These authors make a valuable contribution to the understanding of knee arthrofibrosis, by going into the anatomy of the areas where the fibrous tissue of arthrofibrosis tends to cause problems:
There are good illustrations of the anatomical areas involved. They describe
how they surgically explore each of these areas and cut the tissues free. Surgery is performed under
epidural anaesthesia, and they leave an indwelling
epidural catheter in to provide further pain relief after surgery and which also allows earlier rehab in the immediate period after surgery. Once the epidural is in effect, the authors attempt to distend the
joint cavity ('capsular distension') with 120 to 180 mls of saline fluid - this both helps to open up the joint to facilitate surgery, but also gives an idea of how tight the scarring is.
The suprapatellar pouch
The suprapatellar pouch is an 'pouch-like' extension of the joint space up behind the patella, extending 3 to 4 centimetres above it. It helps to lubricate knee motion, and the interior is lined with synovium, the tissue that lines the rest of the joint and produces the lubricating fluid. The authors stress that one must continue releasing scar tissue in this area until the pouch is fully released.
Medial and lateral gutters
These are also extensions of the joint [like the cheek gutters in the mouth, alongside the teeth] and the medial and lateral gutters are synovial-lined spaces on each side of the knee joint alongside the tibia and femur bones, and their outer aspect is part of the capsule of the knee. The authors note that adhesions often form here between the capsule and the femur in the lateral gutter, and that these should be released during surgery.
Anterior interval
The anterior interval is the region behind the patellar tendon, where one finds the patellar fat pad and the pouch known as the 'pre-tibial' recess. Scar tissue can form here right up to the front edge (anterior horn) of the menisci. The auathors explain that the procedure to remove the scar tissue here is called 'anterior interval release', and that this involves removing scarring from the front of the menisci right down to the tibia bone, making sure that there is no residual bleeding and taking care not to burn the bone during cautery (burning the ends of vessels to seal them).
Lateral and medial retinaculum
The lateral and medial retinaculum are fibrous bands that stretch from the side edges of the patella like guy ropes holding it in a central position. If the patella is tight in this area due to arthrofibrotic scar tissue, then it is selectively released, allowing improved movement of the patella and also improved surgical access into the joint.
Intercondylar notch
The intercondylar notch is the area between the rounded ends of the femur, and this region can be the focus of problems after anterior cruciate ligament (ACL) reconstruction, where a narrow notch can lead to abrasion of the graft, with nodules of proliferative graft material also forming there, and these may even become bony. The authors advocate widening the notch if there is impingement, a procedure known as 'notchplasty' and removal of any fibrous nodules or bony nodules, although they stress that osteophytes are not routinely removed because of potential bleeding. [Osteophytes are abnormal mushroom-like outgrowths of bone and these may form from the bony edges of the notch]. The authors do not mention the 'cyclops' lesion by name, but a larger fibrous nodule arising from the graft tissue would be called a cyclops lesion].
Posterior capsule
At the end of all these above procedures the knee flexion and extension is tested, and if the knee is still tight, then the authors say that they continue onto the 'open' procedure known as 'capsulotomy', where a small incision is made and scar tissue is removed from the medial and lateral capsule at the back of the knee. Then the capsule is stripped back from its attachment to the tibia and femur bones, initially on the medial side and if necessary also on the lateral side.
