chapter 11: Articular Cartilage Lesions in Patellofemoral Pain Patients
In 1908, Budinger (2) drew attention to the importance of cartilage lesions on the undersurface of the patella, characterized by fissures and softening, with his report of 15 cases. Injury was involved in each of the case histories and the etiology was interpreted to be traumatic rupture of articular cartilage. He reported treatment by excision with good results. In 1910, Ludloff (3) reported the single case history of a 15‑year‑old girl who likewise was cured by chondrectomy. Axhausen (4) in 1922, was the next to carry on the work of the German school in drawing attention to patellar lesions causing symptoms similar to meniscal lesions. All three of these authors indicated trauma to the patella, mostly in the form of a direct blow, as the cause of patellar cartilage lesions. In each case, their work was based upon both clinical symptoms and findings at operation. Laden (5) and Found (6) used the term "chondropathy" in describing the articular surface of the patella to which they attributed symptoms. They, too, considered injury as the main cause and found good results after excision of damaged cartilage. The term chondropathy has been widely utilized in the European literature.
Koenig, in 1924, was the first to use the term chondromalacia patellae. According to Carlson (7), this term had been in use in Aleman's clinic since 1917, popularized with the reading of Aleman's classic paper (8) in Gutenberg in 1927. This term became widely used in Scandinavia and, subsequently, in the English literature (9, 10). Until that time, trauma in the production of cartilage lesions had been universally accepted and the cases reported were of patients with pain attributed to the pathological articular lesion.
Ogre (11) made the study of chondromalacia the subject of his doctoral thesis, examining 106 cadavers. He found an increasing incidence of cartilage lesions on the undersurface of the patella with age. Lesions were evident in a significant percentage, even in the teen years. Use of the term "chondromalacia" to associate these pathologic changes noted at autopsy with clinical symptoms has subsequently contributed to a great deal of confusion. Reports of clinical series began to appear more frequently with Silfverskiöld (12) adding his experience in 1938.
Wiberg (13), in his monumental work on the patellofemoral joint, defined the three main anatomic variations that carry his name, and made important observations concerning the relationship between the medial and odd facets and loading during function. Although he suspected that the Type III patella was a form more associated with "chondromalacia," he was not able to prove this.
In 1944, Hirsch (14), in a comprehensive work, related loss of mucopolysaccharide in the ground substance to change in physical characteristics of articular cartilage. He hypothesized that the loss of mucopolysaccharides was on the basis of faulty cartilage nutrition, which then led to softening and, finally, to the formation of fissures. His original observation of the dependence of the physical characteristics of intact articular cartilage on the quality of ground substance has been confirmed by others.
Since these earlier reports, there has been considerable literature concerning chondromalacia patellae. However, rather than leading to a precise definition of chondromalacia, the term came to be used more loosely, not even requiring a description of the status of the articular cartilage by some authors. Darracott and Vernon‑Roberts (15) published a report on the bone changes in chondromalacia. Furthermore, Robinson and Darracott (16) published criteria for establishing the diagnosis of chondromalacia patellae that are entirely clinical.
By the mid 1970s, there was growing awareness that soft tissue surgery, particularly lateral retinacular release, could give relief for many patients with patellofemoral pain (17‑19) suggesting that pain might originate somewhere aside from the softened articular cartilage. Meanwhile, Goodfellow et al (20), Radin (21), Abernathy et al (22), and others were emphasizing that soft cartilage on the patella is common and not necessarily a cause of pain. Casseells (23), Stougard (24), and others emphasized the frequency of chondromalacia at routine autopsy. Metcalf (25), McGinty and McCarthy (26), and others noted that lateral retinacular release was effective in relieving anterior knee pain.
We (27) noted in 1982 that the lateral retinaculum itself might be painful in patients with patellar malalignment, and later substantiated these results with histologic studies (28), using Gomeri's trichrome stain to show microscopic nerve injury in the excised lateral retinaculum from patients with localized preoperative retinacular pain. This work, then, helps explain complaints of anterior knee pain in patients with no chondromalacia, and patients with no real correlation between arthroscopic quantification of chondromalacia and pain (25). The eccentrically aligned patella will inevitably cause abnormal stresses on its supporting retinaculum as well as on its articular cartilage.
The surgeon should recognize that, historically, operations to relieve the pain of chondromalacia have involved alteration of retinacular structures. Even the arthrotomy used by earlier surgeons to do patellar debridement would cause striking alteration of retinacular strains after closure and healing. Such shifting of retinacular strains may be significant in relieving pain of retinacular origin. Certainly, patellectomy markedly reduces retinacular strain by removing the fulcrum (patella) tethering the retinaculum.
If chondromalacia patella is to have any meaning whatsoever in clinical‑pathological terms, then it must not be used as a synonym for patellofemoral pain (29).
Inside Chapter 11: