Hyaline articular cartilage is critical for the normal functioning of the knee joint. Untreated focal cartilage defects have the potential to rapidly progress to diffuse osteoarthritis. Over the last several decades, a variety of interventions aiming at preserving articular cartilage and preventing osteoarthritis have been investigated. There have been numerous clinical studies that support the use of marrow-stimulation techniques.
Reparative cartilage procedures, such as microfracture, penetrate the subchondral bone plate in effort to fill focal cartilage defects with marrow elements and stimulate fibrocartilaginous repair.
Although microfracture is still a popular iteration of marrow stimulation, many leaders in the field question the technique’s sustainability (1,2). Unquestionably, the early clinical outcomes of microfracture have been proven positive; however, a loss of benefit has been described after ~2 years raising concerns of the technique’s validity (3). Complications are not uncommon, such as early OA reported in 40–50% of cases (4,5) and bone overgrowth which is visualized on MRI in 63% of cases at 2 years. Whilst over- growth is rarely symptomatic, with no significant difference in KOOS scores between those radiographically diagnosed with or without overgrowth, it does predict a significantly higher failure rate (25% vs. 3%) (6). Risk factors for poorer outcomes include long-standing symptoms, poor baseline Lysholm score, concurrent mild degenerative changes or partial meniscectomy (7). Long-term outcomes have been negatively correlated with increased age, larger defects ( > 2.5 cm2), and increased BMI (BMI > 30 kg/m2) (8). Furthermore, several authors have reported suboptimal outcomes in highly active and athletic patients (9). Microfracture when applied in young patients with smaller lesions can offer good clinical results at short- and long-term follow-up; lesion size is more important prognostic factor of outcome than age. Deterioration of the clinical outcome should be expected after 2 and 5 years post-treatment and degenerative changes are present at long-term follow-up corroborated by several authors.
Conclusion: Isolated microfracture is a non anatomical treatment compromising intact anatomical structures leading to avoidable complications and therefore should be abandoned instead of superior alternative therapies which furthermore have proven to be more cost effective in the long run.
1)Case JM, Scopp JM. Treatment of articular cartilage defects of the knee with microfracture and enhanced microfracture techniques. Sports Med Arthrosc Rev. 2016;24:63–68.
2) Steinwachs MR, Guggi T, Kreuz PC. Marrow stimulation techniques. Injury. 2008;39(suppl 1):S26–S31.
3)Gudas R, Gudaite A, Pocius A, et al. Ten-year follow-up of a prospective, randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint of athletes. Am J Sports Med. 2012;40:2499–2508.
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8)Mithoefer K, McAdams T, Williams RJ, et al. Clinical efficacy of the microfracture technique for articular cartilage repair in the knee: an evidence-based systematic analysis. Am J Sports Med. 2009;37:2053–2063.
9)Harris JD, Walton DM, Erickson BJ, et al. Return to sport and performance after microfracture in the knees of National Basketball Association Players. Orthop J Sports Med. 2013;1: 2325967113512759.