If a diagnosis is to be made for hip pain, the first thing many think of: osteoarthritis – specifically coxarthrosis. However, osteoarthritis is often only ruled out, leading to the assumption that there is therefore no serious hip problem. This is dangerous. Because there are numerous hip disorders, which are congenital or develop in childhood/adolescence – and can cause significant symptoms, even if signs of osteoarthritis appear late or not at all. For younger patients, this can have fatal consequences if changes are missed 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 in which there is a degenerative wear of the joint cartilage. In hip joints one specifically speaks of 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, where no clear triggering mechanism (such as malalignment, injury, pre-existing disease etc.) can be identified. Usually slow and age-related.
• Secondary osteoarthritis: Osteoarthritis that arises as a result of a known prior load on the hip, such as malalignment, childhood disease, trauma, overloading etc. These forms often start earlier and can progress more severely.

Why ruling out osteoarthritis ≠ problem solved

• Nur weil in Bildern (z. B. Röntgen) keine eindeutige Arthrose zu sehen ist, heißt das nicht, dass keine Hüftprobleme bestehen. Viele Erkrankungen verursachen Schmerzen, Bewegungseinschränkungen, Muskulaturprobleme oder mechanische Konflikte, die noch nicht zu sichtbarem Knorpelverschleiß geführt haben oder bei denen der Verschleiß nicht in typischer Weise dargestellt wird.
• 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 childhood-unrecognized malalignment of the hip joint. It leads to the femoral head not being completely and stably seated in the acetabulum. Patients often feel pain in the groin or laterally at the hip, especially during prolonged walking or standing. A slight limp or muscle tension can also occur. Diagnosis is performed via clinical examinations, gait analysis as well as special X-ray images, where angles such as the acetabular roof angle or centre-edge angle are measured. Often an additional MRI is performed to display labrum or cartilage lesions. If hip dysplasia remains untreated, a secondary coxarthrosis often develops already in young adulthood. In severe cases a hip-THA is therefore required already in young years

Retroverted Acetabulum
In retroverted acetabulum, it is a malposition of the hip socket that is rotated too far backward. This can be congenital or acquired. Affected individuals frequently report groin pain or discomfort during flexion and internal rotation of the hip. Diagnostic imaging requires special X-ray and CT/MRI scans to determine the acetabular angle and version. If untreated, the malposition leads to increased mechanical pressure on the joint cartilage, which can cause labrum injuries and premature cartilage wear. In the long term, this often results in secondary osteoarthritis.

Femoroacetabuläres Impingement (FAI)
The femoroacetabuläre impingement is caused by a deformity of the femoral neck (CAM type) or an überhängende Hüftpfanne (Pincer type). During movement there is a mechanical conflict between the acetabulum and the femur bone. Typical are groin pains that occur with deep flexion or rotational movements, but also at night or with längerem sitting. Häufig the range of motion is significantly limited. For diagnosis, clinical impingement tests, special Röntgenaufnahmen and an MRI, often with contrast medium to depict labrum tears. If the impingement is not treated, können cartilage and labrum Schäden occur, which can progress to secondary Coxarthrose übergehen and a Hüft-TEP required

Morbus Perthes
Morbus Perthes is a blood flow disturbance of the Hüftkopfes in childhood, usually between the 4th and 11th year of life, more common in boys. Symptoms are limping, pain in the Hüfte or in the knee as well as movement restrictions. In the course it can lead to a permanent deformation of the Hüftkopfes. The diagnosis is made by Röntgenbilder, often supplemented by MRI, to assess the Ausmaß of the blood flow disturbance. Without timely treatment the deformations can lead to uneven loading in the joint, which long term causes secondary Coxarthrose. Many affected individuals therefore need a Hüft-TEP in middle adulthood.

Epiphysiolysis capitis femoris (SCFE, Hip head slip)
This condition usually occurs during the growth phase in puberty, often in overweight adolescents. The femoral head epiphysis slips on the growth plate. Symptoms are gradual pain in the hip or knee, a marked limitation of internal rotation and sometimes sudden acute complaints with complete slip. Affected individuals develop an outward rotation position of the leg. Diagnosis uses special X‑ray images such as the Lauenstein projection. An acute slip must be surgically stabilized immediately to avoid permanent damage. If the condition is not recognized in time, it leads to a permanent deformation of the femoral head, which in turn causes labrum and cartilage damage and a secondary arthrosis or coxarthrosis in young adulthood.

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

Late consequences: secondary osteoarthritis & coxarthrosis

• As mentioned above, it arises secondary osteoarthritis through pre-existing damage: misalignments, childhood diseases, slippage, overload etc.
• Studies show, 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-ray images: pelvic overview, 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 hip socket (e.g., periacetabular osteotomy according to Ganz etc.), femoral osteotomies, triple osteotomy etc. Goal: correct malalignment, bring socket and femoral head optimally together. For example in hip dysplasia or retroversion.
• Corrections in adolescence or childhood: Perthes disease: surgery to improve containment, reduce deformities.
• Hip head slip (Epiphysiolysis capitis femoris): Immediate surgery for acute slip; in chronic course also operative for stabilization and prevention of gait disturbance.
• Procedures for Impingement: Arthroscopic or open, to remove bone overgrowths and repair labral damage.
• Artificial joint (Hip-THR): If the joint is already severely damaged, pain persists despite conservative and joint-preserving measures, or malalignment and wear are so advanced that quality of life is significantly reduced. Young patients can also be affected by this, especially if pre-existing conditions such as dysplasia etc. are present.

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

• If already severe pain, resting pain, movement restrictions exist, which conservative and joint-preserving surgical procedures do not sufficiently relieve.
• 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. Go to a Hüftspezialist – not only a general Orthopäde. Specialists für Hüft- and joint surgery, preferably with experience in Hüftendoprothetik and joint-preserving procedures.
2. Insist on comprehensive diagnostics – also, even if osteoarthritis has been ruled out. Ask specifically about malalignments, childhood diseases (Perthes, SCFE), impingement.
3. Request special imaging – special Röntgenbilder, MRI etc., to assess version of the acetabulum, shape of the femoral neck, deformity and labrum.
4. Early therapy – physiotherapy, load modification, weight management; if indicated, joint-preserving surgeries.
5. Learn about modern Hüftprotheses – especially important if your symptoms 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 Hüfterkrankungen – congenital or in childhood/adolescence – that already cause symptoms earlier and can lead in the long term to secondary osteoarthritis / coxarthrosis can lead.
• 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 especially helpful to consult a hip specialist. The ENDOPROTHETICUM Rhein-Main under the leadership 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 Arthrose often arises from neglected or late-treated misalignments 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 so far only heard that „Arthritis excluded“ was, do not just ignore it. It could be another hip disease that needs to be treated. Make an appointment with Prof. Kutzner at ENDOPROTHETICUM Rhein-Main (www.endoprotheticum.de). Here you will find a hip specialist with a lot of experience and modern hip endoprosthetics. Together a precise diagnosis can be made and you will receive a therapy that suits you.