Results of Cemented Posterior-Stabilized Total Knee Arthroplasty in Obese Patients With an Average 10-Year Follow-Up

BackgroundObese and morbidly obese patients undergoing primary total knee arthroplasty (TKA) place significant stress at the bone-cement-implant interface over the life of the patient. The purpose of this study is to evaluate results of cemented, posterior-stabilized TKA in obese and morbidly obese patients at an average follow-up of 10 years.MethodsRetrospective study of 181 patients who had a cemented, posterior-stabilized TKA between 2000 and 2013 with body mass index >35 at the time of surgery was conducted. Clinical data and radiographs were evaluated along with survivorship, complications, and revisions. Minimum follow-up was 5 years with an average follow-up of 10 years.ResultsThere were 135 women and 46 men in the study, with mean age of 60.2 years (range 43-80), mean body mass index of 42.0 (range 35.1-66.1), and an average follow-up of 10 years (range 5-18). There were a total of 39 failures (22%) that underwent revision TKA surgery with mean time to revision of 8 years. Failures included 25 (14%) cases of aseptic loosening; 9 (5%) polyethylene wear; 2 (1%) prosthetic joint infection; and 3 additional revisions for instability, pain, and stiffness. There were a total of 11 cases of isolated tibial component loosening and 13 for both tibial and femoral loosening. Survivorship at 15 years with aseptic loosening as the endpoint was 86.7%, and for all causes 79.6% at 15 years.ConclusionAseptic loosening is the leading cause of failure following TKA in obese and morbidly obese patients with decreasing survivorship from 96.1% to 91.2% and 86.7% at 5, 10, and 15 years, respectively.     

Comparing the Effects of Single Shot Sciatic Nerve Block Versus Posterior Capsule Local Anesthetic Infiltration on Analgesia and Functional Outcome After Total Knee Arthroplasty : A Prospective,Randomized, Double-Blinded,Controlled Trial

Peripheral nerve blocks appear to provide effective analgesia for patients undergoing total knee arthroplasty. Although the literature supports the use of femoral nerve block, addition of sciatic nerve block is controversial. In this study we investigated the value of sciatic nerve block and an alternative technique of posterior capsule local anesthetic infiltration analgesia. 100 patients were prospectively randomized into three groups. Group 1: sciatic nerve block; Group 2: posterior local anesthetic infiltration; Group 3: control. All patients received a femoral nerve block and spinal anesthesia. There were no differences in pain scores between groups. Sciatic nerve block provided a brief clinically insignificant opioid sparing effect. We conclude that sciatic nerve block and posterior local anesthetic infiltration do not provide significant analgesic benefits.     

Conventional Versus Computer-Assisted Technique for Total Knee Arthroplasty: A Minimum of 5-Year Follow-up of 200 Patients in a Prospective Randomized Comparative Trial

In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term period are not conclusive and long-term data are rare. In a prospective, randomized, comparative study 100 conventional TKAs (group REG) were compared with 100 computer-assisted TKAs (group NAV). Minimum follow-up was 5 years. No difference in implant failure was found with 1.1% in group NAV versus 4.6% in group REG (P = 0.368). Group NAV showed a significantly less mean deviation of mechanical limb axis (P = 0.015), more TKAs (90% versus 81% in group REG) were within 3° varus/valgus and a higher tibial slope and lateral distal femoral angle (LDFA) accuracy was found (P ≤ 0.034). Clinical investigational parameters showed no differences (P ≥ 0.058). Insall and HSS score total were also higher in group NAV (P ≤ 0.016).     

In Vivo Movement of Femoral Flexion Axis of a Single-Radius Total Knee Arthroplasty

The objective of this study was to investigate in vivo femoro-tibial motion using the movement of femoral flexion axis of a single-radius TKA. We examined 20 clinically successful knees with a single-radius posterior stabilized TKA to evaluate the kinematics of deep knee flexion using 2–3-dimensional registration techniques. The mean knee flexion range of motion was 117.8°. The mean rotation of the femoral component was 7.6° external rotation. The mean knee flexion angle at initial post-cam engagement was 55.2°. No paradoxical movement of femoral component was shown until 70° flexion, afterward the femoral component rolled back with flexion. The data showed that the design of this prosthesis might contribute to reduce the paradoxical anterior femoral movement and provide stability in mid-flexion ranges.     

Comparison of Intravenous versus Topical Tranexamic Acid in Total Knee Arthroplasty: A Prospective Randomized Study

The purpose of this study was to compare the efficacy of topical Tranexamic Acid (TXA) versus Intravenous (IV) Tranexamic Acid for reduction of blood loss following primary total knee arthroplasty (TKA). This prospective randomized study involved 89 patients comparing topical administration of 2.0 g TXA, versus IV administration of 10 mg/kg. There were no differences between the two groups with regard to patient demographics or perioperative function. The primary outcome measure, perioperative change in hemoglobin level, showed a decrease of 3.06 ± 1.02 in the IV group and 3.42 ± 1.07 in the topical group (P = 0.108). There were no statistical differences between the groups in preoperative hemoglobin level, lowest postoperative hemoglobin level, or total drain output. One patient in the topical group required blood transfusion (P = 0.342). Based on our study, topical Tranexamic Acid has similar efficacy to IV Tranexamic Acid for TKA patients.     

Doctor,What Does my Knee Arthroplasty Weigh?

The aim of this study was to compare the weight of the total knee arthroplasty (TKA) implants and the weight of the natural knee. A prospective study was conducted with two different brands of cemented primary TKA. During the procedure, we collected the removed bone, soft tissues and the post-implantation cement and weighed them all separately at the end. In both groups, the implants plus cement were significantly heavier than the removed bone and soft tissues. The average weight gained was 266.7 ± 35.1 g for group 1 and 279.1 ± 48.7 g for group 2. This significant local weight gained after TKA is a new parameter that should be taken into account for further studies and when creating new implants.     

Does Resident Involvement Impact Post-Operative Complications Following Primary Total Knee Arthroplasty? An Analysis of 24,529 Cases

Little is known about the impact of resident involvement on complication rates following total knee arthroplasty (TKA). The goal of our study was to determine the impact of resident involvement on complications following primary TKA. Using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database (2005–2012) we identified 24,529 patients who underwent primary TKA. Of these, 5960 (24.3%) had a resident involved in a primary TKA. Using a multivariate logistic regression which incorporated propensity score adjustment, no differences were seen in morbidity and mortality following those cases with resident involvement (OR: 1.15, P = 0.129). In the first large scale, comprehensive analysis of resident impact on short-term morbidity and mortality, no increase in complications was observed with resident involvement in primary TKA.     

TKA术后感染诊断的研究进展

人工膝关节置换术(TKA)已经成为治疗膝关节疾患最为有效的方法,目前对于TKA术后感染的诊断仍然是一个巨大的挑战,特别是存在亚急性和低毒性等非典型感染的情况下。本文综述了目前对人工膝关节感染的主要诊断方法。