Hip dysplasia, a congenital or early childhood developmental disorder of the hip joint, poses complex decisions for both patients and healthcare providers. Two common therapeutic approaches, periacetabular osteotomy (PAO) and implantation of a short-stem prosthesis, offer different advantages and challenges. This article highlights the indication criteria, advantages, and disadvantages, as well as the suitable patient groups for these methods.

What is hip dysplasia?

Hip dysplasia is a malformation of the hip socket (acetabulum), in which the socket does not adequately cover the femoral head. This results in instabilities and an increased risk of osteoarthritis. Typical symptoms include pain in the groin radiating to the thigh, knee, and lower back. In advanced stages, there is a progressive limitation of movement伴 with pain.

Periacetabular osteotomy (PAO)

Definition and objective

Periacetabular osteotomy (PAO) is a surgical procedure for treating hip dysplasia, aiming to preserve natural joint function by reshaping the pelvic bone. The procedure was developed by Professor Reinhold Ganz and is characterized by its joint-preserving philosophy.

Procedure sequence

During the PAO, the bony acetabular part of the pelvis near the hip joint is controlledly severed at three locations in several steps. Subsequently, the acetabulum is aligned in a more optimal position, so that the femoral head is better covered. To stabilize the new acetabular position, metallic screws are used, which can usually remain in the body.

Goal of the PAO

• Improved biomechanics: Through better alignment of the joint, the load is distributed more evenly, reducing wear.
• Osteoarthritis prevention: The anatomical correction can slow or stop the progression of already developing osteoarthritis.
• Preservation of the natural joint: Unlike implantation of a prosthesis, the patient's own hip joint remains intact.

Indication criteria

The PAO is particularly suitable for:

• Younger patients (15-40 years) with stable cartilage conditions.
• Low to moderate osteoarthritis: The method is not suitable when there are already severe wear signs.
• Sufficient bony structure: A strong and healthy pelvic and hip bone is a prerequisite for the success of the operation.

Benefits of PAO

• Joint-preserving: Avoidance of an endoprosthetic replacement.
• Longevity: Aims for long-term reduction of osteoarthritis risk.

Disadvantages of PAO

• Long rehabilitation: Load only gradually möglich.
• Technical Komplexität: High demand on the surgeon.
• Alterseinschränkung: Less suitable for älteren patients or advanced osteoarthritis.
• Difficult implantation of a later hip prosthesis: If a späteren time an endoprosthetic treatment becomes necessary, the previously performed PAO can alter the anatomy of the Hüftgelenks such that prosthesis implantation is technically more difficult and with a höheren complication risk.

Aftercare

1. Load building: Initially only partial load (ca. 20-30 kg) is allowed. The full load capacity is reached gradually über weeks or months.
2. Physiotherapy: Intensive mobilization to restore joint function.
3. Long-term monitoring: Regular follow-up examinations to ensure treatment success.

Short-stem prosthesis

Definition and objective

The short stem prosthesis is a modern form of endoprosthetics, in which the femoral neck is largely preserved. It is used for degenerative changes of the hip and offers a bone-sparing alternative to the standard prosthesis.

Indication criteria

A short-stem prosthesis is suitable for patients who:

• Existing osteoarthritis or other degenerative changes present.
• The desire for quick recovery and mobility exists.

Benefits of the short stem prosthesis

• Bone-sparing: Preserves the femoral neck.
• Rapid rehabilitation: Full weight-bearing often possible early.
• High success rate: Modern short-stem prostheses show impressive durability. Studies suggest that such prostheses, when indicated correctly, can last 30 years or longer without problems today. This means that the need for a revision surgery has dropped dramatically.

Disadvantages of the short stem prosthesis

• Implant wear: Despite modern materials, loosening remains theoretically possible in the long term.
• No joint-preserving option: The natürliche Hüftkopf is removed.
• Lifespan: May be limited depending on load.

Aftercare

• Mobilization usually from the first postoperative day.
• Continuous physiotherapy for optimal mobility and muscle building.

Comparison of the two procedures

Age and cartilage status

• Jüngere patients (< 40 years): Joint preservation through PAO is recommended.
• Ältere patients (> 60 years): Short-stem prosthesis due to degenerative changes is more appropriate.

Professional and family-related stress

• Körperliche occupations: Short-stem prosthesis allows faster load-bearing.
• Low-load Tätigkeiten: PAO can offer long-term benefits.

Post-treatment duration

• PAO: Längere rehabilitation with partial weight-bearing.
• Short-stem prosthesis: Frühe full weight-bearing possible.

Pre-existing osteoarthritis

• Low or no osteoarthritis: PAO can show good results.
• Advanced osteoarthritis: Short-stem prosthesis clearly preferred.

Modern developments in short-stem prosthetics

Hip arthroplasty has made enormous progress over the past few decades. In particular, short-stem prostheses have proven convincing through innovative design and material developments, such as modern articulating pairs with extremely low wear rates. These developments minimize the risk of implant loosening and ensure a lifespan of up to 30 years or more. The procedure is now also possible with minimally invasive techniques, yielding excellent results in terms of patient activity. Due to this success rate, the decision-making process is increasingly shifting in favor of short-stem prostheses, even in younger patients.

Conclusion

The choice between PAO and short-stem prosthesis depends on a variety of individual factors. While PAO is suitable for younger, active patients with preserved cartilage, short-stem prosthesis is a better choice for older patients with degenerative changes. Both procedures have their justification and should be carefully weighed considering the individual life situation, professional requirements, and health status. The decision is sometimes one of the most difficult in the field. However, with modern advances in endoprosthetics, the short-stem prosthesis has gained a remarkably high significance, as it offers a combination of longevity, bone-sparing design, and faster rehabilitation.