Femoral head necrosis

Anatomy and disease mechanism

The femoral head is the spherical part of the thigh bone (femur) that lies in the socket of the pelvis (acetabulum). It is supplied with blood via fine vessels. If this supply is interrupted or restricted, bone necrosis occurs. The initially soft, weakened bone can collapse under stress (subchondral collapse). The result is cartilage damage, loss of shape of the femoral head and secondary osteoarthritis.

• The upper front area of ​​the femoral head is usually affected (typical load zone).
• Early stages still show normal x-rays; Microstructural changes are visible on MRI.
• A collapse leads to permanent shape changes and increasing pain.

Causes and risk factors

Femoral head necrosis occurs multifactorially. In addition to mechanical factors, metabolism, blood vessels and coagulation play a role. The disease is often bilateral, even if initially only one side causes symptoms.

• Systemic factors: long-term or high-dose cortisone, excessive alcohol consumption, lipid metabolism disorders, sickle cell disease, systemic diseases (e.g. lupus), coagulation disorders.
• Trauma: femoral neck fractures, hip dislocations – the vascular supply can be damaged.
• Medications/Exposures: Immunosuppressants, chemotherapy drugs; rarely diving sickness.
• Anatomy and biomechanics: Impingement, misalignments or high load peaks.
• Idiopathic: In some cases the cause remains unclear.

Risk modification is an important component of therapy: reducing alcohol, stopping nicotine, optimizing vitamin D status and metabolic parameters.

Symptoms and stages

The main symptom is stress-dependent pain in the groin. Radiation to the buttocks, the front of the thigh or the knee is possible. Early stages are nonspecific; Later, start-up pain, stress and night pain as well as movement deficits (internal rotation, flexion) occur.

When should I seek medical advice?

• Persistent groin pain for several weeks, especially under stress.
• Persistent hip pain after trauma (fall, dislocation).
• Known risk factors (e.g. cortisone therapy) plus new hip problems.
• Increasing limitation of walking distance, pain at rest, pain at night.

Early diagnosis improves the chances of joint-preserving treatment.

Diagnostics in orthopedics

Diagnosis is based on history, physical examination and imaging. The aim is to record the stage and extent of the necrosis and to rule out differential diagnoses.

• Clinic: Pain location (groin), provocation tests, range of motion.
• X-ray: basic diagnostics. Early stages often inconspicuous; later sclerosis, cysts, collapse.
• MRI: method of choice in early stages; shows borders of necrosis, bone marrow edema, accompanying reactions.
• CT: Detailed assessment of bone fractures and shape changes.
• Laboratory: Rule out inflammatory or infectious causes; Control of vitamin D, metabolism.

Important differential diagnoses: hip impingement, labral lesion, stress fracture of the femoral neck, coxarthrosis, iliopsoas bursitis, osteitis pubis, lumbar radiculopathy.

Conservative therapy: what is possible?

Conservative measures aim to relieve pain, reduce load peaks in the femoral head and slow progression. They can be effective in early stages and in small areas of necrosis. However, safe healing cannot be guaranteed.

• Load control: Partial weight bearing with forearm crutches for 6-12 weeks, depending on MRI findings and pain.
• Activity modification: Avoiding jumps, deep squatting movements, rapid changes of direction.
• Physiotherapy: Joint-preserving mobilization, stabilization, hip, pelvic and trunk strength.
• Pain therapy: Short-term NSAIDs in conservative doses; Be aware of stomach/kidney risks.
• Metabolism optimization: Check vitamin D and calcium supply; Alcohol and nicotine reduction.
• Aids: cane/forearm crutches, if necessary temporary insoles to guide the load.

Substances such as bisphosphonates or iloprost are discussed. The evidence is heterogeneous; Use is cautious and individual, after weighing up the benefits and risks.

Stress control and everyday tips

• Favor cyclic, low-impact activities (cycling on flat terrain, aqua jogging, swimming).
• Short, frequent exercise sessions are better than long, stressful sessions.
• Stairs slowly, use handrails; carry heavy loads distributed on both sides.
• Choose the seat height so that you can stand up without having to bend deeply.
• Weight management: Every kilogram less reduces hip joint loads.

Physiotherapy: goals and content

Therapy programs are dosed individually. The focus is on pain-adapted mobility, stability and coordination. The aim is to improve joint centering and avoid evasive movements.

• Mobilization: Gentle capsule and soft tissue techniques, improvement of internal rotation.
• Stability: gluteal muscles, hip external rotators, trunk and pelvic stability.
• Gait school: step width, pelvic positioning, use of sticks, symmetry.
• Stretches: hip flexors, adductors – pain-guided, without end ranges under load.
• Return-to-Activity: Gradual increase in exercise according to clinical course and imaging.

Pain therapy and medication

Medication relieves symptoms but does not cure the necrosis. They are used in a targeted manner, for a limited period of time and with consideration of side effects.

• NSAIDs for short periods of time when pain peaks, not permanently without medical supervision.
• Paracetamol as an alternative in case of intolerance, observe maximum daily dose.
• For edema-accentuated symptoms: Interdisciplinary discussed options (e.g. iloprost) – decision made on a case-by-case basis.
• Supplements only if there is a proven deficiency (e.g. vitamin D).

Biological and joint-preserving procedures

In early stages and limited necrosis, joint-preserving procedures can be considered. The aim is to relieve pressure on the necrotic area and stimulate regeneration. The data situation varies; Careful indication is crucial.

• Core decompression: Relieves the necrotic area and stimulates blood circulation. Makes sense v. a. before collapse; Partial weight-bearing rehabilitation required.
• Bone replacement/spongioplasty: Filling the defect with the body's own bone or replacement material.
• Vascularized bone transfers: microsurgical procedure in selected younger patients; high effort, specialized centers.
• Supplements such as BMAC/PRP or Shockwave are being researched; Use only after clarifying unclear evidence.

Whether and which procedure is suitable depends on the size of the necrosis, location, stage, age, activity level and comorbidities.

Surgical therapy in advanced stages

If collapse and arthritic changes have occurred, joint-preserving therapy is usually no longer sufficient. Then a joint replacement (total hip endoprosthesis, H-TEP) can effectively reduce the stress-related pain and restore function.

• Indication: Failure of conservative/joint-preserving therapies, structural collapse, significant osteoarthritis, relevant reduction in quality of life.
• Alternatives: In selected cases, adjustment osteotomy to shift the load.
• Follow-up treatment: early mobilization, physiotherapy, gradual increase in activity.
• Implant choice and access depend on individual anatomy and bone quality.

The decision to have an operation is made together and after thorough information. Prognosis and risks depend on the stage and individual factors.

Prognosis and course

The course varies. Small necroses that are discovered early can remain stable with consistent weight relief and joint-preserving therapy. Larger, central load-bearing necrosis has a higher risk of collapse. Concomitant factors such as persistent alcohol or nicotine consumption worsen the prognosis.

• Early diagnosis (MRI) improves the chances of joint preservation.
• Consistent partial loading in vulnerable phases protects against collapse.
• Regular follow-up checks (clinical, imaging) are important.
• Pay attention to bilaterality: check the opposite side clinically and, if necessary, in the MRI.

Prevention and aftercare

• Address risk factors: reducing alcohol, stopping smoking, optimizing vitamin D.
• Medication such as cortisone only in the required dose and duration, closely accompanied.
• Dose stress, optimize technique for sport and work.
• After therapy: gradually increase the load, stick to the rehabilitation plan, pay attention to warning signs.

Related topics about hips and pelvis

Not every cause of groin pain is necrosis of the femoral head. Common differential diagnoses and accompanying problems include stress fractures of the femoral neck, misalignments or problems in the pelvic ring such as osteitis pubis. A careful assessment helps to provide targeted treatment.