Rotating-hinge total knee for revision total knee arthroplasty

Rotating-hinge knee implants are used for revision total knee arthroplasty in patients with severe ligament instability and bone loss. This study evaluated the outcomes of a series of rotating-hinge knees. Thirty-one NexGen Rotating Hinge Knees (Zimmer, Warsaw, Indiana) were implanted in 29 patients (2 bilateral), with an average age of 72.8 years. Indications for surgery were aseptic loosening (n=23), septic loosenings (n=4), tibiofemoral instability (n=3), and wear (n=1). The Hospital for Special Surgery Knee Score and the Knee Society Roentgenographic Evaluation System were used. Statistical and cumulative survival rate analyses were performed. Average follow-up was 60.3 months (range, 32-100 months). The Hospital for Special Surgery Knee Score results indicated statistically significant improvement; the total score increased from 65.5 preoperatively to 88.4 postoperatively. Average range of motion increased from 90.9° preoperatively to 114.4° postoperatively. Radiographs showed no periprosthetic bone fractures or implant ruptures. Radiolucent lines were found in 20 of 26 patients and were progressive in 2 (both revised). Complications occurred in 10 patients. The rigidity of the hinge may be associated with a risk of aseptic loosening due to the increased stress transfer to the bone from the prosthesis through the locked hinge. Rotating-hinge knee implants provided acceptable mid-term outcomes for revision knee surgery with ligamentous instability. They are not at higher risk for early loosening unless short tibial stems are used. The high percentage of failures is more related to the complex surgery and to the status of the patients than to the hinged mechanism.     

人工全膝关节感染翻修医疗费用相关性调查

目的探讨人工全膝关节感染翻修医疗费用中的各项组成与手术方式的相关性,为人工全膝关节感染翻修方式的选择提供参考。方法统计2000年到2010年于本组因感染行人工全膝关节翻修术的患者,并按纳入标准选取符合要求的患者23例,男5例,女18例;年龄50～85岁,平均66．6岁。分析并比较其围手术期发生相关费用组成,同时选取同期年龄、性别、基础疾病匹配的初次人工关节置换患者,并对一期、二期翻修及初次人工关节置换进行费用对比,应用SPSS16．0统计软件对数据进行处理。结果23例患者翻修手术的平均费用为（98736．94±44330．23）元,一期翻修住院时问及治疗费用明显较二期翻修者少,差异具有统计学意义（t=2．84,P〈0．05;t=2．94,P〈0．05）;与初次膝关节置换相比,翻修手术住院13及翻修费均明显增加,差异具有统计学意义（t=7．165,P〈0．05;t=5．678,P〈0．05）。翻修手术中更换部分关节假体组件的翻修方式较全部更换更为经济,但风险更大。翻修假体及围手术期抗生素的应用仍然是整个医疗费用中最大的部分,占整个治疗疗费用77．42％。结论膝关节感染是膝关节置换术后翻修的重要原因,选择合适的治疗方式和手术方案可以极大的减少医疗费用的消耗。     

Pseudoaneurysm after revision total knee arthroplasty

Arterial vascular complications following knee replacement are uncommon with reported incidence ranging from 0.03 to 0.12%. The complication rate is rising with increased number of primary and revision total knee replacements. Vascular complications following TKR can result in arterial thrombosis, AV fistula, haemorrhage, pseudoaneurysm and arterial transection. They are associated with significant morbidity and can be limb-threatening. Early recognition and management of vascular injury is essential although some times its presentation may be delayed. We report a case of pseudoaneurysm arising from inferior lateral genicular branch of the anterior tibial artery after revision right total knee replacement.     

Cemented long-stem revision total knee arthroplasty

From 1981 to 1989, 38 cemented, posterior, stabilized, revision, total knee arthroplasties (TKAs) were performed at the authors' institution using the stemmed kinematic stabilizer prosthesis of a single design. The mean clinical follow-up after the index procedure was 10.1 years. The Knee Society pain score averaged 17 points before revision and improved to 51 points at last follow-up, and the function score averaged 48 points before revision and improved to 57 at last follow-up. Ten-year component survival free of revision or removal for any reason was 96.7%; 11-year component survival free of revision for aseptic loosening was 95.7%. Cemented stem fixation in revision TKA provides good clinical results with durable fixation at an average of 10 years' follow-up.     

Functional outcome after total knee arthroplasty revision

The objective of this study was to perform a systematic literature review to describe patient outcome after total knee arthroplasty revision procedures using various global knee score ratings. English language articles published from 1966 through 2000 were identified through a computerized literature search and bibliography review. A multistage assessment was used to determine the articles containing data that could meet our objective. Meta-analyses of global knee scores were undertaken using a fixed effects model with the assumption that the variances of each individual measurement were identical across studies. The initial inclusion criteria were met by 58 articles with a total of 1,965 patients. There were 42 articles comprising 45 unique patient cohorts and a total of 1,515 patients that had sufficient global knee score data for analysis and were used in the meta-analyses. Revision total knee arthroplasty is an effective procedure for failed knee arthroplasties based on global knee rating scales.     

Blood management in revision total knee arthroplasty

Much attention has been focused on blood management issues in orthopaedic surgery in recent years, but blood management in patients having revision total knee arthroplasty is not well-established. Hematologic values and transfusion records of 100 patients (52 women, 48 men; mean age, 65 years) who had aseptic revision total knee arthroplasty at the authors' institution were evaluated retrospectively. Two- or three-component revisions comprised 66% of the procedures, and 58 patients participated in a preoperative autologous donation program. The mean preoperative hemoglobin level was 12.1 g/dL in the women and 14.1 g/dL in the men, but the men experienced a greater decrease in hemoglobin level (mean largest decrease, 4.2 g/dL versus 3.1 g/dL), possibly caused by the higher allogeneic transfusion rate in women (19.2%) versus men (4.2%). Patient age did not influence hemoglobin level or transfusion rates. Patients who participated in a preoperative autologous donation program had significantly higher hemoglobin levels before donation (14.4 g/dL versus 13.3 g/dL for patients who did not participate in a program) but comparable hemoglobin levels after predonation (12.9 g/dL). Patients with preoperative hemoglobin levels less than 13 g/dL were significantly more likely to have a transfusion. Symptom-based transfusion strategies and blood management approaches such as epoetin alfa that elevate preoperative hemoglobin level therefore may be beneficial in patients having revision total knee arthroplasty.     

Endosteal referencing in revision total knee arthroplasty

A method of orienting the femoral and tibial bone cuts relative to the endosteal cortex of the femur and tibia was used in 32 patients who underwent revision total knee arthroplasty. The mean orientation of the femoral component was 96.74° ± 1.03°, mean orientation of the tibial baseplate was 90.71° ± 1.10°, mean anatomic tibiofemoral alignment was 7.42° ± 1.69° of valgus, and mean mechanical tibiofemoral alignment was 1.09° ± 1.83° of valgus. Mean tibial bowing was 1.63° ± 1.57° of valgus, and mean femoral bowing was 0.58° ± 1.53° of varus. Valgus tibial bowing was correlated with valgus orientation of the tibial component (r = .86, P < .000001), and varus femoral bowing was correlated with orientation of the femoral component (r = .54, P = .0054). Referencing the implant position from the endosteal cortex of the intramedullary canals provides a reliable method of achieving satisfactory alignment in most revision total knee arthroplasties; however, bowing of the femur or tibia can affect alignment.     

Structural allografting in revision total knee arthroplasty

Between 1985 and 1991, 15 patients underwent structural allografting as part of revision total knee arthroplasty. All patients had large segmental, cavitary, or combination defects of the femur and/or tibia. Seven distal femurs and 12 proximal tibias required allografting. Patients were evaluated with physical examination, radiographs, and The Hospital for Special Surgery knee rating scale. Three patients died, leaving 15 allografts for follow-up study. The average age at surgery was 63 years. The follow-up period averaged 47 months (range, 30–101 months). Average range of motion before surgery was 4° to 93°, and after surgery, 2° to 104°. Average knee score was 47 before and 86 after surgery. Preoperative alignment averaged 5° varus, ranging from 25° valgus to 20° varus, and postoperative alignment averaged 4° valgus, ranging from neutral to 6° valgus. All patients, except one, had improvement of pain and stability. All of the 15 allografts healed to host—bone and 13 showed evidence of incorporation. There were no infections or fractures of the allografts. One complication directly related to the allograft occurred; that patient had a tibial component fracture over a proximal tibial allograft 3 years after surgery. Three other complications occurred. One was tibial loosening in a patient who received a distal femoral allograft, the second was a proximal tibial fracture in a patient who received a distal femoral allograft, and the third was an intraoperative patellar tendon avulsion. These results suggest that structural allografting can provide a satisfactory method of managing large bone defects in the failed total knee arthroplasty.     

Ligament balancing in revision total knee arthroplasty

Ligament balancing in revision total knee arthroplasty involves placement and sizing of the femoral and tibial components and balancing procedures for the ligaments. A simplified technique is presented for sizing and positioning the implants and for balancing the ligaments. Eighty-nine knees with severe bone loss were treated with ligament-sparing exposure and bone-sparing resection techniques. The knees were stabilized by the spacer effect of the implants in flexion and extension, and nonlinked components were used. None of the knees had symptomatic instability, recurvatum, or flexion contracture. Five years after surgery the mean valgus laxity was 3 degrees +/- 2.5 degrees and the mean varus laxity was 4.5 degrees +/- 3.3 degrees Laxity did not increase after 10 years followup. The techniques used in this series have proven to be simple and reproducible, and to provide long-term reliability.     

Heterotopic ossification after revision total knee arthroplasty

A consecutive series of revision total knee arthroplasties done at two centers was evaluated for the presence of heterotopic ossification on radiographs taken before and after revision using the classification system of Harwin et al. Knee Society scores were obtained preoperatively and at annual intervals postoperatively. The patients' demographics and clinical scores were correlated with the incidence and grade of heterotopic ossification. Minimum 2-year followup was obtained in 135 of 151 patients who had revision total knee arthroplasty during this period (89%). The incidence of heterotopic ossification before revision surgery was 23%, which increased to 56% at most recent followup (mean, 30 months; range, 24-48 months). The only risk factor identified for the development of heterotopic ossification was the presence of infection (76%), which was significantly higher than the 47% incidence of heterotopic ossification in patients who did not have an infection. The average postoperative Knee Society score was lower in patients with heterotopic ossification compared with patients without heterotopic ossification (129 points versus 148 points). Patients with heterotopic ossification had significantly lower functional scores particularly on stair climbing but did not have a significantly decreased range of motion. Parameters not associated with subsequent development of heterotopic ossification included gender (males), patient size (body mass index), surgical time, operative approach, or number of prior knee procedures.     

The results of revision total knee arthroplasty

The results of 65 consecutive revision total knee arthroplasties performed for mechanical failure were reviewed. Fifty-nine of the knees were followed for an average of five years (range, 2-10 years). The types of implants used included: total condylar, posterior stabilized, total condylar III, and the kinematic rotating hinge prostheses. Only 46% of the knees were considered excellent or good; 42% either had poor results or failed. The infection rate was 4.5%. Poor results were generally caused by patellofemoral problems and kinematic abnormalities. Revision total knee arthroplasty is a technically demanding procedure that can improve function when anatomic relationships of the knee are restored.     

New concepts in revision total knee arthroplasty

Revision knee arthroplasty should be regarded as a discipline separate from primary surgery. A disciplined approach to diagnosis is mandatory in which the following categories for failure are useful: (a) sepsis, (b) extensor mechanism rupture, (c) stiffness, (d) instability, (e) periprosthetic fracture, (f) aseptic loosening and osteolysis, (g) patellar complications and malrotation, (h) component breakage, and (i) no diagnosis. In the event of no coherent explanation for pain and disability, the possibilities of chronic regional pain syndrome, hip or spine pathology, and inability of current technology to meet patient expectations should be considered and revision surgery should be avoided. Revision arthroplasty cannot be performed as if it were a primary procedure and indeed will be eight (or more) different surgeries depending on the cause of failure. Though perhaps counterintuitive, there is a logical rationale and empirical evidence to support complete revision in virtually every case. In general, revision implant systems are required. The early dependence on the "joint line" is inadequate, failing as it does to recognize that the level of the articulation is a three-dimensional concept and not simply a "line." The key to revision surgery technique is that the flexion gap is determined by femoral component size and the extension gap by proximal distal component position. Accordingly, a general technical pathway of three steps can be recommended: 1) tibial platform; 2) stabilization of the knee in flexion with (a) femoral component rotation and (b) size selected with evaluation of (c) patellar height as an indication of "joint line" in flexion only; and 3) stabilization of the knee in extension, an automatic step. Stem extensions improve fixation and, if they engage the diaphysis, may be used as a guide for positioning. Porous metals designed as augments for bone defects may prove more important as "modular fixation interfaces." It is postulated that with the exception of septic and extensor mechanism complications, first revision knee arthroplasty may exceed the durability of primary knee arthroplasty.     

人工膝关节翻修假体的选择

随着全膝关节置换病例的增加及患者低龄化 ,全膝关节置换术后翻修病例也呈快速增长趋势 ,仅美国每年就有 2万多例患者需行全膝关节翻修术[1] ;据统计 ,翻修率为 5 %～ 10 % [2 ,3 ] 。翻修时往往由于骨缺损、关节周围软组织及韧带平衡失调、关节力线不正等原因 ,所以在技术上更具挑战性。研究表明 ,普通假体并不完全适合人工膝关节翻修 ,为了提高全膝关节翻修的效果 ,已经研制开发出翻修假体系统 ,包括各种厚度的楔形金属垫块和不同长度和粗细的股骨和胫骨假体柄组件、特制假体以及同种异体骨制成的全膝假体等。然而 ,通过严格病例随访和分…     

Patellar options in revision total knee arthroplasty

There are numerous options that need to be considered by the surgeon at the time of revision total knee arthroplasty (TKA). One needs to consider the reason for the revision, the type of patella in place, and the length of time the patella has been in place. The surgeon also needs to consider the status of the patellar bone stock, the stability of the patellar component (well-fixed or loose), and the component type (cemented or metal-backed). Assuming that the existing prosthesis is not metal-backed and has minimal PE wear, then it is preferable to retain a well-fixed all-PE cemented patellar button. However, if the button is metal-backed, then it probably is best to remove the button and replace it with an all-PE domed patellar component. Assuming more than 8 mm of patellar bone stock is remaining, it usually is best to cement an all-PE dome-shaped patella. However, if less than 8 mm is remaining, then that patient can be left with a patelloplasty, recognizing that this individual is going to continue with a high likelihood of anterior knee pain, subluxation, and poor functional results. In that situation, it may be preferable to consider a bone stock augmentation.     

Early patellofemoral revision following total knee arthroplasty

A consecutive series of 289 Miller-Galante (Zimmer, Warsaw, IN) total knee arthroplasties were studied, with particular reference to the patellofemoral joint. Sixteen knees were initially excluded; the remaining 273 arthroplasties were followed for 14 to 44 months. Thirty patients (11%) had patellofemoral pain. Twenty patients (7.3%) had revision patellofemoral surgery. Fourteen patients had revision surgery for patellar maltracking, of which 10 had resolution of their symptoms, 2 were improved, 1 had no change, and 1 developed a prosthetic infection. Six patients who had no evidence of patellar maltracking had revision surgery with a cemented metal-backed patellar component. Only two of these patients had symptom improvement from their revision surgery. A higher than usual incidence of patellar maltracking (5%) is reported. The first-generation Miller-Galante femoral component may contribute to the relative instability of patellofemoral tracking. Those patients with patellar maltracking were greatly improved by revision surgery; the results of revision surgery for anterior knee pain without associated patellar maltracking were disappointing.