This is the editor's interpretation of the above paper published in the orthopaedic literature in 1999 - our attempt to make relevant medical articles accessible to lay readers. If you want to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library. [Or click here for open access] [/no-lexicon]
This paper reviews the literature prior to 1999. It is a very well written, clear paper.
The authors begin by defining arthrofibrosis as a condition of restricted knee motion characterised by dense proliferative scar formation, in which adhesions - both intra-articular (within the joint space) and extra-articular (outside the joint space) - can progressively spread to limit joint motion.
Before getting into the meat of their paper they point out that, although range of motion had classically been quoted as being from 0-135 degrees of flexion, really it is the comparison with the other normal knee which is important, as the 'normal' range of motion differs in different people.
They stress the importance of excluding those conditions which affect the range of motion (ROM) but which are not arthrofibrosis (although most can co-exist with arthrofibrosis) -
The authors then go on to disuss arthrofibrosis itself. They feel that, although there may be a primary condition where a patient makes excessive scar tissue, more often the trigger to arthrofibrosis is 'multifactorial' - a combination of factors which sets off the arthrofibrosis process.
Symptoms of arthrofibrosis
They note that the symptoms vary and often do not correlate with the severity of the condition -
- stiffness - often worse in the morning
- pain - patients complain of a warm, swollen knee which hurts when they try to move it. The nature of the pain may vary - pain which is constant may hint of complex regional pain syndrome; pain varying with activity may hint at underlying joint damage. The pain may itself trigger quads inhibition - the knee may be held in flexion, and the posterior capsule and hamstring may tighten up.
- swelling - may be worse after prolonged standing or walking
- noises - there may be crackly noises (crepitus) in the knee
- weakness - the quads may be weak
Clinical signs are also present in varying degrees -
- flexed knee gait - the knee is held in flexion to avoid triggering pain
- difficulty palpating the anatomy - there may be an effusion but also the capsular and peri-capsular tissues may be thickened and the patella and the rest of the knee anatomy may be hard to identify
- quadriceps atrophy - the quads may not only be inhibited, but may have physically wasted. Quads strength is weak
- restricted ROM - restricted active and passive flexion and extension, with loss of patellar glide. Passive motion may demonstrate a 'spring-like' end point. ROM may become progressively limited.
Notable findings frequently found at operation include -
- loss of extension was associated with scar formation mostly in the anterior compartment of the knee - the infrapatellar fat pad (with obliteration of the infrapatellar bursa), the intercondylar notch obstructing the ACL, the coronary ligaments (tethering the anterior horns of the menisci). Contracture of the posterior capsular structures aggravated the situation.
- loss of flexion was associated with intra-articular fibrosis and scarring in the patellofemoral mechanism with decreased patellar mobility - adhesions of the quadriceps expansion to the lateral and medial recesses, adhesions within the suprapatellar bursa, adhesions of the quads muscle to the femur, patella infera, shortening of the rectus femoris muscle
- degenerative changes in the joint
The authors stress that the best management is 'prevention'.
Early Focused Intervention
When rehabilitation fails to progress as expected, with either a plateau beyond which no further progress is made or things seem to be moving backwards with ROM actually getting worse, then the authors advocate 'early additional intervention'. Focused physical therapy emphasising restoration of ROM and occasionally gentle manipulation under anaesthetic (MUA) may result in improvement. They feel that after the third month these efforts are less likely to be successful.
They emphasise that forced manipulation or vigorous attempts to gain passive motion may be harmful - indiscriminately tearing tissues inside the joint, damaging the joint surfaces and patellar tendon, and even leading to fracures or triggering complex regional pain syndrome.
Arthroscopic treatment (editor: note that this was only generally available from the early 80s) the authors believe to be the treatment of choice when ROM still does not progress, and particularly if the loss of motion mainly involved flexion and the arthrofibrosis limited to a discrete region - the procedure being known as 'arthroscopic lysis of adhesions'.
Where the arthofibrosis is more generalised, and if it is mainly a loss of extension, then a combination of arthroscopic and open methods ('open debridement') is likely to be needed. A lateral retinacular release may be indicated. Careful MUA may be indicated after the surgical procedure.
The authors stress that, after either surgery, appropriate rehabilitation is essential. In patients who have had extensive releases they recommend continuous epidural anaesthesia, both during surgery and continued in the ward after surgery. They advocate CPM (continued passive motion) after the drains are removed, but they prefer active motion where possible. If extension has been a problem they prefer to concentrate on this - applying an extension splint and advocate 'heel-hangs' (face down with the thigh supported and lower leg and foot off the bed) to maintain extension. Alternatively with the patient on his/her back the heel may be supported on a bolster and weights or manual pressure applied hourly to the knee. And in addition at night the knee is splinted in full extension.
The authors emphasise that most patients will benefit from timely and appropriate intervention. But they feel that when as much as a year has passed since the initial incident the chances of a good response to surgery are low. They note that there is, however, a small group of people who show an intense inflammatory reaction after injury or surgery - in this group further surgery aggravates things and they recommend only medical treatment of the pain and inflammation combined with gentle motion until things have settled down.
The authors go into considerable detail about the surgery and the common surgical findings and it makes very interesting reading, but probably too much to go into in a summary like this. This is certainly a very nice paper to read once you get a handle on the medical terminology.