Histologic Evidence of Retinacular Nerve Injury Associated with Patellofemoral Malalignment

Healing of the patellar tendon donor defect created after central-third patellar tendon autograft harvest

“…Thus, neural changes (i.e., neuroma of amputation) observed in the PTDD could explain, to some degree, the anterior knee pain in some patients. These neural changes are similar to those observed in the lateral retinaculum in patients with anterior knee pain syndrome and patellofemoral malalignment [9,31]. On the other hand, we have found inflammatory changes in the paratenon that also could explain the "self-limiting anterior knee pain" after PTA [27].…”

Hypothesis: Anterior knee pain in the young patient-what causes the pain?"Neural model"

“…During flexion of the knee, the patella migrates medially into the femoral trochlea (Sanchis-Alfonso et al 1994). This produces recurrent stretching on the shortened lateral retinaculum that may cause secondary changes in the nerve, such as neuromas ( Figure 7) and neural myxoid degeneration (Fulkerson 1983, Fulkerson et al 1985. As for neuromas, we found a clear relationship between neuromas and pain; as regards neural myxoid degeneration, we detected no relationship between it and pain (SanchisAlfonso et al 1998).…”

“…It is well-known that pain in patients with PFM can not be ascribed to a single factor, but to several. The infrapatellar fat pad, subchondral bone, the quadriceps tendon, patellar ligament, synovium, the medial and lateral retinaculum all have a rich nerve supply and these structures, individually or in combination, may cause pain (Fulkerson 1983, Fulkerson et al 1985, Wojtys et al 1990, Dye et al 1998, Witonski and Wagrowska-Danielewicz, 1999, Sanchis-Alfonso et al 1999, Biedert and Sanchis-Alfonso 2002.…”

Adolescent patellofemoral pain: Implicating the medial patellofemoral ligament as the main pain generator

“…Ideal function of the patellofemoral joint is predicated on the presence of balanced medial and lateral patellar restraints [44][45][46]. In that MPFL pain is uncommon until the adolescent growth spurt, rapid growth likely causes a mild imbalance in these restraints, and the relationship of the quadriceps to the hamstrings and the vastus medialis to the vastus lateralis [5,20,21,47,48]. As stated by Fulkerson ''While opinions vary, there is little question that imbalance (malalignment) of the extensor mechanism can lead to overload of the retinaculum and subchondral bone.…”