Review article: bone defect classifications in revision total knee arthroplasty

There are several classification systems for bone defects in revision total knee arthroplasty. Each has its own drawbacks, and none satisfies all the clinical demands. Therefore, a new classification system and treatment guideline based on a combination of criteria (location, side, containment, and severity of the bone defect) is necessary.     

Review article: knee flexion after total knee arthroplasty

Many factors affect or predict the flexion range achieved after total knee arthroplasty. While the knees that have good preoperative flexion have better final flexion, knees with good preoperative flexion do lose some flexion whereas those with poor preoperative flexion can gain flexion. Although studies of different prosthetic designs have produced conflicting results, recent studies appear to favour posterior cruciate ligament (PCL)--substituting over PCL-retaining prostheses. Several factors related to surgical techniques have been found to be important. These include the tightness of the retained posterior cruciate ligament, the elevation of the joint line, increased patellar thickness, and a trapezoidal flexion gap. Vigorous rehabilitation after surgery appears useful, while continuous passive motion has not been found to be effective. Obesity and previous surgery are poor prognostic factors; certain cultural factors, such as the Japanese style of sitting, offer 'unintentional' passive flexion and result in patients with better range. If the flexion after surgery is unsatisfactory, manipulation under anaesthesia within 3 months of the total knee arthroplasty can be beneficial.     

Results of revision total knee arthroplasty associated with significant bone loss

The results of 40 revision total knee arthroplasties (TKAs) in 38 patients performed for aseptic failure with significant bone loss were reviewed. All knees were evaluated for at least two years, with an average of 41 months (range, two to nine years.) Seventy-five percent of the knees were considered excellent or good. Ten percent were considered failures. There were no infections. Overall complication rate was 30%, of which wound complications were the most common. Revision TKA remains demanding, but results can be improved by (1) restoring the mechanical alignment of the knee with accurate component positioning; (2) filling all bone defects with bone, cement, or modular spacers; (3) using stems to assist in component support; and (4) adherence to soft-tissue balancing and care.     

Cementless reconstruction of massive tibial bone loss in revision total knee arthroplasty

Reconstruction of massive proximal tibial defects caused by failed cemented total knee arthroplasty (TKA) was evaluated using cancellous allograft and a rigidly fixed tibial component. Twenty patients with massive tibial defects requiring revision TKA were operated on using this technique from December 1984 to December 1986. All these had tight mediolateral capsular structures so that satisfactory varus-valgus stability was achieved. Only three had competent posterior cruciate ligaments. The tibial component had a cobalt chromium tray with a six-inch-long smooth stem, porous undersurface, and peripheral smooth pegs. Fixation was augmented with four cancellous screws that passed through the periphery of the tray and penetrated the cortical surface of the tibia. Good fixation of the tibial component was achieved in all cases at the time of surgery. All patients achieved full weight bearing within six months, and all but two were free of walking aids at one year postoperation. None of the patients developed apparent loosening of the femoral or tibial components. Two patients complained of mild pain and one who had revision of a painful but nonloosened cemented TKA complained of severe pain. Range of motion was 93 degrees +/- 7.6 degrees. Roentgenographic evaluation showed progressive increase in radiodensity in the grafted areas one year after surgery in all knees. One knee was revised for recurrent dislocation one year postoperation and had a biopsy of the allografted area. This biopsy showed trabeculae with empty lacunae surrounded by viable new bone. Allograft reconstruction of the proximal tibia for failed cemented TKA was highly successful using morselized allograft and rigid fixation of the tibial component.(ABSTRACT TRUNCATED AT 250 WORDS)     

Distal femoral allograft reconstruction for massive osteolytic bone loss in revision total knee arthroplasty

Massive osteolytic bone loss in revision total knee arthroplasty has been an uncommon challenge. From 2001 to 2002, 11 knees in 10 patients underwent revision of failed modular PFC (Johnson and Johnson Orthopaedics, Raynham, Mass) total knee arthroplasties with distal femoral allografts and long-stemmed revision implants for massive osteolytic induced femoral bone loss. The mean follow-up was 42 months (range, 36-48 months). Radiographic graft incorporation was demonstrated in all 11 knees with no cases of loosening. The Knee Society Pain Scores improved by an average of 25.4 points, and the function scores improved by an average of 23.3 points. The outcomes of distal femoral allografts in the reconstruction of massive osteolytic bone loss associated with failed modular PFC (Johnson and Johnson Orthopaedics) total knee arthroplasties are favorable.     

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.     

Bone-grafting for severe patellar bone loss during revision knee arthroplasty

BACKGROUND: Severe patellar bone loss may preclude adequate fixation of another patellar prosthesis as a part of revision knee replacement. The purpose of this study was to describe the surgical technique and early clinical results of an alternative to the conventional treatment options of either patellectomy or retention of the remaining patellar osseous shell. The goals of this procedure are to restore patellar bone stock and potentially to improve the functional outcome. METHODS: Severe patellar bone loss had left a "patellar shell" that precluded insertion of another patellar implant in nine of 100 consecutive knees undergoing revision total knee arthroplasty. Rather than performing a patellectomy or simply retaining the patellar osseous shell in these nine knees (eight patients), I performed a surgical procedure in which a tissue flap was secured to the patellar rim to contain cancellous bone graft inserted into the patellar bone defect. Final follow-up was at a mean of 36.7 months (range, twenty-four to fifty-five months) after the patellar bone-grafting procedure. RESULTS: The mean preoperative Knee Society scores for function and pain were 39 points (range, 18 to 82 points) and 40 points (range, 20 to 80 points), respectively. At the time of final follow-up, the Knee Society function and pain scores had improved significantly, to a mean function score of 91 points (range, 80 to 98 points) and a mean pain score of 84 points (range, 65 to 100 points) (p<0.05). The point of greatest patellar thickness measured intraoperatively ranged from 7 to 9 mm. Patellar thickness on immediate postoperative Merchant radiographs averaged 22 mm (range, 20 to 25 mm) whereas, at the time of final follow-up, patellar thickness averaged 19.7 mm (range, 17 to 22.5 mm). CONCLUSIONS: In contrast with other treatment alternatives, this surgical procedure imparts the potential for restoring patellar bone stock and may improve functional outcome by facilitating patellar tracking and improving quadriceps leverage. On the basis of satisfactory short-term to mid-term clinical results, this technique of patellar bone-grafting appears to be an important addition to the armamentarium of surgeons performing revision knee arthroplasties.     

全膝关节置换翻修术中骨缺损的处理

全膝关节翻修术中导致骨缺损的因素很多,包括松动假体的沉降、应力遮挡效应、假体周围骨溶解、坏死及感染等。对于骨缺损处理方法的选择,应综合考虑缺损区的大小及位置,患者的年龄、健康状况以及参与术后康复训练的能力等多方面因素。1骨缺损的分型骨缺损可分为包容性和非包容性骨缺损。包容性骨缺损周围仍有完整的骨皮质进行包绕,翻修时可通过颗粒骨植骨或骨水泥螺钉技术进行处理;而非包容性骨缺损周围的骨皮质部分会全部丧失,通常需要通过组培式垫块、结构性植骨、干骺端金属袖套或锥形套进行重建。     

Use of a trabecular metal patella for marked patella bone loss during revision total knee arthroplasty

This study evaluates the short-term results following patellar resurfacing with a trabecular metal patella shell in the setting of marked patellar bone loss at the time of revision total knee arthroplasty (TKA). Twenty consecutive patients undergoing revision TKA with the use of a trabecular metal patella were evaluated at a mean 23-month follow-up. All patients had marked patellar bone loss at surgery precluding resurfacing with a standard cemented patellar button. Results were good or excellent in 17 of 20 patients. There were no displacements of any trabecular metal patella shells, and the fixation appeared excellent despite the poor quality of bone remaining. Complications included 3 patients with polar patella fractures postoperatively. Qualitatively, these results compare favorably with patellar resection arthroplasty in this setting.     

Review article: Risk factors of infection following total knee arthroplasty

22 PubMed articles in English were identified using the key words: 'risk factors', 'infection', and 'primary total knee arthroplasty (TKA)'. The 10 most relevant articles were reviewed. In one study, obesity and diabetes were considered risk factors for infection following TKA. In another study, postoperative infection correlated with a history of open reduction and internal fixation, male gender, remnants of previous internal fixation material, and body mass index. In yet another study, the risk factors were (in decreasing order of significance): congestive heart failure, chronic pulmonary disease, preoperative anaemia, diabetes, depression, renal disease, pulmonary circulation disorders, obesity, rheumatologic disease, psychoses, metastatic tumour, peripheral vascular disease, and valvular disease.     

Management of acetabular bone loss in revision total hip arthroplasty

Most acetabular revisions can be managed with a hemispherical component with screw fixation. Areas of segmental bone loss that preclude acetabular component stability may be managed with structural allograft or second-generation porous metal augments. Acetabular cages have a limited application but can be a useful tool in the management of massive bone loss and pelvic discontinuity.     

The management of bone loss in revision total knee replacement

The management of bone loss in revision replacement of the knee remains a challenge despite an array of options available to the surgeon. Bone loss may occur as a result of the original disease, the design of the prosthesis, the mechanism of failure or technical error at initial surgery. The aim of revision surgery is to relieve pain and improve function while addressing the mechanism of failure in order to reconstruct a stable platform with transfer of load to the host bone. Methods of reconstruction include the use of cement, modular metal augmentation of prostheses, custom-made, tumour-type or hinged implants and bone grafting. The published results of the surgical techniques are summarised and a guide for the management of bone defects in revision surgery of the knee is presented.     

Morselized bone grafting of defects in revision total knee arthroplasty.

In a prospective, multicenter study evaluating one revision knee system, 33 of 409 patients underwent morselized bone grafting for tibial and femoral defects. Fifty-four percent of defects were bicondylar and the defect volumes averaged 36 cc3. There was no difference in preoperative or postoperative knee scores between patients undergoing morselized grafting and the entire group. Radiographic evaluation showed remodeling of the grafted areas consistent with viable incorporation of the graft. The incidence of radiolucent lines, at 2 years followup, was not different between the patients who received grafting and the patients who did not receive grafting. There have been no clinical failures or reoperations in the patients who received morselized bone grafting. Morselized bone grafting seems to offer a viable alternative in the reconstruction of osseous defects in patients undergoing revision total knee arthroplasty.     

Femoral bone grafting in primary and revision total knee arthroplasty.

The purpose of this study was to evaluate the clinical and radiographic results of TKA's with morsellized and solid femoral bone grafting. From April 1989 to February 1996, 6 primary and 18 revision TKA's with femoral bone grafting were performed in 22 patients with an average age of 62 years. Eleven knees were affected by rheumatoid arthritis, 10 by osteoarthritis, 2 by osteonecrosis and one by hemophiliac arthropathy. The femoral bone defects were large in 12, medium in 9, small in 3, contained in 10 and uncontained in 14 cases. Reconstruction was done with impacted morsellized fresh frozen trabecular bone grafts in 13 knees, with solid bone grafts in 7 knees and with combined grafts in 4 knees. Twenty-one cases were clinically evaluated at an average of 38 months (range: 9-89 months). The average Knee Society knee score increased by 39 points to 85 points at follow-up. The average functional score increased by 22 points to 48 points. Two cases with solid femoral bone grafts failed due to aseptic loosening. There were no infections. Radiographic follow-up revealed osteopenia around the femoral component in 10 knees. Two knees showed circumferential radiolucency around the femoral stem, and 5 knees had minor radiolucency at the anterior part of the femoral component. Radiographic incorporation was present in 5 of the 6 cases that could be evaluated. Histologic analysis of two biopsies revealed incorporation of the morsellized bone graft. The authors advocate impacted morsellized bone grafting for contained and small-to-medium uncontained femoral bone defects in combination with cemented TKA.     

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.