Patellar chondromalacia among adolescent athletes-A systematic review

Knee joint anatomy and biomechanics: Knee joint is consisted of tibiofemoral and patellofemoral joint, covered with articular cartilage and reinforced with articular capsule and ligaments. Both medial and lateral (bigger, more mobile, less vascularized) meniscus, fi brocartilagionous structures absorb the intraarticular pressure. According to some authors, in patients with a total meniscectomy, the force of pressure of the femur on the condyles of the tibia increases by as much as 350%. Knee fl exion and extension movements, in the range of 1500 are enabled by quadriceps femoris muscle and hamstrings. The maximum degree of internal and external rotation, depending on cruciate ligaments tightening and relaxation is 5-200, while lateral sliding movement are slight, due to collateral ligaments’ tightening [1-9].

Citation: Milanovic  Defi nition and epidemiology: Patellar chondromalacia is defi ned as a painful retropatellar condition, caused by damage of the patellar cartilage, due to repeated stress to the articular surface. Being a common reason for patellofemoral pain syndrome -anterior knee pain, this condition might limit daily life activities. Patients are usually young female athletes in the second decade of life [4,11].
Etiopathogenesis: Patellar chondromalacia can be idiopathic, post-traumatic and also a consequence of biomechanical disorders of the extensor apparatus of the knee, such as: reduced strenght of the quadriceps femoris muscle, reduced Q-angle, patella alta or patella infera, patellofemoral malalignment. Patellar malalignment may be related to patellar (sub)luxation, dysplasio of the femoral trochlea as well as deformities of proximal tibia anatomical parameters such as: tibial slope, trochlear depth, lateral trochlear inclination, and lateral patellar tilt. According to some authors, articular cartilage damage (ICRS grade 1-4: cartilage softening, cartilage surface fi ssures, cartilage fragmentation, cartilage necrosis) in the region of patellofemoral joint is arthroscopically detected in 71% patients with different types of knee trauma, such as: menisci rupture (46%), anterior cruciate ligament rupture (34%) and recurrent patellar luxation (15%) Cartilage damage stimulates transition of proinfl ammatory cytokines to cartilage as well as the local metabolic changes; chondrocytes increase the secretion of proteglycans and collagen, enzymatic tissue degradation accelerates so the subchondral bone might terminally be affected with sclerosis, while cartilage becomes softer [6,7,13,14].

Clinical presentation
Patients suffering from patellar chondromalacia usually feel anterior knee pain. Pain may increase during activities, especially due to prolonged walking, climbing or descending stairs, walking on uneven surfaces, squats, lifting heavy loads. Occasionally, patients may also experience pain during prolonged sitting when the knee is bent. In severe cases, patients cannot walk properly.

Diagnosis
Considering the fact that pathological changes occur in cartilage, radiography is usually not a signifi cant diagnostic method in the examination of patellar chondromalacia. Knee arthroscopy as well as Magnetic Resonance Imaging (MRI) can indicate the extent and degree of tissue damage and decide on further treatment. MRI with a high tissue contrast can detect chondromalacia in the lower stages: signal irregularities, fi ssures and chondral thinning thus leading to earlier diagnosis and treatment [11,13].

Treatment
Treatment can be preventive (elimination of causes such as static disorders), conservative (physical therapy, quadriceps exercises, non-steroid antiifl ammatory drugs) and surgical (chondrectomy, ventralization and medialization of the patella, sagittal osteotomy of the patella) [11,15]. The existance of excessive distance between tibial tuberosity and tibial groove, patella alta or patella infera, patellofemoral instability as a functional problems must be treated with tibial tubercle osteotomy, often combined with a soft tissue procedures, in order to obtain a satisfactory result, with a good prognosis and positive functional capacity outcome [16][17][18]. The most usually used soft tissue procedure is medial patellofemoral ligament reconstruction, as one of the primary methods in the treatment of patellar instability, using hamstring or peroneus longus muscle tendon as a graft [19,20].

Conclusion
Repetitive microtrauma in physically active adolescents might also generate patellar cartilage damage, causing anterior knee pain that can signifi cantly reduce daily activities, especially in females. As the most frequent entitity of the anterior knee pain, patellar chondromalacia is characterized by the presence of cartilage softening, fi ssures, fragmentation and necrosis, producing pain that is usually localized retropatellary and stimulated during and after activities, more often in patients with different types of patellofemoral malalignment and anatomical deformities of the femoral trochlea. Early diagnosis and treatment are essential in achieving a good prognosis in patients with patellar chondromalacia.