Objective To compare the clinical outcomes of patients who underwent remnant-preserved anterior cruciate ligament (ACL) reconstruction with those who underwent conventional ACL reconstruction (ACLR).Methods From January 2010 to October 2012,93 eligible patients suffered from ACL injuries were randomly allocated into remnant-preserved group (ACLR with remnant preservation;n=48;Male/Female=34/14;Left/Right=25/23) and conventional group (ACLR without remnant preservation;n=45;Male/Female=33/12;Left/Right=22/23).The mean age of patients,time from injury to surgery,rates of combined meniscal injuries,and medial collateral ligament injury all showed no significant difference between the two groups preoperatively.All the patients underwent ACL reconstruction using 4-strand hamstring autografts.The postoperative assessments included knee functional scales (IKDC grade classification and Lysholm score),stability examinations (Lachman,pivot-shift,and KT-1000 arthometer),proprioceptive evaluations,and second-look arthroscopy.Results The average follow-up time was 25.4 months for the remnant-preserved group and 25.2 months for the conventional group.For IKDC grade classification,there were 32 patients with grade A,9 with grade B,1 with grade C in remnant-preserved group,whereas 30 with grade A,8 with grade B,2 with grade C in conventional group,which showed no significant difference between the two groups.Moreover,the Lysholm score (95.9±5.2 vs.95.4±1.7),Lachman test,pivot-shift test,KT-1000 arthometer (1.1±1.2 mm vs.1.2±0.9 mm),proprioceptive evaluations (joint position sense:3.6°± 1.8° vs.3.9°±2.2°) all showed no significant differences between the two groups.Additionally,the synovial coverage of grafted tendon under second-look arthroscopy was categorized as grade A in 11,grade B in 6,grade C in 2,grade D in 2 in remnant-preserved group,whereas grade A in 10,grade B in 5,grade C in 2,and grade D in 2 in conventional group,which still showed no significant difference.Conclusion In terms of the knee functional scales,stability examinations,joint position sense and graft synovial coverage,remnant-preserved ACLR group showed no superiority to the conventional ACLR group.

Objective To investigate the clinical outcome of dual?plane high tibial osteotomy to treat posterolateral corner injuries combined with varus and/or hyperextension deformity. Methods From October 2008 to March 2014, there were 12 patients (13 knees) undergoing high tibial osteotomy. All the patients were double or triple varus knee combined with posterior cruciate ligament and posterolateral corner (PLC) injuries. During the surgery, the weight bearing line of lower extremity was set to 62%position of the tibial plateau on the coronal plane. The tibial slope was increased to diminish the hyperextension on the sagit?tal plane. Full?length weight bearing X?ray was used to evaluate the position of weight bearing line, femoral?tibial angle and tibial slope pre? and post?operatively. The stress radiograph was used to evaluate the posterior and posterolateral stability. The Op?ti_knee gait analysis system was used to evaluate the varus of angle during weight bearing stage. Results The weight bearing line was corrected from 19.6%±19.1% preoperatively to 42.6%±17.9% postoperatively (t=-4.178, P=0.002). The femoral?tibial angle was 172.8°±4.2° preoperatively and improved to 178.1°±4.2° postoperatively (t=-4.520, P=0.001). The tibial slope was increased from 10.2° ± 5.3° preoperatively to 18.4° ± 6.3° postoperatively (t=-5.735, P=0.000). The tibial posterior translation was decreased from 11.4±5.3 mm preoperatively to 8.1±6.9 mm postoperatively (t=2.415, P=0.042) in 9 patients. The separa?tion of lateral compartment was decreased from 16.3 ± 6.5 mm preoperatively to 14.2 ± 4.9 mm postoperatively (t=3.194, P=0.019). Gait analysis was performed in 7 patients and showed that the varus was improved from 3.0° ± 2.6° preoperatively to-2.7°±2.5° postoperatively during weight bearing stage (t=-8.500,P=0.014). Eight patients had sufficient improvement in knee function so that a subsequent posterolateral corner reconstruction was not necessary. Conclusion The dual?plane medial open wedge high tibial osteotomy can improve the alignment of lower extremity and the stability of knee joint, and 67%patients do not need a staged PLC and posterior cruciate ligament reconstruction.

Objective To investigate the effects of excessive pre?operative anterior tibial translation (ATT) on post?opera?tive knee stability after anterior cruciate ligament (ACL) reconstruction. Methods From January 2016 to December 2016, a total of 348 patients with noncontact ACL injuries who underwent primary anatomic single?bundle ACL reconstruction were retrospec?tively analyzed. The hamstring autograft was used as the grafted tendon. The ATT relative to the lateral femoral condyle was mea?sured on pre?operative magnetic resonance imaging (MRI) scans. Among them, twenty patients (ATT positive group) who demon?strated>10 mm ATT distance were matched in a 1∶2 fashion to 40 control participants (ATT negative group) with<3 mm ATT dis?tance. All patients were followed for at least 2 years. The post?operative clinical outcomes, including the ATT distance, the KT?1000 side?to?side difference, and the pivot?shift tests were compared between the two groups. Results The ATT distance of the ATT positive group was 13.5±1.3 mm, which was significantly larger than that of the ATT negative group (2.5±1.4 mm) (t=45.435, P=0.013) pre?operatively. At 2?year follow?up, the ATT distance of the ATT positive group was 9.7±1.8 mm, which was significant?ly larger than that of the ATT negative group (0.9±1.6 mm) (t=49.655, P=0.011). Moreover, the KT?1000 side?to?side difference of the ATT positive group was 4.4±1.5 mm, which was also significantly larger than that of the ATT negative group (0.8±1.1 mm) (t=38.945, P=0.014). There was significantly difference in the pivot?shift test between the two groups (ATT positive group: 1 grade 0, 18 grade I, 1 grade II vs. ATT negative group: 39 grade 0, 1 grade I) (χ2=40.521, P=0.012). Conclusion Excessive ATT could not be completely restored to normal after isolated anatomic single?bundle ACL reconstruction. Compared to the ATT negative group, the ATT positive group has inferior knee stability at 2?year follow?up.

Objective To investigate the incidence of concomitant anterolateral ligament (ALL) abnormality by magnetic resonance imaging (MRI) on patients with high-grade pivot-shift after anterior cruciate ligament (ACL) injuries.Methods From January 2016 to June 2016,one hundred and sixty-four consecutive patients with acute ACL injury were retrospectively reviewed.All patients underwent comprehensive pre-operative physical examinations and MRI scans.Sixty-eight patients with acute ACL injury who showed high-grade (grade Ⅱ and Ⅲ) pivot-shift phenomenon were enrolled in the high-grade pivot-shift group.They were matched in a 1:1 fashion to another 68 ACL-injured participants who showed low-grade (grade 0 and Ⅰ) pivot-shift phenomenon during the same study period.The grade of ALL injury was divided into grade Ⅰ (sprain),grade Ⅱ (partial tear) and grade Ⅲ (complete tear),and they were further compared between the high-grade pivot-shift group and the low-grade pivot-shift group on the coronal view of their T2WI MRI scans.Results The mean age of the patients in all groups was 29.3 years old.There were 43 male and 25 female patients in each group.There were no significant differences in terms of the time from injury to surgery,the body mass index and the KT-1000 side-to-side difference.Overall,there were 105 patients (77.2％,105/136) showed abnormal signal of the anterolateral ligament on MRI scans.The incidence of concomitant ALL injury in the high-grade pivot-shift group (94.1％,64/68) was significantly higher than that in the low-grade pivot-shift group (60.3％,41/68,x2=10.786,P=0.013).Specifically,there were 15,19 and 30 patients who showed grade Ⅰ,Ⅱ and Ⅲ ALL abnormality in high-grade pivot-shift group.However,there were only 29,8 and 4 patients who showed grade Ⅰ,Ⅱ and Ⅲ ALL abnormality in low-grade pivot-shift group.The incidence of patients who showed grade Ⅱ/Ⅲ MRI evidence of concomitant ALL injury was 76.6％ (49/64) in the high-grade pivot-shift group,which was also significantly higher than that in the low-grade pivot-shift group (29.3％,12/41,x2=18.452,P=0.009).Conclusion In the present study,77.2％ of the patients who showed high-grade pivot-shift demonstrated combined ALL injury on the MRI scan.In addition,patients in the high-grade pivot-shift group showed significantly higher incidence of combined ALL MRI abnormality compared with those in the low-grade pivot-shift group.The high-grade pivot-shift phenomenon might be caused by combined ACL and ALL injury.

Objective To quantify the patellar mal-tracking combined with J-sign using the computed tomography (CT).Method Fifty-three adult patients diagnosed as recurrent patellar dislocation (RPD) were chosen.According to their patellar tracking during knee active flexion and extension,they were divided into group A(with positive J-sign) and group B(with negative J-sign).The CT examinations were performed in all patients at 0°extension of the knee and the patella bisect offset index (BOI),patella troehlear-groove distance (PTG) and patella lateral tilt (PLT) were measured in the axial position and compared.The receiver operating characteristic analysis (ROC) curve was used to analyse the accuracy and stability of the three J-sign parameters.Results In all the 53 patients,thirty-seven(69.8％) knees were of positive J-sign,while the rest 16 were of negative J-sign.The mean values of CT parameters BOI,PTG and PLT in group A were significantly larger than those of group B.Moreover,the area under the curve for BOI,PTG and PLT were 0.906,0.883 and 0.833 respectively.The sensitivity and specificity of BOI were 83.3％ and 87.5％,while the predicting cut-off value was 97.5％.Conclusion In all the 53 recurrent patella instability patients,the morbidity of patella proximal mal-trackingis 69.8％.The CT parameter BOI can be used to quantify the J-Sign into positive and negative groups.

Objectives To evaluate the clinical outcome of lateral structure release in the treatment of patients with mild or moderate habitual dislocation of patella(HDP).Methods From 51 HDP patients undergoing surgical treatment between April 2010 and 2014,23 patients were chosen and given the lateral structure release,including isolated lateral retinaculum release (LRR) and LRR combined with vastus lateralis oblique(VLO) lengthening.Other auxiliary surgeries included medial patellofemoral ligament(MPFL) reconstruction and tibial tubercle medialization.Radiological,objective and subjective evaluations were performed at 4 and 8 weeks,as well as and 1 year after the surgery and every year afterwards.Results There were 21 patients followed for a minimum of 2 years.Their average age was 25.0 + 7.4 years (ranging from 17 to 38 years old),and the mean follow-up period was 30.5 ± 5.8months(ranging from 24 to 36 months).Isolated LRR was performed in 42.9％(9/21) of the patients,and LRR combined with VLO lengthening was performed in 57.1％(12/21) of them.No redislocation was reported.Significant improvement was observed in the subjective evaluation score.Conclusions For patients with mild to moderate HDP,lateral structure release can achieve satisfactory results.

Purpose To determine the incidence,degree and radiographic characteristics of knee Jsign in recurrent patella dislocation patients.Method It was a retrospective review of a consecutive series of 59 recurrent patella dislocation patients.The knee J-sign was classified into negative (-),positive one degree(mild,l+)and positive two degree(gross,2+)based on the severity of patellar lateral translation at the extreme extension of knees with quadriceps contracted actively.The computed tomography(CT)examination at 0° extension of the knee was performed to quantify the degree of patellar lateral translation and tilt,with three CT parameters measured and calculated in axial slices:patella bisect offset index (BOI),patella trochlear-groove (PTG) distance and patella lateral tilt (PLT) angle.Results In all the 59 patients,72.9％(43/59)showed positive J-sign,27.1％(16/59)of positive one degree(1+) and 45.8％(27/59)of positive two degree(2+).All the three CT parameters increased with the severity of Jsign(P＜0.05).Conclusion Among 59 recurrent patella dislocation patients,we have found 72.9％ of positive knee J-sign.The severity of J-sign has a positive correlation with the degree of patellar lateral translation and tilt.

Objective To explore the incidence and clinical characteristics of the anterior tibial translation(ATT) after anterior cruciate ligament injury.Methods One hundred and fifty-three patients with the anterior cruciate ligament injury underwent standard magnetic resonance imaging scans with full knee extension.Based on the relative location between the lateral tibial plateau and the lateral femoral condyle,all the patients were divided into an ATT positive group and an ATT negative group.Moreover,the posterior tibial slope angle(PTSA),the continuity of anterolateral ligament(ALL),and the integrity of posterior horn of the lateral meniscus of all the patients were detected so as to find the risking factors for ATT.Results Among the 153 patients,46 patients were finally confirmed to have ATT.Moreover,the average PTSA of the ATT positive group was significantly larger than that of the ATT negative group.However,there were no significant differences between the two groups in the continuity of ALL and the integrity of posterior horn of lateral meniscus.Conclusion In this study,the incidence of ATT was 30.1％,which may be correlated to the increased PTSA.

Objective To evaluate the effectiveness of anterior cruciate ligament (ACL) reconstruction combined with anterolateral ligament(ALL)reconstruction in ACL injury patients with high-grade pivot shift.Methods From May 2015 to April 2016,156 patients underwent ACL reconstruction by the same surgeon,and 22 of them with grade 2/3 pivot shift were included in this study.Anteroposterior knee stability was evaluated using KT1000 measurement,and the rotatory stability was assessed using the pivot-shift test.The Lysholm score was used to monitor the clinical function.Results There were 14 male subjects and 8 females,with an average age of 29.3 years.The mean follow-up period was 8.6 months.The mean side-to-side difference of anteroposterior knee laxity was 2.1 ± 0.6 mm,significantly improved compared with the preoperative 8.9 ± 3.1 mm.The preoperative pivot-shift indicated 2+ in 20 patients and 3+ in 2 patients,while at the final follow-up,21 patients had negative pivot shift with 1 of 1+ pivot shift.The difference was significant.The average Lysholm score improved significantly from 60.5 ± 12.3 preoperatively to 79.2 ± 7.8 at the final follow-up.Conclusion The rotatory instability can be effectively restored through the ACL reconstruction combined with ALL reconstruction in patients with high-grade pivot shift.The early-stage knee stability and functional outcomes indicate significant improvement postoperatively.

Objective To identify the incidence of the anteromedial impingement fracture of tibial plateau in the posterolateral corner injuries,and to confirm the relationship between the extent of the anteromedial tibial impingement fracture and the severity of the posterolateral instability of the knee joint.Methods The radiographic images of the posterolateral corner injuries were reviewed retrospectively to identify the incidence of the anteromedial impingement fracture of the tibial plateau.A matched group of the posterolateral corner injury patients without the anteromedial impingement fracture was compared with the anteromedial impingement fracture group for the posterior instability and varus instability.And the anteromedial impingement fracture group was subdivided into a marginal fracture group and a compression fracture group based on the size of the fracture,and the posterior instability and medial instability were compared between the two groups.Results From January 2007 to January 2017,there were 266 patients with posterolateral corner injuries admitted,with 19 (7.1％) combined with the anteromedial impingement fractures of the tibial plateau.The posterior instability was significantly severer in the fracture group than the control group (P=0.030),while there were no significant differences in the varus instability between them (P=0.800).Similarly,the posterior instability was significantly severer in the marginal group compared to the compression group (P=0.026),but without significant differences in the varus instability (P=0.397).However,the compression fracture group had a higher risk to have neurovascular injuries (of the popliteal artery and the common peroneal nerve) compared with the marginal fracture group.Conclusion The incidence of the anteromedial impingement fracture of the tibial plateau in posterolateral corner injuries was 7.1％.The anteromedial impingement fracture of the tibial plateau may indicate more severe posterior instability,and a compression fracture may suggest more severe posterior instability compared with the marginal fracture.If there is a compression type fracture,the neurovascular status must be carefully evaluated in addition to the examination of the posterolateral and posterior instability.