When diagnosing hip pain, the first thing many people think of is: Osteoarthritis – specifically Hip Osteoarthritis. However, often Osteoarthritis is only ruled out, and it's concluded that it can't be a serious hip problem. This is dangerous. Because there are numerous Hip Diseases that are congenital or develop in childhood/adolescence – and can lead to significant complaints, even if signs of osteoarthritis are only apparent later or not clearly visible. For younger patients, this can have fatal consequences if changes are overlooked or treated too late.

In this article you will learn:

• how osteoarthritis and coxarthrosis are defined and how they develop
• what secondary osteoarthritis is
• which hip diseases are often overlooked (e.g., hip dysplasia, retroverted acetabulum, Perthes disease, slipped capital femoral epiphysis, femoroacetabular impingement)
• how these diseases are recognized, diagnosed and treated – also with reference to artificial hip joints (hip TEP)
• when surgery is useful – and why “waiting as long as possible” is not always the best
• what patients should pay attention to – including advice to consult a hip specialist

Osteoarthritis, Coxarthrosis, and Secondary Osteoarthritis: Terms and Fundamentals

What is osteoarthritis?

• Osteoarthritis is a joint disease characterized by degenerative wear of the joint cartilage. In hip joints, it is specifically referred to as hip osteoarthritis or coxarthrosis
• Characteristic symptoms include pain during exertion, initial pain (e.g., after prolonged sitting), limited mobility, and possibly friction or grinding noises.

What is Coxarthrosis?

• Coxarthrosis refers to the osteoarthritis of the hip joint. Here, the cartilage between the femoral head and acetabulum deteriorates, leading to impaired joint function.
• Causes are diverse: age, overuse, malalignment, previous illnesses or injuries.

Primary vs. secondary osteoarthritis

• Primary Osteoarthritis: Osteoarthritis in which no clear triggering mechanism (such as malposition, injury, pre-existing condition, etc.) can be identified. Usually slow and age-related.
• Secondary Osteoarthritis: Osteoarthritis that occurs as a result of a known pre-load on the hip, such as malalignment, childhood illness, trauma, overloading, etc. These forms often start earlier and can progress more severely.

Why ruling out osteoarthritis ≠ problem solved

• Just because images (e.g., X-rays) do not show clear osteoarthritis does not mean that there are no hip problems. Many conditions cause pain, limited mobility, muscle problems, or mechanical conflicts that have not yet led to visible cartilage wear or are not represented in a typical manner.
• Especially young adults and adolescents often have anatomical malalignments that only later lead to osteoarthritis – but already cause significant symptoms.

Common hip diseases that are often overlooked – explained in detail

Hip dysplasia
Hip dysplasia is a congenital or undiagnosed in childhood malposition of the hip joint. It leads to the femoral head not being fully and stably seated in the acetabulum. Patients often experience pain in the groin or laterally on the hip, especially during prolonged walking or standing. Also, a slight limp or muscle tension can occur. Diagnostics are performed via clinical examinations, gait analysis, and special X-rays, in which angles such as the acetabular angle or center-edge angle are measured. Often, an MRI is additionally performed to visualize labrum or cartilage damage. If left untreated, hip dysplasia often develops into secondary coxarthrosis already in young adulthood. In severe cases, a hip replacement is required at a young age.

Retroverted Acetabulum
A retroverted acetabulum is a malalignment of the hip socket that is rotated too far back. This can be congenital or acquired. Affected individuals often report groin pain or discomfort during flexion and internal rotation of the hip. Diagnostic imaging, such as X-ray and CT/MRI scans, are necessary to determine the acetabular angle and version. If left untreated, the malalignment can lead to increased mechanical pressure on the articular cartilage, resulting in labral lesions and premature cartilage wear. Long-term, this can often develop into secondary osteoarthritis.

Femoroacetabular impingement (FAI)
Femoroacetabular impingement occurs due to a deformity of the femoral neck (CAM type) or an overhanging acetabulum (Pincer type). During movement, a mechanical conflict arises between the acetabulum and the femoral bone. Typical symptoms include groin pain, which occurs during deep flexion or rotational movements, but also at night or during prolonged sitting. Often, mobility is significantly restricted. Diagnostic procedures include clinical impingement tests, special X-rays, and MRI, often with contrast agent to visualize labral tears. If left untreated, cartilage and labral damage can occur, leading to secondary coxarthrosis and potentially requiring hip replacement surgery.

Perthes disease
Perthes disease is a circulatory disorder of the femoral head in childhood, usually between 4 and 11 years of age, more common in boys. Symptoms include limping, pain in the hip or knee, and limited mobility. Over time, it can lead to a permanent deformity of the femoral head. The diagnosis is made by X-ray, often supplemented by MRI to assess the extent of the circulatory disorder. Without timely treatment, the deformities can lead to uneven stress on the joint, resulting in secondary coxarthrosis in the long term. Many affected individuals require a total hip replacement in middle adulthood.

Slipped capital femoral epiphysis (SCFE, femoral head displacement)
This condition typically occurs during the growth phase in puberty, often in overweight adolescents. The femoral head epiphysis slips off the growth plate. Symptoms include gradual pain in the hip or knee, a significant limitation of internal rotation, and sometimes sudden, acute complaints upon complete slippage. Affected individuals develop an external rotation position of the leg. Special X-rays, such as the Lauenstein projection, are used for diagnosis. An acute slippage must be surgically stabilized immediately to prevent permanent damage. If the condition is not recognized in time, it leads to a permanent deformity of the femoral head, which in turn triggers labral and cartilage damage and can cause secondary osteoarthritis or coxarthrosis in young adulthood.

Other causes of hip pain
In addition to these typical conditions, there are other, less common causes. These include avascular necrosis of the femoral head outside of childhood, inflammatory joint diseases such as rheumatoid arthritis, infections, or consequences of injuries. Also, axial malalignments or muscular imbalances can lead to chronic hip complaints. All these conditions can - if left untreated - lead to secondary osteoarthritis and thus to a significant loss of function of the hip joint.

Late consequences: secondary osteoarthritis & coxarthrosis

• As mentioned above, secondary osteoarthritis results from pre-damage: malpositions, childhood diseases, slippage, overloading, etc.
• Studies show that, for example, hip dysplasia is a significant risk factor for early hip osteoarthritis - many patients with dysplasia need an artificial hip joint between the ages of 25-50.
• After Perthes disease, many affected individuals develop a deformity of the femoral head in adulthood, which can disrupt joint congruence, potentially leading to premature coxarthrosis.
• In cases of slipped capital femoral epiphysis, the risk for later osteoarthritis - depending on the severity and treatment - is high: studies indicate a risk between approximately 15% and 70% if the slippage is pronounced.

Diagnosis: How to detect hip diseases early?

To avoid misdiagnosis or underdiagnosis, the following steps are crucial:

1. Medical history

• Onset of symptoms: sudden or gradual, since when, progression
• Type of pain: exertion, rest, night, sitting, walking, sports
• Radiation: Groin, Thigh, Knee
• Previous hip diseases or childhood illnesses, operations, malalignments
• Growth age, weight, lifestyle (sports, stress)

1. Clinical examination

• Check hip mobility: flexion, extension, internal/external rotation, abduction
• Special tests for impingement (e.g. flexion + internal rotation)
• Gait pattern, leg length, external rotation, limping
• Muscle status, stability

1. Imaging

• X-rays: Overview of the pelvis, special projections (Lauenstein, Dunn, etc.)
• View of acetabular roof angles, acetabular coverage, version of the acetabulum (retroversion), shape of the femoral neck (CAM/Pincer)
• MRI: Cartilage, labrum, early signs of deformities or cartilage damage
• If necessary, CT for exact 3D assessment of malalignments

1. Further diagnostics as needed

• Lab tests if inflammatory causes are suspected
• Gait analysis
• If necessary, consultation with pediatric orthopedics if childhood pre-existing conditions are suspected

Treatment options

Depending on the disease, age, extent, and complaints, there are various therapeutic approaches.

Conservative (non-surgical)

• Physiotherapy: Building and maintaining the musculature around the hip joint, stretching exercises, mobilisation
• Load adjustment: Choose sports that spare the joint (cycling, swimming vs. jumping, abrupt twisting movements)
• Weight reduction in case of overweight to reduce mechanical stress
• Pain therapy as needed: e.g. NSAIDs
• Regular monitoring: possibly follow-up imaging (X-ray, MRI)

Conservative treatment can be very effective, especially if started early. However, many of the mentioned hip diseases lead to pronounced malalignment or growth-related changes, making conservative measures alone insufficient sooner or later.

Operative Therapy

• Osteotomy: Reorientation of the acetabulum (e.g., periacetabular osteotomy according to Ganz, etc.), femoral osteotomies, triple osteotomy, etc. Goal: correct malalignment, optimize acetabulum and femoral head alignment. For example, in hip dysplasia or retroversion.
• Corrections in adolescence or childhood: Perthes disease: surgery to improve containment, reduce deformities.
• Femoral head slippage (Epiphysiolysis capitis femoris): Immediate surgery for acute slippage; in chronic cases, also surgical stabilization and prevention of further slippage.
• Surgical interventions for Impingement: Arthroscopic or open surgery to remove bone spurs and repair labral damage.
• Artificial joint (hip replacement)

When is a hip replacement necessary, even in young patients?

• If there are already severe pain, rest pain, limited mobility that are not sufficiently alleviated by conservative and joint-preserving surgical procedures.
• If malalignments are so pronounced that they can no longer be corrected or their correction entails a high risk.
• If the articular cartilage, labrum, and bone are already severely damaged, continuing without artificial joint replacement would lead to permanent functional impairment, protective postures, or osteoarthritis symptoms.
• Modern hip arthroplasty has improved significantly - materials, operative techniques, minimally invasive approaches mean better durability, faster rehabilitation and often very good functional results.

“Waiting as long as possible” for a hip replacement – curse or blessing?

• There is a common recommendation to postpone surgery for as long as possible, so that a hip prosthesis can be used later - if necessary. This may be useful in certain cases, but not in general.
• If malalignments exist, especially in childhood/adolescence, late intervention often leads to irreversible damage (deformed femoral head, cartilage tear, labral tears). Even if osteoarthritis is not yet visible, the function can already be severely limited.
• In young people with hip dysplasia or impingement, for example, it is worth performing joint-preserving surgery early enough to delay or prevent the development of coxarthrosis or secondary osteoarthritis.
• Even if a TEP is necessary earlier, many patients benefit from modern hip prostheses in the form of freedom from pain, freedom of movement, and high quality of life. The durability of modern prostheses is significantly better than before; many studies show that after 10 years, more than 90% of the prostheses are still intact; after 20 years, usually still over 80-90%, depending on age, stress, material, etc.

Diagnostic and therapeutic: What patients should pay attention to

If you have hip pain, here are some tips to ensure that nothing is overlooked:

1. Consult a hip specialist – not just a general orthopedist. Specialists in hip and joint surgery, ideally with experience in hip arthroplasty and joint-preserving procedures.
2. Insist on comprehensive diagnostics – even if osteoarthritis has been ruled out. Ask specifically about malalignments, childhood diseases (Perthes, SCFE), impingement.
3. Request specialized imaging – special X-rays, MRI, etc., to assess the version of the acetabulum, shape of the femoral neck, deformity, and labrum.
4. Early therapy – physical therapy, load modification, weight management; if indicated, joint-preserving surgery.
5. Inform yourself about modern hip prostheses – especially important if your complaints are severe and your quality of life suffers.
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Summary

• Not all hip complaints are osteoarthritis, and just because osteoarthritis is not visible, it does not mean that there is no serious hip disease present.
• There are many causes of hip diseases - congenital or in childhood/adolescence - that can cause symptoms earlier and lead to secondary osteoarthritis / coxarthrosis in the long term.
• Diagnosis and treatment must be individualized; conservative methods can be helpful, but in cases of pronounced malalignment or damage, surgical interventions or hip replacement are necessary, even in young people.

Hip diseases in focus: Examples and special cases

To make the above principles more tangible, here are some case examples or typical courses, as observed in specialized clinics:

Case example A: Hip dysplasia, undetected until young adulthood

• Patient, early 30s, has had occasional groin pain since childhood, which was attributed to "muscle tension". Sporting activities are possible, but tension in the groin occurs with prolonged stress. X-ray shows acetabular undercoverage, slight coverage of the femoral head, but no major arthrotic changes yet.
• Measures: targeted physiotherapy, load reduction, possibly corrective osteotomy of the acetabulum to correct malposition. If this is done early, pain can be greatly alleviated, quality of life significantly improved - and the onset of coxarthrosis delayed.

Case example B: SCFE (Slipped Capital Femoral Epiphysis), late diagnosis

• Adolescent, overweight, pain initially in the knee, later also in the hip. Diagnosis SCFE in the intermediate stage; slip angle clear. Without treatment, there is a risk that the femoral head remains deformed, cartilage is damaged, and later coxarthrosis develops.
• Measures: depending on the stage, immediate surgical fixation, possibly corrective osteotomy later, monitoring, possibly early hip replacement if function is severely limited.

Case example C: Femoroacetabular impingement

• Young active patient, athletic. Recurring complaints when squatting deeply, when sitting for long periods, pain in the groin. Osteoarthritis not yet visible. Examinations show CAM deformity, labral tear.
• Treatment: arthroscopic correction (removal of bone excess, labrum repair), movement training, possibly modification of sports. Goal: prevention of premature secondary arthrosis or coxarthrosis.

Why ENDOPROTHETICUM Rhein-Main & Prof. Kutzner

If you are in this situation, it is particularly helpful to consult a hip specialist. The ENDOPROTHETICUM Rhein-Main under the direction of Prof. Dr. med. Kutzner offers:

• very much experience with all hip diseases - dysplasias, impingement, SCFE, Perthes disease and modern hip arthroplasty
• Expertise in joint-preserving surgeries as well as hip replacement in young patients
• modern diagnostic procedures and imaging
• Individual treatment planning that does not prematurely dismiss

Conclusion & Recommendation

• Hip diseases go far beyond osteoarthritis. For hip pain, it is worth taking differential diagnoses seriously.
• Secondary osteoarthritis often results from neglected or late-treated malalignments or childhood diseases.
• Especially for young patients: the earlier diagnosis and intervention occur, the better the function and quality of life – and the later or less frequently an artificial joint is needed.

Call to action

If you suffer from hip pain and have only been told that “arthritis has been ruled out” , don't just leave it at that. There could be another hip condition present that needs treatment. Make an appointment with Prof. Kutzner at ENDOPROTHETICUM Rhein-Main (www.endoprotheticum.de). Here you will find a hip specialist with extensive experience and modern hip arthroplasty. Together, a precise diagnosis can be made and you will receive a therapy tailored to your needs.