Partial Knee Replacement (Unicompartmental)

<p>Partial knee replacement, also known as unicompartmental knee replacement, is a surgical procedure used to treat arthritis that is limited to one part of the knee. Instead of replacing the entire knee joint, only the damaged compartment is resurfaced with an implant, while the healthy bone, cartilage, and ligaments in the unaffected parts of the knee are preserved. For carefully selected patients, this can provide effective pain relief, improved function, and a more natural-feeling knee compared with a total knee replacement.</p>

<h2>What is a partial knee replacement?</h2>
<p>The knee is made up of three compartments. These include the medial compartment on the inner side of the knee, the lateral compartment on the outer side, and the patellofemoral compartment at the front of the knee between the kneecap and the thigh bone. A partial knee replacement is performed when arthritis is affecting only one of these compartments. Instead of replacing the whole joint, the surgeon removes the damaged bone and cartilage from the affected area and replaces it with metal and plastic components designed to restore smooth movement.</p>

<h2>Who may be suitable for partial knee replacement?</h2>
<p>Partial knee replacement is generally considered for patients whose arthritis is confined to a single compartment of the knee and whose ligaments remain stable and functional. It is most often used for isolated medial compartment osteoarthritis, although in selected cases the lateral or patellofemoral compartment may be treated. Suitability depends on a combination of symptoms, imaging findings, knee stability, range of motion, alignment, and the absence of widespread inflammatory or multi-compartment disease.</p>

<h2>When is surgery considered?</h2>
<p>Surgery may be considered when knee pain, stiffness, and reduced function are affecting daily life and non-surgical treatment is no longer providing adequate relief. This may include difficulty walking, pain with stairs, pain during sport or exercise, and discomfort that interferes with work, sleep, or independence. Before recommending surgery, treatment options such as activity modification, anti-inflammatory medication, physiotherapy, injections, bracing, and weight management are usually considered where appropriate.</p>

<h2>Advantages of partial knee replacement</h2>
<p>Because only the damaged part of the knee is treated, partial knee replacement is a smaller operation than total knee replacement. It preserves more of the patient’s natural knee structures, including healthy bone and often the cruciate ligaments, which may allow the knee to feel more normal during movement. In appropriate patients, potential benefits can include a smaller incision, less postoperative pain, less blood loss, quicker recovery, shorter hospital stay, and better range of motion.</p>

<ul>
<li>Only the diseased compartment of the knee is replaced.</li>
<li>Healthy bone, cartilage, and ligaments are preserved.</li>
<li>The knee may feel more natural than a total knee replacement.</li>
<li>Recovery is often faster than with total knee replacement.</li>
<li>There may be less pain, swelling, and blood loss after surgery.</li>
</ul>

<h2>How the procedure is performed</h2>
<p>Partial knee replacement is usually performed under general or spinal anaesthesia. During the operation, the surgeon accesses the affected compartment of the knee through an incision, removes the worn cartilage and a small amount of underlying bone, and then prepares the surfaces for the implant. Metal components are fixed to the femur and tibia, and a plastic insert is placed between them to create a smooth gliding surface. The exact surgical technique and implant choice depend on the patient’s anatomy and the location of the arthritis.</p>

<p>A typical partial knee replacement procedure may include:</p>
<ul>
<li>Anaesthesia and positioning of the patient.</li>
<li>An incision over the knee to access the affected compartment.</li>
<li>Inspection of the knee to confirm that the disease is limited to one compartment.</li>
<li>Removal of damaged cartilage and a small amount of bone from the femur and tibia.</li>
<li>Preparation of the bone surfaces for the prosthetic components.</li>
<li>Insertion and fixation of the metal components.</li>
<li>Placement of a plastic spacer between the components.</li>
<li>Assessment of alignment, stability, and range of motion.</li>
<li>Closure of the tissues and skin.</li>
</ul>

<h2>Robotic-assisted partial knee replacement</h2>
<p>In some cases, partial knee replacement may be performed using robotic-assisted technology. This can help the surgeon plan implant positioning more precisely and tailor the procedure to the individual patient’s anatomy. Robotic assistance does not replace the surgeon, but it may support accuracy in bone preparation and implant alignment where this technology is used.</p>

<h2>Risks and complications</h2>
<p>As with any knee replacement procedure, there are potential risks and complications. These may include infection, bleeding, blood clots, stiffness, nerve or blood vessel injury, fracture, ongoing pain, loosening of the implant, bearing wear, and the possibility that arthritis may later develop in the remaining compartments of the knee. In some cases, a further operation or conversion to a total knee replacement may be required in the future.</p>

<h2>Recovery and rehabilitation</h2>
<p>Recovery after a partial knee replacement is often quicker than recovery after a total knee replacement, although rehabilitation is still important. Patients are usually encouraged to mobilise early, often on the day of surgery or soon after, and physiotherapy is used to restore movement, walking pattern, strength, and confidence. Many patients return to normal daily activities within a matter of weeks, although improvement can continue for several months.</p>

<p>A general recovery pathway may include:</p>
<ul>
<li>Early walking with the help of crutches or a walker.</li>
<li>Exercises to improve knee extension, flexion, and muscle strength.</li>
<li>Pain management, swelling control, and wound care.</li>
<li>Gradual return to driving, work, and light activities as advised by your surgeon.</li>
<li>Continued improvement in movement and function over the following months.</li>
</ul>

<h2>Partial knee replacement versus total knee replacement</h2>
<p>A partial knee replacement is not simply a smaller version of a total knee replacement. It is a different procedure intended for a specific group of patients whose arthritis is limited to one area of the knee. If arthritis is affecting multiple compartments, if the knee is unstable, or if there is significant deformity, a total knee replacement may be more appropriate. A thorough assessment is needed to determine which option is most suitable.</p>

<h2>Is partial knee replacement right for you?</h2>
<p>If knee pain is limiting your quality of life and imaging shows that arthritis is confined to a single compartment, partial knee replacement may be an appropriate treatment option. A detailed consultation, examination, and imaging review can help determine whether your symptoms are best managed with conservative treatment, a partial knee replacement, or a total knee replacement. The goal is to relieve pain, improve function, and help you return to daily activities with a more comfortable and reliable knee.</p>