Arthritis of the knee. Therapy | Comparison: Joint cleansing versus prosthesis
No total joint replacement if there is one-sided wear and tear.
The good news: A complete replacement of the knee joint is not immediately inevitable if arthritis is one-sided. As an alternative joint cleansing and a corrective osteotomy are options (HTO). Also only a partial prosthesis can be used, what is known as a unicompartmental knee arthroplasty (UCA).
The bad news: Both methods mean a knee operation followed by rehabilitation.
Corrective osteotomy or partial knee replacement - what is this?
In the case of a corrective osteotomy the leg axis is corrected in the area of the tibial head. The bone is cut through and either a bone wedge inserted or removed. In the case of the unicompartmental arthroplasty (UCA) a part of the knee joint is replaced. The partial prosthesis takes on the job of the joint cartilage - that of a spacer. The joint bones in the knee are no longer able to rub against each other.
Both methods have a definite place as valued treatment of arthritis of the knee joint.
Which method for which patient?
Advantage of corrective osteotomy: In particular younger more active patients with obvious bow legs or knee instability benefit from this method. A unicompartmental knee arthroplasty (UCA) on the other hand can become loose with too much movement. Then revision surgery is needed, i.e. the operation has to be repeated and this is very complex and can have risks.
Advantages of a unicompartmental knee arthroplasty: A partial prosthesis is recommended in particular for older patients. They benefit from obviously shorter rehabilitation period compared to joint cleansing.
When choosing between a corrective osteotomy and implantation of a unicompartmental knee prosthesis however, other criteria have to be given consideration. The decision then goes far beyond the schema of young - corrective osteotomy, old - unicompartmental knee arthroplasty and should involve various patient and procedure-related criteria.
Durability: Corrective osteotomy versus partial knee replacement (unicompartmental knee arthroplasty).
One of the most frequent question when it comes to choosing between a corrective osteotomy and a unicompartmental knee arthroplasyy (UCA) is the question of durability.
Both methods achieve durability today well over 10 years. Studies show that a corrective osteotomy in more than 80% of cases can sometimes delay a knee replacement by as much as 20 years.
Advantages and disadvantages of the techniques:
|Age||Osteotomy < 60-65 years of age||Unicompartmental knee arthroplasty/partial knee replacement <50 - 55 years of age|
|Varus (bow leg)||+||-|
|Arthritis of the patella||-||-|
|Life time (durability)||+||+|
Surgical technique for a corrective osteotomy: Closed wedge und Open wedge
For axial correction with the aid of a corrective osteotomy, two operative procedures are available: the „Closed wedge“ (Fig. a) und „Open wedge“ (Fig. b) techniques are options. With the Closed Wedge method a (bone) wedge is removed. This is advantageous for a loose or defective anterior cruciate ligament and for pain in the patellofemoral joint.
With the Open wedge procedure it is the other way round a (bone) wedge is added. This is the method of choice for loose inner ligaments or if the posterior cruciate ligament is damaged. The Open wedge procedure also presents fewer risks.