ABSTRACT
Objective:To assess the early clinical outcomes of Oxford cementless unicompartmental knee arthroplasty (UKA) in the management of anteromedial osteoarthritis of the anterior medial knee (AMOA).Methods:A retrospective review was conducted on a cohort of 90 patients who underwent primary UKA for AMOA at the Fuzhou Second Hospital between January 2020 and June 2021. The patients were divided into two groups based on the type of prosthesis used: the cementless UKA group and the cemented UKA group. The cementless UKA group included 45 patients (22 males and 23 females), with a mean age of 65.6±7.0 years (ranging from 52 to 81 years). The cemented UKA group consisted of 45 patients, including 21 males and 24 females, with a mean age of 67.9±6.1 years (ranging from 55 to 79 years). The study compared various parameters between the two groups, including the duration of surgery, amount of blood loss, length of hospitalization, pain visual analogue scale (VAS) scores, Hospital for Special Surgery (HSS) scores, and forgotten joint score (FJS). Additionally, radiolucency around the prosthesis, medial proximal tibial angle (MPTA), and mechanical axis deviation (MAD) were observed and measured before and after surgery to assess prosthesis stability, improvement of knee deformity, and knee joint mobility, respectively.Results:Both groups were followed up for a minimum of 18 months. No statistically significant differences were found in demographic data such as gender, age, and body mass index between the two groups. The cementless UKA group demonstrated superior results in terms of shorter duration of surgery (97.8±21.1 min) and less blood loss (70.8±37.6 ml) compared to the cemented UKA group ( P<0.05). However, no significant difference in length of stay was observed between the groups. Postoperative VAS scores, HSS scores, MPTA, and MAD were significantly improved compared to preoperative values in both groups ( P<0.05). The median VAS scores for the cementless UKA group at 6, 12, and 18 months postoperatively were 4.0(3.0, 5.0), 2.0(2.0, 3.0), and 2.0(1.0, 3.0) respectively. The corresponding median HSS scores for the cemented UKA group were 78(75, 82), 85 (80, 89), and 86(82, 90) preoperatively and at 6, 12, and 18 months postoperatively, respectively. The median FJS scores for the cementless UKA group were 73.0(70.5, 76.0), 76.0(74.0, 78.0), and 66.0(63.0, 68.0) preoperatively and at 6, 12, and 18 months postoperatively, respectively. There was no statistically significant relationship between preoperative VAS scores and preoperative FJS scores ( P>0.05). However, there was a significant difference in VAS scores between the two groups at 6 months postoperatively ( P<0.05). The cementless UKA group consistently exhibited better VAS scores and HSS scores compared to the cemented UKA group at 6, 12, and 18 months postoperatively ( P<0.05). The median MPTA values for the cementless UKA group were 85.41°(84.22°, 86.54°), 85.80°(84.74°, 87.41°), 86.51°(85.47°, 88.14°), and 86.80°(86.09°, 88.27°) preoperatively and at 6, 12, and 18 months postoperatively, respectively. The median MAD values for the cementless UKA group were 2.29(1.79, 2.65) cm, 1.11(0.69, 1.75) cm, 1.02(0.65, 1.66) cm, and 0.91(0.61, 1.63) cm preoperatively and at 6, 12, and 18 months postoperatively, respectively. There were no significant differences in MPTA and MAD between the two groups at all time points, except for the preoperative MPTA and postoperative MAD at 6 and 12 months. The incidence of physiological radiolucency around the prosthesis was significantly lower in the cementless UKA group 3 than in the cemented UKA group 28 ( P<0.05). However, no complete radiolucency was observed in either group. Conclusion:Oxford cementless UKA is a highly effective treatment for relieving joint pain and correcting knee deformity in patients with knee AMOA. It offers the advantages of shorter surgical duration, reduced blood loss, and improved subjective outcomes for patients after the operation.