Knee replacement surgery is one of the most frequently performed orthopedic operations worldwide. Although most patients experience significant pain relief and improved function after the operation, a considerable number report post-operative dissatisfaction. This blog will detail the most common reasons for this dissatisfaction and discuss strategies for improving patient satisfaction.

Properties of an artificial knee joint

An artificial knee joint typically consists of several components that have been carefully designed to mimic the function of the natural knee joint as closely as possible. Here are some key features:

1. Components of an artificial knee joint

• Femoral component: This is made of metal and is attached to the lower end of the femur.
• Tibial component: This is attached to the upper end of the shinbone and is also made of metal, often combined with a plastic cushion for shock absorption.
• Patellar component: This replaces the back of the kneecap and is made of plastic.

2. Materials

The materials used to make an artificial knee joint are crucial for its function and longevity. Typically, high-strength metals such as titanium or cobalt-chromium alloys, as well as durable plastics like polyethylene, are used. These materials are biocompatible, meaning they are well tolerated by the body and exhibit a low rate of wear.

3. Mechanics of Motion

An artificial knee joint should mimic the natural movements of the knee joint as closely as possible. Modern prostheses are designed to offer full range of motion, allowing both flexion and extension of the knee. Some models are specifically designed to provide a particular type of movement or stability tailored to the individual needs of the patient.

4. Lifespan

The lifespan of an artificial knee joint depends on various factors, including the patient's activity level, weight, and the accuracy of the implantation. With optimal care and under normal circumstances, an artificial knee joint can last 15 to 20 years or longer.

Common reasons for dissatisfaction after knee replacement surgery

1. Pain after surgery

Pain after knee replacement surgery is a major source of dissatisfaction. Although the pain is expected to decrease over time, some patients experience persistent or even chronic pain. This can be caused by various factors:

• Nerve injuries: Nerves can be damaged during surgery, which can lead to long-term pain.
• Implant misplacement: A poorly positioned artificial knee joint can lead to unnatural stress and pain.
• Scar tissue and adhesions: These can restrict the movement of the artificial knee joint and cause pain.

2. Functional limitations

Another common problem is that the artificial knee joint does not provide the expected functionality. Patients may be disappointed to find that they are not completely pain-free or that they can no longer perform certain activities. The most common functional limitations include:

• Movement restrictions: Some patients cannot fully bend or straighten their artificial knee joint.
• Instability: A feeling of insecurity or instability can occur, especially during activities such as climbing stairs.
• Loss of strength: Despite intensive physiotherapy, some patients report a persistent loss of strength in the affected leg.

3. Psychosocial factors

Psychological and social factors play an important role in the perception of surgical success. Patients with pre-existing mental health conditions such as depression or anxiety disorders have a higher risk of postoperative dissatisfaction. Unrealistic expectations and a lack of support from family and friends can also contribute to dissatisfaction.

4. Patient-specific factors

Certain patient groups have an increased risk of post-operative dissatisfaction:

• Younger patients: With increasing age, the risk of dissatisfaction and poorer outcomes with an artificial knee joint decreases.
• Patients with comorbidities: Comorbidities such as diabetes and obesity can slow down the healing process and increase the risk of complications.
• Patients with high preoperative pain medication: Patients who required strong painkillers before surgery often have poorer pain control after surgery.

5. Implant-specific factors

The type and quality of the artificial knee joint used can also influence satisfaction:

• Implant wear and tear: Over time, the artificial knee joint can wear out, leading to pain and loss of function.
• Reactions to the material: Some patients may have an allergic reaction to the materials of the implant, leading to inflammation and pain.

6. Surgical factors

The surgeon's experience and technique play a crucial role in the surgical outcome. Technical errors, such as incorrect alignment of the artificial knee joint or insufficient soft tissue balance, can lead to pain and functional impairment.

Strategies for improving satisfaction

To improve patient satisfaction with an artificial knee joint, several strategies are necessary:

• Preoperative education: Patients should have realistic expectations regarding the results of the artificial knee joint.
• Optimizing surgical technique: Careful planning and execution of the operation can minimize complications.
• Multimodal pain therapy: Effective pain treatment that combines different approaches can improve postoperative pain management.
• Rehabilitation and physiotherapy: Structured aftercare is crucial for restoring the functionality and strength of the artificial knee joint.
• Psychosocial support: Treating mental health conditions and providing support from family and friends can improve postoperative satisfaction.

Conclusion

An artificial knee joint offers many people a significant improvement in their quality of life by relieving pain and improving mobility. Nevertheless, there are various reasons for postoperative dissatisfaction, ranging from pain and functional limitations to psychosocial factors. However, comprehensive education, meticulous surgical technique, and structured aftercare can significantly improve the outcomes for patients with an artificial knee joint.