Operative treatment of arthrofibrosis of the knee.

Lindenfeld TN, Wojtys EM, J Bone Joint Surg 81-A:1772-1784;1999.

This is the editor's interpretation of a paper published in the orthopaedic literature in 1999 - our attempt to make relevant medical articles accessible to lay readers. If you wish to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library.

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) -

  • mechanical causes (eg a bone fracture, damage to the extensor or flexor mechanism, meniscal tear, loose body, big effusion, cyclops lesion, poor ACL graft placement. They offer their opinion that the 'localised intra-articular variant' - the so-called cyclops lesion - is a condition which is not part of the general picture of arthrofibrosis, but a separate clinical entity.
  • nerve damage ('neuropraxia') - which can be caused by the tourniquet applied and inflated during surgery, or to other nerve damage, even that from a lumbar disc.
  • infection
  • inflammation - the timing of surgery after an injury - particularly ACL injury - is believed by most surgeons to be important, so that surgery is not undertaken during the period of inflammation.
  • quadriceps muscle inhibition due to general pain and effusion, or as part of the pain disorder known as 'complex regional pain syndrome'.
  • quadriceps muscle contracture
  • disuse from immobilisation - classically in a plaster cast.
  • poor rehab protocols


Clinical picture

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
Signs of arthrofibrosis

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.


Pathological findings

Notable findings frequently found at operation include -


Management and Prevention

The authors stress that the best management is 'prevention'.

  • reduce inflammation - 'RICE' regime (rest, ice, compression, elevation)
  • manage inflammation - with non-steroidal anti-inflammatory medication. Oral steroids maybe appropriate in selected patients where there is severe inflammation
  • pay regard to timing of surgery - operations after injury should, where possible, be delayed until the acute inflammatory response has abated, tissue swelling (oedema) and pain have subsided, and muscle strength and range of motion are regained - typically at 1-3 weeks after the injury
  • manage pain - aspirate effusions and make use of narcotic pain medication
  • concentrate on regaining extension - flexion is more easy to regain than extension
  • keep immobilisation to a minimum
  • institute early rehabilitation
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

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'.

Open Surgery

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.

Appropriate Rehabilitation

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.


Results of Treatment

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.