Partial knee replacement, also known as unicompartmental knee replacement, involves replacing only the damaged part of the knee (such as the medial or lateral compartment) while preserving healthy bone and tissue. This procedure is ideal for patients with arthritis confined to one part of the knee, offering pain relief and improved function while maintaining as much of the natural knee as possible.
The surgery itself is painless due to anaesthesia, but post-operative pain and discomfort are expected. Effective pain management and physiotherapy are crucial for recovery.
Partial knee replacement is effective for patients with localized arthritis, providing significant pain relief and improved knee function. It allows for quicker recovery and more natural knee movement compared to total knee replacement.
The surgery for a partial knee replacement typically takes about one to two hours to complete. This can vary slightly depending on the complexity of the case and the specific surgical approach used. Because only one compartment of the knee is being replaced—usually the medial (inner), lateral (outer), or patellofemoral (front) portion—the procedure is generally less invasive than a total knee replacement. This means less time under anaesthesia, reduced blood loss, and often a faster recovery. Before surgery, additional time is needed for preparation, including anaesthesia and surgical setup. After the procedure, patients are moved to recovery where they’re closely monitored as the anaesthetic wears off. In total, the hospital stay around the time of surgery may span several hours, even if the actual operation is relatively short. Surgeons with extensive experience in partial knee replacements, like Dr Oliver Khoo, often perform the procedure efficiently with a high degree of precision. This contributes not only to shorter operating times but also to better outcomes and quicker return to function.
A partial knee replacement can last a long time, often 10 to 15 years or more, depending on various factors. While it's generally true that total knee replacements have slightly longer longevity overall, modern partial knee implants have improved significantly in both design and durability. Several elements influence how long a partial knee replacement lasts, including the patient’s age, weight, activity level, and overall joint health. Younger, more active patients may experience wear sooner, while older or less active individuals may see their implants last much longer. Implant positioning and surgical technique also play a major role—when performed by an experienced orthopaedic surgeon like Dr Oliver Khoo, outcomes tend to be better and longer-lasting. It’s also worth noting that unlike a total knee replacement, partial knee replacements preserve more of the knee’s natural anatomy. This allows for more natural movement, but may also mean other parts of the joint could develop arthritis over time, possibly requiring conversion to a total knee replacement in the future. With proper care, regular check-ups, and maintaining a healthy lifestyle, many patients enjoy long-term function and pain relief from their partial knee replacement for over a decade—sometimes even two.
A partial knee replacement can last a long time—often 10 to 15 years or more—depending on several individual factors. Advances in implant design, surgical technique, and patient rehabilitation have all contributed to better long-term results over recent years. One of the key advantages of a partial knee replacement is that it only involves resurfacing the damaged part of the joint, preserving more of your natural knee structure. This means the implant typically experiences less mechanical stress compared to a total knee replacement, especially when patients maintain a healthy weight and avoid high-impact activities. However, over time, wear and tear may affect the implant or the remaining parts of the knee joint. In some cases, arthritis may progress in the untreated compartments, potentially requiring revision surgery or conversion to a total knee replacement down the track. Age, activity level, surgical technique, and adherence to rehabilitation also play a role in how long the implant lasts. In general, people who are older and lead moderately active lifestyles are more likely to enjoy long-lasting results. Regular follow-ups allow your surgeon to monitor the implant and detect any early signs of wear or complications before they become serious.
As with any surgery, a partial knee replacement carries some risks, although serious complications are relatively uncommon. The most common risks include infection, blood clots in the legs (deep vein thrombosis), and stiffness or limited movement in the knee after surgery. There's also a small chance of nerve or blood vessel injury around the knee during the procedure. Another risk specific to partial knee replacement is the possibility that arthritis could develop in the parts of the knee not replaced. If this occurs, or if the implant wears out over time, a revision to a total knee replacement may be needed in the future. Some patients may experience persistent pain, either from scar tissue, implant positioning, or unrelated issues like referred pain from the hip or spine. In rare cases, the implant may loosen or fail prematurely, requiring additional surgery. Complications are more likely in patients with certain risk factors, such as obesity, smoking, poorly controlled diabetes, or a history of previous knee problems. However, careful patient selection, precise surgical technique, and following post-operative instructions significantly reduce these risks. Dr Oliver Khoo will assess your individual situation and discuss any specific risks relevant to you before proceeding with surgery.
Recovery after a partial knee replacement is generally quicker and less intensive compared to a total knee replacement. Because only one compartment of the knee is resurfaced, less bone and soft tissue are disturbed, which allows many patients to regain mobility sooner. Most people are able to stand and walk with assistance within a day of surgery, and many are discharged from hospital within one to three days. Early recovery often includes the use of walking aids like crutches or a walker, as well as a physiotherapy program to help restore strength and movement in the knee. Pain and swelling are normal in the first few weeks, but these symptoms usually improve steadily with appropriate pain relief, rest, and activity modification. By around two to four weeks, many people can drive again and return to light household tasks. Most patients are able to resume low-impact activities, such as walking or swimming, within six to eight weeks. A full recovery may take three to six months, depending on the individual. Because the natural ligaments are preserved, the knee often feels more normal than after a total knee replacement, but regular follow-up is still important to monitor the joint over time.
The recovery process after a partial knee replacement is typically smoother and faster than that of a total knee replacement, but it still requires commitment and care. Most patients are encouraged to start moving the knee on the same day or the day after surgery, often with the help of a physiotherapist. Walking aids such as crutches or a walker are usually used initially, with the goal of gradually reducing dependence on them over the following weeks. In the first few days to weeks, managing pain and swelling is a priority. Patients are advised to rest, elevate the leg, use ice packs, and take prescribed medications. A tailored physiotherapy program begins early, focusing on improving range of motion, reducing stiffness, and rebuilding strength in the leg muscles. Adherence to these exercises plays a key role in how quickly and completely a patient recovers. By around two to four weeks, most people can return to basic daily activities, and many are back to driving if they meet safety and mobility requirements. Full recovery—including return to low-impact sports or active hobbies—may take around three to six months. While the process varies from person to person, many patients report less pain, better knee function, and a more natural feel compared to other types of knee surgery.
It’s possible, but not guaranteed, that you may need a second surgery after a partial knee replacement. The procedure is designed to last many years—often 10 to 15 or more—but over time, the implant can wear out, loosen, or other parts of the knee joint not initially involved may develop arthritis. In those cases, a second surgery may be needed to revise or convert the partial knee replacement to a total knee replacement. That said, many patients enjoy long-term benefits from their original surgery without requiring further procedures. The likelihood of needing a second surgery depends on several factors, including age, activity level, overall joint health, and how well the knee responds to the initial operation. Younger, more active individuals may put more stress on the implant, which can shorten its lifespan. The good news is that if revision surgery is needed in the future, the process is generally straightforward when converting a partial to a total knee replacement. Having a partial knee replacement first does not typically make the second procedure more complex, especially when it was done using a precise and conservative surgical approach. Regular follow-up with your orthopaedic surgeon helps catch any issues early, improving long-term outcomes.
Most patients experience a significant improvement in knee movement after a partial knee replacement, but whether full range of motion returns can vary from person to person. Because this procedure preserves the healthy parts of the knee, including the ligaments and unaffected cartilage, many patients find their knee feels more natural and flexible compared to a total knee replacement. Before surgery, limited motion is often caused by pain, swelling, or joint damage. After the damaged section is replaced, those symptoms usually improve, allowing greater mobility. Many people regain close to full extension (straightening) and a high degree of flexion (bending), often enough to perform daily activities comfortably—like walking, climbing stairs, or getting in and out of a car. However, full return to pre-arthritis flexibility isn’t guaranteed. Factors like preoperative stiffness, the extent of joint damage, muscle strength, and adherence to physiotherapy can all influence outcomes. In general, patients who had a good range of motion before surgery tend to recover more motion afterwards. With consistent rehabilitation and realistic expectations, most people are very satisfied with the function of their knee, even if a small degree of stiffness remains. For many, the pain relief and improved mobility outweigh any minor limitations in motion.
After a partial knee replacement, many patients do regain a near-normal range of motion, especially compared to what they had before surgery. Because this procedure only replaces the damaged part of the knee and preserves healthy ligaments and bone, it often allows for more natural movement than a total knee replacement. If you had good flexibility before surgery and your muscles are in reasonable condition, there’s a good chance you’ll recover a high degree of bending and straightening after the operation. Most people can expect to bend their knee enough to walk, climb stairs, get in and out of a car, and return to activities like swimming or cycling. That said, not everyone regains full range of motion. Factors such as pre-existing stiffness, the extent of joint damage, and how consistently you follow your physiotherapy plan can all affect your final outcome. Recovery also takes time—while improvements in motion begin early, it may take several months to reach your full potential. In general, patients are very satisfied with the improvement in function, even if the final range of motion isn’t completely perfect. For most, the pain relief and improved mobility after surgery make a big difference in everyday life.