When it comes to diagnosing hip pain, the first thing many people think of is osteoarthritis —specifically coxarthrosis . However, osteoarthritis is often simply ruled out, concluding that it therefore cannot be a serious hip problem. This is dangerous. There are numerous hip conditions that are congenital or develop in childhood or adolescence—and that can lead to significant symptoms, even if signs of osteoarthritis are not apparent until late or not at all. For younger patients, this can have fatal consequences if changes are overlooked or treated too late.

In this article you will find out:

• how osteoarthritis and coxarthrosis are defined, how they arise
• what secondary osteoarthritis is
• which hip diseases are often overlooked (e.g. hip dysplasia, retroverted acetabulum, Perthes disease, epiphysiolysis capitis femoris, femoroacetabular impingement)
• how these diseases are detected, diagnosed and treated – also with regard to artificial hip joints (hip THA)
• When an operation makes sense – and why “waiting as long as possible” is not always the best option
• What patients should pay attention to – including advice on consulting a hip specialist

Osteoarthritis, coxarthrosis and secondary osteoarthritis: terms and basics

What is osteoarthritis?

• Osteoarthritis is a joint disease characterized by degenerative wear of the articular cartilage. In hip joints, it is specifically referred to as hip osteoarthritis or coxarthrosis .
• Typical symptoms include pain during exercise, pain when starting to move (e.g. after sitting for a long time), restricted movement, and possibly rubbing or grinding noises.

What is coxarthrosis?

• Coxarthrosis refers to osteoarthritis of the hip joint. This involves wear and tear of the cartilage between the femoral head and the acetabulum, resulting in impaired joint function.
• The causes are varied: age, overuse, misalignment, previous illnesses or injuries.

Primary vs. secondary osteoarthritis

• Primary osteoarthritis : Osteoarthritis in which no clear triggering mechanism (such as misalignment, injury, pre-existing condition, etc.) can be identified. It usually progresses slowly and with age.
• Secondary osteoarthritis : Osteoarthritis that occurs as a result of a known pre-existing condition on the hip, such as misalignment, childhood illness, trauma, overuse, etc. These forms often begin earlier and can be more severe.

Why osteoarthritis exclusion ≠ problem solved

• Just because images (e.g., X-rays) don't clearly show osteoarthritis doesn't mean there are no hip problems. Many conditions cause pain, restricted movement, muscle problems, or mechanical conflicts that haven't yet led to visible cartilage wear or where the wear isn't typically visible.
• Young adults and adolescents in particular often have anatomical misalignments that only later lead to osteoarthritis – but already cause significant discomfort.

Common hip diseases that are often overlooked – explained in detail

Hip dysplasia
Hip dysplasia is a malposition of the hip joint that is either congenital or undetected in childhood. It results in the femoral head not sitting fully and securely in the socket. Patients often experience pain in the groin or on the side of the hip, especially when walking or standing for long periods. A slight limp or muscle tension may also occur. Diagnosis is made through clinical examinations, gait analysis, and special X-rays that measure angles such as the acetabular roof angle or the center-corner angle. An MRI is often performed in addition to visualize labral or cartilage damage. If hip dysplasia is left untreated, secondary coxarthrosis often develops in young adulthood. In severe cases, a total hip replacement (THR) is therefore necessary at a young age.

Retroverted Acetabulum:
A retroverted acetabulum is a malposition of the hip socket that is rotated too far backward. This can be congenital or acquired. Those affected often report groin pain or discomfort during flexion and internal rotation of the hip. Special X-rays and CT/MRI scans are required to determine the socket angle and position. If left untreated, the malposition leads to increased mechanical pressure on the articular cartilage, which can cause labral injuries and premature cartilage wear. In the long term, this often leads to secondary osteoarthritis.

Femoroacetabular impingement (FAI)
Femoroacetabular impingement is caused by a malformation of the femoral neck (CAM type) or an overhanging acetabulum (pincer type). During movement, a mechanical conflict occurs between the acetabulum and the femur. Groin pain is typical and occurs during deep flexion or twisting movements, but also at night or during prolonged sitting. Mobility is often significantly restricted. Diagnosis includes clinical impingement tests, special X-rays, and an MRI, often with contrast medium to visualize labral tears. If the impingement is left untreated, cartilage and labral damage can occur, progressing to secondary coxarthrosis and necessitating total hip arthroplasty.

Perthes
disease is a circulatory disorder of the femoral head that occurs in childhood, usually between the ages of 4 and 11, and is more common in boys. Symptoms include limping, hip or knee pain, and restricted mobility. Over time, it can lead to permanent deformity of the femoral head. Diagnosis is made using X-rays, often supplemented by an MRI scan to determine the extent of the circulatory disorder. Without timely treatment, the deformities can lead to uneven loading in the joint, which in the long term causes secondary coxarthrosis. Many affected individuals therefore require a total hip replacement in middle adulthood.

Slipped femoral head epiphysis (SCFE)
This condition usually occurs during the growth phase of puberty, often in overweight adolescents. The femoral head epiphysis slips along the growth plate. Symptoms include gradual pain in the hip or knee, a significant restriction of internal rotation, and sometimes sudden, acute discomfort when the femoral head slips completely. Those affected develop an external rotation of the leg. Special X-rays such as the Lauenstein projection are used for diagnosis. An acute slip must be stabilized immediately with surgery to prevent permanent damage. If the condition is not detected early, it leads to 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 femoral head necrosis outside of childhood, inflammatory joint diseases such as rheumatoid arthritis, infections, or the consequences of injuries. Axial misalignments or muscular imbalances can also lead to chronic hip pain. All of these conditions—if left untreated—can eventually lead to secondary osteoarthritis and thus to a significant loss of function of the hip joint.

Late effects: Secondary osteoarthritis & coxarthrosis

• As mentioned above, secondary arthrosis by previous damage: misalignments, childhood illnesses, slipping, overloading, etc.
• hip dysplasia , for example, is a significant risk factor for early hip osteoarthritis – many patients with dysplasia require an artificial hip joint between the ages of 25 and 50.
• After Perthes disease, many affected individuals develop a deformity of the femoral head in adulthood, which can disrupt joint congruence, which in turn can lead to early coxarthrosis.
• In cases of epiphysiolysis capitis femoris, the risk of later osteoarthritis is high, depending on the severity and treatment: studies indicate a risk of between approximately 15% and 70% if slippage is pronounced.

Diagnosis: How can hip diseases be detected early?

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

1. anamnese

• Onset of symptoms: sudden or slow, since when, course
• Type of pain: exercise, rest, night, sitting, walking, sports
• Radiation: groin, thigh, knee
• Previous hip diseases or childhood illnesses, operations, misalignments
• Growth age, weight, lifestyle (sports, stress)

1. Clinical examination

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

1. Imaging

• X-rays : pelvic overview, special projections (Lauenstein, Dunn, etc.)
• View of acetabular roof angles, acetabular roofing, 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 misalignments

1. Further diagnostics if required

• Laboratory if inflammatory causes are suspected
• Gait analysis
• If necessary, consultation with pediatric orthopedics if pre-existing childhood diseases are suspected

Treatment options

Depending on the disease, age, extent and symptoms, there are different treatment approaches.

Conservative (non-surgical)

• Physiotherapy: Building and maintaining the muscles around the hip joint, stretching exercises, mobilization
• Load adaptation: Choose sports that are gentle on the joint (cycling, swimming vs. jumping, abrupt twisting movements)
• Weight reduction in overweight individuals to reduce mechanical stress
• Pain therapy as needed: e.g., NSAIDs
• Regular monitoring: if necessary, follow-up imaging checks (X-ray, MRI)

Conservative treatment can achieve a great deal, especially if started early. However, many of the hip diseases mentioned above, in cases of severe misalignment or after growth-related changes, sooner or later lead to conservative measures alone no longer being sufficient.

Surgical therapy

• Osteotomy : Repositioning the acetabulum (e.g., periacetabular osteotomy according to Ganz, etc.), femoral osteotomies, triple osteotomy, etc. Goal: Correcting malalignment, optimally aligning the acetabulum and femoral head. For example, in cases of hip dysplasia or retroversion.
• Corrections in adolescence or childhood : Perthes disease: Surgeries to improve containment and reduce deformities.
• Femoral head slippage (epiphysiolysis capitis femoris) : Immediate surgery in the case of acute slippage; in the case of chronic slippage, surgery is also required to stabilize the femoral head and prevent progression.
• Impingement procedures : Arthroscopic or open to remove bone protrusions and repair labral defects.
• Artificial joint (hip arthroplasty) : When a joint is already severely damaged, pain persists despite conservative and joint-preserving treatments, or misalignment and wear are so advanced that quality of life is significantly impaired. Young patients can also be affected, especially if they have pre-existing conditions such as dysplasia.

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

• If there is already severe pain, pain at rest, and restricted movement that conservative and joint-preserving surgical procedures do not provide sufficient relief.
• When misalignments are so severe that they can no longer be corrected or their correction involves a high risk.
• If the articular cartilage, labrum and bone are already so severely damaged that continuing without an artificial joint would lead to permanent loss of function, protective posture or osteoarthritis symptoms.
• Modern hip arthroplasty has improved significantly – materials, surgical techniques, and 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?

• It's often advised to postpone surgery as long as possible so that a hip replacement can be fitted later, if necessary. This may be advisable in certain cases, but not generally.
• If malalignments exist, especially in childhood/adolescence, late intervention often leads to irreversible damage (deformed femoral head, cartilage tears, labral tears). Even if osteoarthritis is not yet visible, function can already be severely limited.
• In young people with hip dysplasia or impingement, for example, it is worthwhile to perform joint-preserving surgery early enough to delay or prevent the development of coxarthrosis or secondary osteoarthritis.
• Even if a total hip replacement becomes necessary sooner, many patients benefit from modern hip replacements in the form of pain relief, freedom of movement, and a high quality of life. The durability of modern prostheses is significantly better than before; many studies show that after 10 years, over 90% of prostheses are still intact; after 20 years, the figure is usually still over 80-90%, depending on age, load, material, etc.

Diagnostic and therapeutic: What patients should pay attention to

If you have hip pain, here are some tips to make sure nothing is overlooked:

1. See a hip specialist —not just a general orthopedic surgeon. See a specialist in hip and joint surgery, ideally with experience in hip arthroplasty and joint-preserving procedures.
2. Insist on a comprehensive diagnostic evaluation —even if osteoarthritis has been ruled out. Ask specifically about misalignments, childhood conditions (Perthes syndrome, SCFE), and impingement.
3. Request special imaging – special x-rays, MRI, etc., to assess acetabular version, femoral neck shape, deformity, and labrum.
4. Early treatment – ​​physical therapy, exercise modification, weight management; if indicated, joint-preserving surgery.
5. Find out about modern hip prostheses – especially important if your symptoms are severe and your quality of life is suffering.
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Summary

• Not all hip problems are osteoarthritis, and just because osteoarthritis is not visible does not mean that there is not a serious hip condition.
• There are many causes of hip diseases – congenital or in childhood/adolescence – that cause symptoms at an early stage and can lead secondary osteoarthritis/coxarthrosis
• Diagnosis and treatment must be individualized; conservative methods can be helpful, but in cases of severe misalignment or damage, surgery 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 studies or typical courses of events as observed in specialty clinics:

Case study A: Hip dysplasia, undetected until young adulthood

• The patient, in her early 30s, has had occasional groin pain since childhood, which was attributed to "muscle tension." She is able to engage in sports activities, but experiences tension in the groin during prolonged exercise. An X-ray shows under-roofing of the acetabular roof, slight over-roofing of the femoral head, but no major arthritic changes.
• Measures include targeted physiotherapy, weight-bearing reduction, and, if necessary, a corrective osteotomy of the acetabulum to correct misalignment. If this is done early, pain can be significantly reduced, quality of life significantly improved, and the onset of coxarthrosis delayed.

Case study B: SCFE (epiphysiolysis capitis femoris), late diagnosis

• Teenager, overweight, pain initially in the knee, later also in the hip. Diagnosis of SCFE in the middle stage; angle of slippage is significant. Without treatment, there is a risk that the femoral head will remain deformed, cartilage will be damaged, and coxarthrosis will develop later.
• Measures: depending on the stage, immediate surgical fixation, if necessary corrective osteotomy later, monitoring, possibly early hip replacement if function is severely restricted.

Case Study C: Femoroacetabular Impingement

• Young, active patient, active in sports. Recurrent discomfort when squatting deeply or sitting for long periods, and groin pain. Osteoarthritis not yet visible. Examinations show CAM form and labral tear.
• Treatment: Arthroscopic correction (removal of bone protrusion, labral repair), movement training, and possible modification of sports. Goal: Prevention of premature secondary osteoarthritis or coxarthrosis.

Why ENDOPROTHETICUM Rhein-Main & Prof. Kutzner

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

• Extensive experience with all hip diseases – dysplasia, impingement, SCFE, Perthes disease and modern hip arthroplasty
• Expertise in joint-preserving operations as well as hip replacements for young patients
• modern diagnostic procedures and imaging
• individual therapy planning that does not put off prematurely

Conclusion & Recommendations for Action

• Hip diseases extend far beyond osteoarthritis. When it comes to hip pain, it's worth taking the differential diagnoses seriously.
• Secondary osteoarthritis often occurs due to neglected or late-treated misalignments or childhood illnesses.
• Especially for young patients, the earlier the diagnosis and intervention are made, the better the function and quality of life – and the later or less frequently an artificial joint is needed.

Call to action

If you're suffering from hip pain and have only heard that "osteoarthritis has been ruled out," don't just leave it at that. There may be another hip condition that requires treatment. Make an appointment with Prof. Kutzner at ENDOPROTHETICUM Rhein-Main ( www.endoprotheticum.de ) . Here, you'll find a hip specialist with extensive experience and modern hip arthroplasty techniques. Together, we can conduct a precise diagnosis, and you'll receive a treatment that's right for you.