 sets of each exercise to be used
• Improve gait and functional mobility
• Follow the referring physician’s guidelines for WB status
• Transfer training and bed mobility to maximize independence with ADL’s
• Gait training with the appropriate assistive device, focusing on safety and independence.
• Improving skin integrity
• Scar massage and desensitization to minimize adhesions )
• Warm bath to improve skin integrity following cast removal, if feasible in the home environment
• Warm whirlpool may be utilized if the patient is unable to safely utilize a warm bath for skin integrity management
• PT is supervised at a frequency of 2-3 time per week (weekly)

Intermediate Phase (2-6 weeks post-cast removal)

Goals of the Intermediate Phase

• Minimize pain (see ‘initial phase’)
• Normalize ROM of the knee and ankle and optimize ROM of hip in all directions
• Increase strength of the knee and hip
• Isotonic exercises of the hip in gravity lessened positions and advancing to against gravity positions
• Isotonic exercises of the knee and ankle in gravity lessened and against gravity positions
• Maintain independence with functional mobility maintaining WB status and use of appropriate assistive devices
• Improving gait and functional mobility
• Follow the referring physician’s guidelines for WB status
• Continue gait training with the appropriate assistive device focusing on safety and independence
• Begin slow walking in chest deep pool water with arms submerged
• Improving Skin Integrity
• Continue with scar massage and desensitization
• PT is supervised at a frequency of 2-3 time per week (weekly)
• It is recommended that activities outside of PT are restricted at this time due to WB status. If the referring physician allows, swimming is permitted

Advanced Phase (6-12 weeks post-cast removal)

Goals

• Minimize pain (see ‘initial phase’)
• optimize ROM and flexibility of the hip, knee, and ankle
• Increase strength of the knee and hip, except for hip abductors, to at least 70% of the uninvolved lower extremity and increase strength of the hip abductors to at least 60% of the uninvolved lower extremity due to mechanical disadvantage
• Isotonic exercises of the hip, knee, and ankle in gravity lessened and against gravity positions, including concentric and eccentric contractions
• WB and non-weight bearing (NWB) activities can be used in combination based on the patient’s ability and goals of the treatment session
• Begin upper extremity supported functional dynamic single limb activities (e.g. step ups, side steps)
• Continue with double limb closed chain exercises with resistance, progressing to single limb closed chain exercises with light resistance if WB status allows
• Use of a stationary bike in an upright or recumbent position keeping the hip in less than 90 degrees of flexion
• Ambulation without use of an assistive device or pain
• Negotiate stairs independently using step to pattern with upper extremity (UE) support
• Improve balance to greater than 69% of the maximum Pediatric Balance Score (39/56) or single limb stance of the uninvolved side
• Improving gait and functional mobility
• PT is supervised at a frequency of 1-2 time per week (weekly)
• It is recommended that activities outside of PT are limited to swimming if the referring physician allows.
• Note: Running and jumping activities are restricted at this time.

Pre-Functional Phase (12 weeks to 1+ year post-cast removal)
Goals

Minimize pain (see ‘initial phase’)

• Optimize ROM and flexibility of the hip, knee, and ankle
Static stretch
• Increase strength of the knee and hip, except for hip abductors, to at least 80% of the uninvolved lower extremity and increase strength of the hip abductors to at least 75% of the uninvolved lower extremity due to mechanical disadvantages
• Negotiate stairs independently with reciprocal pattern an upper extremity support
• Improve balance to 80% or greater of the maximum Pediatric Balance Score (at least 45/56) or single limb stance of the uninvolved side
• Non-painful gait pattern with minimal deficits and normal efficiency
• PT is supervised at a frequency of 1-2 time per week (weekly)
• It is recommended that activities outside of PT include swimming and bike riding as guided by the referring physician .

Note: Running and jumping activities are restricted at this time.

Functional phase
Goals

• Reduce pain to 1/10 or less (see ‘initial phase’)
• Normalizing ROM: Increase ROM to 90% or greater of the uninvolved side for the hip, knee, and ankle, except for hip abduction and Increase hip abduction ROM to 80% or greater due to potential bony block
• Static stretch
• Normalizing strength: Increase strength of the knee and hip, except for hip abductors, to 90% or greater of the uninvolved lower extremity and Increase strength of the hip abductors to at least 85% of the uninvolved lower extremity due to mechanical disadvantage
• Progress isotonic exercises of the hip, knee, and ankle and include concentric and eccentric contractions.
• WB and NWB activities used in combination based on the patient’s ability (4) and goals of the treatment session.
• Functional dynamic single limb activities (e.g. step ups, side steps) with upper extremity support as needed for patient safety
• Progress single leg closed chain exercises with resistance
• Use of a stationary bike in an upright or recumbent position keeping the hip in less than 90 degrees of flexion
• Ambulation with a non-painful limp and normal efficiency
• Negotiation of stairs independently using a reciprocal pattern without UE support
• Improve balance to 90% or greater of the maximum score on the Pediatric Balance Scale (at least 51/56) or single limb stance of the uninvolved side. It is recommended that progression to the Functional Phase occur when the physician has determined there is sufficient re-ossification of the femoral head based on radiographs. Note: Jumping and other impact activities are still limited and only progressed per instruction from the physician based on healing and progression of the disease process.