Objective To evaluate the clinical efficacy of OWHTO assisted by 3D printing print-assisted instrumentation (PSI) combined with knee arthroscopy in the treatment of medial knee compartment osteoarthritis.

Methods Forty medial knee compartment osteoarthritis patients treated with OWHTO combined with knee arthroscopy were retrospectively analyzed. Twenty cases were treated with osteotomy assisted by 3D printing PSI (PSI) (3D group), and 20 cases were treated with traditional osteotomy (traditional group). The surgical indicators and pain visual analogue scale (VAS), Hospital Score for Special Surgery (HSS), knee flexion and extension range of motion (ROM), lower limb line of force ratio (WBLR), medial proximal tibial angle (MPTA), and posterior tibial plateau angle (PTS) were compared between two groups.

Results The operative time, intraoperative fluoroscopy times, hospital stay and surgical incision length in the 3D group were significantly better than those in conventional group (P ＜ 0.01), and there was no statistical significance in the incision healing grade between two groups (P ＞ 0.05). There was no statistical significance in the VAS score, knee HSS score and ROM angle between two groups before operation and after 3, 6 and 12 months of surgery (P ＞ 0.05). There was no statistical significance in the PTS between two groups after 3, 6 and 12 months of surgery (P ＞ 0.05), and the MPTA and WBLR in the 3D group were significantly better than those in conventional group (P ＜ 0.01).

Conclusions The OWHTO assisted by 3D printing PSI combined with knee arthroscopy in the treatment of medial knee compartment osteoarthritis is helpful to shorten the operation time, reduce the number of intraoperative fluoroscopy, and make the lower limb force line correction more accurate.