Knee replacement is a highly successful operation with excellent long-term survivorship. Problems like loosening and wear have been successfully addressed through implant design and the focus today is on facilitating rapid recovery to a high level of function. Rapid recovery involves a host of factors that include pain management, immediate range of motion, modern implants and management of the soft tissues. Historically the quadriceps tendon which provides the power of knee extension, has been divided in what is called a medial parapatellar approach. This approach separates the powerful medial quad muscle from the rest of the muscle belly. While this division heals after it is repaired, it does cause significant delay in recovery of quad function and the potential for more muscle atrophy that is difficult to recover after surgery.
To reduce violation of the extensor mechanism, the midvastus technique was developed where the vastus medialis (medial quad muscle) is split within the muscle fibers keeping the tendon intact. While this technique has the advantage of not violating the important tendon structure, it can cause some damage to the muscle which has to be repaired and must heal. This too can cause some delay in recovery of quad function and perhaps some persistent extensor weakness.
The subvastus technique completely spares both the quadriceps tendon and muscle. The capsule below the quad muscle is divided allowing the entire extensor mechanism to be displaced providing exposure of the knee joint for the replacement operation. At the end of the case, the entire mechanism is brought back into anatomic alignment. The capsule is then closed and muscle remains completely intact. This provides almost immediate return of quadriceps function allowing rapid rehabilitation and perhaps less work to recover strength and function after surgery.
This technique is not widely practiced and no other surgeons in southern New Hampshire are currently doing this. When the subvastus approach is combined with our AVATAR joint replacement program, patients can recover comfort and function substantially sooner than historical norms for knee replacement. AVATAR is a comprehensive rapid recovery program that we have developed that targets the many assets that are required to enjoy early improvement and pain relief.