Microfracture Versus Drilling of Articular Cartilage Defects: A Systematic Review of the Basic Science Evidence

Abstract

Background: Microfracture (MFx) is one of the most common techniques used for the treatment of articular cartilage defects, although recently there has been a trend toward the use of drilling rather than MFx for the treatment of these defects. Purpose: To perform a systematic review of basic science studies to determine the effect of microfracture versus drilling for articular cartilage repair. Study Design: Systematic review. Methods: A systematic review was performed by searching PubMed, the Cochrane Library, and EMBASE to identify basic science studies comparing outcomes of MFx versus drilling. The search phrase used was microfracture AND (drilling OR microdrilling). Inclusion criteria were basic science studies that directly compared the effect of MFx versus drilling on subchondral bone, bone marrow stimulation, and cartilage regeneration. Results: A total of 7 studies met the inclusion criteria and were included in this systematic review. Of these, 4 studies were performed in rabbits, 1 study in sheep, and 2 studies in humans. All of the included studies investigated cartilage repair in the knee. In the animal studies, microfracture produced fractured and compacted bone and led to increased osteocyte necrosis compared with drilling. Deep drilling (6 mm) was superior to both shallow drilling (2 mm) and MFx in terms of increased subchondral hematoma with greater access to marrow stroma, improved cartilage repair, and increased mineralized bone. However, the overall quality of cartilage repair tissue was poor regardless of marrow stimulation technique. In 2 studies that investigated repair tissue after MFx and/or drilling in human patients with osteoarthritis and cartilage defects, the investigators found that cartilage repair tissue did not achieve the quality of normal hyaline articular cartilage. Conclusion: In the limited basic science studies that are available, deep drilling of cartilage defects in the knee resulted in improved biological features compared with MFx, including less damage to the subchondral bone and greater access to marrow stroma. Regardless of marrow stimulation technique, the overall quality of cartilage regeneration was poor and did not achieve the characteristics of native hyaline cartilage. Overall, there is a general lack of basic science literature comparing microfracture versus drilling for focal chondral defects.

Marked differences in local bone remodelling in response to different marrow stimulation techniques in a large animal

“…Previous studies have highlighted the variability in MST, from the technique itself (Kroell et al, 2016;Theodoropoulos et al, 2012) to patient outcomes (Knutsen et al, 2007;Mithoefer et al, 2009). There is considerable intra-and inter-surgeon variability with MST (Kroell et al, 2016), which likely contributes to Bone remodelling in response to marrow stimulation the variable cartilage fill grade (18 to 95 %) (Mithoefer et al, 2009).…”

“…While there is growing evidence to support the use of smaller diameter and deeper access for MST, the mechanism for creating these narrow, extended holes (whether it be by impaction, drilling or another method) is not yet determined. To date, only 7 studies have directly compared the standard MST approaches -microfracture and subchondral drilling -and only 3 of these studies included multiple outcome measures (Kraeutler et al, 2020). Thus, there is a lack of knowledge regarding how the method of hole creation impacts the subchondral bone.…”

Intra-articular Injection of Bevacizumab Enhances Bone Marrow Stimulation–Mediated Cartilage Repair in a Rabbit Osteochondral Defect Model

“…Furthermore, drilling is more reproducible with regard to depth and location, particularly in a small-animal model. 17…”

Marked differences in local bone remodeling in response to different marrow stimulation techniques in a large animal

“…While there is growing evidence to support the use of smaller diameter and deeper access for MST, the mechanism for creating these narrow, extended holes (whether it be by impaction, drilling, or another method) is not yet determined. To date, only 7 studies have directly compared the standard MST approaches – microfracture and subchondral drilling, and only 3 of these studies included multiple outcome measures (Kraeutler et al, 2020). There is thus a lack of knowledge regarding how the method of hole creation impacts the subchondral bone.…”