Cost-effectiveness analysis of custom total knee cutting blocks

The purposes of this study were to examine the cost-effectiveness of this technology and to determine improvements in patient outcome needed to make custom total knee cutting blocks cost-effective. A Markov decision model was used to evaluate the cost-effectiveness of custom cutting blocks compared with traditional instrumentation in total knee arthroplasty. The analysis demonstrates routine use of custom cutting blocks for total knee arthroplasty will not be cost-effective unless it results in a significantly reduced revision rate. The reduction necessary increases with increasing costs for the custom blocks. Further research will be necessary to determine if this can be achieved using custom cutting blocks. Patients, surgeons, payers, and institutions should consider this when determining their support of this technology in the absence of supportive data.     

Characterizing the motion of total knee replacements in laboratory tests

The purposes of determining the motion of a total knee replacement in vitro are to characterize the stability and laxity characteristics and to predict the kinematic behavior of the total knee replacement when implanted. With this information, different total knee replacement designs can be compared, the stability of the implanted knee replacement with and without the retention of ligaments can be assessed, and tests can be formulated to measure the wear and deformation of the materials, the strength of the components, and the fixation to the bone. Initially, different ways are described for characterizing the kinematics of the natural knee. We propose a rationale for the kinematic testing of total knee replacements in vitro using mechanical tests. One of the key questions is whether there is an objective method of measuring the kinematics of a total knee replacement in vitro, which will relate to or predict its behavior in vivo.     

Strategies for enhancing proprioception and neuromuscular control of the knee

Proprioception and neuromuscular control of the knee are compromised after ligament injury and must be regained if the athlete is to return to high level sports at a normal injury risk level. The anterior cruciate ligament deficient and reconstructed knee will be used as a model to describe differences in proprioception and neuromuscular control to those of an uninjured knee. The purpose of the current review is threefold. First, the basic science of proprioception and neuromuscular control specific to the knee will be summarized and reviewed. The review will include an overview of terminology, neurophysiology, and the effects of injury on the function of both lower limbs. Second, tools used for assessment and rehabilitation of proprioceptive deficits will be evaluated. Specific rehabilitation procedures that incorporate prophylactic conditioning that focus on transitioning the injured athlete back into sport will be presented. Finally, the literature with respect to gender variation in proprioception and neuromuscular control will be evaluated. The goal of the current review is to provide the clinician and the clinical scientist with sufficient background information for the development of quantitative methods to evaluate a patient's functional capacity and to assist in preventative, preoperative, and postoperative decision-making strategies.     

Version of the osteoarthritic knee

Version of normal and osteoarthritic knees is evaluated by computed tomography in this study. Version of the knee is defined as the static rotation of the tibia with respect to the femur in full knee extension. It is measured as the difference between the transverse axes of the femoral condyles and tibia. The average knee version, or external rotation of the tibia with respect to the femur across the normal knee, was 0°. Version of the osteoarthritic knee was 5°. Rotation of the tibia with respect to the femur across the extended osteoarthritic knee is a relationship that will affect the placement of components in total knee arthroplasty. This relationship should be addressed in alignment instrumentation and technique to avoid component malalignment in total knee arthroplasty.     

The Knee Society total knee arthroplasty roentgenographic evaluation and scoring system

A roentgenographic knee evaluation system endorsed by The Knee Society is included in this year's proceedings to encourage uniform reporting of the results of total knee arthroplasty. No rating system is ideal, but if many surgeons and centers use the same reporting system, then relative comparisons will at least become possible. Agreement on a new system by many experienced surgeons and institutions with a large clinical volume represents a sacrifice because old rating system data will have to be discarded.     

Orthopedic management of spina bifida. Part I: hip, knee, and rotational deformities

Children with spina bifida develop a wide variety of congenital and acquired orthopedic deformities. Among these are hip deformities such as contracture, subluxation, or dislocation. Patients may also have problems with the knee joint, such as knee flexion or extension contracture, knee valgus deformity, or late knee instability and pain. In addition, rotational deformities of the lower extremities, either internal or external torsion, are common as well. This paper will review both the overall orthopedic care of a patient with spina bifida and provide a focused review of the diagnosis and management of the above deformities. In addition, this paper will review the incidence, etiology, classification, and prognosis of spina bifida. The use of gait analysis and orthoses will be covered as well. The forthcoming Part II will cover foot and ankle deformities in spina bifida.     

Excision of the cruciate ligaments in total knee replacement

The cruciate ligaments (and the intercondylar eminence of the tibia) should be removed when the knee is replaced. A mechanically unlinked prosthesis can be designed which will then be capable of restoring "cruciate" stability, i.e., anteroposterior stability of the tibia in the flexed knee. A knee replaced with such a prosthesis will only be stable if the prosthesis is inserted using the correct instruments and technique. Stability depends as much on precise surgical technique as it does on prosthetic design.     

The Knee Clinical Assessment Study – CAS(K). A prospective study of knee pain and knee osteoarthritis in the general population

Background

Knee pain affects an estimated 25% of the adult population aged 50 years and over. Osteoarthritis is the most common diagnosis made in older adults consulting with knee pain in primary care. However, the relationship between this diagnosis and both the current disease-based definition of osteoarthritis and the regional pain syndrome of knee pain and disability is unclear. Expert consensus, based on current evidence, views the disease and the syndrome as distinct entities but the clinical usefulness of these two approaches to classifying knee pain in older adults has not been established. We plan to conduct a prospective, population-based, observational cohort study to investigate the relative merits of disease-based and regional pain syndrome-based approaches to classification and prognosis of knee pain in older adults.

Methods

All patients aged 50 years and over registered with three general practices in North Staffordshire will be invited to take part in a two-stage postal survey. Respondents to this survey phase who indicate that they have experienced knee pain within the previous 12 months will be invited to attend a research clinic for a detailed assessment. This will consist of clinical interview, physical examination, digital photography, plain x-rays, anthropometric measurement and a brief self-complete questionnaire. All consenting clinic attenders will be followed up by (i) general practice medical record review, (ii) repeat postal questionnaire at 18-months.     

Editorial Commentary: Radiographic Measurements of Knee Joint Space Are Inadequate for Demonstrating Chondral Restoration

Orthopaedic advancements into the 21st century will increasingly focus on chondral restoration to either halt or reverse degenerative processes. Researchers and clinicians will need tools beyond patient-reported outcomes to measure the effectiveness of these treatment efforts. The use of joint space width (JSW) as a surrogate for chondral restoration is inadequate. At a minimum, such observations must standardize load transmission across the joint to be useful. Simple, readily available, standardized, and clinically useful measures of knee chondral restoration would facilitate and accelerate advances in the field. For now, it may be that improvement in JSW after chondral restoration could be attributable to changes in mechanical alignment of the knee and not the chondral restoration. JSW is an inadequate surrogate for chondral restoration, and anyone doing a stress radiograph of a unicompartmental degenerative knee recognizes this point.     

Changes in in vivo knee loading with a variable‐stiffness intervention shoe correlate with changes in the knee adduction moment

External knee adduction moment can be reduced using footwear interventions, but the exact changes in in vivo medial joint loading remain unknown. An instrumented knee replacement was used to assess changes in in vivo medial joint loading in a single patient walking with a variable‐stiffness intervention shoe. We hypothesized that during walking with a load modifying variable‐stiffness shoe intervention: (1) the first peak knee adduction moment will be reduced compared to a subject's personal shoes; (2) the first peak in vivo medial contact force will be reduced compared to personal shoes; and (3) the reduction in knee adduction moment will be correlated with the reduction in medial contact force. The instrumentation included a motion capture system, force plate, and the instrumented knee prosthesis. The intervention shoe reduced the first peak knee adduction moment (13.3%, p = 0.011) and medial compartment joint contact force (12.3%; p = 0.008) compared to the personal shoe. The change in first peak knee adduction moment was significantly correlated with the change in first peak medial contact force (R² = 0.67, p = 0.007). Thus, for a single subject with a total knee prosthesis the variable‐stiffness shoe reduces loading on the affected compartment of the joint. The reductions in the external knee adduction moment are indicative of reductions in in vivo medial compressive force with this intervention. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1548–1553, 2010     

A physiotherapist-delivered integrated exercise and pain coping skills training intervention for individuals with knee osteoarthritis: a randomised controlled trial protocol

ABSTRACT: BACKGROUND: Knee osteoarthritis (OA) is a prevalent chronic musculoskeletal condition with no cure. Pain is the primary symptom and results from a complex interaction between structural changes, physical impairments and psychological factors. Much evidence supports the use of strengthening exercises to improve pain and physical function in this patient population. There is also a growing body of research examining the effects of psychologist-delivered pain coping skills training (PCST) in improving pain and psychological impairments particularly in other chronic pain conditions. Though typically provided separately, there are resource and personnel advantages of exercise and PCST being delivered together by a single healthcare professional. Physiotherapists are a logical choice to be trained to deliver a PCST intervention as they already have expertise in administering exercise for knee OA and are cognizant of the need for a biopsychosocial approach to management. No studies to date have examined the effects of an integrated exercise and PCST program delivered solely by physiotherapists in this population. The aim of this randomised controlled trial is to investigate whether an integrated 12-week PCST and exercise treatment program delivered by physiotherapists is more efficacious than either program alone in treating pain and physical function in individuals with knee OA. METHODS: This will be an assessor-blinded, 3-arm randomised controlled trial of a 12-week intervention involving 10 physiotherapy visits together with home practice. Participants with symptomatic and radiographic knee OA will be recruited. Participants will be randomised into one of three groups: exercise alone, PCST alone, or integrated PCST and exercise. Primary outcomes will be pain measured by a Visual Analogue Scale (VAS) and physical function measured by the Western Ontario and McMaster Universities Osteoarthritis Index subscale. Measurements will be taken at baseline and immediately following the intervention (12 weeks) as well as at 32 weeks and 52 weeks to examine maintenance of any intervention effects. Specific assessment of adherence to the treatment program will also be made at weeks 22 and 42. The study will be conducted at two sites, Melbourne and Brisbane, Australia to facilitate generalizabilty of the results and to ensure timely recruitment. CONCLUSION: The findings from this randomised controlled trial will provide evidence for the efficacy of an integrated PCST and exercise program delivered by physiotherapists in the management of painful and functionally limiting knee OA. The trial design will conform to CONSORT requirements for non-pharmacological treatment. Trial Registration: Australian New Zealand Clinical Trials Registry reference number: ACTRN12610000533099.     

Arthritis and osteotomies in anterior cruciate ligament reconstruction

Unfortunately, young patients with active life-styles who present with an ACL-deficient knee and early evidence of arthritis remain a very difficult population to treat. Arthroscopic ACL reconstruction is a proven and effective way to treat patients with anterior knee instability [2]. In addition, numerous authors have demonstrated that knee osteotomies are effective in addressing isolated medial or lateral compartment degenerative disease, even in the presence of anterior knee instability [7, 9, 22, 43]. A comprehensive evaluation of pain, alignment, and stability are necessary in order to formulate the best treatment plan for each patient. Patients with combined chronic instability secondary to ACL insufficiency and unicompartmental arthritis will generally benefit from arthroscopic debridement, ACL reconstruction, knee osteotomy, or any combination thereof. Expectations of patients should be managed according to their underlying pathology, and this is a critical component for the success of the surgery. Most patients will get some degree of symptomatic relief and functional improvement. A return to competitive or high-level sports is an unrealistic goal, however, and should be discouraged.     

Entwicklung, Terminologie, Prinzipien und Kontroversen bei der minimal-invasiven Knieendoprothetik

Minimally invasive total knee arthroplasty is a logical and further improvement of the good results achieved with minimally invasive unicondylar knee arthroplasty. The terminology for minimally invasive surgery (MIS) is confusing and comparison of different techniques is therefore difficult. A simple separation between less invasive and minimally invasive techniques will be presented. Besides the approach, minimally invasive surgical principles are very important. MIS in total knee arthroplasty is discussed very controversially at the moment. The preliminary results of these new techniques are very promising. Up to now there is much more feeling then knowing. Important questions (risk-benefit analysis, which technique for which patient and surgeon, education and cost-effectiveness) must be addressed by the proponents of this MIS technique. Step by step learning of these new techniques (evolution instead of revolution) in specific education centres is strongly recommended. Ultimately, patients and surgeons will have to decide whether these new techniques will only be a modern trend or represent the future.     

Avoiding instability: The features that matter

When replacing the human knee, we attempt to reproduce the stability of the normal knee so that the patient perceives the knee arthroplasty to feel and function similar to a normal knee. Avoiding instability requires understanding the definition and implication of stability to the implant design features and the arthroplasty procedure. The purpose of this paper is to define the elements of stability in total knee arthroplasty and to explain the mechanics of the knee that will translate to optimal knee stability after TKA.     

Is above knee bypass defunct?

As endovascular treatments improve, the inevitable progress will result in the abandonment of conventional bypasses. First and foremost in this regard is the use of above knee bypass, particularly with prosthetic graft material. Already, endovascular success approaches or exceeds the patency seen with this bypass technique. As a result, in centers with endovascular expertise in infrainguinal intervention, bypass surgery is increasingly being replaced by these techniques and conventional bypass surgery is disappearing. Over the next few years, above knee bypass will be replaced by endovascular techniques in most centers as our results with these techniques improve.     

Is hydroxyapatite a reliable fixation option in unicompartmental knee arthroplasty? A 5- to 13-year experience with the hydroxyapatite-coated unix prosthesis

Hydroxyapatite-coated unicompartmental knee arthroplasty (UKA) is a debatable approach to unicompartmental knee arthritis because UKA isoften viewed as a short-term solution, at best, fora condition that will eventually require a total knee arthroplasty (TKA). Unicompartmental knee arthroplasty is a more technically demanding procedure than TKA, and appropriate patient selection, careful surgical technique, and correct choice of implant geometry are all critical components to its success. A fundamental issue surrounding UKA is whether hydroxyapatite-coated unicompartmental components can provide a long-term solution to unicondylar arthritis. We address this issue in the current study, which is based on a prospective series of 125 hydroxyapatite-coated Unix knee prostheses implanted consecutively between 1994 and 2002, with a 5-year minimum follow-up and a 13-year maximum follow-up. The results of our study indicate that uncemented hydroxyapatite-coated UKA can be successful in the long term.     

膝关节骨关节炎的基础研究进展

膝关节骨性关节炎(knee osteoarthritis,KOA)的确切病因和发病机制仍不太清楚,尚无法从根本上阻止和治疗骨性关节炎。随着治疗新方法、新技术的不断出现,有望在不久的将来可改变治疗膝关节骨关节炎的现状。而膝关节骨关节炎的基础研究将有助于发病机制的阐明和治疗方法的深入探索。本文广泛查阅近年来关于膝关节骨关节炎基础研究的文献,并对其进行总结与分析。     

全膝关节置换术后伸膝装置受损治疗的研究现状

全膝关节置换术后伸膝装置破坏是一种罕见但具有毁灭性的并发症,经股骨截肢被认为是膝关节置换术失败的最后治疗选择,严重影响患者生活质量.目前对于全膝关节置换术后伸膝装置破坏已有多种治疗方法,但并没有文献进行系统的评价.因此本文总结全膝关节置换术后伸膝装置受损治疗的相关文献,从全膝关节置换术后伸膝装置破坏的研究现状、治疗具体...     

膝关节单髁置换术下肢力线纠正及假体位置角度研究进展

下肢力线与单髁假体位置角度是影响单髁置换术假体长期生存率及临床疗效的重要因素。下肢力线矫正不足将加速假体磨损进而减少假体生存率,下肢力线矫正过度会加速对侧间室关节炎的进展。通常认为单髁置换术下肢力线应纠正轻度内翻,然而部分学者的研究认为术后下肢力线对单髁置换术后功能评分和假体生存率无影响。股骨、胫骨假体位置不佳将造成患者膝关节不明原因疼痛甚至假体磨损,但股骨胫骨假体最佳位置存在争议。通常认为单髁置换术胫骨平台后倾角应纠正在3°~7°,但部分学者认为胫骨平台后倾角的改变过大也将影响膝关节间隙平衡及膝关节活动度。本文研究认为单髁置换术下肢力线的纠正至轻度内翻仍是单髁置换术最佳下肢力线,股骨与胫骨假体最佳位置有待进一步生物力学研究证实,胫骨平台后倾角的纠正应该根据术前患者具体原始解剖角度而变化。     

Osteotomie bei Zugängen zum Kniegelenk

The present article summarizes the different osteotomy techniques for an extension of standard surgical approaches to the knee joint in selected patients. The aim is to achieve satisfactory exposure and reduce potential postoperative complications compared to alternative techniques, such as the V-Y plasty or the quadriceps snip procedures. Osteotomy of the tibial tubercle is a reasonable extension of the anteromedial or the anterolateral surgical approach in selected patients undergoing revision total knee replacement. This osteotomy will provide excellent surgical exposure of the knee without the risk of avulsion of the patellar tendon and will preserve the blood supply of the patella and the surrounding soft tissue. Moreover, functional clinical outcome will be improved by minimizing damage to the extensor mechanism. Osteotomy of the lateral femoral condyle gives excellent exposure of the posterolateral aspect of the knee joint which might be necessary in some patients with fractures of the posterolateral tibial plateau as well as patients undergoing open allograft transplantation of the lateral meniscus. An alternative option for an extended exposure to the posterolateral knee joint is accomplished by osteotomy or partial resection of the fibular head which is also described as having good clinical results and a low complication rate.