To investigate which orthosis results in (1) fewer complications; (2) the least extensor lag; and (3) the highest rates of treatment success according to the Abouna and Brown criteria for soft tissue mallet injury in adults.Electronic databases AMED, CINAHL, Embase, MEDLINE, PubMed, OTseeker, and PEDro were searched from the earliest available date until September 16, 2014.Controlled trials evaluating orthosis type in the conservative management of mallet injury were included. Database searching yielded 1024 potential studies, of which 7 met inclusion criteria with a total of 491 participants.Data were extracted using an author-designed extraction form by one reviewer, and accuracy was assessed by a second reviewer. The PEDro scale was used to assess methodological quality.Results were pooled using a random-effects model with inverse variance methods. Dichotomous outcomes are expressed as risk ratios (RRs) and 95% confidence intervals (CIs) and continuous outcomes as standardized mean differences and 95% CIs. There is moderate quality evidence that prefabricated orthoses had 3 times the risk of developing skin complications as compared with all other orthoses (RR, 3.17; 95% CI, 1.19-8.43; I(2)=47%) and nearly 7 times the risk of developing skin complications as compared with custom-made thermoplastic orthoses (RR, 6.72; 95% CI, 1.59-28.46; I(2)=0%). Treatment outcomes were found to be similar for treatment success when prefabricated orthoses were compared with custom-made orthoses (RR, .99; 95% CI, 0.80-1.22; I(2)=39%; very low quality evidence), as well as for extensor lag when custom-made thermoplastic orthoses were compared with other orthoses (standardized mean difference, .03; 95% CI, -.29 to .36; I(2)=0%; moderate quality evidence).Prefabricated orthoses were found to increase the risk of developing skin complications as compared with custom-made orthoses, but there were no differences in treatment success, failure, or extensor lag.