摘要:

Biological resurfacing of articular cartilage lesions is an exciting field. Advances in understanding the biology of articular cartilage in health and disease, and the development of new techniques in repair, regeneration, and replacement of articular cartilage have led to the application of new therapies. These therapies can be classified into reparative therapies and restorative therapies. In reparative therapies, tissue that can function as an articular surface but that is not histologically equivalent to hyaline articular cartilage is regenerated. In restorative therapies, mature hyaline cartilage is implanted into a chondral lesion. The most common clinically relevant cartilage resurfacing techniques presently in use include microfracture, autologous chondrocyte implantation (ACI), autologous osteochondral transfer (OATS or mosaicplasty), and osteochondral allograft transplantation. Although the indications for each technique differ, published clinical outcomes are generally similar. In addition, many experimental therapeutic options for articular cartilage defects are presently being investigated and are likely to be introduced into clinical practice in the near future.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Isolated degenerative arthritis of a single compartment within the knee, particularly the medial compartment, represents a significant treatment challenge in orthopedic practice. Once the diagnosis of isolated compartmental arthritis has been established, and all conservative treatment measures have failed to provide adequate relief of symptoms, surgery becomes a consideration. The goals of tibial osteotomy in the treatment of unicompartmental arthritis would be to significantly diminish pain and improve knee joint function and alignment, while preserving the patients' natural articular anatomy. Since initially introduced by Jackson in 1958 and later popularized by the work of Coventry, the high tibial osteotomy has been the source of many debates within the literature. The debates center not only on the indications for the procedure, but also on the technique of performing the osteotomy that would be most likely to produce the best outcome. The longer term data supporting the most tested standard techniques using uniplanar and biplanar osteotomy in conjunction with internal fixation or casting are available and continually being updated. Longer follow-up has helped to define the expectation of the procedure, as well as critical issues associated with converting a high tibial osteotomy to a total knee replacement. Newer techniques with shorter term follow-up data have clearly provided innovation by suggesting less invasive surgical methods, more rigid fixation, accelerated rehabilitation, and perhaps improved accuracy of angular correction. The purpose of this review is to address the question of whether these newer techniques will produce improved outcomes as defined both as pain free functional knees and as transition to total knee arthroplasty.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The new recent emphasis in cost containment and the introduction of minimally invasive techniques have brought back unicondylar knee arthroplasty. Many surgeons now perform the unicondylar arthroplasty through a small arthrotomy, abandoning the full parapatellar approach. With this technique, the patella is not dislocated, and there may be fewer extensor mechanism problems. Postoperative rehabilitation is markedly improved. There is also a significant cost savings because patients are discharged home earlier. One of the biggest drawbacks of the minimally invasive approach to unicondylar arthroplasties involves the revision procedure. The skin around the knee is extremely sensitive to multiple approaches and a surgeon revising a unicompartmental total knee replacement might have significant trouble incorporating the incision from the minimally invasive unicondylar arthroplasty in the revision procedure. Although this is an exciting time for the development of this procedure, the consequences of the approach, its long-term success with avoidance of complications, and the subsequent outcome of revision surgery remains to be determined.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The emergence of the mobile-bearing articulating polyethylene surfaces in total knee arthroplasty reflects designers' efforts to optimize wear while dealing with complex function.In vivodynamic video fluoroscopy has provided extensive knowledge of the precise articulation mechanisms in total knee arthroplasty. The convergence of kinematic data with the analysis of prosthetic retrievals from failed total knees has given a clear understanding of the functional requirements for improved mobile-bearing total knee devices. Design issues include femoral condyle geometry, single versus polycentric radius of curvature, devices that restrict certain bearing motions and disarticulation such as stops or pegs, a medial versus more central longitudinal axis of rotation on the proximal tibia, surgical technique, implant stability, contact area, and patellofemoral design. The question of posterior cruciate retention, sacrifice, or stabilization regarding mobile bearing designs is discussed. Current mobile bearing designs are reviewed with available technical information.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

This review deals with the pros and cons of using fixed or mobile bearing designs in the treatment of the young active patient. The risk of failure after total knee arthroplasty (TKA) in younger patients has not been fully defined but does not appear to be as high as that in total hip arthroplasty. Osteolysis is still a concern but is much lower in cemented TKA designs. Younger, more active patients may demand better function than is currently possible with fixed bearing designs. Mobile bearing TKA offers the advantages of increased conformity and greater mobility. This theoretically translates into improved function and range of motion and reduced stresses and wear. Although mobile bearing TKA designs have demonstrated survival rates comparable to successful fixed bearing designs, no conclusive evidence has been presented to support improved function and/or range of motion. Evidence of reduced wear has been reported, but the issue of undersurface wear has yet to be fully addressed. The potential that mobile bearing designs could be successfully used in younger more demanding patients has therefore not been realized. Currently, there is no overwhelming evidence available to favor either fixed or mobile bearing designs in this patient population.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Secure fixation of components to bone is necessary for the long-term durability of total knee arthroplasty. Stereophotogrammetric and biomechanical studies have shown that cemented tibial components provide for the least amount of subsidence. The medium term results (5–10 years) of a variety of cementless total knee components have shown a higher rate of failure than cemented components. However, certain designs of cementless total knee components are relatively successful and have fewer complications.Retrospective studies comparing cementless with cemented total knee arthroplasty have shown a significantly higher rate of femoral and tibial component loosening and osteolysis. A prospective randomized study of cementless versus cemented components demonstrated no advantage to the more expensive cementless components. The gold standard for total knee arthroplasty in 2001 remains a cemented tricompartmental arthroplasty.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Tibial femoral instability is a common cause of early or late failure of total knee prostheses. Instability may be related to unbalanced ligaments, improper alignment, component malposition, or faulty component design. A patient with an unstable total knee prosthesis may present with pain, giving way, or other mechanical symptoms. The instability may be subtle or may lead to complete dislocation of the tibiofemoral articulation. Several large revision series document instability as the cause of failure and the reason for revision in 10 to 22% of cases. However, detailed analysis of this subset of patients is lacking in these studies. This review examines the causes of total knee instability and presents guidelines for its prevention and treatment.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Evaluation of the painful knee arthroplasty requires a careful history and examination with judicious use of laboratory tests, aspiration of joint fluid for synovial fluid analysis and culture testing, and occasional use of radionuclide imaging tests. The investigative process requires differentiation of the potential extrinsic and intrinsic causes of knee pain. Classification of intrinsic sources of knee pain into aseptic loosening, infection, instability, impingement, wear debris, and miscellaneous categories facilitates the evaluation process. Use of an algorithm to proceed through the process of selecting appropriate testing modalities is helpful. Newer technologies hold promise for differentiating certain entities such as infection or polyethylene wear.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Uncemented fixation of the femur has become widely accepted as an excellent option for select groups of patients requiring total hip arthroplasty. This article reviews recent clinical series, animal studies, and basic science research on cementless femoral components. Despite clear biomechanical differences between chromium cobalt and titanium implants, clinical superiority of one over the other has not been demonstrated. The optimal type and extent of surface enhancement is also not known, although it has been universally accepted that noncircumferential coatings lead to early failure by promoting distal femoral particulate wear. High rates of bone ingrowth and excellent clinical results are reported for femoral components with a wide variety of geometries, despite differences in stress shielding and periprosthetic bone remodeling. Cementless femoral implant characteristics have evolved to address earlier shortcomings that caused unacceptable rates of loosening and thigh pain. However, long-term polyethylene wear and associated osteolysis remains problematic.

ISSN:1041-9918    

出版商:OVID    

年代:2001

数据来源: OVID