Chondromalacia patellae is softening and edema of the cartilage underneath the patella due to posttraumatic injuries or abnormal patellar tracking and muscle imbalance. Treatment is physical therapy, analgesics, and sometimes surgery.
Chondromalacia patellae often causes generalized knee pain especially when climbing or descending stairs, playing sports that exert an axial load on the knee, or sitting for a long time (theater sign). Usually the pain occurs without external swelling.
This disorder probably results from angular or rotational changes in the leg that unbalance elements of the quadriceps and cause patellar misalignment during movement (1). Misalignment can result from injuries such as a patellar dislocation, overuse or microtrauma (eg, with repetitive jumping), and rapid increases in training volume or intensity.
Diagnosis of chondromalacia patellae is typically by history and physical examination; diagnostic testing, when performed, may include radiography to evaluate for bony lesions and MRI to evaluate the extent of cartilage involvement.
General reference
1. Duong V, Oo WM, Ding C, Culvenor AG, Hunter DJ. Evaluation and Treatment of Knee Pain: A Review. JAMA. 2023;330(16):1568-1580. doi:10.1001/jama.2023.19675
Treatment of Chondromalacia Patellae
Physical therapy
Analgesics
Sometimes arthroscopic procedures
Acute pain due to chondromalacia patellae is treated with physical therapy to improve the mechanics and by applying ice and taking analgesics. (See also Knee Pain for details about stretching and strengthening exercises.)
Children with chondromalacia patellae should avoid pain-causing activities (typically, those that involve bending the knee) for several days.
Persistent or recurrent pain due to chondromalacia patellae may rarely require arthroscopic smoothing of the patella’s undersurface.
Mesenchymal stem cell therapy for cartilage regeneration has been promising (1). Other intra-articular therapies, such as glucocorticoids and hyaluronic acid, are used primarily for osteoarthritis and lack evidence of benefit for chondromalacia patellae (2, 3).
Treatment references
1. Zheng W, Li H, Hu K, Li L, Bei M. Chondromalacia patellae: current options and emerging cell therapies. Stem Cell Res Ther. 2021;12(1):412. Published 2021 Jul 18. doi:10.1186/s13287-021-02478-4
2. Macri EM, Hart HF, Thwaites D, et al. Medical Interventions for Patellofemoral Pain and Patellofemoral Osteoarthritis: A Systematic Review. J Clin Med. 2020;9(11):3397. Published 2020 Oct 23. doi:10.3390/jcm9113397
3. Duong V, Oo WM, Ding C, Culvenor AG, Hunter DJ. Evaluation and Treatment of Knee Pain: A Review. JAMA. 2023;330(16):1568-1580. doi:10.1001/jama.2023.19675
