This is the editor's interpretation of a paper published in the orthopaedic literature in 2003 - 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.

Rehabilitation of the arthrofibrotic knee.

Millett PJ, Johnson B, Carlson J, Krishan S and Steadman JR. Am J Orth. 2003;11:531-538. [Click here for open access]

This is a review article discussing the significance of prevention and early recognition of arthrofibrosis. The authors note that arthrofibrosis of the knee can be localised or global, and can restrict flexion or extension of the knee or movement of the patellofemoral joint. They stress that rehabilitation of arthrofibrosis of the knee is amongst the toughest challenges in orthopaedics.


Prevention and Early Detection of knee arthrofibrosis after ACL surgery

Because arthrofibrosis is so difficult to treat, they stress that prevention is the best approach and especially preventing prolonged immobilisation, infection or poor positioning of an anterior cruciate ligament (ACL) graft. With respect to ACL injuries they stress that -

  • surgery should be avoided if the knee lacks full ROM
  • placement of the graft in the right position needs to be meticulous
  • bleeding after surgery needs to be avoided
  • rehabilitation needs to be early and appropriate

The authors stress that once arthrofibrosis has developed it needs to be recognised early and treated appropriately. After any knee surgery, but especially after cruciate surgery, it is important to closely monitor knee motion, to identify early motion problems, and also to monitor pain which may be indicative of tissue tethering.


Monitoring the patient with suspected arthrofibrosis

Both flexion and extension need to be monitored via:

  • serial measurement of prone heel hangs (monitored against the other leg). The goal should be full extension and 120 degrees of flexion by two weeks
  • patellar mobility assessment, both side-to-side and up-and-down. This should include assessment of:
    • the patella itself
    • the patellar tendon below the patella
    • the quads tendon above the patella
  • serial assessment of patellar height, both by examination and X-rays - this should detect any tendency towards 'patella baja', which is when the scar tissue pulls the patella downward.


The authors point out that before a diagnosis of arthrofibrosis is assumed when there is early motion loss, other possible causes of the motion loss need to be excluded. These other causes can include:

  • an ACL nodule (also called a 'cyclops' lesion)
  • fat pad scarring
  • reflex sympathetic dystrophy

An MRI examination can be helpful in identifying an ACLnodule or fat pad scarring, and may also reveal the adhesions characteristic of arthrofibrosis. An ACL nodule is also associated with a subtle crepitus (fine crackling with joint movement), and a 'clunk'. Reflex sympathetic dystrophy can be suspected if the patient has disproportionate pain, and skin blotching.

The authors refer to the paper by Noyes and others (Noyes FR, Mangine RE, Barber SD. The early treatment of motion complications after reconstruction of the anterior cruciate ligament. Clin Orthop Relat Res. 1992 Apr;(277):217-28.) where those authors emphasised the importance of early recognition and intervention in preventing the sequelae of arthrofibrosis, such as patella baja and progressive joint degeneration. Noyes and his colleagues had found that outcomes could be improved by placing patients with early motion problems into an aggressive rehabilitation programme, which included serial casting of the knee.


Surgical Management of established knee arthrofibrosis

The authors point out that details of the specific surgical procedures for arthrofibrosis have already been published by others, and briefly outline that where surgery is necessary they manage to treat most of their patients with arthroscopic rather than open surgery.

Arthroscopic surgery concentrates on -

  • re-establishing the suprapatellar pouch
  • releasing the medial and lateral retinacula
  • maintaining the pre-tibial recess
  • inspecting the notch for impingement

For open surgery they have a 9-step procedure where each of these areas above is systematically examined and any adhesions or scarring are freed. In addition attention is paid to inspecting the posterior capsule and releasing any adhesions around the -

  • tibial insertion of posterior capsule
  • femoral insertion of posterior

and doing a lateral capsulotomy (cutting the capsule itself) if needed.

They stress that surgery should be followed by an appropriate rehabilitation and pain management protocol.


The Role of Manipulation

The authors suggest that manipulation can play a role, but generally they advocate that it is best to relieve the adhesions surgically, as this is more precise and causes less damage and bleeding than manipulation. They suggest that manipulation may have a role before the immature scar tissue stiffens up - about 3-4 months after the initiating insult - but they themselves they rarely use isolated manipulation once the knee is chronically stiff as this can lead to joint surface damage and even bone breaks. Even if used earlier it should be used with caution as the quads muscle can tear (leading to muscle inflammation - 'myositis') or even rupture.

They do note that other authors have apparently used manipulation more freely than they themselves would advocate.


Pain killers and anti-inflammatories

Pain control after surgery is considered to be essential, and may include opioids by mouth or injection, and in many cases an indwelling epidural for several days after surgery. Anti-inflammatories are general advocated - usually NSAIDS but occasionally intravenous steroids.



The authors stress that early motion and weight bearing are essential in -

  • post ACL surgery
  • post arthrofibrosis surgery

There is some variation between individuals but they feel that the normal ROM is -

  • Normal extension is hyperextension - % degrees in males and 6 degrees in females
  • Normal flexion is 140 degrees in men and 143 degrees in women



  • passive ROM via wall slides, seated flexion and extension exercises, prone flexion exercises, heel slides, propping the heels up when resting on the back, and hanging the legs off the bed when resting on the tummy. Passive exercises should be 3-4 times daily and 15-20 minutes with each session. See A-Z of exercises.
  • re-education of the quads - including straight leg raises and isometric quads exercises
  • hamstring and calf strengthening to stretch the posterior capsule and soft tissues

The authors stress that these regimes must not be over-agressive as this will cause pain and inflammation and actually lead to new adhesions.

  • patellar mobilisation - probably the most important aspect of rehabilitation. Patellar mobilisations should be done in all planes of motion 5-6 times a day for 5-10 minutes each time. The patient should make sure that someone else performs the mobilisations as the knee will not be properly relaxed if the patient tries to do them him/herself. Mobilisation should include the soft tissues above and below the patella.
  • CPM - the authors routinely use CPM after arthrofibrosis surgery particularly for its beneficial actual on joint cartilage and the patients are sent home with a CPM for the first 2 weeks to use 6-8 hours a day. They caution that this helps flexion but that extension must not be forgotten.
  • bracing - if bracing is needed to help achieve extension, the knee should be braced at full extension, and they alternate periods of bracing with periods of motion. Motion problems are likely to arise from bracing in flexion. On their patients they us a JAS brace (Joint Active Systems) 2-3 times a day for 30 minutes, with the patient being instructed to actively increase the stretch every 5 minutes. They caution that improper use of a brace can damage the knee.
  • stationary bicycle - the authors suggest that the static bike can be used after a week, although they often delay its use until the third week otherwise the joint may become swollen and irritated. No resistance is applied for the first 6 weeks and then revs and resistance are increased as long as there is no swelling, heat or reduction in ROM.
  • treadmill - this can be introduced as early as one week postoperatively at a 7%-12% incline. This angle is not hard on the patella. At 6 weeks backward walking on the treadmill is introduced - this is good for quads conditioning and does not place much stress on the patellofemoral joint.
  • aquatherapy - once the surgical wounds are healed (2-6 weeks), deep water jogging is introduced 2-3 days per week for 20-30 minutes per session. By 6-8 weeks resistance is increased by the use of training fins.
  • elastic resistance strengthening - once strengthening is allowed, the principle is high repetitions with moderate resistance. If any swelling or stiffness occurs these exercises are delayed.


When not to be aggressive

The authors particularly advocate caution when -

  • the knee is hot
  • reflex sympathetic dystrophy is suspected
  • myositis is suspected (calcification can be seen in the muscles on X-ray)


eBook - How to perform Patellar Mobilisations

This ebook is fully illustrated.


Key resource -




prone hangs

Prone heel hangs - the difference in height between the two heels can be recorded and monitored to give a quick idea of improvement or deterioration in extension.