Outcomes After Marrow Stimulation with Traditional Awl vs. Drilling

Abstract

Marrow stimulation has traditionally utilized an awl to create perforations; however, recent attention has been drawn to the use of drilling to maintain the integrity of the subchondral plate, while improving marrow access. However, it is not clear if these different approaches result in differing clinical outcomes. The purpose of this study was to analyze longitudinal outcomes comparing marrow stimulation utilizing an awl versus a drilling technique. Marrow stimulation patients were identified from a single institution database between 2001-2016. Patient-reported outcome measure (PROM) data were collected at preoperative, 6- and 12-month time points, including the International Knee Documentation Committee score, Short Form 12 Physical (PCS) and Mental Component Scores (MCS), and all Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. A matching algorithm based on previous procedures, lesion size, and demographic factors created two technique-based cohorts. Outcomes including revision rates of the awl and microdrill cohorts were compared using univariate statistics. A total of 68 patients (32.0±13.1 years, 48.5% female, BMI 26.7±5.3 kg/m2) were included (n=34 per group) (Table 1). At 6-months, the micro drilling group demonstrated significantly greater levels of improvement than the awl group on the IKDC, SF12 PCS, and KOOS Pain, Symptom, Sport, and QOL (p<0.04). However, differences at 1 year were only maintained on the SF12 PCS instrument (p<0.001). With respect to MCID achievement, the micro drilling group demonstrated greater achievement rates at 6 months on the IKDC, KOOS Pain and KOOS Sport (p<0.04). The awl group demonstrated a higher rate of revision surgery (41.10% vs. 17.60%, p=0.02) and a greater likelihood to require multiple subsequent procedures (17.60% vs. 0%, p=0.03). Micro drilling demonstrated superior outcomes relative to microfracture awl techniques with respect short-term outcomes and revision rates within 3-years of follow-up. Long-term follow up is required to determine if these differences are sustained.