MR Imaging of Cartilage Repair in the Knee and Ankle

Abstract

Because of the relative avascularity of articular cartilage, lesions that are caused by trauma or degeneration of the cartilage do not heal spontaneously and must be repaired surgically. The interventional procedures that have been developed for the repair of such lesions include abrasion, microfracture, autologous osteochondral transplantation, allograft transplantation, and autologous chondrocyte implantation. An accurate imaging assessment of the repair tissue is necessary in order to objectively evaluate the postoperative outcome. Magnetic resonance (MR) imaging and arthroscopy provide complementary information and are especially useful for follow-up evaluation of cartilage repair in the knee and ankle. Standard MR imaging techniques may be used postoperatively to evaluate the success of implantation and the state of cartilage healing. Newer matrix assessment techniques, which include delayed gadolinium-enhanced MR imaging and mapping of T1rho and T2 values, may provide useful supplemental information about the histologic and biochemical contents of reparative tissue. The normal postoperative appearance of the joints after cartilage repair varies according to the surgical technique used and the stage of healing. To identify potential complications, it is important to be familiar with the various repair procedures and the characteristic MR imaging features of the repair tissue at various postoperative intervals.

Treatment of deep articular talus lesions by matrix associated autologous chondrocyte implantation—results at five years

“…MRI has become more important for morphological evaluation of the repair tissue after cartilage repair procedures in the ankle [18,19]. In our study, the MOCART score increased over time indicating radiological maturation towards a normal hyaline signal of the repair tissue.…”

Modern Cartilage Imaging of the Ankle

“…This can be accomplished, on the one hand, by fibrocartilaginous repair tissue, e. g. after micro-fracturing or retrograde drilling of osteochondral lesions, or via transplant, using osteochondral autograft transfer (OATS) or the matrix-induced autologous chondrocyte transplantation (MACT) [27,44]. In addition, micro-fracturing can be combined with matrix implantation as part of autologous matrix-induced chondrogenesis (AMIC) at the ankle joint; [19] provides a current overview of this.…”

“…Therepair tissue. The newly developing fibrous cartilage after microfracturing does not have the biomechanical load-bearing capacity as hyaline articular cartilage, but it can maintain normal joint function over an extended period [44]. It is important to assess whether the articular surface is congruent, the cartilaginous tissue has the same thickness as the surrounding cartilage, the transition to the rest of the cartilage is continuous, and the surface of the repair tissue is smooth.…”

“…It is important to assess whether the articular surface is congruent, the cartilaginous tissue has the same thickness as the surrounding cartilage, the transition to the rest of the cartilage is continuous, and the surface of the repair tissue is smooth. Morphologically, this characterizes a successful course of therapy 1 -2 years after microfracturing [44]. Assessment of the cartilage layer over time is important, since damage rules out a repeated retrograde repair of the osteochondral fragment [25].…”

“…Assessment of the cartilage layer over time is important, since damage rules out a repeated retrograde repair of the osteochondral fragment [25]. In the course of successful therapy, the signal intensity of the repair tissue decreases in liquid-sensitive sequences and is similar to that of the rest of the cartilage; likewise the subchondral bone marrow edema disappears [44]. Signs of therapy failure can be the persistence of subchondral cysts and / or bone marrow edema, an irregular cartilage surface, incomplete defect filling as well as delamination of the cartilage layer, which usually occurs within the first 6 months after MACT or AMIC [44,46] (▶ Fig.…”