Table 2

Study characteristics for microfracture studies of the knee

StudyYearStudy designLevel of evidenceCountrySample sizeMale (%)Age (year)Follow-up (months)Follow-up (%)Number of patients completing studySurgeon expertise (as reported in the study manuscript)GRADE
Asik et al252008Case seriesIVTurkey904834.5 (Range 20–58)62 (Range 24–108)NRNRNR1
Basad et al262010RCTIIGermany208537.5 (Range 18–50)24 (Range 3–24)7515Expert3
Chung et al272014RCTIISouth Korea191744.3 (SD 10.7)24 (SD 24)6312NR3
Crawford et al282012RCTIIUSA96739 (SD 10)24 (SD 24)31009NR3
Gobbi et al292014Case seriesIVItaly6770.4031.4 (SD 1.8)181.23 (Range 120–240)9161Expert1
Gudas et al302012RCTILithuania295924.3 (SD 6.8)125 (Range 108–132)9728NR3
Knutsen et al312004RCTINorway/UK406031.1 (Range 18–45)24 (NR)9638NR3
Kon et al322011Prospective cohortIIItaly2010026.5 (SD 4.5)89 (SD 25; Range 48–132)NRNRExpert1
Kon et al332009Prospective cohortIIItaly406830.6 (NR)60 (NR)10040NR1
Krych et al342012Retrospective cohortIIIUSA486632.5 (Range 15–46)53 (NR)7938Expert1
Lim et al352012Prospective cohortIISouth Korea305832.9 (Range 22–42)80 (Range 42–126)8325Expert3
Marder et al362005Case–controlIIIUSA505639.7 (Range 16–66)50 (Range 24–108)8643Expert1
Mithoefer et al372006Case seriesIVUSA328438 (SD 2)41 (Range 24–54)NRNRExpert1
Mithoefer et al382005Case seriesIVUSA487741 (SD 12)41 (SD7)10048Expert1
Petri et al392013Case seriesIVGermany106041.7 (SD 13.2)36 (NR)10010NR1
Saris et al402014RCTIMulticenter726732.9 (SD 8.8)24 (NR)9367NR2
Saris et al412008RCTIMulticenter616733.9 (SD 8.6)18 (NR)8451NR3
Stanish et al422013RCTICanada, Spain, South Korea396437.2 (SD 10.6)12 (NR)9537NR2
Steadman et al72003Case seriesIVUSA2510029 (Range 22–36)54 (Range 24–168)10025NR1
Ulstein et al432014RCTIINorway115537.1 (SD 8)188 (Range 59–137)10011NR3
Van Assche et al442010RCTIIBelgium/the Netherlands616734 (SD 8)24 (NR)4326‘Extensive training’3
Vanlauwe et al452011RCTIMulticenter Europe616732 (Range 18–45)60 (NR)NRNRNR3
  • GRADE: 1=very-low-quality evidence; 2=low-quality evidence; 3=medium-quality evidence; 4=high-quality evidence.

  • GRADE, Grades of Recommendation, Assessment, Development and Evaluation; NR, not reported; RCT, randomised controlled trial.