Partial knee replacement, also known as Unicompartmental Knee Arthroplasty or Microplasty, is a surgical procedure that has gained popularity in recent years due to its effectiveness in treating localized knee arthritis mainly on the inner aspect of the knee joint. Unlike total knee replacement, which involves replacing the entire knee joint, partial knee replacement targets only the damaged compartments of the knee, preserving the healthy parts of the joint thereby giving a feeling of natural knee even after surgery. Although the word “Replacement” is a misnomer as actually it’s “Resurfacing” procedure where only few millimetres of damaged cartilage surface is changed leaving the underlying bone untouched. This approach offers several advantages, including quicker recovery times, less pain, and a more natural-feeling knee after the surgery.
Partial Knee Replacement or Microplasty
The knee joint is divided into three compartments: the medial (inside), lateral (outside), and patellofemoral (front) compartments. Partial knee replacement is typically performed on the medial or lateral compartments, where arthritis is most localized. The procedure involves removing the damaged bone and cartilage from the affected compartment and replacing it with metal and plastic components. This helps restore the knee’s function and alleviate pain caused by arthritis.
The ideal Candidate
Not everyone with knee arthritis is a candidate for partial knee replacement. Ideal candidates are those who have arthritis confined to a single compartment of the knee, have intact ligaments mainly ACL & MCL, maintain a good range of motion, less severe deformity and no other form of inflammatory arthritis. Advance age and obesity are not the contra indications for partial knee replacement surgery. Patients with significant damage in multiple compartments or those with severe deformities may be better suited for total knee replacement. A thorough evaluation by an orthopaedic surgeon, including imaging tests like X-rays (or sometimes MRI) is essential to determine the best course of action.
Procedure
Partial knee replacement is usually performed under spinal or combined spinal epidural anaesthesia that makes you numb below waist down. The surgeon makes a small incision over the knee to access the affected compartment. Using specialized instruments, the damaged bone and cartilage are carefully removed, and the area is prepared for the prosthetic components. The metal at lower end of thigh bone and upper end of leg bone with a highly cross linked plastic implants in between these two are then secured in place, and the incision is closed with sutures or staples. The entire procedure typically takes around one hour.
Recovery and Rehabilitation
One of the significant benefits of partial knee replacement is the relatively quick recovery time compared to total knee replacement. Most patients can begin walking with assistance on the same day as the surgery. Physical therapy is a crucial component of the recovery process, helping patients regain strength, flexibility, and range of motion in the knee. Most people can return to their normal activities within six weeks, although full recovery may take around 3 months.
Risks and Complications
As with any other surgical procedure, partial knee replacement carries some risks. Potential complications include infection, fracture and implant loosening or implant failure. However, these risks are generally lower compared to total knee replacement. Patients are advised to follow their surgeon’s post-operative care instructions closely to minimize the risk of complications. Microplasty is a technically demanding surgery which requires precision and optimal implant positioning that impacts the survivorship of the implant and surgical outcomes.
Advantages Over Total Knee Replacement
Partial knee replacement offers several advantages over total knee replacement. Because the procedure is less invasive that involves less tissue cutting, less bone cutting, less blood loss, patients typically experience less pain and a quicker recovery. Additionally, by preserving the healthy parts of the knee, the joint often feels more natural, and patients may have better knee function and range of motion. Studies have shown that many patients who undergo partial knee replacement report high levels of satisfaction and improved quality of life. The implant life also gives a satisfactory survivorship of more than 10 years. Some people who have a partial knee replacement may need a total knee replacement in the future if arthritis starts affecting their other knee compartments. Due to the long survivorship of this procedure Microplasty has been considered as a final solution to arthritis contrary to the earlier belief that it’s a time buying procedure.
Long-Term Outcomes
The long-term outcomes of partial knee replacement are generally positive. Many patients experience significant pain relief and improved knee function for many years after the surgery. However, it is important to note that some patients may eventually require a total knee replacement if arthritis progresses to other compartments of the knee. Regular follow-up appointments with an orthopaedic surgeon are essential to monitor the condition of the knee and the integrity of the implants.
Conclusion
Partial knee replacement is a valuable surgical option for patients with localized knee arthritis who suffered with arthritis at an early age. It offers the benefits of quicker recovery, less pain, and a more natural-feeling knee compared to total knee replacement. However, careful patient selection, thorough pre-operative evaluation and surgery with precision are crucial to achieving the best outcomes. As with any medical procedure, it is important for patients to discuss their options with their healthcare provider to determine the most appropriate treatment for their individual needs.
