Sport practice and osteoarthritis of the limbs

Revisiting prostaglandin E2: A promising therapeutic target for osteoarthritis

Osteoarthritis (OA) is a complex disease characterized by cartilage degeneration and persistent pain. Prostaglandin E2 (PGE2) plays a significant role in OA inflammation and pain. Recent studies have revealed the significant role of PGE2-mediated skeletal interoception in the progression of OA, providing new insights into the pathogenesis and treatment of OA. This aspect also deserves special attention in this review. Additionally, PGE2 is directly involved in pathologic processes including aberrant subchondral bone remodeling, cartilage degeneration, and synovial inflammation. Therefore, celecoxib, a commonly used drug to alleviate inflammatory pain through inhibiting PGE2, serves not only as an analgesic for OA but also as a potential disease-modifying drug. This review provides a comprehensive overview of the discovery history, synthesis and release pathways, and common physiological roles of PGE2. We discuss the roles of PGE2 and celecoxib in OA and pain from skeletal interoception and multiple perspectives. The purpose of this review is to highlight PGE2-mediated skeletal interoception and refresh our understanding of celecoxib in the pathogenesis and treatment of OA.

Finding the Goldilocks Zone of Mechanical Loading: A Comprehensive Review of Mechanical Loading in the Prevention and Treatment of Knee Osteoarthritis

In this review, we discuss the interaction of mechanical factors influencing knee osteoarthritis (KOA) and post-traumatic osteoarthritis (PTOA) pathogenesis. Emphasizing the importance of mechanotransduction within inflammatory responses, we discuss its capacity for being utilized and harnessed within the context of prevention and rehabilitation of osteoarthritis (OA). Additionally, we introduce a discussion on the Goldilocks zone, which describes the necessity of maintaining a balance of adequate, but not excessive mechanical loading to maintain proper knee joint health. Expanding beyond these, we synthesize findings from current literature that explore the biomechanical loading of various rehabilitation exercises, in hopes of aiding future recommendations for physicians managing KOA and PTOA and athletic training staff strategically planning athlete loads to mitigate the risk of joint injury. The integration of these concepts provides a multifactorial analysis of the contributing factors of KOA and PTOA, in order to spur further research and illuminate the potential of utilizing the body's own physiological responses to mechanical stimuli in the management of OA.

The effect of attending rehabilitation after traumatic knee joint injury on femoral articular cartilage morphology in collegiate rugby players with a history of intracapsular knee joint injury during two-year consecutive rugby seasons

Introduction

This present study aimed to compare ultrasonographic measures of femoral articular cartilage during two-year seasons between collegiate rugby players who have attended supervised rehabilitation following intracapsular knee joint injury and those without a history of knee injury.

Methods

Using a prospective observational study design, 12 male collegiate rugby players with a previous history of intracapsular knee joint injury who have received and completed supervised rehabilitation following their injury and 44 players without knee joint injury participated in this study. Ultrasonographic images were used to verify changes in femoral articular cartilage thickness and cross-sectional area (CSA) with or without a previous history of knee joint injury over two consecutive rugby seasons.

Results

Significant time main effects were observed for the lateral condylar thickness (p < 0.001), the intercondylar thickness (p = 0.001), the medial condylar thickness (p < 0.001), and CSA (p < 0.001). No significant interactions nor group main effects were identified for all femoral articular cartilage (p < 0.05).

Conclusions

Collegiate rugby players demonstrated a decrease in femoral articular cartilage thickness and CSA over two-year consecutive rugby seasons. These findings indicate that engaging in collegiate rugby induces alterations in femoral articular cartilage structure. Furthermore, there were no differences in all femoral cartilage outcome measures between rugby players with and without a previous history of traumatic knee joint injury. Therefore, attending supervised rehabilitation at the time of their knee joint injury appeared to reduce the impact of a previous history of intracapsular knee joint injury on the change in femoral articular cartilage thickness and CSA among active rugby players.

Mechanotransduction pathways in articular chondrocytes and the emerging role of estrogen receptor-α

In the synovial joint, mechanical force creates an important signal that influences chondrocyte behavior. The conversion of mechanical signals into biochemical cues relies on different elements in mechanotransduction pathways and culminates in changes in chondrocyte phenotype and extracellular matrix composition/structure. Recently, several mechanosensors, the first responders to mechanical force, have been discovered. However, we still have limited knowledge about the downstream molecules that enact alterations in the gene expression profile during mechanotransduction signaling. Recently, estrogen receptor α (ERα) has been shown to modulate the chondrocyte response to mechanical loading through a ligand-independent mechanism, in line with previous research showing that ERα exerts important mechanotransduction effects on other cell types, such as osteoblasts. In consideration of these recent discoveries, the goal of this review is to position ERα into the mechanotransduction pathways known to date. Specifically, we first summarize our most recent understanding of the mechanotransduction pathways in chondrocytes on the basis of three categories of actors, namely mechanosensors, mechanotransducers, and mechanoimpactors. Then, the specific roles played by ERα in mediating the chondrocyte response to mechanical loading are discussed, and the potential interactions of ERα with other molecules in mechanotransduction pathways are explored. Finally, we propose several future research directions that may advance our understanding of the roles played by ERα in mediating biomechanical cues under physiological and pathological conditions.

The Association Between Sex and Osteoarthritis in the Physically Active Population: A Systematic Review

PURPOSE

Intense sporting activity and certain types of work increase the risk of early osteoarthritis (OA). OA can be idiopathic or associated to certain predisposing factors: female sex, obesity, history of joint injury, and joint overuse. The role of gender among the active population as a predisposing factor for OA is not well clear. This study investigated whether the risk of OA changes with age in both sexes in physically active individuals.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines 2020. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in April 2021. No time constrains were used for the search. All the published clinical studies reporting data about relationship between physical activity and OA were included.

RESULTS

Data from 7 articles were retrieved including 360,053 patients (271,903 males; 88,150 females). The mean age was 48.2±16.7 years. Males, under the age of 60 had a higher risk of developing OA. People undertaking intense physical activity, such as professional athletes or heavy workers, are more prone to develop early OA.

CONCLUSION

Physically active males demonstrated a higher risk of developing OA.

Intensive Physical Activity Increases the Risk of Knee and Hip Arthroplasty: A Systematic Review

PURPOSE

The present study investigated the type of sport and activity level of athletes before they underwent knee and/or hip arthroplasty for osteoarthritis (OA), and compared them with a control group of subjects who did not undergo knee and hip arthroplasty. We hypothesed athletes exposed to high physical loads during sports had the highest risk of developing OA requiring arthroplasty.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. All the comparative clinical trials to August 2021 investigating the sport activity level between subjects who underwent arthroplasty versus those who did not undergo arthroplasty for OA were considered.

RESULTS

Data from 5 studies and 3638 patients were collected. The mean age for both groups was 47.61±15.5 years, and the mean body mass index was 24.6±2.1 kg/m2 17.6% were women. The Newcastle-Ottawa scale attested good quality of the methodology of the investigations included in the present study.

CONCLUSION

Intense physical exercise, implying a high cumulative number of hours of exercise which can lead to excessive joint overload, in both sexes is associated with greater likelihood of early knee and hip OA which may lead to prosthetic surgery. Moderate and recreational exposure to sport has minor degenerative effects, and is not associated with early onset OA requiring arthroplasty.

The Risk of Knee Osteoarthritis in Professional Soccer Players

BACKGROUND

We address the question whether professional soccer players with and without macroinjury of the knee joint are at an elevated risk for knee osteoarthritis.

METHODS

A systematic review with meta-analyses was conducted. The study protocol was prospectively registered (registration number CRD42019137139). The MEDLINE, EMBASE, and Web of Science databases were searched for relevant publications; in addition, forward searching was performed, and the listed references were considered. All steps of the process were undertaken independently by two reviewers, and any discordances were resolved by consensus. For all publications whose full text was included, the methods used were critically evaluated. The quality of the evidence was judged using the GRADE criteria.

RESULTS

The pooled odds ratio for objectively ascertained osteoarthrosis of the knee was 2.25 (95% confidence interval [1.41-3.61], I² = 71%). When only radiologically ascertained knee osteoarthrosis was considered, the odds ratio was 3.98 [1.34; 11.83], I² = 58%). The pooled risk estimator in studies in which knee joint macroinjury was excluded was 2.81 ([1.25; 6.32], I² = 71%).

CONCLUSION

A marked association was found between soccer playing and knee osteoarthritis in male professional soccer players. For female professional soccer players, the risk of knee osteoarthritis could not be assessed because of the lack of data. Knee injuries seem to play an important role in the development of knee osteoarthritis in professional soccer players.

Potential Mechanism of Action of Current Point-of-Care Autologous Therapy Treatments for Osteoarthritis of the Knee-A Narrative Review

Osteoarthritis (OA) is a progressive degenerative disease that manifests as pain and inflammation and often results in total joint replacement. There is significant interest in understanding how intra-articular injections made from autologous blood or bone marrow could alleviate symptoms and potentially intervene in the progression of the disease. There is in vitro an in vivo evidence that suggests that these therapies, including platelet-rich plasma (PRP), autologous anti-inflammatories (AAIs), and concentrated bone marrow aspirate (cBMA), can interrupt cartilage matrix degradation driven by pro-inflammatory cytokines. This review analyzes the evidence for and against inclusion of white blood cells, the potential role of platelets, and the less studied potential role of blood plasma when combining these components to create an autologous point-of-care therapy to treat OA. There has been significant focus on the differences between the various autologous therapies. However, evidence suggests that there may be more in common between groups and perhaps we should be thinking of these therapies on a spectrum of the same technology, each providing significant levels of anti-inflammatory cytokines that can be antagonists against the inflammatory cytokines driving OA symptoms and progression. While clinical data have demonstrated symptom alleviation, more studies will need to be conducted to determine whether these preclinical disease-modifying findings translate into clinical practice.

STUDY ON MECHANICAL PROPERTIES OF TOTAL KNEE ARTICULAR CARTILAGE UNDER DIFFERENT LOADING RATES

Knee joint is the main weight bearing tissue of human body, also it is one of the prone parts of the clinical disease. Under different sports conditions, knee joint was loaded at different forms. In this study, the changes of average contact pressure, peak contact pressure, contact area and pressure-sharing regions were researched using the intact and defect pig knee joints under different loading rates and loads, including fast rates and large loads. These data were measured and recorded by usage of the sensor plate that placed between the unilateral meniscus and the femur cartilage during loading process. As for the intact cartilage samples, the average contact pressure and peak contact pressure of the femur cartilage increase with the loading rate, while the contact area is contrast to it. As for defect cartilage samples, it not only emerged stress concentration on the edge of the defect and pressure distribution in joint cavity was different with intact cartilage samples, but also the main bearing region was transferred from the femur cartilage-meniscus contact area to the femur cartilage-tibial cartilage contact area at different loading forms. In different loading stages, the pressure-sharing regions between the cartilage and the meniscus also changes. Different loading rates, different loads and defects will change the mechanical states of the knee joint. In loading forms, the mechanical condition may cause or aggravate damnification of the knee joint cartilage. Therefore, this study is beneficial for promoting and perfecting the research of mechanical properties of knee joint cartilage and provides a theoretical basis for the prevention and treatment of knee cartilage injury.

Age, but not short-term intensive swimming, affects chondrocyte turnover in zebrafish vertebral cartilage

Both age and intensive exercise are generally considered critical risk factors for osteoarthritis. In this work, we intend to establish zebrafish models to assess the role of these two factors on cartilage homeostasis. We designed a swimming device for zebrafish intensive exercise. The body measurements, bone mineral density (BMD) and the histology of spinal cartilages of 4- and 12-month-old zebrafish, as well the 12-month-old zebrafish before and after a 2-week exercise were compared. Our results indicate that both age and exercise affect the body length and body weight, and the micro-computed tomography reveals that both age and exercise affect the spinal BMD. However, quantitative analysis of immunohistochemistry and histochemistry indicate that short-term intensive exercise does not affect the extracellular matrix (ECM) of spinal cartilage. On the other hand, the cartilage ECM significantly grew from 4 to 12 months of age with an increase in total chondrocytes. dUTP nick end labeling staining shows that the percentages of apoptotic cells significantly increase as the zebrafish grows, whereas the BrdU labeling shows that proliferative cells dramatically decrease from 4 to 12 months of age. A 30-day chase of BrdU labeling shows some retention of labeling in cells in 4-month-old spinal cartilage but not in cartilage from 12-month-old zebrafish. Taken together, our results suggest that zebrafish chondrocytes are actively turned over, and indicate that aging is a critical factor that alters cartilage homeostasis. Zebrafish vertebral cartilage may serve as a good model to study the maturation and homeostasis of articular cartilage.

Relative efficacy and safety of topical non-steroidal anti-inflammatory drugs for osteoarthritis: a systematic review and network meta-analysis of randomised controlled trials and observational studies

Objectives

To compare the efficacy and safety of topical non-steroidal anti-inflammatory drugs (NSAIDs), including salicylate, for the treatment of osteoarthritis (OA).

Methods

PubMed, Embase, Cochrane Library and Web of Science were searched from 1966 to January 2017. Randomised controlled trials (RCTs) comparing topical NSAIDs with placebo or each other in patients with OA and observational studies comparing topical NSAIDs with no treatment or each other irrespective of disease were included. Two investigators identified studies and independently extracted data. Bayesian network and conventional meta-analyses were conducted. The primary outcomes were pain relief for RCTs and risk of adverse effects (AEs) for observational studies.

Results

43 studies, comprising 36 RCTs (7 900 patients with OA) and seven observational studies (218 074 participants), were included. Overall, topical NSAIDs were superior to placebo for relieving pain (standardised mean difference (SMD)=−0.30, 95% CI −0.40 to –0.20) and improving function (SMD=−0.35, 95% CI −0.45 to –0.24) in OA. Of all topical NSAIDs, diclofenac patches were most effective for OA pain (SMD=−0.81, 95% CI −1.12 to –0.52) and piroxicam was most effective for functional improvement (SMD=−1.04, 95% CI −1.60 to –0.48) compared with placebo. Although salicylate gel was associated with higher withdrawal rates due to AEs, the remaining topical NSAIDs were not associated with any increased local or systemic AEs.

Conclusions

Topical NSAIDs were effective and safe for OA. Diclofenac patches may be the most effective topical NSAID for pain relief. No serious gastrointestinal and renal AEs were observed in trials or the general population. However, confirmation of the cardiovascular safety of topical NSAIDs still warrants further observational study.

Effects of isokinetic, isometric, and aerobic exercises on clinical variables and knee cartilage volume using magnetic resonance imaging in patients with osteoarthritis

Objectives

This study aims to evaluate the effect of isokinetic, isometric, and aerobic exercise protocols on pain, disability, physical function, and articular cartilage in osteoarthritis.

Patients and methods

A total of 45 women (mean age 52.1 years; range 45 to 65 years) who were admitted to the Physical Medicine and Rehabilitation outpatient clinic and were diagnosed with primary bilateral knee osteoarthritis between May 2008 and January 2010 were included. The patients were randomly divided into three groups as isokinetic (n=15), aerobic (n=15), and isometric exercise groups (n=15). Exercise protocols were applied five days a week for four weeks. Pain was evaluated using a 10 cm Visual Analog Scale for Pain (VAS-pain), pain, joint stiffness and physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and disability was assessed using the Lequesne Index before and after the interventions. Isokinetic knee muscle strength measurements were also obtained. Patellar and femoral cartilage volumes were analyzed using magnetic resonance imaging.

Results

The VAS-pain, WOMAC, and Lequesne scores and peak torque values of knee extension improved in all groups with the highest improvement in the isokinetic group. For the knee flexion peak torque values, improvements were significant only in the isokinetic group at both velocities. There was no significant change in the femoral cartilage volume in any group after the interventions. However, patellar cartilage volume significantly increased in the isometric group (p=0.036).

Conclusion

A four-week isokinetic, aerobic, and isometric exercise programs improved pain and functional capacity in patients with knee osteoarthritis. Isokinetic exercise also increased the muscle strength with improved maintenance of the quadriceps/hamstring ratio. Only isometric exercise increased the patellar cartilage volume.

The Impact of Previous Athletic Experience on Current Physical Fitness in Former Collegiate Athletes and Noncollegiate Athletes

Background:

Physical activity performed at moderate intensity is associated with reduced risk of mortality, cardiovascular disease, hypertension, and some types of cancers. However, vigorous physical activity during participation in college athletics may increase the risk of injury, which might limit future physical activity levels.

Purpose:

To evaluate differences in current physical fitness levels between former Division I athletes and noncollegiate athletes.

Study Design:

Cross-sectional study.

Level of Evidence:

Level 3.

Methods:

The sample was recruited from a large midwestern university alumni database and consisted of 2 cohorts: (1) former Division I athletes (n = 100; mean age, 53.1 ± 7.4 years) and (2) nonathletes who were active in college (n = 100; age, 51.4 ± 7.3 years). Individuals answered a demographics questionnaire and completed a physical fitness assessment consisting of 7 measures: percent body fat, 1-mile walk, sit-to-stand test, push-up, half sit-up test, sit and reach test, and back scratch test.

Results:

Performance was significantly worse for former Division I athletes compared with nonathletes for percent body fat (mean difference, 7.58%; F_{(1, 198)} = 59.91; P < 0.01), mile time (mean difference, 2.42 minutes; F_{(1, 198)} = 1.74; P = 0.03), sit-to-stand test (mean difference, 4.3 repetitions; F_{(1, 198)} = 6.59; P = 0.01), and push-up test (mean difference, 8.9 repetitions; F_{(1, 198)} = 7.35; P = 0.01).

Conclusion:

Former Division I athletes may be limited because of previous injury, inhibiting their ability to stay active later in life.

Clinical Relevance:

It is imperative that clinicians, coaches, and strength and conditioning specialists understand the possible future repercussions from competing at the Division I level.

Does sports participation (including level of performance and previous injury) increase risk of osteoarthritis? A systematic review and meta-analysis

BACKGROUND

To assess the relationship between sport and osteoarthritis (OA), and specifically to determine whether previous participation, in terms of level (elite or non-elite), type of sport, intensity or previous injury, was associated with OA.

METHODS

This systematic review was developed using PRISMA guidelines. Databases were searched (to May 2016). Narrative review and meta-analysis (with risk ratio (RR) and 95% CIs) approaches were undertaken where appropriate. Study quality was assessed using GRADE.

RESULTS

46 studies were included. Narratively, 31 studies reported an increased risk of OA, with 19 demonstrating an increased risk in elite athletes. There was an increased risk after sports exposure (irrespective of type; RR 1.37; 95% CI 1.14 to 1.64; 21 studies). It remained uncertain whether there was a difference in risk of OA between elite and non-elite athletes (RR 1.37; 95% CI 0.84 to 2.22; 17 studies). The risk was higher in soccer (RR 1.42; 95% CI 1.14 to 1.77; 15 studies) but lower in runners (RR 0.86; 95% CI 0.53 to 1.41; 12 studies). 9 studies showed an association with the intensity of sport undertaken and OA. 5 studies demonstrated a higher prevalence of OA following meniscectomies and anterior cruciate ligament tears. Overall, the evidence was of GRADE 'very low' quality.

CONCLUSIONS

There was very low-quality evidence to support an increased relationship between sports participation and OA in elite participants. It is unclear whether there is a difference in risk between elite and non-elite participants with further prospective studies needed to evaluate this. Pooled findings suggested that significant injuries were associated with OA in soccer players.

Development and Prevention of Running-Related Osteoarthritis

Studies investigating the effect of running on risk for developing osteoarthritis at weight-bearing joints have reported with conflicting results. Generally, moderate-level running is not likely detrimental to joint health. However, many factors may be associated with the increased risk of developing osteoarthritis in runners. Factors often implicated in the development of osteoarthritis comprise those that increase joint vulnerability and those which increase joint loading. It is therefore suggested that running has different effects on different people. Efforts should be made to identify those with joint vulnerability and joint loading, and measures should be taken to have those factors and/or their running programs modified to run safely. Further investigations are needed to examine the effect of running on joint health under different conditions to confirm the association between exposure to risk factors and development of osteoarthritis, as well as to validate the effectiveness of measures for preventing running-related osteoarthritis.

Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

Lower limb clinical and radiographic osteoarthritis in former elite male athletes

PURPOSE

To investigate the prevalence of lower extremities clinical and radiographic OA in former elite male athletes and referents from the general population and to examine its association with the participants' demographic characteristics.

METHODS

Two hundred and eighteen former elite male athletes (soccer, volleyball, martial arts, track and field and basketball players, and skiers) and 181 male controls that reported no systematic athletic activity were examined by means of questionnaire, clinical and radiographic evaluation. Exclusion criteria were age younger than 40 years and a positive history of lower extremity surgery, bone or soft tissue trauma and inflammatory arthropathy.

RESULTS

Overall, the prevalence of clinical OA between former elite athletes (15.6 %) and controls (14.4 %) was similar (n.s.). The prevalence of radiographic OA was significantly higher (p = 0.03) in former elite athletes (36.6 %) compared with controls (23.9 %). All the participants with clinical OA who underwent radiographic examination also had radiographic OA. The prevalence of clinical and radiographic OA was similar (n.s.) between former athletes of different sports. Age, body mass index (BMI) and occupation variably predicted the prevalence of hip, knee and ankle OA in both study groups.

CONCLUSIONS

In the absence of major bone and soft tissue lower limb trauma during their athletic career, former elite athletes may not be at increased risk of developing clinical OA. Radiographic signs of OA present at a significantly higher incidence and possibly precede the clinical onset of OA. Age, BMI and occupation are identified as strong predictors of the development of OA in former elite athletes.

Asymmetrical loading demands associated with vertical jump landings in people with unilateral transtibial amputation

Loading symmetry during vertical jump landings between a person with amputation's intact and prosthetic limbs was assessed to determine the role of each limb in controlling the downward momentum of the center of mass during landing. Six participants with unilateral transtibial amputation (TTA) and ten nondisabled participants completed 10 maximal vertical jumps, of which the highest jump was analyzed. Contralateral symmetry was assessed through the Symmetry Index (SI), while symmetry at the group level was assessed through a Mann-Whitney U test. Participants with TTA performed quasi-unilateral landings onto the intact limbs, resulting from either the incapability of the prosthetic ankle to plantar flex or increased residual-limb knee and hip flexion. In the loading phase, the participants with TTA displayed reduced prosthetic-side peak vertical forces (p = 0.04) along with reduced prosthetic-side ankle range of motion (p < 0.001), extensor moments (p = 0.03), and negative work generated (p = 0.00). Individual asymmetries were evident in the peak vertical force magnitudes (SI = 51%-140%), duration from touchdown to peak vertical force (SI = 52%-157%), ankle joint angles at touchdown (SI = 100%-538%), ranges of motion (SI = 147%-200%), knee (SI = 66%-179%) and hip (SI = 87%-132%) extensor moments, and work done at the ankle (SI = 155%-199%) and hip (SI = 83%-204%). High peak forces (25.25 +/- 4.89 N·kg(-1) intact limb and 14.61 +/- 8.28 N·kg(-1) prosthetic limb) from significantly lower (p < 0.001) landing heights than the nondisabled participants indicate a potential injury risk associated with landing for people with TTA.

Evaluation of the effect of a chicken comb extract-containing supplement on cartilage and bone metabolism in athletes

In a previous study, we revealed that a commercially available product of dietary supplement containing a chicken comb extract (CCE), which is rich in hyaluronan, not only relieves joint pain and other symptoms, but also potentially improves the balance of type II collagen degradation/synthesis in patients with knee osteoarthritis. Since soccer is one of the sports most likely to cause knee osteoarthritis (OA), we evaluated the effect of a CCE-containing supplement on cartilage and bone metabolism in athletes. Fourteen and 15 subjects (all midfielders) were randomly assigned to receive the test product (test group) and the dummy placebo containing only vehicle (placebo group), respectively, for 12 weeks. The daily oral intake of the CCE-containing test product clearly decreased the urinary levels of both C-terminal crosslinked telopeptides of cartilage-specific type II collagen (CTX-II) as a type II collagen degradation marker and the N-terminal telopeptides of bone-specific type I collagen (NTx) as a marker of bone resorption at 12 weeks after the initiation of the intervention. By contrast, no significant reduction was detected in the placebo group at any timepoint during the intervention. These observations indicate that the test product is effective in inhibiting, not only cartilage degradation, but also bone remodeling. Thus, the CCE-containing supplement may be useful for the management of joint health in athletes.

Genetic evidence of the regulatory role of parathyroid hormone-related protein in articular chondrocyte maintenance in an experimental mouse model

OBJECTIVE

Parathyroid hormone-related protein (PTHrP) regulates the rate of differentiation of growth chondrocytes and is also expressed in articular chondrocytes. This study tested the hypothesis that PTHrP might have a regulatory role in articular chondrocyte maintenance.

METHODS

Control sequences of growth differentiation factor 5 were used to delete PTHrP from articular chondrocytes in the mid-region of mouse articular cartilage. Mice with conditional deletion of PTHrP (knockout [KO]) and littermate control mice were evaluated for degenerative changes using both a time-course design and destabilization of the medial meniscus (DMM) technique. A total histologic score of degenerative changes was determined for the femoral and tibial articular surfaces (total maximum score of 60).

RESULTS

The time-course study revealed degenerative changes in only a minority of the KO mice. In the DMM model, male KO mice were highly susceptible to DMM-induced degenerative changes (mean ± SEM total histologic score 45 ± 2.7 in KO mice versus 23 ± 1.4 in controls; P < 0.0001 by Mann-Whitney U test), with virtually no overlap between groups. PTHrP normally functions in a feedback loop with Indian hedgehog (IHH), in which a reduction in one signaling partner induces a compensatory increase in the other. A number of phenotypic and functional markers were documented in KO mice to suggest that the IHH-PTHrP axis is capable of compensating in response to a partial Cre-driven PTHrP deletion, a finding that underscores the need to subject the mouse articular cartilage to a destabilizing challenge in order to elicit frankly degenerative findings.

CONCLUSION

PTHrP may regulate articular chondrocyte maintenance in mice.

Development and validation of a motion and loading system for a rat knee joint in vivo

The influence of biomechanical stimuli on modulating cartilage homeostasis is well recognized. However, many aspects of cellular mechanotransduction in cartilage remain unknown. We developed a computer-controlled joint motion and loading system (JMLS) to study the biological response of cartilage under well-characterized mechanical loading environments. The JMLS was capable of controlling (i) angular displacement, (ii) motion frequency, (iii) magnitude of the axial compressive load applied to the moving joint, and it featured real-time monitoring. The accuracy and repeatability of angular position measurements, the kinematic misalignment error as well as the repositioning error of the JMLS were evaluated. The effectiveness of the JMLS in implementing well-defined loading protocols such as moderate Passive Motion Loading (PML) and increased Compressive Motion Loading (CML) were tested. The JMLS demonstrated remarkable accuracy and reliability for the measurement and kinematics tests. Moreover, the effectiveness test demonstrated the ability of the JMLS to produce an effective stimulus via PML that led to the suppression of the catabolic effects of immobilization. Interestingly, the biological response of the CML group was catabolic and exhibited a pattern similar to that observed in the immobilization group. This novel non-invasive system may be useful for joint biomechanics studies that require different treatment conditions of load and motion in vivo.

The short-term effects of running on the deformation of knee articular cartilage and its relationship to biomechanical loads at the knee

OBJECTIVE

To investigate the short-term effects of recreational running on the deformation of knee articular cartilage and to examine the relationship between changes in knee cartilage volume and biomechanical modulators of knee joint load.

METHOD

Twenty healthy volunteers participated in a two phase cross-sectional study. Session 1 involved Magnetic Resonance Imaging (MRI) of femoral and tibial cartilage volumes prior to and following a 30 min period of relaxed sitting, which was directly followed by a recreational run of 5000 steps. Subsequently, all participants undertook a laboratory study of their running gait to compare biomechanical derived measures of knee joint loading with changes in cartilage volume. Estimates of knee joint load were determined using a rigid-link segment, dynamic biomechanical model of the lower limbs and a simplified muscle model.

RESULTS

Running resulted in significant deformation of the medial (5.3%, P<0.01) and lateral femoral cartilage (4.0%, P<0.05) and lateral aspect of the tibial cartilage (5.7%, P<0.01), with no significant differences between genders. Maximum compression stress was significantly correlated with percentage changes in lateral femoral cartilage volume (r(2)=0.456, P<0.05). No other biomechanical variables correlated with volume changes.

CONCLUSION

Limited evidence was found linking biomechanical measures of knee joint loading and observed short-term deformation of knee articular cartilage volume following running. Further enhancement of knee muscle modelling and analysis of stress distribution across cartilage are needed if we are to fully understand the contribution of biomechanical factors to knee joint loading and the pathogenesis of knee osteoarthritis (OA).

Biomechanical implications of degenerative joint disease in the apophyseal joints of human thoracic and lumbar vertebrae

An experimental technique for quantifying load-sharing in cadaveric spines is used to test the hypothesis that degenerative changes in human apophyseal joints are directly related to high levels of compressive load-bearing by these joints. About 36 cadaveric thoraco-lumbar motion segments aged 64-92 years were subjected to a compressive load of 1.5 kN. The distribution of compressive stress was measured in the intervertebral discs using a miniature pressure transducer, and stress measurements were summed over area to give the compressive force resisted by the disc. This was subtracted from the applied 1.5 kN to indicate compressive load-bearing by the apophyseal joints. The cartilage of each apophyseal joint surface was then graded for degree of degeneration. After maceration, each joint surface was scored for degenerative joint disease (DJD) affecting the bone. Results demonstrated that the apophyseal joints resisted 5-96% (mean 45%) of the applied compressive force. A significant positive correlation was demonstrated between age and cartilage degeneration, age and DJD bone score, apophyseal joint load-bearing and bone score, and cartilage score and load-bearing. The latter correlation was strongest for load-bearing above 50%. Ordinal regression showed that the variables describing bone DJD (marginal osteophytes, pitting, bony contour change, and eburnation) were significantly correlated with degree of cartilage degeneration. It is concluded that in elderly individuals apophyseal joint load-bearing above a threshold of 50% is associated with severe degenerative changes in cartilage and bone, and that markers of DJD observed palaeopathologically may be used as predictors of such loadingin life.

Hyaluronic acid and chondroitin sulfate content of osteoarthritic human knee cartilage: site-specific correlation with weight-bearing force based on femorotibial angle measurement

This study analyzed glycosaminoglycan (GAG) content in specific compartments of the knee joint to determine the impact of malalignment and helped refine indications for osteotomy. To assess malalignment, the radiological femorotibial angle (FTA) was measured and knee joints were also graded for OA severity with the Kellgren/Lawrence (K/L) classification. Cartilage samples were obtained from 36 knees of 32 OA patients undergoing total knee replacement surgery. Explants were harvested from the medial femoral condyle (MFC), lateral femoral condyle (LFC), patellar groove (PG), and lateral posterior femoral condyle (LPC). Concentrations of hyaluronic acid (HA) and chondroitin sulfate (CS) were measured by high-performance liquid chromatography (HPLC). With OA severity, the average FTA significantly increased. HA and CS content in MFC was negatively correlated with radiographic FTA. In LFC, HA ratio, which is HA content in lateral condyle divided by medial condyle and chondroitin 6 sulfate, increased until about 190 degrees FTA. Importantly, at >190 degrees these contents were significantly decreased. HA and CS content of the femoral condyle shows topographic differences that are related to OA grade and weight-bearing force based on FTA. The clinical relevance is that osteotomy may not be indicated for patients with severe varus (>190 degrees) abnormalities.

Recovery of the menisci and articular cartilage of runners after cessation of exercise: additional aspects of in vivo investigation based on 3-dimensional magnetic resonance imaging

BACKGROUND

It is still unclear whether long-distance running has a deleterious effect on joint health; therefore, this study was undertaken to examine the rate of recovery from alterations occurring at the knee joint in marathon runners due to loading.

HYPOTHESIS

Tibial, patellar, and meniscal cartilaginous volumes are able to recover adequately from changes due to repeated loading immediately after cessation.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty knees of male athletes were studied (mean age, 38 +/- 14 years). The participants ran 20 km around a predetermined and precisely measured course. Cartilaginous volume was measured by magnetic resonance imaging before the run (60-min rest before exercise), immediately after the run (3-min delay), and after a recovery period of 1 hour.

RESULTS

After the 20-km run, there was a significant transient decrease in cartilage volume. After 1 hour of rest, no significant reduction of cartilage volume was measured for the patella (-2.1%), the tibia (-1.2%), the lateral meniscus (-3.2%), or the medial meniscus (-5.9%). However, the values recorded for the menisci were borderline, which indicates that recovery of meniscus volume lags behind that of articular cartilage.

CONCLUSION

Our data indicate a clear tendency toward rapid recovery of the cartilaginous and meniscal volumes at the knee. The results of this study lead to the assumption that the cartilage and the menisci are well able to adapt to the loads caused by running. Investigation of more subtle changes would require more specific magnetic resonance imaging techniques, including T2-weighted mapping and T1-weighted rho sequences, to assess cartilage biochemistry.

CLINICAL RELEVANCE

The articular structures were investigated on a general magnetic resonance imaging level and were found to recover rapidly so that exercise could be continued after a short time without reservation.

Autologous interleukin-1 receptor antagonist improves function and symptoms in osteoarthritis when compared to placebo in a prospective randomized controlled trial

INTRODUCTION

Incubation of blood with CrSO(4)-coated glass beads stimulates the synthesis of anti-inflammatory cytokines, such as interleukin-1 receptor antagonist (IL-1ra), IL-4, IL-10, and IL-13. As IL-1beta is thought to play a key role in the development of osteoarthritis (OA), this product, also known as Orthokin, might be a viable treatment for symptomatic knee OA. The aim of the current study was to evaluate the efficacy of Orthokin for treatment of symptomatic knee OA in a randomized, multicentre, double-blind, placebo-controlled trial.

PATIENTS AND METHODS

One hundred and sixty-seven patients received six intra-articular injections either with Orthokin or physiological saline. The primary efficacy objective consisted of 30% superiority on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 3, 6, 9, and 12 months post-treatment. Additionally, the patients completed the visual analogue scale for pain, the Knee injury and Osteoarthritis Outcome Score (KOOS) and Knee Society Clinical Rating System.

RESULTS

Orthokin and placebo treatment resulted in similar improvements on the WOMAC (16.8% vs 16.5%, respectively; n.s.). Orthokin resulted in significantly more improvement for KOOS symptom (P = 0.002) and KOOS sport (P = 0.042) parameters as compared to placebo treatment. For most other outcome parameters, Orthokin-treated patients consistently showed higher improvement compared to placebo-treated patients, although none of these differences were statistically significant. Two serious adverse events were observed in the Orthokin group: one patient with repeated severe inflammatory reactions of the knee joint within hours after the injection and one patient with septic arthritis which was attributed to the injection procedure rather than the product.

CONCLUSION

The statistically significant improvement of KOOS symptom and sport parameters together with the consistently higher, though non-statistically significant, improvement of most other parameters demonstrates that Orthokin clearly induces a biological response different from placebo treatment and warrant future investigations into the possible chondroprotective effect of Orthokin. However, in the current study the primary efficacy objective was not met and, therefore, the use of Orthokin currently cannot yet be recommended for the treatment of OA.

Fratura-luxação traumática do quadril no futebol: relato de caso

De ocorrência rara no futebol, esporte coletivo mais praticado no mundo, as fraturas de acetábulo que se associam às luxações da articulação do quadril são lesões com grande potencial de gerar seqüelas graves e limitantes. O rápido atendimento, a precisão do diagnóstico e procedimentos de salvamento da articulação pela redução e correta fixação são essenciais para perspectiva de retomar a atividade física regular praticada anteriormente ou outra que se adapte à nova situação.

Knee injuries account for the sports-related increased risk of knee osteoarthritis

Increased risk of osteoarthritis has been found among athletes active in different kinds of sports. Knee injury is an established risk factor for knee osteoarthritis. In this population-based case-control study we investigated the risk of knee osteoarthritis with respect to sports activity and previous knee injuries. A total of 825 cases with x-ray-verified femorotibial osteoarthritis were identified at six hospitals in southern Sweden. The cases were matched (age, sex and residential area) with 825 controls from the general population. Mailed questionnaire data on sports activity for more than 1 year after the age of 16, knee injuries and confounding variables (weight, height, heredity, smoking and occupation) were collected and analyzed using logistic regression models. The response frequency was 89%. Among men knee osteoarthritis was related to soccer (odds ratio (OR) 1.6, 95% confidence interval (CI) 1.1-2.2), ice hockey (OR 1.9, 95% CI 1.2-3.0) and tennis (OR 2.0, 95% CI 1.1-3.8) but not to track and field sports, cross-country skiing, and orienteering. After adjustment for confounding variables soccer and ice hockey remained significantly related to knee osteoarthritis, but after adjustment for knee injuries no significant relation remained. The sports-related increased risk for knee osteoarthritis was explained by knee injuries.

Volume changes in the menisci and articular cartilage of runners: an in vivo investigation based on 3-D magnetic resonance imaging

BACKGROUND

Articular cartilage contributes to transferring enormous loads as uniformly as possible from one skeletal segment to the next. Whether it manages this task when subjected to the high repetitive loading cycles occurring during long-distance running and can remain intact is still the topic of controversy.

PURPOSE

To investigate the changes in cartilaginous volumes of the tibia, patella, and medial and lateral menisci after extreme dynamic loading as occurs in long-distance runners.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-eight knees of male athletes were studied (38 +/- 14 years). The subjects ran around a predetermined and precisely measured course (5, 10, 20 km), the beginning and end of the run being in the magnetic resonance imaging investigation room. The scan protocol was 60-minute rest period, first measurement, run, 3-minute delay, and second measurement.

RESULTS

Overall, there were significant reductions in volume (P < .05) for the patella, tibia, and menisci. There was evidence of significant change after a running distance of 5 km. A further statistical reduction of the volume could only be demonstrated for the medial meniscus after 10 and 20 km.

CONCLUSION

Tibial, patellar, and meniscal cartilaginous volumes show not only load-dependent volume changes but also an asymptotic curve. This is the first time that meniscal volume changes due to loading have been used as an indicator of the important mechanical contribution that the menisci make to sustaining the knee during repetitive loading.

CLINICAL RELEVANCE

On the basis of the results of this study, the authors assume that the cartilage is able to adapt well to the loads caused by running.

[Physical therapy of osteoarthritis]

Physical therapy is part of guidelines and recommendations in the treatment of osteoarthritis. Different methods of physical therapy are used in osteoarthritis. There is evidence that manual physical therapy and exercise improve function and reduce pain in osteoarthritic joints. Thermal modalities are employed for short-term pain relief and change the intraarticular temperature. Electrotherapy, therapeutic ultrasound and balneotherapy show positive therapeutic effects. Based on studies and clinical experience, physical therapy must be recommended in the therapy of osteoarthritis.

Impact of an exercise and walking protocol on quality of life for elderly people with OA of the knee

BACKGROUND AND PURPOSE

The knee is the weight-bearing joint most commonly affected by osteoarthritis (OA). The symptoms of pain, morning stiffness of short duration and physical dysfunction in the activities of daily living (ADL) can have an effect on many aspects of health, affecting quality of life. Regular and moderate physical activity adapted to individuals' life-styles and education, and joint protection strategies have been advocated as conservative management. The purpose of the present study was to assess the impact of an exercise and walking protocol on the quality of life of elderly people with knee OA.

METHOD

The study design was a randomized controlled clinical trial. The subjects comprised 50 elderly people, aged 65 or more, with knee OA who had been referred to the geriatric outpatient unit for rehabilitation. Changes in severity of pain and quality of life were compared between a control group (CG) and an experimental group (EG). Both groups participated in an educational session and the EG also received a 12-week exercise and walking protocol. Both groups were assessed at baseline and after three and six months by an independent observer. The Lequesne Index of Knee OA Severity (LI), the Health Assessment Questionnaire (HAQ) and the Medical Outcomes Short-Form Health Survey (SF-36) were used as measurement instruments.

RESULTS

In the CG, the measures of quality of life (SF-36), the HAQ and the LI between subjects did not yield statistically significant differences over the three measurement points. For the EG, there was a significant improvement in function, measured by HAQ, and decreasing OA symptom severity, measured by LI. For the SF-36 there were significant improvements in physical function, functional role limitation and pain. Comparisons between the groups showed statistically significant differences after three and six months for all measures, except for the SF-36 emotional domains.

CONCLUSION

The exercise protocol and walking programme had a positive effect on the quality of life of elderly individuals with knee OA.

Osteoarthritis: an overview of the disease and its treatment strategies

Osteoarthritis (OA) is currently defined by the American College of Rheumatology as a "heterogeneous group of conditions that leads to joint symptoms and signs which are associated with defective integrity of articular cartilage, in addition to related changes in the underlying bone at the joint margins." Its prevalence after the age of 65 years is about 60% in men and 70% in women. The etiology of OA is multifactorial, with inflammatory, metabolic, and mechanical causes. A number of environmental risk factors, such as obesity, occupation, and trauma, may initiate various pathological pathways. OA indicates the degeneration of articular cartilage together with changes in subchondral bone and mild intraarticular inflammation. The principal treatment objectives are to control pain adequately, improve function, and reduce disability. Acetaminophen is frequently used for symptomatic OA with mild to moderate pain. Nonsteroidal antiinflammatory drugs (NSAIDs) are more effective in the case of moderate-severe pain, but they have an increased risk of serious upper gastrointestinal adverse events. The newer cyclooxygenase COX-2 specific inhibitors (Coxibs) are as efficacious as traditional NSAIDs and have a better gastrointestinal safety profile. Other compounds (eg, chondroitin sulfate, diacerein, glucosamine sulfate) have a symptomatic effect that is slower and less than that of NSAIDs. The structure-modifying effects of drugs are currently being evaluated, and both glucosamine sulfate and diacerein have been shown in some trials to have a beneficial structural effect. Nonpharmacological interventions are frequently and widely used in the management of OA patients, but there is little evidence that they are effective: the best studied and most successful nonpharmacological interventions are patient education, self-management, and exercise. There is some evidence for the pain-relieving efficacy of thermotherapy and transcutaneous electrical nerve stimulation (TENS) but not of electrotherapy, acupuncture, homeopathy, or manual therapy. The value of interventions aimed at improving function and maximizing independence (occupational therapy, walking aids, workplace adaptation) is also unclear. The disease course and patient's requirements often change over time, thus requiring a periodic review and readjustment of therapy rather than the rigid continuation of a single treatment.

The Role of Mechanical Loading in the Onset and Progression of Osteoarthritis

Osteoarthritis is a progressive joint disease characterized by an imbalance of articular cartilage biosynthesis and degradation attributed to both inflammatory and biomechanical factors. Whereas moderate mechanical loading appears necessary for maintaining healthy cartilage, abnormal joint loading increases the risk of osteoarthritis. Obesity-induced osteoarthritis and the benefits of physical activity may be mediated by systemic levels of proinflammatory mediators as well as local biomechanical factors in the joint.

Changes in knee cartilage volume and serum COMP concentration after running exercise

OBJECTIVE

Investigate the relationship between running induced joint loading at the knee, changes in cartilage volume and serum cartilage oligomeric matrix protein (COMP) concentration.

DESIGN

Serum COMP levels and knee cartilage volumes of experienced runners were tested before and after running. Joint loading was determined using a biomechanical model of the lower extremity.

BACKGROUND

To date no biomechanical rationale has been identified to explain the role of mechanical load in the aetiology of running injuries.

METHODS

Blood samples and magnetic resonance imaging scans were taken before and following a 1h training run. Knee cartilage volume and serum COMP concentration were determined. Individual knee joint loading parameters were calculated from positional data and ground reaction forces. Electromyography was employed to quantify activity of main muscle groups crossing the knee joint.

RESULTS

Changes in cartilage volume and COMP showed significant correlations. Net joint forces did not explain the differences in cartilage changes. Multiple regression revealed that resting COMP, COMP change after exercise and the time of co-activation of flexor and extensor muscles explain the variance of cartilage volume changes.

CONCLUSIONS

Muscular co-activation was the main mechanical parameter related to cartilage changes. The current investigation elucidates the interaction of factors related to cartilage degeneration on an individual basis. Applications to altered loading conditions such as equipment or training methods offer an auspicious way of quantifying effects of interventions.

Impact of osteoarthritis on sports careers

The number of people participating in sports continues to increase. The relationship between sports participation, joint injury, and subsequent osteoarthritis is complex. A history of joint injury and participation in high joint loading sports increases the risk of subsequent osteoarthritis changes in affected joints. The impact of osteoarthritis on sports careers depends on multiple factors including the joint involved, the location within that joint, and the physical demands of the chosen sport.

Osteoarthritis in Other Joints (Hip, Elbow, Foot, Ankle, Toes, Wrist) after Sports Injuries

Osteoarthritis of nonknee joints, although less common than knee osteoarthritis, remains a significant and disabling condition for many present and former athletes. These injuries can be caused by repeated loads or following a specific traumatic event. The resulting pain and loss of motion can limit function and ability. Arthroscopic techniques in many cases enable surgeons to symptomatically treat limitations of range of motion and pain, prolonging active careers. Joint replacement remains the ultimate solution for hip osteoarthritis, and may be a viable option in ankle osteoarthritis.

MR imaging of the hip and knee before and after marathon running

BACKGROUND

Despite its obvious benefits regarding aerobic fitness, the possible deleterious effects of long-distance running remain controversial. The repetitive loading associated with this activity could potentially predispose to the subsequent development of osteoarthritis. Lower extremity malalignment can also result in abnormal joint loading and is another possible contributing factor for premature articular cartilage degeneration. The purpose of this study is to investigate whether external impact loading in marathon runners creates internal stresses on bone and cartilage that are demonstrable on MR images. Participants were separately assessed for static lower extremity alignment, using standard radiographs.

METHODS

Six recreational and two semi-professional runners underwent magnetic resonance (MR) imaging of the hip and knee before and after a marathon run using coronal T1-weighted and coronal STIR sequences.

RESULTS

The pre-run and post-run scans failed to demonstrate marrow oedema, periosteal stress reactions, or joint effusions in seven runners. One patient who underwent a reconstruction of his anterior cruciate ligament 18 months ago demonstrated a small effusion in the reconstructed knee before and after the race.

CONCLUSIONS

Our results suggest that the high impact forces in long-distance running are well tolerated and subsequently do not demonstrate changes on MR images.

An investigation of risk factors for symptomatic osteoarthritis of the knee in women using a life course approach

STUDY OBJECTIVE

To explore risk factors for symptomatic knee osteoarthritis (OAK) in women, which included wearing high heeled shoes.

DESIGN

Matched case-control study. Exposure information obtained by interview, included details about past footwear. Self reported weight and height data obtained representing when women left school, were aged 36-40 and were aged 51-55. Regular work activities (including periods when homemaker or carer), smoking, and hormone related data gathered using a life-grid.

SETTING

Interviews in participants' homes. Cases identified from orthopaedic hospital surgical waiting list, controls identified by general practitioners (GPs)

PARTICIPANTS

Women aged 50 to 70 years. Cases awaiting knee replacement surgery. Controls, who had no past knee surgery and no knee pain in the past three years, were matched for age and GP. Altogether 111 eligible women were interviewed (29 cases, 82 controls).

MAIN RESULTS

Univariate analyses identified several significant associations with OAK including past knee injury, arthritis of the feet, heavy smoking, being overweight (BMI 25 or above) and various occupational activities. Virtually all measures of high heeled shoes use were associated with reduced risk of OAK, although none of these findings were statistically significant. In multivariate analysis only BMI 25 or above at age 36-40 remained significantly associated with OAK (OR 36.4, 95% CI 3.07 to 432, p=0.004), although weak evidence suggested certain occupational activities might increase risk. Weight gain in early adult life was particularly pronounced among cases.

CONCLUSIONS

Being overweight before the age of 40 considerably increased the risk of subsequent symptomatic OAK in women. Wearing high heeled shoes did not.