An artificial hip joint improves the quality of life for millions of people worldwide. However, despite all advances in endoprosthetics, complications can occur, including so-called periprosthetic fractures. These fractures in the immediate vicinity of the prosthesis can arise from different reasons and pose a major challenge for physicians and patients. Especially with short-stem prostheses, specific biomechanical factors must be considered that influence the fracture risk. In this article, we will examine in detail the causes, diagnosis, treatment options, and prevention of periprosthetic fractures in short-stem prostheses.

What are periprosthetic fractures?

Periprosthetic fractures are bone fractures that occur in the area of an already implanted artificial joint. These fractures typically occur in the vicinity of the prosthetic stem anchorage and can occur both intraoperatively and postoperatively.

Classification of periprosthetic fractures

Periprosthetic fractures are classified according to different systems. The commonly used Vancouver classification system divides fractures into:

• Type A
• Type B1: Fractures in the area of the prosthesis stem with stable prosthesis
• Type B2: Fractures with loosening of the prosthesis
• Type B3: Fractures with poor bone quality
• Type C: Fractures below the prosthetic shaft

The distinction between these fracture types is crucial for the choice of treatment method.

Why do fractures occur with short-stem prostheses?

Short-stem prostheses are designed to enable bone-sparing implantation as much as possible. The fixation is primarily done in the proximal femur, which results in a different distribution of stress and force compared to conventional long-stem prostheses.

Factors that increase the risk of fracture:

• Incorrect loading after surgery: Incorrect loading in the first weeks after implantation can increase the risk of microfractures.
• Insufficient primary anchoring: Poor fit or non-optimal positioning of the implant can compromise bone stability.
• Age and bone density of the patient: Patients with osteoporosis have a higher risk of periprosthetic fractures.
• Falls and trauma: Direct impacts or falls can cause a fracture in the area of the prosthesis.

Risk factors for periprosthetic fractures in short stem prostheses

Patient-related factors:

• Osteoporosis or other diseases with reduced bone density
• Advanced age
• Lack of muscle mass and poor balance
• Inadequate postoperative rehabilitation

Implant-related factors:

• Insufficient bony integration of the prosthesis
• Choosing a prosthesis that is too small or too large
• Use of a design that is not optimally adapted to the patient

Surgical factors:

• Careless intraoperative manipulation of the bone
• Inadequate fixation of the prosthesis
• Use of unsuitable approaches (minimal versus conventional incisions)

Differences in periprosthetic fractures between short stems and straight stems

1. Different anchoring in the bone

• Short-stem prostheses are anchored metaphyseally, i.e., in the upper region of the femur. As a result, the diaphysis (the long tubular part of the femur) remains largely intact.
• Straight stem prostheses extend deeper into the diaphysis and are firmly anchored there.

This different anchorage influences the type of fractures:

• Fractures occur more frequently in the proximal (upper) thigh region with short-stem prostheses, especially if the metaphyseal anchorage is not optimal.
• In straight stem prostheses, fractures often occur in the diaphysis, i.e. further down the femur. These fractures are more difficult to treat as they are often associated with a renewed, deep anchoring of the implant.

2. Stability and bone reserves

• One advantage of short-stem prostheses is that the shorter anchorage in the bone preserves more bone substance. This can be helpful in the event of a fracture, as more bone material is available for surgical stabilization.
• With straight stem prostheses a periprosthetic fracture can be more critical, as the bone structure has been more significantly altered by the long anchorage and often fewer bone reserves are available.

3. Risk in the event of falls and accidents

• Straight stem prostheses increase the risk of distal fractures (lower femoral fractures), as the rigid, long anchorage transmits leverage forces to the lower part of the femoral bone.
• Short-stem prostheses generally have a lower risk for such distal fractures, as they are shorter and the force is limited to a smaller bone region.

4. Treatment options for fractures

• In the case of fractures around a short-stem prosthesis it is often possible to treat them with plate osteosynthesis or other stabilizing measures without having to replace the prosthesis.
• In the case of fractures around a straight stem prosthesis a change to a longer, shaft-guided or modular revision prosthesis is often necessary.

5. Are short stem prostheses advantageous?

• Short stem prostheses show a lower risk of serious diaphyseal fractures, as the bone structure is largely preserved.
• If fractures occur, they usually occur proximal to the bone, which offers better treatment options.
• Straight stem prostheses, on the other hand, have a higher risk of fractures in the middle and lower thigh area, which are more difficult to treat.

Overall, short-stem prostheses offer certain advantages with regard to periprosthetic fractures, particularly in terms of bone preservation and treatment options in the event of a fracture.



Diagnosis of a periprosthetic fracture

A quick and accurate diagnosis is essential to initiate adequate treatment. Typical symptoms include sudden pain, swelling, and limited mobility of the affected leg.

Diagnostic procedures:

1. X-rays for localization of the fracture
2. Computed Tomography (CT) for better visualization of fractures and implant position
3. Magnetic Resonance Imaging (MRI) if suspected soft tissue injuries

Treatment options for periprosthetic fractures

The therapy is based on the fracture type, the stability of the prosthesis, and the bone quality of the patient.

Conservative therapy

• Only applicable for stable fractures without prosthesis loosening
• Immobilization through partial weight-bearing and physiotherapy

Operative Therapy

1. Osteosynthesis: Screw fixation or plate osteosynthesis for stable prostheses
2. Revision prosthesis: If the prosthesis is loosened or there is massive bone damage
3. Bone transplantation or augmentation procedures: For severe osteoporosis or bone loss

Prevention of fractures with short stem prostheses

Since periprosthetic fractures represent serious complications, preventive measures are essential.

Selection of the correct implant

• Individual adaptation to the patient's bone anatomy
• Use of modern implants with optimized anchoring

Optimization of bone density

• Osteoporosis medication and vitamin D supplementation
• Strength training to strengthen the muscles

Patient behavior after surgery

• Prevention of falls through balance training
• Adherence to the recommended postoperative load limits

Conclusion and Recommendation

Periprosthetic fractures represent a serious complication in endoprosthetics. Especially with short-stem prostheses, individual adaptation to the patient is crucial to minimize the risk. Modern implants and improved surgical techniques have reduced the occurrence of such fractures, yet precise diagnostics and treatment remain essential.

Patients who require a hip replacement or are already wearing an implant should consult specialized centers to achieve the best possible results. The combination of precise surgical technique, high-quality implant selection, and adapted rehabilitation minimizes the risk of complications and improves long-term results for the patient.