Retropatellar osteoarthritis, also known as patellofemoral osteoarthritis or kneecap osteoarthritis, is a degenerative joint disease affecting the cartilage behind the kneecap. This condition can lead to significant pain and restricted movement. When conservative treatments are no longer sufficient, joint replacement surgery offers an effective solution for restoring joint function and improving quality of life. This article explores the various aspects of retropatellar osteoarthritis surgery, including indications, procedures, benefits, and aftercare.

Fundamentals of retropatellar osteoarthritis

Causes and symptoms

Retropatellar osteoarthritis develops due to a combination of factors such as mechanical overload, injuries, and degenerative processes. Excess weight and athletic activities that place high stress on the knee can accelerate cartilage degeneration. Injuries such as patellar dislocations and malalignments like knock-knees or bowlegs also contribute to the condition.

Typical symptoms are:

• Pain behind the kneecap, especially when climbing stairs or sitting for extended periods.
• Stiffness and swelling in the knee.
• Grinding noises during movement.

Diagnosis of retropatellar arthrosis

The diagnosis of retropatellar osteoarthritis begins with a thorough medical history and physical examination. Imaging procedures such as X-rays, MRI, and CT scans are crucial for accurately assessing cartilage damage and planning endoprosthetic treatment.

Conservative treatment options

Before considering endoprosthetic treatment, conservative treatment approaches are often tried:

• Physiotherapy: Strengthening the muscles around the knee, improving mobility and reducing the load on the kneecap.
• Drug therapy: Use of painkillers and anti-inflammatory drugs.
• Orthopedic aids: Use of knee braces and specially adapted shoe inserts.

Indications for endoprosthetics

Endoprosthetic replacement is considered when:

• Conservative treatments do not provide sufficient pain relief.
• The quality of life is significantly impaired.
• Progressive joint damage occurs.

The decision also depends on individual factors such as age, activity level and general health.

Endoprosthetic options for retropatellar osteoarthritis (mini-implants)

Patellofemoral partial prosthesis (Wave / PFJ)

In cases of osteoarthritis limited to the patellofemoral region, a partial patellofemoral replacement can be implanted. This prosthesis replaces only the damaged area behind the kneecap and preserves the remaining joint structures.

A patellofemoral partial knee replacement is a specialized type of knee prosthesis specifically designed to treat damage to the patellofemoral joint, the area behind the kneecap (patella) and the front part of the thighbone (femur). This prosthesis is a less invasive alternative to a total knee replacement and is used in cases where osteoarthritis or cartilage damage is limited to the patellofemoral joint.

Indications for patellofemoral partial prosthesis

A patellofemoral partial prosthesis is considered in the following cases:

• Localized osteoarthritis: Patients with isolated osteoarthritis of the patellofemoral joint.
• Patellar malposition: Patients with patellar dislocations or instabilities leading to chronic pain and functional limitations.
• Failure of conservative therapies: When physical therapy, medication and other conservative measures do not provide sufficient relief.
• Younger patients: Patients who, due to their age and activity level, do not need or want a total denture.

Advantages of the patellofemoral partial prosthesis

The patellofemoral partial prosthesis offers several advantages over the total knee replacement:

• Less invasive surgery: Since only part of the knee is replaced, the procedure is less invasive.
• Preservation of natural knee anatomy: Only the damaged area is replaced, thus preserving the majority of the natural knee joint.
• Faster recovery: Patients usually recover faster and can return to their normal activities sooner.
• Less postoperative pain: Due to the reduced surgical trauma, patients often experience less postoperative pain.

Total knee replacement (TKR)

A total knee replacement is used in cases of advanced osteoarthritis involving multiple joint compartments. This comprehensive solution replaces the entire knee joint and offers long-term pain relief and improved function. Modern materials and techniques ensure a long lifespan and a better quality of life.

Surgical procedure

The surgical procedure involves several steps:

• Preparation: Comprehensive preoperative planning, including imaging and physical examination.
• Surgery: Removal of the damaged cartilage and insertion of the prosthesis. The procedure is usually performed under general anesthesia.
• Aftercare: Intensive physiotherapy to promote healing and restore joint function.

Postoperative rehabilitation

Postoperative rehabilitation is crucial for the success of endoprosthetic treatment:

• Early mobilization: Movement therapies to prevent joint stiffness and promote healing.
• Physiotherapy: Individual training plans to strengthen muscles and improve mobility.
• Pain management: Use of medication and alternative methods such as acupuncture and TENS for pain relief.

Long-term results and forecast

Endoprosthetic treatment of retropatellar osteoarthritis can lead to a significant improvement in quality of life. Successful surgeries offer long-term pain relief and allow a return to an active lifestyle. Correct indication, regular follow-up care, and physiotherapy are crucial to maintaining prosthesis function and preventing complications.

Conclusion

Endoprosthetic replacement offers an effective solution for patients with retropatellar osteoarthritis for whom conservative treatments are insufficient. The use of modern techniques and materials can alleviate pain and sustainably improve joint function. Careful preoperative planning, a well-executed surgical procedure, and comprehensive postoperative rehabilitation are crucial for the success of the treatment.