NIH Consensus Statement on Total Knee Replacement December 8-10, 2003*:

Midterm results with the PFC Sigma total knee arthroplasty system

We prospectively studied 207 consecutive patients (284 knees) undergoing total knee arthroplasty (June 1996 to December 1997) with a cemented tricompartmental Sigma PFC (DePuy Orthopaedics, Warsaw, Ind) total knee arthroplasty via a standard procedure (median follow-up, 87 months). Cruciate-retaining (272 knees, 96%) and cruciate-substituting (12, 4%) implants were used. There was one revision secondary to a ligament disruption after a fall. No implants were radiographically loose or at risk for loosening. Radiolucencies (none>2 mm or progressive) were shown on anteroposterior (7% of medial tibias) and lateral (17% of posterior femora) radiographs. Knee Society pain scores improved significantly (preoperative median, 20 points; postoperative median, 50 points [P<.001]). The PFC Sigma Knee system has excellent midterm durability.

What patient and surgical factors contribute to implant wear and osteolysis in total joint arthroplasty?

Total joint arthroplasty has been a successful operation for decades. Our current patients are younger and more active than those in the past. They place higher demands on themselves and have expectations commensurate with their lifestyles. Time-limited longevity with the large number of anticipated total joint replacement procedures and their potential burden to health care is a growing concern. In the past two decades, implant wear and osteolysis have been identified as major causes for the failure of otherwise well-functioning implants. Osteolysis can be divided into several categories: patient-specific, implant-specific, and the result of surgical factors. Although these categories are interrelated and not mutually exclusive, they enable us to build a framework in which to further advance our understanding of osteolysis and apply this information in a clinically relevant manner.

Assessing recovery and establishing prognosis following total knee arthroplasty

BACKGROUND AND PURPOSE

Information about expected rate of change after arthroplasty is critical for making prognostic decisions related to rehabilitation. The goals of this study were: (1) to describe the pattern of change in lower-extremity functional status of patients over a 1-year period after total knee arthroplasty (TKA) and (2) to describe the effect of preoperative functional status on change over time.

SUBJECTS

Eighty-four patients (44 female, 40 male) with osteoarthritis, mean age of 66 years (SD=9), participated.

METHODS

Repeated measurements for the Lower Extremity Functional Scale (LEFS) and the Six-Minute Walk Test (6MWT) were taken over a 1-year period. Data were plotted to examine the pattern of change over time. Different models of recovery were explored using nonlinear mixed-effects modeling that accounted for preoperative status and gender.

RESULTS

Growth curves were generated that depict the rate and amount of change in LEFS scores and 6MWT distances up to 1 year following TKA. The curves account for preoperative status and gender differences across participants.

DISCUSSION AND CONCLUSION

The greatest improvement occurred in the first 12 weeks after TKA. Slower improvement continued to occur from 12 weeks to 26 weeks after TKA, and little improvement occurred beyond 26 weeks after TKA. The findings can be used by physical therapists to make prognostic judgments related to the expected rate of improvement following TKA and the total amount of improvement that may be expected.

OARSI recommendations for the management of hip and knee osteoarthritis, part I: critical appraisal of existing treatment guidelines and systematic review of current research evidence

PURPOSE

As a prelude to developing updated, evidence-based, international consensus recommendations for the management of hip and knee osteoarthritis (OA), the Osteoarthritis Research Society International (OARSI) Treatment Guidelines Committee undertook a critical appraisal of published guidelines and a systematic review (SR) of more recent evidence for relevant therapies.

METHODS

Sixteen experts from four medical disciplines (primary care two, rheumatology 11, orthopaedics one and evidence-based medicine two), two continents and six countries (USA, UK, France, Netherlands, Sweden and Canada) formed the guidelines development team. Three additional experts were invited to take part in the critical appraisal of existing guidelines in languages other than English. MEDLINE, EMBASE, Science Citation Index, CINAHL, AMED, Cochrane Library, seven Guidelines Websites and Google were searched systematically to identify guidelines for the management of hip and/or knee OA. Guidelines which met the inclusion/exclusion criteria were assigned to four groups of four appraisers. The quality of the guidelines was assessed using the AGREE (Appraisal of Guidelines for Research and Evaluation) instrument and standardised percent scores (0-100%) for scope, stakeholder involvement, rigour, clarity, applicability and editorial independence, as well as overall quality, were calculated. Treatment modalities addressed and recommended by the guidelines were summarised. Agreement (%) was estimated and the best level of evidence to support each recommendation was extracted. Evidence for each treatment modality was updated from the date of the last SR in January 2002 to January 2006. The quality of evidence was evaluated using the Oxman and Guyatt, and Jadad scales for SRs and randomised controlled trials (RCTs), respectively. Where possible, effect size (ES), number needed to treat, relative risk (RR) or odds ratio and cost per quality-adjusted life year gained (QALY) were estimated.

RESULTS

Twenty-three of 1462 guidelines or consensus statements retrieved from the literature search met the inclusion/exclusion criteria. Six were predominantly based on expert opinion, five were primarily evidence based and 12 were based on both. Overall quality scores were 28%, 41% and 51% for opinion-based, evidence-based and hybrid guidelines, respectively (P=0.001). Scores for aspects of quality varied from 18% for applicability to 67% for scope. Thirteen guidelines had been developed for specific care settings including five for primary care (e.g., Prodigy Guidance), three for rheumatology (e.g., European League against Rheumatism recommendations), three for physiotherapy (e.g., Dutch clinical practice guidelines for physical therapy) and two for orthopaedics (e.g., National Institutes of Health consensus guidelines), whereas 10 did not specify the target users (e.g., Ontario guidelines for optimal therapy). Whilst 14 guidelines did not separate hip and knee, eight were specific for knee but only one for hip. Fifty-one different treatment modalities were addressed by these guidelines, but only 20 were universally recommended. Evidence to support these modalities ranged from Ia (meta-analysis/SR of RCTs) to IV (expert opinion). The efficacy of some modalities of therapy was confirmed by the results of RCTs published between January 2002 and 2006. These included exercise (strengthening ES 0.32, 95% confidence interval (CI) 0.23, 0.42, aerobic ES 0.52, 95% CI 0.34, 0.70 and water-based ES 0.25, 95% CI 0.02, 0.47) and nonsteroidal anti-inflammatory drugs (NSAIDs) (ES 0.32, 95% CI 0.24, 0.39). Examples of other treatment modalities where recent trials failed to confirm efficacy included ultrasound (ES 0.06, 95% CI -0.39, 0.52), massage (ES 0.10, 95% CI -0.23, 0.43) and heat/ice therapy (ES 0.69, 95% CI -0.07, 1.45). The updated evidence on adverse effects also varied from treatment to treatment. For example, while the evidence for gastrointestinal (GI) toxicity of non-selective NSAIDs (RR=5.36, 95% CI 1.79, 16.10) and for increased risk of myocardial infarction associated with rofecoxib (RR=2.24, 95% CI 1.24, 4.02) were reinforced, evidence for other potential drug related adverse events such as GI toxicity with acetaminophen or myocardial infarction with celecoxib remained inconclusive.

CONCLUSION

Twenty-three guidelines have been developed for the treatment of hip and/or knee OA, based on opinion alone, research evidence or both. Twenty of 51 modalities of therapy are universally recommended by these guidelines. Although this suggests that a core set of recommendations for treatment exists, critical appraisal shows that the overall quality of existing guidelines is sub-optimal, and consensus recommendations are not always supported by the best available evidence. Guidelines of optimal quality are most likely to be achieved by combining research evidence with expert consensus and by paying due attention to issues such as editorial independence, stakeholder involvement and applicability. This review of existing guidelines provides support for the development of new guidelines cognisant of the limitations in existing guidelines. Recommendations should be revised regularly following SR of new research evidence as this becomes available.

The 2007 ABJS Marshall Urist Award: The impact of direct-to-consumer advertising in orthopaedics

Direct-to-consumer advertising (DTCA) has become an influential factor in healthcare delivery in the United States. We evaluated the influence of DTCA on surgeon and patient opinions and behavior in orthopaedics by surveying orthopaedic surgeons who perform hip and knee arthroplasties and patients who were scheduled to have hip or knee arthro-plasty. Respondents were asked for their opinions of and experiences with DTCA, including the influence of DTCA on surgeon and patient decision making. Greater than 98% of surgeon respondents had experience with patients who were exposed to DTCA. The majority of surgeon respondents reported DTCA had an overall negative impact on their practice and their interaction with patients (74%), and their patients often were confused or misinformed about the appropriate treatment for their condition based on an advertisement (77%). Fifty-two percent of patient respondents recalled seeing or hearing advertisements related to hip or knee arthroplasty. These patients were more likely to request a specific type of surgery or brand of implant from their surgeon and to see more than one surgeon before deciding to have surgery. Direct-to-consumer advertising seems to play a substantial role in surgeon and patient decision making in orthopaedics. Future efforts should be aimed at improving the quality and accuracy of information contained in consumer-directed advertisements related to orthopaedic implants and procedures.

Balancing Modern Medical Benefits And Risks

The changing landscape of medical benefits and risks creates new challenges for all stakeholders in health care. We offer examples of different medical interventions to help illustrate the complexity and diversity of considerations that define the trade-offs between benefits and risks for each patient. As more information becomes available at all stages of a product's life cycle, the Food and Drug Administration (FDA) needs to play a central role as an authoritative voice in communicating drugs' benefits and risks and must have the resources to perform the functions necessary to keep pace with this accelerating rate of change.

Engineering long term clinical success of advanced ceramic prostheses

Biocompatability and, in some applications, esthetics make all-ceramic prostheses compelling choices but despite significant improvements in materials properties and toughening mechanisms, these still have significant failure rates. Factors that contribute to the degradation in strength and survival include material selection and prosthesis design which set the upper limit for performance. However, fabrication operations introduce damage that can be exacerbated by environmental conditions and clinical function. Using all-ceramic dental crowns as an example, experimentally derived models provide insight into the relationships between materials properties and initial critical loads to failure. Analysis of fabrication operations suggests strategies to minimize damage. Environmental conditions can create viscoplastic flow of supporting components which can contribute additional stress within the prosthesis. Fatigue is a particularly challenging problem, not only providing the energy to propagate existing damage but, when combined with the wet environment, can create new damage modes. While much is known, the influence of these new damage modes has not been completely elucidated. The role of complex prosthesis geometry and its interaction with other factors on damage initiation and propagation has yet to be well characterized.

Quadriceps sparing total knee replacement. The initial experience with results at two to four years

The aim of this study was to compare the results in patients having a quadriceps sparing total knee replacement (TKR) with those undergoing a standard TKR at a minimum follow-up of two years. All patients who had a TKR with a high-flex posterior-stabilised prosthesis prior to December 2002 were reviewed retrospectively. There were 57 patients available for follow-up. Those with a quadriceps sparing TKR had less pain peri-operatively with a greater degree of flexion at all the post-operative visits and at the final follow-up, but their operations took longer, with less accurate radiological alignment. There was no difference in the complications and in the Knee Society scores between the two groups at the final follow-up. Total knee replacement through a quadriceps sparing approach has some peri-operative advantages over the standard incision. At a minimum follow-up of two years the clinical results were similar to those with a standard incision, but the radiological outcomes of the quadriceps sparing group were inferior.

A pilot study on continuous femoral perineural catheter for analgesia after total knee arthroplasty: the effect on physical rehabilitation and outcomes

Two techniques of postoperative analgesia for primary total knee arthroplasty were compared retrospectively. Twenty-four patients received a femoral nerve catheter with continuous infusion of ropivacaine (FNC group), whereas 26 patients received intravenous (IV) opioids (IV opioid group). Pain and rehabilitation scores and hospital length of stay (LOS) were compared. On the first postoperative day, both groups reported similar pain scores. After 4 sessions of twice-daily rehabilitation, the FNC group used less IV patient-controlled opioids (29.1% vs 84.5%, P = .0001) and demonstrated better performance with knee flexion and mobility. Hospital LOS was significantly less in the FNC group (3.6 vs 4.2 days, P = .034). Femoral nerve catheters with continuous infusion of ropivacaine provide satisfactory analgesia, improve rehabilitation, and shorten hospital LOS.

Pilot study of methods to document quantity and variation of independent patient exercise and activity after total knee arthroplasty

Variation in patients' independent exercise and activity after total knee arthroplasty (TKA) surgery may contribute to variable functional gains but have never been quantified. We pilot tested daily exercise logs and step activity monitors to quantify exercise and general home activity post-TKA. Patients successfully maintained logs and wore activity monitors. Logs documented significant variation in quantity of daily exercises. Women with poor emotional health recorded fewer repetitions and greater variation. More daily exercise repetitions correlated with larger 6-month functional improvement. Activity peaks on step monitors correlated with logged exercise sessions. However, most step activity was in addition to exercise sessions. Further research is needed to validate these findings and to clarify the relationship among post-TKA exercise, activity, and functional gain.

The increasing financial burden of knee revision surgery in the United States

The popularity of total knee arthroplasty combined with the aging US population indicates a dramatic increase in revision TKA procedures. Our objective was to project revision surgery costs in the United States, and to estimate the financial burden for hospitals historically under-reimbursed for these complex surgical procedures. Inflation adjusted charge data derived from a series of knee revision surgeries performed by a single surgeon practice (CJL) (n = 100) were applied to population projections of the number of revision surgeries expected for the Medicare population from 2005-2030. The average charge of TKA revision surgery was 73,696 dollars, (Cost was 36,848 dollars) with substantially higher costs for patients undergoing surgery because of deep joint infection, patients receiving a three component exchange, and patients receiving hinged or constrained condylar knee implants. The number of revision procedures is expected to increase from 37,544 in 2005 to 56,918 in 2030. Projected hospital costs for these procedures may exceed 2 billion dollars by 2030. The number of revision knee surgeries may increase by 66% in the next 25 years. Reimbursement rates will not cover hospital costs for this procedure despite recent increases in Medicare payments for revision arthroplasty.

LEVEL OF EVIDENCE

Economic analysis study, level III. See the Guidelines for Authors for a complete description of levels of evidence.

Renewal of surgical quality and safety initiatives: a multispecialty challenge

The quality and safety movement in surgical specialty practice is gaining momentum. On the basis of risk-adjusted outcomes of coronary artery surgery and the improved risk assessment in the Veterans Affairs system, a growing array of surgical specialists has focused on recognition of legitimate risk factors, identification of performance measures that are valid surrogates for better practices, and refinement of risk-adjusted outcomes. Recognition of educational needs, personal practice patterns, and systems deficiencies now permits a broad-based application of long-standing primarily medical issues to elective surgical procedures in an organized and Integrated fashion. Approximately 85,000 patients per day undergo elective operations in the United States. A platform based on physician involvement and leadership has been tested in the Surgical Care Improvement Project, funded by a subcontract from the Centers for Medicare and Medicaid Services. This effort has defined factors worthy of further verification and provides a framework for an ethical and valid pay-for-performance scheme.

Stem-cell-driven regeneration of synovial joints

Mammalian skeletal motion is made possible by synovial joints. Widespread suffering from arthritis and joint injuries has motivated recent effort to regenerate a stem-cell-driven synovial joint condyle implantable in total joint replacement. A single adult stem cell lineage, mesenchymal stem cells, differentiate to form all components of a synovial joint. Whereas localized joint lesions may be repaired by either cell-based or cell-free approaches, regeneration of the entire articular condyle of the synovial joint is unattainable without tissue-forming cells. A series of experiments are presented here to describe our initial attempts to regenerate a synovial joint condyle in the shape and dimensions of a human mandibular condyle, with both cartilaginous and osseous components derived from a single population of rat mesenchymal stem cells. Upcoming challenges are along several intertwining fronts including structural integrity, tissue maturation, mechanical strength and host integration. The synovial joint condyle may turn out to be one of the first 'human body parts' or organs truly regeneratable by stem-cell-derived approaches. Current approaches to regenerate the synovial joint condyle from stem-cell-derived multiple cell lineages may also offer clues for engineering complex organs such as the kidney or liver.

Osteoarthritis - an untreatable disease?

Osteoarthritis is a painful and disabling disease that affects millions of patients. Its aetiology is largely unknown, but is most likely multi-factorial. Osteoarthritis poses a dilemma: it often begins attacking different joint tissues long before middle age, but cannot be diagnosed until it becomes symptomatic decades later, at which point structural alterations are already quite advanced. In this review, osteoarthritis is considered as a disease of the whole joint that may result from multiple pathophysiological mechanisms, one of which is the dysregulation of lipid homeostasis. No proven disease-modifying therapy exists for osteoarthritis and current treatment options for chronic osteoarthritic pain are insufficient, but new pharmacotherapeutic options are emerging.