Partial Knee Replacement in Turkey

Partial knee replacement is surgery in which only the damaged part of the knee joint is replaced. It is also known as unicompartmental knee arthroplasty. During the operation, damaged cartilage and bone in the affected area are removed and replaced with metal and plastic parts. The rest of the knee and its ligaments stay in place.

Partial knee replacement may help ease pain and improve knee function in some people. To decide whether it suits you, your surgeon checks your knee's range of motion, stability and strength, and X-rays show how far the damage extends. Many people are treated without surgery first.

Partial knee replacement is suited only to people whose arthritis is limited to one area of the knee, and you do not choose it on your own: eligibility is decided by your surgeon's examination and imaging. If the damage extends to more than one area, total knee replacement may be the more suitable option. For the basics of knee replacement in general, see our article on knee joint replacement in Turkey.

Why is partial knee replacement done?

The most common reason is to ease pain caused by knee arthritis when it is limited to one area. People usually see a surgeon because the pain limits walking, climbing stairs and getting up from a chair. Non-surgical treatments are tried first, such as physical therapy, injections and weight loss when needed, and surgery is considered only when they are no longer enough, as recommended by Mayo Clinic.

Types of partial knee replacement

The knee has three compartments: the inner one (the side closest to the other knee), the outer one, and the front one between the kneecap (patella) and the thighbone. In knee arthritis, the cartilage that cushions the bones wears away, and this can happen across the whole joint or in just one area. When advanced arthritis is limited to one compartment, replacing the surface of that compartment alone may be enough. Because the surgeon works on a smaller part of the joint, the operation is often done through a smaller incision than total knee replacement.

Inner (medial) replacement. Done when arthritis is limited to the inner side of the knee. Medical sources describe the inner and outer compartments as the main sites for partial replacement, and much of the comparative evidence discussed below concerns the inner side.

Outer (lateral) replacement. Follows the same principle on the outer side. The most prominent comparative trials, including TOPKAT, did not include it, so results for the inner side cannot automatically be applied to it.

Patellofemoral replacement. If the pain is at the front of the knee, under the kneecap, sources point to another type of partial replacement called patellofemoral replacement, which may suit some of these patients instead of inner or outer replacement. This article does not cover its evidence in detail, and the decision rests with the surgeon after examination and imaging.

Partial versus total knee replacement: what the evidence says

Partial replacement offers possible advantages for suitable patients compared with total replacement, as listed by the American Academy of Orthopaedic Surgeons (AAOS): quicker recovery, less pain after surgery, less blood loss, and a lower risk of infection and blood clots. Many patients say the knee feels more natural because the healthy parts were kept. However, a systematic review in the BMJ found no significant difference between the two procedures in pain as measured by patient questionnaires, so these advantages should not be treated as guaranteed for every patient. On the other side, AAOS notes that the main drawback is the possible need for further surgery, including conversion to total replacement if arthritis progresses in the parts that were not replaced.

What the TOPKAT randomised trial found

One large randomised trial that compared partial with total replacement for arthritis of the inner knee is TOPKAT. It concluded that both procedures are effective and that clinical outcomes, reoperation rates and complication rates were similar, although some patient-reported measures of satisfaction were higher after partial replacement. To read it carefully, keep the following in mind:

• It is a single trial, conducted only in inner-knee arthritis, in British hospitals, with surgeons who were relatively experienced in partial replacement.
• Patients could not be kept unaware of which procedure they had (it was unblinded), which may affect measures that rely on their own opinion, including satisfaction.
• The absence of a statistically significant difference between the procedures does not prove they are equivalent.
• Its results do not extend to outer or patellofemoral replacement, or to surgeons with less experience of the procedure.

What reviews and registries say: revision is relatively more common

In contrast, systematic reviews and analyses of national joint registries report that the need for revision surgery is relatively more common after partial than after total replacement, and the strength of this gap varies with the type of study and length of follow-up. Researchers also note that partial replacement is linked to fewer short-term complications and better functional outcomes in some groups of studies, but these are observational studies and may reflect differences in the patients chosen for each procedure.

For this reason we do not present the possibility of later surgery as a minor matter: it is a real part of the trade-off that a patient should understand before deciding.

Why do trials and registries differ?

There is no settled explanation. One possibility is that trials involve carefully selected patients and experienced surgeons, while registries reflect real-world practice, with its variation between surgeons and centres. Some surgeons also believe that partial replacement is easier to revise, which lowers the threshold for deciding to revise it compared with total replacement. This is a proposed explanation that has not been proven.

If a partial replacement needs revision

Surgeons usually convert to a total knee replacement. Data from the Australian registry (from earlier years) suggest this option gives the best result among revision options, but it is not free of the risk of a second revision. Another small systematic review, whose authors acknowledge limited sample size, found that clinical outcomes after converting a partial to a total replacement are weaker than after a first total replacement, and that the operation may need extra components or augments, with similar hospital stay, complications and revision rates between the two groups. So conversion is possible, but it is not the same as a first total knee replacement.

Surgeon volume

Registry studies in the United Kingdom and the US state of Michigan agree that results of partial replacement are linked to how often the surgeon performs it: on average, more experience with the procedure goes with better results. In the Michigan study, the revision rate among the highest-volume surgeons remained above that of total replacement, while in the British study the result came close to total replacement for the highest-volume surgeons after patients were matched. For this reason we list surgeon volume among the questions we advise you to ask before deciding (see the questions section below).

Who is a good candidate?

This is decided after your surgeon's assessment, but sources describe general criteria for people who may be suited to partial replacement:

• Advanced arthritis limited to one compartment, with pain concentrated in a specific area of the knee, inner or outer.
• Preserved knee movement, healthy ligaments, and no marked deformity of the leg axis (among Mayo Clinic's criteria).
• Failure of less invasive treatments, such as weight loss when needed, physical therapy and injections, as recommended by Mayo Clinic.

There is no precise age limit for partial replacement; the decision rests on general health and the degree of arthritis. Mayo Clinic notes that obesity is among the factors its surgeons take into account, and the surgeon decides in each case what effect weight has. Estimates of the proportion of people who suit partial replacement vary between sources according to selection criteria, so no single figure should be relied on.

Who may not be suited to partial replacement?

Partial replacement may not suit people who have:

• Inflammatory arthritis (such as rheumatoid arthritis), because the damage is usually spread across the whole knee.
• Significant stiffness in the knee.
• Ligament damage. Keeping both cruciate ligaments is described as one of the advantages of partial replacement, so an anterior cruciate ligament tear may change the picture, and the surgeon decides after examination what suits your case. You can read more in treatment of anterior cruciate ligament tears in Turkey.
• Pain spread across the whole knee, where total replacement may be more suitable.
• Marked deformity of the leg axis, according to Mayo Clinic.

In short: someone who does not meet the criteria may still be a candidate for total replacement, and this does not reflect any shortcoming in their care.

How is a patient assessed, and what is the surgeon's role?

Assessment starts with a medical history that pins down where the pain is, followed by a clinical examination of knee movement and ligament stability, then X-rays in different positions, and sometimes an MRI to assess the cartilage. Not every knee pain is arthritis that calls for replacement; other problems, such as a meniscus tear, may need a different treatment path that the surgeon considers during assessment.

A practical point for travelers: what if partial replacement turns out not to suit you during the operation?

During the operation the surgeon examines all the compartments to confirm the damage is truly limited, and may decide to convert to total replacement if partial replacement is not suitable. AAOS notes that this back-up plan is discussed with the patient before surgery. If you will travel for the operation:

• Discuss with the surgeon before travelling what will happen if partial replacement does not suit you.
• Ask whether you need to agree in advance to conversion to total replacement, and what the plan for that scenario is.
• Ask how this might affect the length of stay and the cost, and do not assume an answer.

How is the operation done?

The anaesthetist discusses the options with you: general anaesthesia, spinal anaesthesia that numbs the lower half of the body while you stay awake, or a nerve block used with either. The surgeon then makes an incision at the front of the knee, examines the compartments and confirms the ligaments are sound. If partial replacement is confirmed as suitable, the surgeon removes the damaged cartilage and bone in the affected compartment, fixes metal components to the bone either with cement or by press-fit so the bone grows onto them, and then places a plastic spacer that gives a smooth surface for movement. Sources differ in their estimates of how long the procedure takes, and it varies from case to case.

Recovery after partial knee replacement

According to AAOS, patients start putting weight on the knee right after surgery, and may need a walker, cane or crutches for days or weeks until they regain confidence in walking. A physical therapist sets exercises to restore movement and strength, with regular follow-up visits to the surgeon. Sources say most daily activities resume within weeks, while full recovery may take months depending on your activity before surgery, your age and your general health.

Sources also differ on leaving hospital: AAOS says the patient may go home after surgery or stay overnight, while Cleveland Clinic says many patients leave the same day and the medical team decides whether an overnight stay is needed. It depends on your case and the hospital's policy, so do not build your travel plans on a general figure. Ask the surgeon how long you are expected to stay in your case and when it is safe to travel home.

Risks, complications and the possibility of later surgery

AAOS describes the risks as rare, but they can occur, and include:

• Blood clots in the leg veins; the doctor may prescribe blood thinners to prevent them.
• Infection in the skin over the wound or deep in the joint, which can appear days or years later.
• Injury to nerves or blood vessels.
• Persistent pain after surgery.
• Anaesthesia risks.
• Wear or loosening of the implant, scar tissue inside the knee and stiffness, according to Cleveland Clinic.
• The need for further surgery, including conversion to total replacement if arthritis progresses in the parts that were not replaced.

Contact your surgeon immediately if you develop new or worsening pain in the calf, ankle or foot, shortness of breath or chest pain, fever, bleeding, signs of infection in the wound, or severe pain that does not ease with painkillers.

Estimated cost at O9 Medical

O9 Medical's estimated cost for this procedure ranges between USD 4,000 and USD 8,000. This is a preliminary estimate and not a binding offer, and the final price is set after your case is assessed. It is affected by factors including the type of implant, the length of hospital stay, tests, physical therapy and the patient's condition. You should ask clearly what the package includes and what it does not before making a decision.

Partial knee replacement in Turkey and the role of O9 Medical

If, after consulting your surgeon, you decide to consider having the operation in Turkey, O9 Medical's role is one of coordination: reviewing your medical reports and images, arranging a consultation with an orthopaedic surgeon, clarifying the options available, including total replacement if partial replacement does not suit you, and organising appointments and communication before and after travel. We do not promise any particular outcome; assessment and the medical decision rest with the surgeon. You can visit our orthopaedics and joint surgery in Turkey section to learn about related procedures.

Questions to ask your surgeon before deciding

• How many partial knee replacements do you perform each year, and what is the volume at the hospital where the operation will take place? Sources link the results of partial replacement to the surgeon's experience and volume.
• Why do you think partial replacement suits my case rather than total replacement, and which tests is that based on (X-rays, ligament condition, condition of the other compartments of the knee)?
• What happens if you find during the operation that partial replacement does not suit me? Do I agree in advance to conversion to total replacement?
• What if I need further surgery, where would it be done and who would follow me up?
• What is the follow-up and physical therapy plan after I return to my home country?
• What type of implant is proposed, and why?
• What does the package include and what does it not include?

Medical note: this information is for general education. It does not replace consultation with a specialist doctor and is not a diagnosis or a prescription.