Symptoms and Signs:
Arthrofibrosis of the knee is characterized by stiffness. There is inability to bring the knee fully straight (lake of extension or flexion contracture) and decreased bending of the knee (decreased range of flexion). Most patients have both with hard end point to terminal extension and terminal flexion. Arthrofibrosis varies in severity from mild stiffness to complete absence of motion (ankylosis). The stiffness is usually present from the time of knee replacement.
Pain is a prominent symptom. Majority of the patients have severe pain. Patients are frequently on narcotic pain medications. Rarely patients have little or no pain. The pain is long standing (chronic) and is felt either in the front of the knee (anterior knee pain) or throughout the knee (diffuse knee pain). The pain is usually present since the initial knee replacement without a painless time interval following the knee replacement. The pain is unexplained and does not progressively subside over time as it normally does after knee replacement (persistent knee pain).
Sometimes , patients initially progress well for few weeks after the knee replacement and then the pain and stiffness appear.
There is soft tissue swelling, warmth and pain on manual pressure (tenderness) in and around the knee with inflammation.
Soft tissues around knee feel firm (woody fibrosis) or even hard if there is bone formation within the soft tissue (heterotopic ossification).
Scarring (fibrosis) and shortening (contracture) of the extensor mechanism [quadriceps, soft tissue sleeves on either side of patella (medial and lateral retinaculum) and patellar tendon] leads to inefficient quadriceps muscle contraction, failure of the patella to move upwards with quadriceps contraction, restricted side to side (medial-lateral) as well as up and down (superior-inferior) mobility of the patella, limited quadriceps tendon excursion, knee cap (patella) situated lower than its normal position (patella baja – infrapatellar contracture syndrome) and severely limited knee range of flexion.
Knee flexion contracture increases the quadriceps work for ambulation (strain) and can cause quadriceps fatigue, weakness and with time quadriceps wasting (atrophy). This can lead to sense of weakness, instability, giving way, buckling and repeated falls.
The leg may feel shorter (limb length discrepancy) due to the flexion contracture. This can cause flexed-knee gait, hip pain on the same side, knee pain on the opposite side and low back pain. This leads to difficulty in standing, altered walking pattern (gait), hunched over / crouched walking and profound limp.
The patients encounter difficulty with various activities of daily living like difficulty in sitting on a chair, difficulty getting up from chair, difficulty in ascending or descending stairs, difficulty in bathing, difficulty in tying shoe lace as well as difficulty in entering, travelling and leaving a car. Frequently, patients need a cane, crutch or walker. In severe cases, patients are disabled and they are bound to either a wheelchair or a motorized scooter.