Adolescent AKP, insidious onset, profound psychological effect.

This 16-year-old female patient developed AKP insidiously in association with her growth spurt four years earlier. The severe, and constant nature of the pain, a deep, parapatellar ache affected this child profoundly.

Formerly an active dancer, she became sedentary, and psychiatrically disturbed, showing self-destructive behavior, leading to her admission in a pediatric in-patient psychiatric center where she had been housed for 2 years. She was referred by her pediatrician.



She was modestly overweight, having gained 125 lbs since her knee pain began. Both knees showed similar findings: ten degrees of hyperextension, normal axial alignment, tenderness about both patellae which were hypermobile, and positive Hoffa’s sign.

Radiographs demonstrated patella alta, normal axial alignment, and hyperextension of 10 degrees bilaterally. MRI examination showed mild cartilage loss, and reactive edema in the marrow of the inferior patella and in the adjacent superolateral aspect of the fat pad in both knees. There were infrapatellar plicae bilaterally.


The operative findings included: a separate IPP on the right, a fenestrated IPP on the left, both demonstrating non-isometric mechanical behavior, as previously outlined. In both knees the fat pad was completely liberated from attachment to the distal femur and anterior cruciate ligament, thus untethering the fat pad. This involved simple release of the femoral attachment on the right, and resection of the entire plica on the left. Small zones of chondromalacia (grade 2) with adjacent focal synovial proliferation were present, and were debrided to stable surfaces.


The patient experienced immediate, complete relief of pain, with normalization of her mental status, and discharge from the facility 6 months later. She has resumed a normal life.

Outcome scores for this adolescent at 11 months’ post-surgery were excellent:

Right Knee:
  • Lysholm – pre-30, post 90;
  • ADLS – pre 34, post 86.
Left Knee:
  • Lysholm – pre 29, post 94;
  • ADLS – pre 42, post 88.


Her Mother sent an email to the hospital administration that included the following comment:

…what a different girl E… is today than she was in early March of this year (2016). In researching her psychiatric diagnosis, I discovered that, for people with her diagnosis, ongoing pain, experienced outside her control, has been found to result in less internal analgesic protection and cause more anxiety. That description fits in exactly with what Dr. Smallman predicted would happen following surgery -- that once the chronic pain E… had endured for the past four years was removed, her overall anxiety level would go down. In fact, it did, and to my knowledge there were NO attempts of self-inflicted pain after you removed the chronic pain of her knees…”.


In the words of the patient:

“…I don't think my knee situation could be any better. The problems I have now are related to being overweight… Satisfied, quality of life has improved. I am able to be more active which also improves quality of life also.”