To compare the early effects and costs between open wedge high tibial osteotomy(OWHTO)and unicompartmental knee arthroplasty(UKA) for medial compartmental knee osteoarthritis.

A total of 48 patients (48 knees) with medial tibiofemoral arthritis from January 2014 to January 2018 were retrospectively analyzed. The patients with inflammatory knee arthritis and lateral knee osteoarthritis were excluded. According to the different surgical methods, they were divided into the OWHTO group (12 patients received OWHTO, four males and eight females) with an average age of (58.3±3.5)years, and the UKA group (36 patients received UKA, 14 males and 22 females) with an average age of (59.4±4.5)years. Visual analogue score (VAS), hospital for special surgery knee score (HSS) of the two groups were performed before and six months after surgery. X-ray of the antero-posterior and lateral positions to measure the varus angle of the knee, as well as the cost of hospitalization and postoperative rehabilitation. Two independent samples t test and chi-square test were used for statistical analysis.

All the cases were followed up satisfactorily. The follow-up time was(8.5±1.8)months on average. The VAS score of patients in the OWHTO group was (7.62±0.51) points before operation and (2.15±0.26) points after operation. There was a significant difference between the postoperative and preoperative values (t =1.61, P<0.05); the VAS score of UKA group was the points before operation (7.73±0.64) and after operation (2.31±0.14) were statistically significant (t =2.09, P <0.05). The HSS score of patients in the OWHTO group was (56±5) points before operation and (88±3) points after operation. There was a statistically significant difference (t=24.11, P<0.05) in the UKA group. There were (57±6) points before operation and (91±4) points after operation. There was a statistically significant difference between the post-operation and pre-operation (t =26.75, P<0.05). No statistically significant difference was found in VAS and HSS scores between the two groups, while the hospitalization cost of the OWHTO group was remarkably less than that of the UKA group(t=3.59, P<0.05).

Both two methods can achieve good early results, while the cost of hospitalization and postoperative rehabilitation of the OWHTO is less, and may achieve the goal of "knee-preservation" . OWHTO may be a better choice for patients who are suitable for both procedures.