Review Article Arthroscopic Releases for Arthrofibrosis of the Knee Abstract Michael R. Chen, MD Intra-articular inflammation or fibrosis may lead to decreased soft- Jason L. Dragoo, MD tissue and capsular compliance, which may result in pain or loss of motion within the knee. Etiology of intra-articular fibrosis may include isolated anterior interval scarring and posterior capsular contracture, as well as fibrosis that involves the suprapatellar pouch or arthrofibrosis that involves the entire synovial space. Initial nonsurgical management, including compression, elevation, and physical therapy, can decrease knee pain and inflammation and maintain range of motion. Surgical management is indicated in the patient who fails conservative treatment. Surgical options include arthroscopic releases of the anterior interval, posterior capsule, and peripatellar and suprapatellar regions. Recent advances in arthroscopic technique have led to improved outcomes in patients with intra-articular fibrosis of the knee. nee stiffness is a common compli- management of these disorders may Kcation associated with trauma or lead to improved outcomes in this surgery and has been extensively patient population. studied.1-3 Risk factors include injury severity, timing of surgery, delayed Pathophysiology of postoperative rehabilitation, pro- longed immobilization, infection, Arthrofibrosis complex regional pain syndrome, The exact etiology of intra-articular From the Department of and technical errors during intra- tissue fibrosis is unknown, but sev- Orthopaedic Surgery, Stanford articular and extra-articular recon- eral theories exist. Platelet-derived Hospital and Clinics, Redwood City, structive procedures. Extra-articular CA. growth factor and transforming stiffness may be caused by muscular growth factor-beta 1 are inflamma- Dr. Dragoo or an immediate family fibrosis and contracture, heterotopic member serves as a paid consultant tory cytokines produced by the in- to Genzyme and Össur and has ossification, or myositis ossificans. flamed synovium that promote the received research or institutional The inflammatory response to in- proliferation of fibroblasts and ex- support from ConMed Linvatec and ″ jury or surgery can cause fibrosis, re- tracellular matrix proteins, the inhi- Ossur. Neither Dr. Chen nor any sulting in restricted knee motion. An- immediate family member has bition of proteolytic enzymes, and received anything of value from or terior interval scarring, contracture the production of collagen. These cy- has stock or stock options held in a of the posterior capsule or suprapa- tokines are present in intra-articular commercial company or institution tellar pouch, and diffuse arthrofibro- scar tissue and in the synovial fluid related directly or indirectly to the subject of this article. sis may contribute to knee stiffness, of patients with joint trauma, as well lead to alterations in the biomechan- as in fibrosis in the kidney, liver, and J Am Acad Orthop Surg 2011;19: 4-6 7-9 709-716 ics of the joint, and cause pain. lung. Additionally, vascular en- Specific releases can be performed dothelial growth factor is present in Copyright 2011 by the American 8 Academy of Orthopaedic Surgeons. for each fibrotic region. Familiarity the infrapatellar fat pad. This factor with the diagnosis and arthroscopic is released after injury to the fat pad November 2011, Vol 19, No 11 709 Arthroscopic Releases for Arthrofibrosis of the Knee and may lead to vascular ingrowth iofemoral and patellofemoral com- the knee is fully extended. Increased and scarring.4 Another theory posits pression with the risk of chondral pain in the fat pad with knee exten- that injury, whether induced by damage or fracture, rupture of the sion indicates a positive result. Pa- trauma or surgery, produces hemor- patellar tendon, distal femoral frac- tients may also have pain in this area rhage and subsequent fibrosis due to ture, and complex regional pain syn- with forceful hyperextension of the 12,13 the maturation of localized clotting drome. knee. The patellar tendon and patella and induction of progenitor cells. should be carefully examined to rule out other causes of anterior knee Surgical Management pain. Nonsurgical Management Scarring in the fat pad can be visual- Anterior Interval Release ized on standard T1- and T2-weighted Prevention is the most effective The anterior interval is the space be- magnetic resonance images. On sagit- means of avoiding motion loss fol- tween the infrapatellar fat pad and tal T1- and T2-weighted magnetic res- lowing knee injury or surgery. Ini- patellar tendon anteriorly, and the onance images, anterior interval scar- tially, modalities such as ice, com- anterior border of the tibia and ring is indicated by a low signal pression, elevation, aspiration of transverse meniscal ligament posteri- coursing from the posterior portion of effusion, electrical stimulation, phys- orly.4 Trauma or previous surgery the fat pad to the anterior surface of ical therapy, nonsteroidal anti- may cause hemorrhage or inflamma- the tibia and/or transverse meniscal lig- inflammatory drugs, and a short- tion of the fat pad (ie, Hoffa syn- ament. term course of oral corticosteroids drome), which may result in fibrosis. can be used to decrease knee pain Fibrosis that occurs between the fat Surgical Technique and inflammation and maintain mo- pad and the transverse meniscal liga- Arthroscopic management of ante- tion.10 Flexion is more easily ob- ment or the anterior tibia leads to rior interval scarring begins by estab- tained than extension, thus, efforts dysfunction of anterior knee struc- lishing a modified anterolateral should be directed toward maintain- tures (eg, decreased excursion of the viewing portal. The portal is created ing extension. Isometric strengthen- patellar tendon) and results in slightly more lateral and proximal ing of the quadriceps helps to restore stretching of the surrounding syno- than standard arthroscopic portal extension and prevents atrophy. vial tissue, which may cause pain or placement to allow better visualiza- Early patellar mobilization prevents loss of knee extension.4 Fibrosis tion of the anterior interval struc- adhesion formation and contracture within the anterior interval has a tures (Figure 2). The anterior interval of the patellar tendon. Surgery for an spectrum of severity. Paulos et al1 de- can be viewed with a 30° arthro- acute injury is best performed after scribed infrapatellar contracture syn- scope; scarring is indicated by de- inflammation, edema, and pain have drome, which is a severe form of fi- creased opening of the interval with decreased and range of motion brosis of the fat pad and patellar knee extension as well as fibrosis of (ROM) has normalized. Preoperative tendon that severely limits ROM. the infrapatellar fat pad. and postoperative immobilization Fibrosis can be released using a 70° should be kept to a minimum; early History and Physical electrothermal probe inserted via a knee mobilization following surgery Examination modified anteromedial portal (Figure is recommended. Patients with anterior interval scar- 2). Systematic release begins anterior Additional intervention is indicated ring report anterior knee pain and to the transverse ligament, starting in patients who fail initial nonsurgi- frequently describe a sense of fullness just anterior to the anterior horn of cal treatment. Several authors have within the knee, especially with ex- the medial meniscus and proceeding recommended isolated manipulation tension. Physical examination may laterally and anterior to the anterior of the knee under anesthesia within 6 demonstrate a small flexion contrac- horn of the lateral meniscus (Figure to 12 weeks postoperatively in pa- ture, decreased proximal excursion 3). The release continues until the tients who have not regained full of the patella, and a positive Hoffa anterior tibial cortex is encountered ROM following surgery.10,11 How- test.4 This test is performed with the or until normal fat pad tissue is seen. ever, this modality has recently fallen knee in 30° of flexion; the thumbs Adequate release is confirmed by vi- out of favor due to the risk of intra- are placed at the medial and lateral sualization of interval widening with articular hemorrhage and subsequent margins of the infrapatellar fat pad knee extension and closing with flex- postoperative scarring, as well as and patellar tendon (Figure 1). Pres- ion. Care is taken to avoid disrupting complications such as excessive tib- sure is applied with the thumb, and the anterior meniscal attachments or 710 Journal of the American Academy of Orthopaedic Surgeons Michael R. Chen, MD, and Jason L. Dragoo, MD Figure 1 Clinical photographs demonstrating the Hoffa test of the knee. A, The thumb is placed at the lateral margin of the infrapatellar fat pad and patellar tendon with the knee in 30° of flexion. B, Pressure is applied with the thumb as the knee is brought into full extension. (Reproduced with permission from Steadman JR, Dragoo JL, Hines SL, Briggs KK: Arthroscopic release for symptomatic scarring of the anterior interval of the knee. Am J Sports Med 2008;36[9]:1763-1769.) the transverse meniscal ligament. Figure 2 Meticulous hemostasis must be ob- tained to prevent postoperative bleeding and recurrent scarring.4 Postoperatively, the goal of rehabil- itation is to prevent scar reformation while preserving joint mobility. Initially, rehabilitation focuses on establishing full ROM and patellar and patellar ten- don mobility. Patients are