Arthroscopically Assisted Retrograde Intramedullary Nailing for Periprosthetic Fracture of the Femur after Posterior-Stabilized Total Knee Arthroplasty

Retrograde intramedullary nailing (RIMN) has been used for periprosthetic fracture of the distal femur after total knee arthroplasty (TKA), yielding good fracture union rates and satisfactory outcomes. However, RIMN for posterior-stabilized- (PS-) TKA risks malpositioning the entry point and disturbing the post of the tibial insert, and the surgeon therefore usually requires knee joint arthrotomy. We report a case of a 79-year-old male who was involved in bicycle accident resulting in periprosthetic fracture of the distal femur after PS-TKA. We performed osteosynthesis with arthroscopically assisted RIMN to define an appropriate entry point. RIMN for posterior-stabilized- (PS-) TKA risks malpositioning the entry point and disturbing the post of the tibial insert. Because arthroscopy can directly visualize the entry point and the tibial post without arthrotomy, arthroscopically assisted RIMN offers a useful technical option for periprosthetic fracture of the distal femur after PS-TKA

The effects of barbed suture on watertightness after knee arthrotomy closure: a cadaveric study

Abstract Background Wound closure is one of the crucial aspects of total knee arthroplasty (TKA) for patients who perform high-flexion activities of daily living, because the joint capsule is highly stretched and integrity of the arthrotomy closure must be maintained. Watertightness of the knee joint is a different aspect of the repair integrity of arthrotomy closure and is being noticed with increasing usage of the drain clamp method for blood management after TKA. Recently, the barbed knotless suture has been growing in popularity as a strong, secure closure appropriate for high-tension areas, such as the fascia and joint capsule. The purpose of this study was to compare the barbed knotless suture with simple interrupted suture in cadaveric knees. Methods Nine fresh-frozen cadaveric lower extremities were used. After placing a parapatellar incision and setting a closed suction drain, arthrotomies were closed randomly using three suture materials: simple interrupted absorbable suture (No. 0 PDS, group C); or a single running knotless barbed suture Stratafix with 8N (group BS-8N) or 15N (group BS-15N) of tension. After arthrotomy closure, saline was injected in a retrograde manner into the joint through a drain until saline started to leak from the joint. Peak values for intra-articular pressure and infusion volume in each group were recorded and compared. Results Mean infusion volumes were 13.0 ± 7.2 ml, 38.6 ± 10.7 ml, and 5.1 ± 2.5 ml in groups BS-8N, BS-15N, and C, respectively. Mean intra-articular pressures were 0.67 ± 0.47 kPa, 9.44 ± 4.55 kPa, and 0.56 ± 0.44 kPa in groups BS-8N, BS-15N, and C, respectively. Infusion volume and joint internal pressure were significantly higher in group BS-15N than in groups BS-8N (p = 0.008) or C (p = 0.04). Conclusions Barbed suture with 15N appears appropriate for maintaining maximal watertightness after knee joint capsule closure, offering successful drain clamping, higher resistance to early mobilization protocols, and subsequent achievement of early deep knee flexion after TKA

Detection of calcium pyrophosphate dihydrate crystals in knee meniscus by dual-energy computed tomography

Abstract Background Calcium pyrophosphate dihydrate (CPPD) crystals are commonly observed in osteoarthritic joints. The aim of our study was to investigate the efficacy of a dual-energy computed tomography (DECT) for detecting CPPD crystals in knee meniscus. Methods Twenty-six patients undergoing primary total knee arthroplasty were included in the study. Radiographs of knee joint and synovial fluid specimens were analyzed for the presence of CPPD crystals. Meniscus extracted during surgery was scanned using DECT. Sensitivity and specificity of DECT and radiograph for detecting CPPD crystals were calculated against a reference standard (polarizing light microscopy of synovial fluid aspirate). Meniscus in which CPPD crystals were suspected with DECT was further examined to confirm the crystals using a polarized microscopy. Results CPPD crystals in synovial fluid were observed in 9 (36%) patients. The sensitivity and specificity of DECT in the detection of CPPD crystals, against microscopic identification, were 77.8 and 93.8%, respectively. The sensitivity and specificity of conventional radiography in the detection of CPPD crystals were 44.4 and 100%, respectively. DECT was able to detect the area where CPPD crystals were deposited in the meniscus. Conclusion DECT provides good diagnostic sensitivity and specificity for detection of CPPD crystals in knee meniscus as well as spatial information about CPPD crystals. DECT is currently a research tool, but we believe that DECT can be a useful instrument to diagnose CPPD deposition disease, especially for the regions where aspiration is difficult to be performed such as pubic symphysis, atlantoaxial joint, interphalangeal joint

The tibial growth plate as a predictor of the original tibial plateau joint line as a reference for kinematically aligned total knee arthroplasty

Abstract Background Restoration of the natural joint line is a cornerstone for kinematically aligned total knee arthroplasty (TKA). The purpose of this study was to investigate the relative orientation of the tibial growth plate (GP) with respect to the tibial plateau (TP) for possible application in predicting natural joint line for knees with highly advanced osteoarthritis patient at the time of kinematically aligned TKA. Methods Images from computed tomography (CT) of 27 normal knees (9 males, 18 females; mean age, 31.6 years) were studied. Geometry of the GP was extracted from CT images, and its moment-of-inertia axes were calculated for the whole GP and the medial and lateral halves. Angular orientations of each GP axis with respect to the TP plane were measured in anatomical coordinates. Results The TP and GP planes were oriented in 2.3 ± 1.8° of varus and 1.1 ± 1.9° of valgus relative to the tibial mechanical axis, respectively. With respect to the TP plane, the whole GP plane was inclined in 3.4 ± 1.5° of valgus. Orientation of the GP plane differed drastically between medial and lateral halves. The medial GP was in 4.9 ± 2.9° of varus and 1.8 ± 2.5° of anterior inclination, and the lateral half was in 10.4 ± 2.4° of valgus and 18.6 ± 4.0° of anterior inclination relative to the TP. Conclusions Angular orientation of the original TP plane can be predicted in reference to the GP plane and may provide reasonable guidance for the target bone resection angle of the tibia in kinematically aligned TKA

Estimation of the External Knee Adduction Moment during Gait Using an Inertial Measurement Unit in Patients with Knee Osteoarthritis

Although the external knee adduction moment (KAM) during gait was shown to be a quantitative parameter of medial knee osteoarthritis (OA), it requires expensive equipment and a dedicated large space to measure. Therefore, it becomes a major reason to limit KAM measurement in a clinical environment. The purpose of this study was to estimate KAM using a single inertial measurement unit (IMU) during gait in patients with knee OA. A total of 22 medial knee OA patients (44 knee joints) performed conventional gait analysis using three-dimensional (3D) motion capture system. At the same time, we attached commercial IMUs to six body segments (sternum, pelvis, both thighs, and both shanks), and IMU signals during gait were recorded synchronized with the motion capture system. The peak-to-peak difference of acceleration in the lateral/medial axis immediately after heel contact was defined as the thrust acceleration (TA). We hypothesized that TA would represent the lateral thrust of the knee during the stance phase and correlate with the first peak of KAM. The relationship between the peak KAM and TA of pelvis (R = 0.52, p p p = 0.001) showed a significant correlation. The root mean square error (RMSE) of linear regression models of pelvis, shanks, and thighs to estimate KAM were 0.082, 0.079, and 0.084 Nm/(kg·m), respectively. Our newly established parameter TA showed a moderate correlation with conventional KAM. The current study confirmed our hypothesis that a single IMU would predict conventional KAM during gait. Since KAM is known as an indicator for prognosis and severity of knee OA, this new parameter has the potential to become an accessible predictor for medial knee OA instead of KAM