Reports cite up to 20% of total knee arthroplasty (TKA) patients are not satisfied. Recent focus on alignment and balance has perhaps overshadowed kinematics as a key determinant of outcomes. Some propose that reproducing the native knee kinematics of lateral-pivot motion in early flexion during walking will enact optimal TKA outcomes. The purpose of this study was to determine if intra-operative kinematic patterns correlate with patient function, pain and satisfaction after TKA. A retrospective review of consecutive TKA's performed by two surgeons was performed. After final components were implanted and balanced, sensor-embedded tibial trials were inserted and kinematic patterns were recorded through range-of-motion. Femoro-tibial contact points were recorded at four distinct flexion points (0°, 45°, 90° and full flexion). Center of rotation kinematic patterns were calculated and categorized as medial pivot, lateral pivot or translation at each measurement range via established criteria. Knees with lateral (L) pivot in early flexion between 0 and 45 ° and medial (M) pivot beyond 90°, regardless of the mid-flexion pivot pattern, formed the experimental group designated as LXM. All other patterns were designated non-LXM and formed the control group. Modern, validated clinical outcome measures (Knee Society Score, EQ5D, UCLA) were obtained preoperatively and at minimum one-year postoperatively.Introduction
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The direct anterior approach (DAA) for total hip arthroplasty (THA) is marketed with claims of superiority over other approaches. Femoral exposure can be technically challenging and potentially lead to early failure. We examined whether surgical approach is associated with early THA failure. A retrospective review of 478 consecutive early revision THAs within five years of primary THA at three academic centers from 2011 through 2014 was performed. Exclusion criteria resulted in a final analysis sample of 341 early failure THAs. Primary surgical approach was documented for each revision, along with time to revision, and failure etiology.Background
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The purpose of TKA is to restore normal kinematics and functioning to diseased knees. The purpose of this study was to determine whether intraoperative kinematic data are correlated with minimum one-year outcomes following primary TKA. We reviewed data on 185 consecutive primary TKAs in which sensor-embedded tibial trials were used to evaluate kinematic patterns following traditional ligament balancing. Procedures were performed by two board-certified arthroplasty surgeons. The same implant design and surgical approach was used for all knees. Contact locations on the medial and lateral condyles were recorded for each patient at 0°, 45° and 90° of flexion, and full flexion. Vector equations were created by contact locations on the medial and lateral sides and the vector intersections determined the center of rotation between each measurement position. Center of rotation was calculated as the average of vector intersections at 0 to 45°, 45 to 90°, and 90° to full flexion. If the average center of rotation was between 16 and 1000 mm of the contact location on the medial side it was considered a medial pivot knee. Knees were also classified as medial (16 to 200 mm on medial side), lateral (16 to 200 mm on lateral side), translating (> 200 mm medially or laterally), and other (< 16 mm on both medial and lateral sides). The new Knee Society Scoring System (KSSO objective score, KSSS satisfaction score, KSSF function score), the EQ-5D™ Health Status Index, and the University of California Los Angeles (UCLA) Activity Level Score were measured preoperatively and at minimum one-year follow-up (average 20.4 months).INTRODUCTION
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Although commonly used, the clinical performance of highly crosslinked polyethylene in total knee arthroplasty (TKA) remains unknown and concerns exist regarding fatigue resistance and oxidation, particularly in posterior-stabilized (PS) designs. The purpose of this study is to compare highly crosslinked and conventional polyethylene in a PS TKA design at a minimum of 5-years. A prospective cohort study of 114 consecutive TKAs in 83 patients was performed as a subset of a multi-center prospective study. All TKAs utilized an identical PS design. Conventional polyethylene inserts were used in 50 knees and second-generation highly cross-linked polythethylene inserts were implanted in 64 TKAs. All patients were followed with clinical outcome measures (Short-Form 36, Knee Society Scores, WOMAC and LEAS) and radiographically for a minimum of 5 years.Introduction:
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Efforts continue to reduce blood loss in total knee arthroplasty (TKA). Computer assisted surgery (CAS) has been shown to reduce outliers in component position and improve functional outcomes in TKA, yet few studies have reported specifically on blood loss. The primary study objective was to determine whether a modern abbreviated CAS protocol would reduce blood loss in TKA compared to conventional instrumentation. A secondary objective was to assess the effect of CAS on cost and surgical efficiency. A retrospective cohort study of 100 consecutive patients was performed comparing an abbreviated and modern CAS protocol versus conventional IM instrumentation. All TKAs utilized an identical surgical technique without any hemostatic agent. Blood loss was determined using drain output, change in hemoglobin, and calculated blood loss. Tourniquet times were recorded as an indicator of procedural efficiency. A cost analysis compared the CAS protocol to the cost associated with tranexamic acid (TXA) to reduce blood loss and long-leg alignment radiographs to optimize component position.Introduction:
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Although cementless total hip arthroplasty (THA) is well accepted, the optimal femoral component design remains unknown. Among early complications, loosening and periprosthetic fracture persist and are related to implant design. The purpose of this study is to compare the anatomic fit and early subsidence of two different stem designs: a modern, short taper-wedge design and a traditional fit-and-fill design. A retrospective cohort study of 129 consecutive cementless THAs using two different femoral stems was performed. A modern taper-wedge stem was used in 65 hips and a traditional proximal fit-and-fill stem was used in 64 hips. Radiographic analysis was performed at preoperative, immediate postoperative and 1-month postoperative intervals. The radiographic parameters of bone morphology via the canal-flare index, implant subsidence at 1 month, sagittal alignment, and the “anatomic fit” metrics of canal fill and associated gaps were measured and recorded.Introduction:
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