From OT Europe

THE Partial Knee Meeting to be held Jan. 25-26, 2018 in Bruges, Belgium

Controversy remains about the optimal treatment for unicompartmental anteromedial bone-on-bone osteoarthritis of the knee. This controversy exists because surgeons are aware that the functional outcome of any total knee arthroplasty is rarely a completely forgotten knee joint. The quest for better results has led to resurfacing techniques that indeed limit the anatomical changes within the joint, but expose the surgeon to more dilemmas and issues.

Emmanuel Thienopnt, MD
Emmanuel Thienpont

The organizers of THE Partial Knee Meeting believe everyone who is open-minded enough to consider partial knee replacement as a potential treatment option for their patients should join us next year for the meeting on 25 to 26 January in Bruges, Belgium.

Whenever unicompartmental knee arthroplasty (UKA) is considered, many questions arise. What is the condition of the remaining compartments of the knee? Will this patient develop arthritis in those other compartments and need further surgery? What is the functional profile of this patient? Is the bone solid enough to bear the unicompartmental implant? Will the remaining deformity lead to bone overload? Am I, as a surgeon, capable of executing the right cuts in all three planes with a smaller margin of error because of the smaller surfaces of fixation? How do my colleagues feel about UKA and will they be quickly tempted to revise my patient’s UKA? The risk ratio of revision after UKA is three-times greater and one-third of revisions after UKA need stem or wedge augmentation.

Issue of UKA vs total knee arthroplasty

Medial bone-on-bone monocompartmental OA can potentially be treated with high tibial osteotomy, unicompartmental knee arthroplasty or TKA. The choice of treatment depends on cultural habits, surgical expertise with one or the other technique, the choice of the patient and the bias of the surgeon. The choice should be based on a risk analysis considering the patient’s age, weight, functional outcome, expectations, comorbidities and the risk of medical complications with each technique and, of course, longevity and risk for revision.

Higher revision rates

Failure of UKA is three-times higher than for TKA. Aseptic loosening, disease progression, instability and unexplained pain are the main reasons for UKA revision. Uncemented components can present subsidence in valgus with increasing posterior slope. Aseptic loosening of a UKA can rarely be resolved with a new tibial baseplate. Disease progression can often be helped by adding another component to the part of the knee that re-developed arthritis, such as the patellofemoral joint or lateral side. About two-thirds of the time, revision to primary TKA is possible. Stems or augments are needed in one-third of revisions. Therefore, the threshold for revision of UKA to TKA remains low because revising surgeons believe they will essentially be performing a primary TKA.

The reason to use UKA is not only a question of early recovery, which is a bit quicker than for TKA, but should be because of better functional outcome. Keeping healthy parts of the knee should not be considered a mistake, but an option worth considering.

New evolutions, new implants or new technologies

New implants should meet the needs of surgeons today, which are better survival of the fixed-bearing polyethylene after the second decade and preferentially the same as for the mobile bearing and a better anatomical fit of the implant. This is especially true on the tibial side where an exact line-to-line fit should exist to provide optimal bone coverage. Finally, the instruments should facilitate alignment and accuracy of the cuts while reducing the risk for overcutting the posterior side or undercutting the ligament island.

A great design opportunity exists on the lateral side where a disease-specific implant should solve the issues we face today when using a medial side-designed UKA prosthesis on the lateral side.

New technologies, like navigation and robotics, should help surgeons avoid outlier mistakes during bone cuts and offer reproducibility to younger surgeons with less surgical experience. The most important added value for these new technologies lies probably in the potential to evaluate the soft tissues and the individual compartment behavior before and after the surgery, and the corrections that come with this. Once the robots become less expensive, they will be available to more surgeons and patients.

A meeting focus on UKA

These and many other issues surgeons can and should discuss about UKA arthroplasty led to the idea of having a meeting focused only on this topic. It allows us to do a deep dive and go into detail about indications, diagnosis and surgical techniques. THE Partial Knee Meeting is fortunate to be able to have the best surgeons worldwide who are specialized in partial knee replacement come to Belgium and join us for this event. The meeting’s format is the unique concept of panel discussions led by the moderator. A new technology used at the meeting will allow the attendees to interact directly with the co-moderators and permit them to submit their burning questions about UKA to the panel.

Disclosure: Thienpont reports being THE Partial Knee Meeting chairman and receiving royalties from Zimmer Biomet for the Persona Partial Knee (PPK) and is an implant designer for Medacta.

Controversy remains about the optimal treatment for unicompartmental anteromedial bone-on-bone osteoarthritis of the knee. This controversy exists because surgeons are aware that the functional outcome of any total knee arthroplasty is rarely a completely forgotten knee joint. The quest for better results has led to resurfacing techniques that indeed limit the anatomical changes within the joint, but expose the surgeon to more dilemmas and issues.

Emmanuel Thienopnt, MD
Emmanuel Thienpont

The organizers of THE Partial Knee Meeting believe everyone who is open-minded enough to consider partial knee replacement as a potential treatment option for their patients should join us next year for the meeting on 25 to 26 January in Bruges, Belgium.

Whenever unicompartmental knee arthroplasty (UKA) is considered, many questions arise. What is the condition of the remaining compartments of the knee? Will this patient develop arthritis in those other compartments and need further surgery? What is the functional profile of this patient? Is the bone solid enough to bear the unicompartmental implant? Will the remaining deformity lead to bone overload? Am I, as a surgeon, capable of executing the right cuts in all three planes with a smaller margin of error because of the smaller surfaces of fixation? How do my colleagues feel about UKA and will they be quickly tempted to revise my patient’s UKA? The risk ratio of revision after UKA is three-times greater and one-third of revisions after UKA need stem or wedge augmentation.

Issue of UKA vs total knee arthroplasty

Medial bone-on-bone monocompartmental OA can potentially be treated with high tibial osteotomy, unicompartmental knee arthroplasty or TKA. The choice of treatment depends on cultural habits, surgical expertise with one or the other technique, the choice of the patient and the bias of the surgeon. The choice should be based on a risk analysis considering the patient’s age, weight, functional outcome, expectations, comorbidities and the risk of medical complications with each technique and, of course, longevity and risk for revision.

Higher revision rates

Failure of UKA is three-times higher than for TKA. Aseptic loosening, disease progression, instability and unexplained pain are the main reasons for UKA revision. Uncemented components can present subsidence in valgus with increasing posterior slope. Aseptic loosening of a UKA can rarely be resolved with a new tibial baseplate. Disease progression can often be helped by adding another component to the part of the knee that re-developed arthritis, such as the patellofemoral joint or lateral side. About two-thirds of the time, revision to primary TKA is possible. Stems or augments are needed in one-third of revisions. Therefore, the threshold for revision of UKA to TKA remains low because revising surgeons believe they will essentially be performing a primary TKA.

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The reason to use UKA is not only a question of early recovery, which is a bit quicker than for TKA, but should be because of better functional outcome. Keeping healthy parts of the knee should not be considered a mistake, but an option worth considering.

New evolutions, new implants or new technologies

New implants should meet the needs of surgeons today, which are better survival of the fixed-bearing polyethylene after the second decade and preferentially the same as for the mobile bearing and a better anatomical fit of the implant. This is especially true on the tibial side where an exact line-to-line fit should exist to provide optimal bone coverage. Finally, the instruments should facilitate alignment and accuracy of the cuts while reducing the risk for overcutting the posterior side or undercutting the ligament island.

A great design opportunity exists on the lateral side where a disease-specific implant should solve the issues we face today when using a medial side-designed UKA prosthesis on the lateral side.

New technologies, like navigation and robotics, should help surgeons avoid outlier mistakes during bone cuts and offer reproducibility to younger surgeons with less surgical experience. The most important added value for these new technologies lies probably in the potential to evaluate the soft tissues and the individual compartment behavior before and after the surgery, and the corrections that come with this. Once the robots become less expensive, they will be available to more surgeons and patients.

A meeting focus on UKA

These and many other issues surgeons can and should discuss about UKA arthroplasty led to the idea of having a meeting focused only on this topic. It allows us to do a deep dive and go into detail about indications, diagnosis and surgical techniques. THE Partial Knee Meeting is fortunate to be able to have the best surgeons worldwide who are specialized in partial knee replacement come to Belgium and join us for this event. The meeting’s format is the unique concept of panel discussions led by the moderator. A new technology used at the meeting will allow the attendees to interact directly with the co-moderators and permit them to submit their burning questions about UKA to the panel.

Disclosure: Thienpont reports being THE Partial Knee Meeting chairman and receiving royalties from Zimmer Biomet for the Persona Partial Knee (PPK) and is an implant designer for Medacta.