Objective To explore the feasibility of predicting the clinical effect of single open door laminoplasty in the treatment of ossification of the posterior longitudinal ligament by the preoperative K line tilt.Methods The data of 52 patients with ossification of the posterior longitudinal ligament (OPLL) with positive K line who were treated by posterior cervical singledoor laminoplasty from February 2019 to January 2022 were analyzed retrospectively.35 male and 17 female were included.The patients age from 47 to 76 years，with an average of (61.46±7.26)years.The score of the Japanese orthopedic association (JOA) before the operation and the JOA score at the oneyear followup after the operation were recorded.The parameters of sagittal plane before operation were measured on the neutral lateral radiograph of cervical spine，which including Kline tilt，C_2~7 Cobb angle，C_2~7sagittal vertical axis (C_2~7 SVA)，center gravity of head (CGH) ~ C₇ sagittal axial distance (CGH~C₇ SVA)，T₁ slope.According to the median JOA score 1 year after surgery，patients were divided into good improvement group and poor improvement group.The preoperative K-line tilt and other sagittal plane parameters were used as independent variables.One-way analysis of variance and Logistic regression were used to analyze the risk factors affecting the postoperative JOA improvement rate.Results The clinical symptoms of all patients were improved.The preoperative C_2~7 Cobb angle was (14.45±8.81)°，C_2~7 SVA was (15.31±4.57)mm，CGH~C₇ SVA was (16.37±5.23)mm，T₁ slop was (26.43±5.65)°，K-line tilt was (12.77±1.49)° and preoperative JOA score of OPLL patients were (7.38±0.89) points.According to the improvement rate of JOA score at 1 year follow-up，the analysis of preoperative cervical sagittal parameters after grouping showed that the preoperative kline tilt，preoperative C_2~7SVA，preoperative CGH~C₇ SVA (P＜0.001，P＝0.013，P＝0.022) were closely related to the postoperative efficacy，and the preoperative K-line tilt was positively correlated with C_2~7SVA，CGH~C₇ SVA(r＝0.411，r＝0.831，P＝0.004，P＝0.023).Logistic regression analysis showed that preoperative K-line tilt and preoperative CGH~C₇ SVA (OR=1.673，OR=1.522，P＝0.024，P＝0.033) were the risk factors affecting postoperative efficacy.Conclusion The postoperative efficacy of patients with OPLL is related to the preoperative K line tilt.The patients with large preoperative K line tilt have poor postoperative efficacy.The K line tilt can be used as a new clinical index to predict the postoperative efficacy of patients with OPLL before single-door surgery through the posterior cervical spine.

Objective To compare the clinical outcomes of 3D printed cutting guides assisted open wedge high tibial osteotomy (OWHTO) to OWHTO with classic AO technique.Methods The clinical data of 98 patients from March to December 2020 were screened and a total of 90 patients met the grouping criteria and were randomized grouping by the random number list provided by PASS software.Finally，45 patients (70 knees) were selected for study group.The patients consisted of 25 males and 20 females，with ages ranging from 19~69 years，mean age (40.48±14.95)years.Patients in study group treated by 3D printed cutting guides assisted high tibial osteotomy (HTO) Another 45 patients (59 knees) were selected for control group.The patients consisted of 19 males and 26 females，with ages ranging from 21~71 years，mean age (48.16±16.65)years.Patients in control group treated by HTO with classical AO technique.The target alignments were planned and recorded before surgery.The differences between the postoperative alignments and the planned target alignments were compared in two groups.Postoperative posterior tibial slope (PTS)，operation time and intraoperative fluoroscopy times were recorded.The differences between preoperative and postoperative Oxford knee score (OKS) were also compared between two groups.Results Intraoperative fluoroscopy times in study group (13.79±8.12) was statistically significant less than control group (23.36±11.80) (P＜0.01).There was no significant difference of postoperative and target weight bearing line ratio (WBLR) in study group (4.29±4.57)% and control group (4.75±4.87)% (P＝0.62).The proportion of patients whose difference between postoperative and target WBLR within ±10% was 75.81% in study group and 73.33% in control group.There was no significant difference between two groups (P＝0.82).There was no significant difference of postoperative and target posterior tibial slope (PTS) in study group (3.16±4.62)° and control group (1.86±2.39)° (P＝0.10).The improvement of OKS in study group (4.27±10.14) was statistically significant higher than control group (－1.83±12.67) (P＜0.01).Conclusion Comparing to HTO with classic AO technique，3D printed cutting guides can significantly decrease the intraoperative fluoroscopy times and increase the postoperative OKS.

Objective To compare the clinical efficacy of anteromedial combined anterolateral approach and posteromedial combined anterolateral approach in the treatment of hyperextension tibial plateau fracture.Methods Data of 72 patients with hyperextension tibial plateau fracture treated with anteromedial or posteromedial combined anterolateral approach in the Department of Orthopedics of Luliang People’s Hospital from April 2018 to April 2022 were retrospectively analyzed，and they were divided into group A and group B according to treatment methods.Patients of Group A underwent anteromedial combined anterolateral approach surgeries.Group A had 35 patients，including 25 males and 10 females.The patients aged 20~73 years，with an average age of (46.31±14.56) years.Patients of Group B underwent posteromedial combined anterolateral approach surgeries.Group B had 37 patients，including 26 males and 11 females.The patients aged 23~73 years，with an average age of (45.30±14.51) years.Operation time，intraoperative blood loss，weightbearing activity time，visual analogue scale (visualanaloguescale，VAS) and postoperative complication rates were compared to assess the clinical efficacy of two groups.American hospital for special surgery (hospitalforspecialsurgery，HSS) Knee joint scoring criteria were used to assess knee joint function.The changes of posterior inclination and varus Angle of tibial plateau were evaluated by X-ray.Results All 72 patients were followed up for 12~28 months，with an average of (17.93±4.13) months.All fractures healed clinically and the function of knee joint returned to normal.There was no statistically significant difference in knee HSS score between the two groups at 6 months after surgery (P＞0.05)，but the knee HSS score of group A was lower than that of group B at 12 months after surgery，the difference was statistically significant (P＜0.05)，and the excellent and good knee function rate of group A was significantly lower than that of group B，the difference was statistically significant (P＜0.05).The operative time，intraoperative blood loss，postoperative 1 d and 3 d VAS scores and posterior inclination of tibial plateau in group A were higher than those in group B.The time of weightbearing activity and the varus Angle on the day after operation in group B were higher than those in group A，and the difference was statistically significant (P＜0.05). Conclusion The short-term follow-up treatment of hyperextension tibial plateau fracture using the posteromedial combined anterolateral approach is more effective.Due to the small number of cases and lack of long-term follow-up results，further observation and study are needed.

Objective To investigate the effect of minimally invasive percutaneous plate osteosynthesis (MIPPO) combined with plateletrich plasma(PRP) for tibial shaft closed fractures.Methods A total of 62 patients with freshly closed tibial shaft fractures admitted to Weihai Central Hospital affiliated to Qingdao University from January 2019 to May 2020 were selected.Patients were divided into control group and treatment group according to random number table method，with 31 cases in each group.The treatment group with minimally invasive percutaneous plate fixation MIPPO at the same time of fracture end applications of PRP treatment.The control group was treated with MIPPO alone without PRP.In the treatment group，there were 19 males and 12 females.The average age was (38.48±12.01)years，ranging from 19~60 years.In the control group，there were 21 males and 10 females.The average age was (39.77±12.31)years，ranging from 19~57 years.Operation time，intraoperative blood loss，fracture healing time，complete weightbearing time，complications，JohnerWruhs excellent and good rate 12 months after surgery were recorded and compared between the two groups.Results All patients were followed up for more than 12 months.The complete weight-bearing time，fracture healing time and incision healing in the treatment group were better than those in the control group，and the differences were statistically significant (P＜0.05).The curative effect was evaluated by Johner-Wruhs criteria 12 months after surgery.In the treatment group，27 cases were excellent，2 cases were good，and 2 cases were medium，with an excellent and good rate of 93.55%.In the control group，19 cases were excellent，3 cases were good，5 cases were medium，and 4 cases were poor，with an excellent and good rate of 70.97%.The therapeutic effect of the treatment group was better than that of the control group，and the difference was statistically significant (P＜0.05).All fractures healed in the treatment group，and no obvious complications occurred after operation.One case of superficial infection in control group was cured by dressing change.Delayed fracture of union was observed in 1 patients，and the fracture healed until 11 months after surgery.Conclusion PRP combined with MIPPO technique can significantly shorten fracture healing time，reduce delayed fracture healing，reduce postoperative complications，and improve the functional activity of the affected limb，without obvious complications，which has clinical application value.