Short-term clinical outcomes of primary total knee arthroplasty with a new-type kinematic retaining implant: A comparison with preexisting cruciate retaining prosthesis.

Despite the success of total knee arthroplasty (TKA), current implant designs could not consistently restore the physiological knee kinematics, especially in cruciate-retaining (CR) implants. This study aimed to investigate the short-term clinical outcomes, particularly patient satisfaction, of primary TKA employing a new-type kinematic retaining (KR) implant. We analyzed 149 cases applied the KR implant at our institutions during June 2017 to May 2019. The effectiveness of this implant design was compared with another CR one (171 cases). Both groups underwent primary TKA in the same period and all patients completed 2 years of follow-up. Perioperative changes in range of motion (ROM), Knee Score, function score, and patient satisfaction by Forgotten Joint Score-12 (FJS-12) method were evaluated. Postoperative ROM, Knee Score, and function score were significantly improved at 1 year after surgeries and maintained for another year in both KR and CR groups. The improvement rate of ROM in KR group (108.1%) was substantially higher than that in CR (104.5%), even 4% increase could have affected patients' satisfaction in a real-world setting. Regarding the patient satisfaction, such 4 items as climbing stairs, walking on a bumpy road, doing housework or gardening, and taking a walk or hiking were significantly enhanced in KR cases compared to CR. There were no loosening or revision cases and the short-term survivorships of both implants were 100%. In addition, there has been no case of obvious complications in both groups during and after surgeries. The results of the present study suggest that this novel KR prosthesis can reproduce physiological knee kinematics, recover its functions, and contribute to pain relief after TKA. TKA procedure using the KR implant should be a good surgical option to improve postoperative outcomes.

Short- to Mid-Term Clinical Outcomes of Posterior-Stabilized Cementless Total Knee Arthroplasty with Trabecular Metal Components.

OBJECTIVE: This study aimed to evaluate the short- to mid-term clinical results of posterior-stabilized trabecular metal total knee arthroplasty (TKA) with cementless fixation of all components and investigate the radiographic changes of tibial and patellar components and cut bone surfaces over time. METHODS: We retrospectively collected the data of 128 knees from 88 consecutive patients who had undergone initial TKA with NexGen LPS-Flex TM implants. A total of 66 knees from 45 patients (mean ± standard deviation age: 70.3 ± 7.5 years) met the selection criteria, which had been employed cementless fixation of all parts and at least 3 years of postoperative follow-up duration. Clinical evaluations included range of motion, conventional knee score, function score, postoperative complications, and revision. For radiological evaluations, the bone contact surface of each implant was divided into 7 zones for tibial component and 2 zones for patellar component. Each region was examined immediately after surgery, at 6 and 12 months, and then every year afterwards. RESULTS: The mean observation period of 45 subjects was 4.2 years. Adequate fixation of tibial components was maintained during follow-up, although the patellar components of 2 knees required revision after repeated falls. No loosening was observed in any implants. The initial gap in tibial components disappeared in all knees, and a reactive line remained in 4 knees. There were no revisions, except for 2 cases, which were ascribed to patellar component fracture caused by repeated falls. CONCLUSION: Cementless posterior-stabilized trabecular metal TKA appears to be a good surgical option. Longer-term examination for revision cases is required to validate our results.

The incidence and risk factor of deep venous thrombosis after arthroscopically assisted anterior cruciate ligament reconstruction.

PURPOSE: To retrospectively analyze the incidence and risk factors of deep venous thrombosis (DVT) detected by ultrasonography after arthroscopically assisted Anterior Cruciate Ligament Reconstruction (ACLR). METHODS: We retrospectively reviewed medical records of arthroscopically assisted ACLR surgery performed at our institution between 2012 and 2015. Revision ACLR, bone patella tendon bone (BTB) graft reconstruction, and concomitant multiple ligament reconstructions were excluded. We performed a standardized double-bundle reconstruction procedure using hamstrings graft for ACLR. All patients routinely received DVT screening by using venous ultrasonography on postoperative day 7 from 2012 to 2013, and postoperative days 7 and 14 from 2014 to 2015. The prevalence of DVT was calculated and clinical factors such as age, gender, Body Mass Index (BMI), operative time, and duration of tourniquet application were evaluated in relation to the risk factor of DVT. RESULTS: Two hundred and fifty-six patients (129 men and 127 women) with a mean age of 28.9 were enrolled. Sixteen patients (6.6%) were detected with DVT on postoperative day 7. Among 146 patients who received venous ultrasonography on both postoperative days 7 and 14, DVT were detected in five additional patients on postoperative day 14. In a total of 21 patients who were diagnosed with DVT, two were proximal, the remaining 19 were distal, and no patient had progressed to pulmonary embolism (PE). In terms of predisposing factors for developing DVT on postoperative day 7, only age ≥30 showed a statistically significant higher risk of DVT (P = 0.03). CONCLUSION: Incidence of DVT after ACLR detected by ultrasonography on postoperative day 7 was 6.6%. Patients aged ≥30 years have a potentially higher risk for developing DVT. Great care for DVT should be taken if prolonged immobilization is applied after ACLR surgery. LEVEL OF EVIDENCE: Level Ⅳ.

Anatomic double-bundle anterior cruciate ligament reconstruction, using CT-based navigation and fiducial markers.

PURPOSE: Accurate placement of separate anteromedial and posterolateral bundle bone tunnels is crucial for anatomic, double-bundle anterior cruciate ligament (ACL) reconstruction. However, identifying the anatomic footprint at which to make the tibial and femoral bone tunnels is not a straightforward procedure. To overcome this problem, we used a CT-based navigation technique with a registration procedure based on fiducial markers (FMs). METHODS: Preoperatively, 10 FM points were placed on skin around knee joint and scanned with CT. Imaging data of the knee were recorded on the computer system for preoperative registration and surgical planning. Intraoperatively, with a reference frame fixed to the distal medial aspect of femur and tibia, paired-point matching registration was performed with the use of points marked on skin through FM center holes. During tibial tunnel guide wire placement, tibial aiming guide with tracking device fed back the position of tip and direction of the guide wire on the three-dimensional (3D) tibia bone surface image and multiple image planes in real time. For the femoral side, the navigation pointer was placed at the footprint center with visual guidance of 3D image of lateral wall sagittal view on navigation monitor and marked with navigation awl. RESULTS: The average registration accuracy of 22 consecutive patients was 0.7 ± 0.2 mm and 0.6 ± 0.2 mm for femoral and tibial bone, respectively. Most of the bone tunnel positions evaluated with 3D-CT image were confirmed to be accurately placed in reference to the preoperative plan. There was no damage to femoral condyle cartilage and no other complication. CONCLUSION: This new CT-based computer navigation system opens the possibility for surgeons to plan bone tunnel positioning preoperatively and control it during technically demanding anatomic double-bundle ACL reconstruction.