The Use of Bone Void Fillers May Not Impact Outcomes After Medial Opening Wedge High Tibial Osteotomy: A Systematic Review

Purpose To examine whether the use of bone void filler significantly influences outcomes of medial opening wedge high tibial osteotomy (OWHTO), with a specific emphasis on gap sizes less than 10 mm. Methods A systematic review of the literature was performed according to Preferred Reporting Items for Systematic Reviews and Meta‐Analysis guidelines. Databases searched included PubMed, MedLine, EMBASE, and Web of Science. Studies were included if they met the following criteria: patients treated by OWHTO, clearly described surgical technique (including osteotomy gap size), filler type (synthetic, allograft, autograft), fixation type (locking versus nonlocking plate), type of plate (e.g., Tomofix, Puddu, Orthomed), and the degree of varus correction. The levels of evidence of the included studies ranged from Level I to Level IV according to the Oxford Centre for Evidence‐Based Medicine classification. The studies must have also been reported in English, peer‐reviewed, and originated in the United States or countries that offer the same procedures, protocol, and outcome reporting. Results Twenty‐eight of 253 identified studies met inclusion criteria. A total of 1640 knees underwent OWHTO in the 28 studies: 598 (36.4%) had allograft, 488 (29.8%) had no bone void filler, 359 (21.9%) had synthetic, and 195 (11.9%) had autograft. Of the total patients, 963 (58.7%) were women and 676 (41.3%) were men. Different types of bone void fillers were used in each study, with no filler being most common (13/28), followed by allograft (12/28). Complications such as nonunion, loss of correction, infection, and lateral hinge fracture were reported across studies, although the overall rates were low in all groups. Most investigations described satisfactory healing regardless of whether a bone void filler was used. Several studies noted that outcomes in procedures performed without bone void filler, particularly when the osteotomy gap was less than 10 mm, were comparable to or slightly better than those in which a filler was used. Conclusions This study revealed that the utilization or absence of bone void filler does not impact the outcomes of OWHTO. In the setting of OWHTO with gap sizes less than 10 mm, placement of a bone void filler may contribute to higher complication rates. Despite the lack of functional advantage of using a bone void filler, OWHTO is still completed with bone void filler in more than 50% of cases. Level of Evidence Level IV, systematic review of Level I to IV studies.