This systematic analysis shows that microfracture provides effective short-term functional improvement of knee function but insufficient data are available on its long-term results. Shortcomings of the technique include limited hyaline repair tissue, variable repair cartilage volume, and possible functional deterioration. The quality of the currently available data on micro-fracture is still limited by the variability of results and study designs. Further well-designed studies are needed to determine the long-term efficacy of microfracture and to define its specific clinical indications compared to other cartilage repair techniques.

ObjectiveTo provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies.MethodsThirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientific definitions of muscle injuries as well as a new and comprehensive classification system.ResultsThe response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub)total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type.ConclusionsA consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature.What are the new thingsConsensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries.Level of evidenceExpert opinion, Level V.

Microfracture repair of articular cartilage lesions in the knee results in significant functional improvement at a minimum follow-up of two years. The best short-term results are observed with good fill grade, low body-mass index, and a short duration of preoperative symptoms. A high body-mass index adversely affects short-term outcome, and a poor fill grade is associated with limited short-term durability.