Management of Chondral Injuries Associated With Patellar Instability

The treatment of cartilage injuries secondary to patellar instability is multifactorial. These factors include the time frame of patellar instability, the pathoanatomic factors, the extent of symptoms, and the size and location of the cartilage injury. The chondral or osteochondral injury which occurs with acute patellar instability is managed with either reduction and internal fixation or removal. The treatment of the patellar instability component is controversial in the acute setting, especially when there is no need for an osteochondral surgery. In such cases, patellar dislocations are treated nonoperatively. However, if the patient is indicated for surgery for treatment of osteochondral fracture and intra-operatively the medial patellofemoral ligament (MPFL) remains pathologically lax and presents with a discrete MPFL injury site, there is the option of acute repair.Chondral injury associated with recurrent patellar instability may be subdivided into 2 overlapping groups: (1) chondral damage resulting from the instability episodes (distal medial region of the patellar and/or lateral proximal region of the lateral femoral condyle) and (2) chondrosis secondary to the chronic lateral tracking of the patella (chronic patellar subluxation) from patholaxity of the MPFL (lateral chondrosis to patella and trochlea in addition to the injuries sustained from the actual instability episodes). The treatment is based on the patient's chief complaints and the unique underlying pathoanatomy. Many of these patients will have one or more predisposing factors, such as patella alta, trochlear dysplasia, patholaxity of the MPFL and an excessively lateral position of the tibial tuberosity. Therefore, the key to managing this patient population is to address each patient's specific pathoanatomy, which by definition will include addressing the MPFL patholaxity. The goals are to stabilize the patella, normalize patellofemoral contact area and/or forces, and then restore the articular cartilage based on relevant symptoms. As of this writing, treatment options in the United States include debridement, marrow stimulation, osteochondral auto and allograft, autologous chondrocyte implantation, and the use of particulate articular cartilage.