Arthrofibrosis is the consequence of fibrotic tissue that occurs as a result of knee injury or surgery of some sort. It is most commonly associated with Anterior Cruciate Ligament (ACL) reconstruction, but may occur with any invasive procedure of the knee such as Total Knee Replacement.

Authored by Ms Michelle Boucher in 2017 and reviewed in September 2023 by Dr Sheila Strover (Clinical Editor)

Arthrofibrosis may result in significant disability to those patients who have unfortunately developed this surgical complication. The disability typically results in pain, lack of the normal range of motion of the knee, extension lag (inability to fully extend the knee) or flexion contracture (the knee “locked” in a bent or flexed position), together with the consequent functional impairment such as the inability to climb stairs, tie one’s shoes etcetera and gait disturbances which negatively impact the person’s quality of life.

It is in the early stages that the process of adhesion development can often be arrested and reversed. Unfortunately the condition can be unrecognised, and the patient pushed harder and harder with their exercise regime, causing more inflammation.


Sprague’s Classification for arthrofibrosis:

Group 1: Discrete bands or a single sheet of adhesions traversing the suprapatellar pouch.

Group 2: Complete obliteration of the suprapatellar pouch and peripatellar (alongside the knee cap) “gutters” with masses of adhesions.

Group 3: Multiple bands of adhesions or complete obliteration of the suprapatellar pouch with extracapsular involvement (outside the knee joint). Adhesions extending to the anterior femur (thigh bone) and to the patella or knee cap.​


The American Academy of Orthopedics (Majit, 2007) has established that the majority of cases of established arthrofibrosis are able to be effectively treated with the following procedures:

  • Manipulation under Anaesthesia (MUA): To forcefully break up the scar tissue or adhesions by the surgeon, while the patient is under general anesthesia.
  • A “first look” arthroscopy: a minimally invasive “key-hole” surgery using a scope with a camera and the ability to break up adhesions and expand the joint with fluid under pressure - used initially before resorting to more aggressive surgical procedures.
  • Lysis of Adhesions (LOA): The mainstay of surgical therapy, often in conjunction with MUAs as adhesions are serially released. Utilizing debridement and/or cautery to cut and simultaneously coagulate the scar tissue, via an arthroscopic approach.
  • Anterior Interval release: Releasing the scar tissue tethering the back of the patellar tendon and fat pad to the tibia bone, in a region where there is usually a gap to allow tendon mobility.
  • Posterior capsulotomy: Releasing the taut capsule at the back of the knee joint.


Salvage Procedures

More aggressive “salvage procedures” are reserved for more severe cases of arthrofibrosis (Freihling, 2006). These procedures may include quadricepsplasty, typically involving releasing the back of the rectus femoris part of the quads muscle where it becomes adherent to the vastus intermedius part behind it. Where the patellar tendon has become stuck and contracted causing the patellar to be too low for proper functioning of the joint, it may be released and an osteotomy performed to reposition the attachment of the tendon higher up the tibia (eg DeLee osteotomy). Another procedure to release tight tissues to the side of the patella is a “Z-plasty” of the reticula.


Contributory Factors

Despite the acceptance and increased understanding of arthrofibrosis, rates of this complication still range from 4-33%, depending on the literature reviewed (Majit, 2007). Factors that affect the development of the problem include technical error on the part of the surgeon, timing of the surgery, high versus low velocity trauma, physiotherapy complications, and the development of Complex Regional Pain Syndrome or CRPS. This latter creates a “vicious cycle” of sorts involving impaired autonomic nerve function with severe pain posing a detriment to necessary physiotherapy and impaired healing. Other factors include impaired healing due to inflammation from a variety of causes and host factors such as genetics.Indications for surgical correction include extension deficits which result in 10 degrees or more of extension lag (Freihling, 2009) or a flexion contracture, limiting mobility. Despite surgical correction the same patient is exposed to the same factors that caused the initial complication, so rates of recurrence after corrective surgical procedures are difficult to come by and not often cited in the literature.



There have been some studies that have demonstrated statistically significant positive results at 2 and even 4 year follow up - however sample sizes have been small so these results have to be interpreted with caution. So while the American Academy of Orthopedics recommends that most cases of arthrofibrosis may be adequately corrected using Lysis of Adhesions and Manipulation under Anesthesia procedures, more severe cases may require the more invasive “salvage” measures, although there is little research to ascertain if these measures are going to result in an adequate functional result for the patient.​

While most research involving the treatment of arthrofibrosis is decades old, some more current studies for the more severe “salvage” cases of arthrofibrosis in which the functional impairment of the patient is severe, often meeting Sprague’s 3 criteria, have utilized a combination of intra-articular and extra-articular procedures. For example, Wang, in 2006, in the treatment of arthrofibrosis patients with severe flexion contractures, incorporated intra-articular arthroscopic lysis of adhesions procedure with an extra-articular (outside the joint) minimally invasive quadricepsplasty with favorable outcomes, even at 24 months follow-up. In his study of patients with severe flexion contractures, with an average degree of knee flexion of 27 degrees preoperatively to an impressive 115 degrees of knee flexion postoperatively, the results remained stable at two years. Now the study only involved 22 patients, so the small sample size impacts our interpretation of results, but they were statistically significant with 16 patients reporting their postoperative functional outcome as “excellent” and 6 as “good”, even at 2 years, so results appear to have remained stable, without recurrence of arthrofibrosis.​

It is clear that more research is required, with larger multi-center trial sites so as to establish sufficient sample sizes to permit evidence-based conclusions to be drawn.

This will empower patients with respect to their surgical options as well as guiding the surgeons themselves as to the best course of action in patients with this debilitating complication.

Of even greater benefit, further research is needed that may enable us to better prevent this complication through appropriate timing of surgery, more knowledge of patient factors predisposing them to arthrofibrosis, and improved training in surgical technique as to correct the known “technical error” component that all are in agreeance is the single most important factor in the development of arthrofibrosis.​


David Majit MD, Andy Wolf MD. Arthrofibrosis of the Knee. Journal of the Academy of Orthopaedic Surgery; American 2007 15 682-694)

D. Freihling MD, P. Lobenhotter MD.The Surgical Treatment of Chronic Extension Deficits of the Knee. Operative Orthopaedic Traumatology; 2009 Dec;21 (6) 545-556)

D. Freihling MD, M. Galla MD, P. Lobenhotter. Arthrolysis for Chronic Knee Flexion Deficits of the Knee: An Overview of Indications and Techniques of Vastus Intermedius Muscle Resection, Transposition and the Tibial Tuberosity and Z-plasty of the Patellar Tendon. Trauma Surgery, 2006; April 109 (4) 285-296).

Jian Wang MD, Jin Zhua MD, Y. He MD. A Knew Treatment Strategy for Severe Arthrofibrosis of the Knee. Journal of Bone and Joint Surgery 2006 June; 88 (6) 1245-1250.​


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According to the American Academy of Orthopedics, “Arthrofibrosis represents a wide spectrum of disease ranging from localized to diffuse involvement of all compartments of the knee and extra-articular soft tissues” - the definition adopted by the academy in 2007.
Early surgical intervention, while no definitive standard exists, is generally acknowledged as within 3 months from the initial triggering surgery, is typically recommended. Surgical treatment depends largely on the location of adhesions, lying inside of the joint (intra-articular) or outside of the joint (extra-articular). Oftentimes an arthroscopic procedure is used initially to identify the location of and treat adhesions within the joint capsule before resorting to more aggressive “open” procedures that may be necessary when the scar tissue extends outside of the joint.
Sprague’s classification may be utilized to determine the anatomic location and severity of the adhesions and therefore the appropriate operative measures.

Once arthrofibrosis is fully established, surgical intervention is indicated.