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Orthopaedic Care of the Aging Athlete Abstract Increasing numbers of middle-aged and older adults participate in sports, and athletes wish to remain active as they age. Understanding the anatomic, physiologic, and psychosocial differences between older and younger athletes can help aging athletes maintain function. Athletic capacity may be sustained well into advanced age, and many of the physiologic consequences of aging may be mitigated or reversed by regular exercise. Most injuries in older athletes are chronic and overuse injuries that result in diminished flexibility and endurance. In addition, many aging athletes have medical and musculoskeletal problems that mandate tailoring athletic activity to the patient’s general health and functional requirements. T raditionally, physical decline has been regarded as a normal part of aging. Although the rate of aging varies, organ functions gradu- ally become impaired and decline, thus increasing vulnerability to en- vironmental stresses, metabolic dis- turbances, and disease. 1 Recent evi- dence, however, suggests that this deterioration is not inevitable and that the so-called effects of aging may be more a result of a sedentary lifestyle and long-standing disuse. 2 In Western industrialized coun- tries, the average life expectancy in- creased from 47 years in 1900 to 75 years in 1988. Increased life expect- ancy and a post-World War II baby boom has contributed to a rapidly growing older population; according- ly, the number of persons older than age 85 years grew 232% from 1960 to 1990, compared with a total pop- ulation growth of 39% during the same period. 3 By 2010, 25% of the American population will be older than age 55 years, and more than 50% of the population will be older than 35 years. 4 In 1996, the American Academy of Orthopaedic Surgeons established the Committee on Aging to address orthopaedic care of the elderly. Geri- atric care has since received more attention at national orthopaedic meetings, 5 with an emphasis on pre- venting injury and promoting phys- ical fitness. Currently 60 nations have adopted the declaration of the present decade as the Bone and Joint Decade. Because older persons today are increasingly physically active, or- thopaedic surgeons need to under- stand the anatomy and physiology of aging in the older athlete and be able to differentiate “normal” from pathologic aging. Treatment should be tailored to meet the pa- tient’s functional requirements as well as treat musculoskeletal prob- lems, such as osteoarthritis, which affects nearly one in three middle- aged and older adults. 6 The treat- ment plan also must be tailored to accommodate any physical or cogni- tive limitations the patient may have. Andrew L. Chen, MD, Simon C. Mears, MD, PhD, and Richard J. Hawkins, MD Dr. Chen is Attending Orthopaedic Surgeon, Littleton Orthopaedics, Littleton, NH. Dr. Mears is Assistant Professor, Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, Baltimore, MD. Dr. Hawkins is Clinical Professor, Department of Orthopaedic Surgery, University of Colorado, Boulder, CO, University of Texas, Southwestern Medical School, Dallas, TX, and Steadman-Hawkins Sports Medicine Foundation, Vail, CO. Reprint requests: Dr. Chen, Littleton Orthopaedics, 81 Bethlehem Road, Littleton, NH 03561. J Am Acad Orthop Surg 2005;13:407- 416 Copyright 2005 by the American Academy of Orthopaedic Surgeons. Volume 13, Number 6, October 2005 407 Physiologic Effects of Aging Systemic Changes Age-related changes occur at the molecular level and affect the perfor- mance of virtually every organ sys- tem in predictable, well-documented ways (Table 1). For example, reduc- tions in maximal heart rate, myocar- dial contractility, and stroke volume decrease cardiac performance so that oxygen utilization in the 60-year-old is typically 80% of that of a 20-year- old. 7 Peripheral vascular resistance increases because of atherosclerosis, vessel-wall rigidity, and baroreceptor tone. Pulmonary efficiency decreases because lung compliance and tho- racic cage elasticity decrease, and gas exchange becomes limited. 1 The net result is an increased risk of acute myocardial events, particularly in sedentary persons who begin inten- sive training rather than gradually in- creasing their exertion level. Various changes characterize a de- cline in renal function. The number of glomeruli decline from a range of 500,000 to one million at age 40 to half that number by the seventh de- cade. 8 From the second to eighth de- cades, renal blood flow and the glomerular filtration rate decrease by half, and the specific gravity of urine decreases from an average of 1.032 to 1.024, with a relative in- crease in water excretion. 8 This is exacerbated by insensible losses dur- ing exercise as well as alterations in the sensitivity of the thirst mecha- nism, rendering adequate hydration Table 1 Physiologic Effects of Aging System Effects of Aging Modification With Regular Exercise Cardiovascular Decreased maximal heart rate Decreased myocardial contractility Decreased stroke volume Decreased oxygen utilization Atherosclerosis Decreased vascular compliance Diminished microcirculation Decreased vascular tone and baroreceptor function Increased cardiac output Increased oxygen utilization Diminution of atherosclerotic plaques Enhanced vascular compliance Enhanced microvasculature Enhanced vascular tone Pulmonary Decreased elasticity Decreased compliance Weaker respiratory effort Increased pulmonary vascular resistance Altered alveolar gas exchange Decreased total lung capacity, vital capacity, and inspiratory/expiratory airflow Increased residual volume Increased ventilation-perfusion ratio Improved gas exchange Decreased sense of breathlessness Strengthening of respiratory muscles Renal Progressive loss of glomeruli Decreased renal perfusion Decreased glomerular filtration rate Decreased specific gravity of urine Increased renal blood flow, mainly via increased cardiac output Neurologic Impaired hearing, short-term memory, cognition, judgment Decreased coordination, balance, fine-motor skills Increased motor response time Decreased visual-spatial orientation Altered sensation and proprioception Decreased peripheral nerve conduction velocity, amplitude, motor unit recruitment Improved sport-specific skills Improved coordination, balance Improved visual-spatial orientation Ophthalmologic Decreased visual acuity and accommodation Diminished peripheral vision, contrast sensitivity Impaired ability to adapt to low-light situations None None of the following authors or the departments with which they are affiliated has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Chen and Dr. Mears. Dr. Hawkins or the departments with which he is affiliated has received research or institutional support from Steadman-Hawkins Research Foundation. Dr. Hawkins or the departments with which he is affiliated has received royalties from Hardcore Books and DePuy. Dr. Hawkins or the departments with which he is affiliated has stock or stock options held in Arthrocare Sports Medicine. Dr. Hawkins or the departments with which he is affiliated serves as a consultant to or is an employee of US Surgical Sports Medicine, DePuy, Arthrocare Sports Medicine, and Encore Medical. Orthopaedic Care of the Aging Athlete 408 Journal of the American Academy of Orthopaedic Surgeons a challenge. 8 Intravascular deple- tion, which typically precedes thirst, can affect cardiac output, athletic performance, cognitive function, and metabolic function in advanced stages of dehydration (Table 1). Central and peripheral nervous system change can impair hearing, memory, balance, motor skills, sen- sation, proprioception, and cogni- tion. 1 Extrapyramidal and vestibular dysfunction may impair coordina- tion and balance. Sensorimotor coor- dination also may be affected by un- derlying dementia, cerebrovascular disease, cognitive dysfunction, de- pression, and medications. Peripher- al nerve dysfunction may be exacer- bated by diseases such as diabetes mellitus and may result in decreased conduction velocity, amplitude, mo- tor unit recruitment, and altered motor unit potentials. Even in the absence of known neurologic dis- ease, the elderly have a 30% to 50% reduction in vibration and position sense at the ankles 9 (Table 1). Musculoskeletal Changes Musculoskeletal changes (Table 2) include those in bone, connective tis- sue, and skeletal muscle. Bone The apparent age-related de- crease in bone mineral density re- sults not from a qualitative defect of mineralization but rather from a quantitative loss of trabecular density. Men lose bone mass at a rate of 0.5% to 0.75% per year after age 40, whereas women lose bone at more than twice that rate (1.5% to 2% per year) before menopause and up to 3% per year after menopause. 10 Moreover, female athletes involved in intensive training since child- hood are at especially high risk of osteoporosis because many experi- enced delayed menarche, oligomen- orrhea, or secondary amenorrhea re- lated to their training and diet. Although physical exercise can in- crease osseous thickness and strength as well as levels of calcium, nitrogen, hydroxyproline, and DNA in bone, 10 physicians nonetheless should be vigilant for injuries to os- teoporotic bone, particularly when a patient older than 50 years begins a new training regimen. Ligaments and Tendons With age, collagen undergoes so- called maturational stabilization, in which the number of reducible col- lagen cross-links stabilizes, thus in- creasing thermal stability, decreasing fiber compliance, and reducing solu- Table 2 Musculoskeletal Manifestations of Aging Area Effects of Aging Protective Modifications/Treatments Bone Progressive loss of mineral density “Tubularization” of diaphyseal bone Regular exercise Well-balanced diet Vitamin D and calcium supplementation Hormone therapy (women) Medical therapy (eg, bisphosphonates) Ligaments and tendons Decreased fiber compliance Stiffness of ligaments and tendons Increased susceptibility to catastrophic failure Decreased glycosaminoglycan concentration Decreased collagen fiber bundle thickness Decreased vascularity Regular exercise Pre-exercise stretching Meniscus Intrasubstance degeneration Loss of ability to dissipate stress Increased propensity to degenerative tears Débridement of unstable degenerative tears* Articular cartilage Decreased concentration of chondroitin sulfate, relative increase in keratan sulfate (nonosteoarthritic) Relative increase in chondroitin sulfate (osteoarthritic) Chondromalacia (cumulative damage) Microfracture for selected full thickness chondral lesions Débridement of unstable chondral lesions* Glucosamine and chondroitin sulfate* Hyaluronate viscosupplementation* Skeletal muscle Sarcopenia Decreased type I and II muscle fiber loss Volumetric loss of individual fiber size Progressive muscle denervation Decreased mitochondrial volume Increased collagen content Degenerative ultrastructural changes Decreased muscle flexibility Regular exercise, muscle training Pre-exercise stretching Hormonal supplementation* Nutritional supplementation* * = routinely used, anecdotal success, but long-term benefits have not been clearly established Andrew L. Chen, MD, et al Volume 13, Number 6, October 2005 409 bility. Hormonal abnormalities (eg, corticosteroid excess, diabetes mel- litus) increase collagen cross-linking and maturation, thereby adding to the stiffness of connective tissues. 10 In addition to ultrastructural changes within the collagen fibers, age-related losses in water content and gains in elastin fibril thickness contribute to connective-tissue stiffness. Physical activity increases the cross-sectional area of ligaments and tendons but en- hances collagen turnover and remod- eling, thus retarding the process of maturational stabilization. Meniscus With age, biomechanical perfor- mance and the ability to dissipate stresses decline in meniscal tissue, increasing its susceptibility to hori- zontal cleavage tears. Peripheral tears may heal in a limited fashion, with metaplasia of the fibrous tissue into fibrocartilage, whereas central and degenerative intrasubstance tears demonstrate a poor capacity for healing. 10 Repetitive loading may propagate these degenerative tears through progressive microtrauma. Articular Cartilage Articular cartilage consists pri- marily of type II collagen embedded in a matrix of proteoglycans, water, glycoproteins, and other proteins in small amounts, interspersed with a sparse population of chondrocytes. With age, the concentration of chon- droitin sulfate relative to that of keratan sulfate decreases in nonar- thritic articular cartilage, whereas it increases in osteoarthritic articular cartilage. 10 Because nutrition and re- moval of metabolic waste occur by diffusion in articular cartilage, mo- tion and mechanical loading greatly facilitate these processes, and the ar- ticular cartilage responds by hyper- trophy. Conversely, when a joint is deprived of mechanical loading, even for relatively short periods of inactivity, disuse atrophy and dimin- ished metabolic activity can occur in the hyaline cartilage. 11 Softening, fis- suring, and fibrillation of the bearing surfaces occur with repetitive joint loading and microtrauma to me- chanically compromised articular cartilage. 10 Therefore, although inac- tivity may lead to disuse atrophy, high-impact repetitive activities to diseased, degenerated cartilage may destroy the joint. 1 Skeletal Muscle Age-related declines in muscle function are thought to have the greatest impact on functional capac- ity. Muscle weakness in the elderly is largely the result of sarcopenia rather than changes in contractility, and weakness may be reversible with exercise. Age-associated mus- cular atrophy arises from the equal loss of type I and II fibers and, to a lesser extent, losses in fiber volume. Denervation, increased total col- lagen content, decreased mitochon- drial volume, and other degenerative ultrastructural changes in muscle fi- bers also occur with age. 10 Muscle activity may mitigate these effects and improve biochemical and oxida- tive capacity. Traditionally, peak muscle strength was thought to oc- cur at age 30 years, decline 15% per decade between age 50 and 70 years, and decline 30% per decade after age 70 years. It is now evident that reg- ular, intensive muscle training can minimize or reverse age-related de- clines in muscle mass well into the eighth decade of life. 12 The musculotendinous unit also loses flexibility with age, which is believed to be influenced by both in- activity and genetics. 1 Muscles may stiffen because of increased actin- myosin cross-linking and changes in the extracellular matrix. Studies of reflex inhibition have shown the latter to be of primar y impor- tance. 13 Stabilization of collagen within myotendinous units also in- creases musculotendinous stiffness. This loss of flexibility is thought to increase the risk of injury. 10 So-called Anti-aging Agents Various endogenous mediators be- come depleted with age (Table 3). Clinical studies have failed to dem- onstrate that replacing them is safe and beneficial in otherwise normal- ly aging persons. 14 Replacing defi- cient growth hormone, for example, increases muscle mass, decreases body fat, and improves oxygen utili- zation and physical endurance; how- ever, comparable benefits have not been demonstrated in persons with normal levels of the hormone. 15 Androgens and androgenic pre- cursors, such as testosterone, dehy- droepiandrosterone (DHEA), andro- stenedione, and androstenediol, have been advocated to restore mus- cle mass and strength, increase vital- ity and libido, decrease oxidative stress, maintain coordination, and diminish erectile dysfunction. These beneficial effects, however, have not been observed in hormonally normal individuals. 15 Moreover, benefits may be offset by the following: downregulation of testosterone syn- thesis, accumulation of estrogenic compounds, unfavorable changes in blood lipid levels and other cardiac risk factors, increased risk of pros- tate disease, and disruption of the equilibrium between plasma cortisol and testosterone levels. 16 Athletes have used recombinant human erythropoietin to stimulate erythropoiesis and increase oxygen- carrying capacity and endurance. In- creasing the hematocrit to supra- physiologic levels carries theoretic risks of intravascular hyperviscosity and vascular sludging, which in- crease the risk of ischemic and thrombotic events, hypertension, and hyperkalemia, particularly in older persons with underlying med- ical problems. 17 Nutritional supplements to coun- teract the effects of aging have gained enormous popularity. Vita- mins A (beta carotene), C (ascorbate), andE(α-tocopherol) are antioxidants Orthopaedic Care of the Aging Athlete 410 Journal of the American Academy of Orthopaedic Surgeons thought to scavenge free-radicals produced during exercise and there- fore limit oxidative stress and free- radical damage. 18 L-carnitine is a qua- ternary amine thought to regulate muscle glycogen breakdown and limit lactic acid formation, thus im- proving endurance and muscle per- formance. 18 Creatine, an amino acid derivative found in skeletal and cardiac muscle and in retinal, testicular, and brain tissues, is important in production of adenosine triphosphate. Creatine is thought to increase the production of phosphocreatine and the pH buf- fering capacity of muscle, thereby enhancing muscular strength and en- durance. In addition, increased intra- cellular creatine and phosphocreatine concentrations may promote fiber hypertrophy and water retention, which may benefit those with sar- copenia. 19 Adverse effects of creatine supplementation are secondary to fluid imbalance and include extracel- lular fluid retention, intravascular de- pletion, dehydration, muscle cramp- ing, nausea, gastrointestinal distress, and possible renal dysfunction. Nutritional supplementation has not been shown to enhance perfor- mance in athletes who train regular- ly and maintain a well-balanced diet. In addition, unbalanced diets and ex- cessive supplementation that substi- tute for regular meals can have ad- verse effects. 20 Musculoskeletal Injury and the Aging Athlete Acute Traumatic Injuries Despite age-related structural and functional declines, older athletes ex- perience a lower incidence of acute traumatic injuries than do their younger counterparts. 1,21,22 This has been attributed to the older athlete’s participation in less violent sports and greater experience, as well as the lower intensity of competition. San- delin 21 reported that only 1% of pa- tients who required hospital care for acute sports injuries were older than 55 years. Although age-related losses in bone density increase bone fragil- ity, 10 acute fractures represent a small Table 3 So-called Anti-aging Agents Agent Intended Effects Potential Adverse Effects/Disadvantages Growth hormone Increased muscle mass Decreased body fat Improved oxygen utilization Improved physical endurance Increased insulin-resistance Increased free-radical formation Increased cancer risk Androgens (eg, testosterone, DHEA, androstenedione, androstenediol) Increased muscle mass Increased strength Increased vitality Increased libido Decreased oxidative stress Decreased erectile dysfunction Maintenance of visual-spatial coordination Downregulation of testosterone synthesis Testicular atrophy Aggressive behavior Accumulation of estrogenic compounds Unfavorable alterations in blood lipid profile Increased cardiac risk Increased prostate disease Dysequilibrium between plasma cortisol and testosterone Recombinant human erythropoietin Increased hematocrit Increased oxygen-carrying capacity Increased muscle endurance Intravascular hyperviscosity Vascular sludging Increased risk of thrombotic events Hypertension Hyperkalemia Nutritional supplements, antioxidant vitamins (A, C, E) Free-radical scavengers Limit oxidative stress Minimize free-radical damage Hypervitaminosis Questionable benefit in individuals with well-balanced diets L-carnitine Limit lactic acid formation Regulate muscle glycogen breakdown Improved endurance and muscle performance Cost Questionable benefit in individuals with well-balanced diets Creatine Increased availability of phosphocreatine Increased pH buffering capacity of muscle Increased muscle strength and endurance Muscle hypertrophy Weight gain Dehydration Muscle cramping Nausea Gastrointestinal distress Renal dysfunction DHEA = dehydroepiandrosterone Andrew L. Chen, MD, et al Volume 13, Number 6, October 2005 411 proportion of aging athletes’ acute traumatic injuries. 23,24 Among aging athletes, acute mus- cular strains predominate. The myo- tendinous junction is especially vul- nerable to injury because the terminal sarcomeres of muscle fiber are less extensible than the middle sarcomeres. 10 Moreover, weakened or fatigued muscles are less able to absorb energy or stretch in response to eccentric muscle activity. The fre- quency with which these muscle- strain injuries are seen likely reflects the decrease in musculoskeletal flexibility of older athletes as well as their greater participation in endur- ance sports, such as long distance running, that result in muscle fa- tigue and predisposition to injury. 10 Ruptures of the Achilles and quadri- ceps tendons tend to occur in middle-aged and older athletes. Most patients who experience these inju- ries report recent changes in their training regimens, although prodro- mal symptoms are uncommon. His- tologic evaluation of these injuries typically reveals disorganized ten- don remodeling, relative avasculari- ty, and intrasubstance tendon degen- eration (the latter also is known as angiofibrotic hyperplasia. 25 Chronic and Overuse Injuries Commonly, injuries in older ath- letes are related to overuse and repetitive microtrauma. A 3-year prospective evaluation of injury pat- terns found that overuse injuries ac- counted for 70% of injuries in veter- an athletes (aged >60 years) but for only 41% of injuries of young ath- letes (aged 21 to 25 years). 23 Dehaven and Littner 24 observed that, by the seventh decade of life, the five most common athletic injuries are related to degeneration and repetitive inju- ry. Chronic or overuse injuries also have been shown to result in pro- longed disability in older persons. Kallinen and Markku 26 observed that 20% of such injuries in older male athletes lasted more than 2 years and altered their training or competition. Tendinosis Tendinosis is common in older athletes and results from repetitive loading and cumulative microtrau- ma to the tendons, which are stiffer and heal more slowly than those of younger athletes. 10 Rotator cuff ten- dinopathy, medial epicondylitis, and inflammation of wrist tendons are the most common tendinoses in old- er golfers; 27 Achilles tendinitis is the most common among older jog- gers. 28 Lateral epicondylitis, or ten- nis elbow, occurs most commonly in middle-aged persons and is related to overuse of the wrist extensors. Subacromial Impingement and Rotator Cuff Tears During repetitive shoulder mo- tion, the rotator cuff can impinge on the coracoacromial arch. This may result in inflammation and tendi- nopathy, 29,30 which can be exacerbat- ed by age-related hypovascularity of the supraspinatus tendon. 31 There- fore, rotator cuff tendinopathy like- ly represents a combination of me- chanical attrition of the cuff and progression of incompletely healed microtears, possibly as a result of hy- povascularity. Subacromial decompression and rotator cuff repair is very successful in older patients. 32,33 Yeletal 32 re- ported a 94% satisfaction rate in pa- tients older than age 65 years who underwent subacromial decompres- sion and rotator cuff repair; most patients reported pain relief, inde- pendent living, and a return to recre- ational sports. In an evaluation of avid middle-aged tennis players, Sonnery-Cottet et al 33 suggested that up to 80% are able to return to full participation at their previous level after rotator cuff repair of the domi- nant shoulder. Osteoarthritis Most older athletes have trained from a very young age, making them vulnerable to osteoarthritis. Vingard et al 34 observed that middle-aged athletes who participate in high- intensity physical loading are 8.5 times more likely to develop os- teoarthritis of the hip than are age- matched controls. Repetitive, high- impact loading results in cartilage microtrauma and degeneration of the weight-bearing joints. 10 This ef- fect may be exacerbated by previous injury or surgery, such as prior men- iscectomy in the knee, which dimin- ishes the ability of the joint to dissi- pate loads. Treating Osteoarthritis Oral Therapy Oral glucosamine and chon- droitin sulfate preparations have re- cently gained popularity. They are purported to be chondroprotective and to promote articular cartilage re- pair. 35 Glucosamine is thought to act as an anti-inflammatory agent by promoting synthesis of proteogly- cans and glycosaminoglycans. Pro- teoglycans form the ground sub- stance in the extracellular matrix of connective tissue; of these, the gly- cosaminoglycan hyaluronic acid is vital for the function of articular car- tilage. Chondroitin sulfate is be- lieved to influence the synthesis and metabolism of glycosaminoglycans, increase total proteoglycan produc- tion by healthy cells, and inhibit the collagenolytic activity of chondro- cytes. Chondroitin sulfate and glu- cosamine are thought to diminish joint pain and tenderness, improve mobility, and sustain clinical im- provement despite cessation of other drug therapy. Although commercial preparations of these compounds are popular, debate continues concern- ing their bioavailability in oral prep- arations as well as the potential for the placebo effect. Further investiga- tion is needed to show whether these agents can treat osteoarthritis effectively. 35 Orthopaedic Care of the Aging Athlete 412 Journal of the American Academy of Orthopaedic Surgeons Viscosupplementation and Chondroplasty Intra-articular hyaluronate visco- supplementation has gained popu- larity as a palliative treatment of osteoarthritis of the knee. Viscosup- plementation is intended to replen- ish the hyaluronate component of the joint, thus reestablishing the rheologic properties of synovial flu- id. Although previous investigations have documented the safety of such procedures, concerns remain regard- ing their efficacy and cost. The most common adverse reaction, occurring in up to 20% of cases, is mild pain or swelling at the site of injection. Rarely, granulomatous inflamma- tion can result in long-term sequelae and compromise clinical success. 36 Moreover, although hyaluronate vis- cosupplementation may partially re- store the lubricating properties of synovial fluid, the procedure is not intended to treat severe cartilage loss definitively. Recent studies have questioned the efficacy of arthroscopic débride- ment, lavage, and chondroplasty for osteoarthritis of the knee. In a ran- domized trial of 180 patients, Mose- ley et al 37 reported no “clinically meaningful differences” in pain or functional scores at 2 years among those who received arthroscopic débridement, lavage, or placebo (ar- throscopic portals alone). However, both the methods for patient selec- tion and the statistical analysis in this study have been challenged. Dervin et al 38 found that in 126 pa- tients who under went arthroscopic débridement for osteoarthritis of the knee, improvement in quality of life was less than expected; however, pa- tients with medial joint-line tender- ness and those with unstable menis- cal tear improved significantly (P = 0.04 and P = 0.01, respectively). Reconstructive Options Numerous reconstructive options have been described for the treat- ment of full-thickness chondral le- sions of the knee; these include autologous chondrocyte transplanta- tion, osteochondral grafts, and mosa- icplasty. Although these procedures are intended for the younger patient with focal articular cartilage lesions with otherwise healthy bearing sur- faces, in general, these procedures fall short of anatomic reestablish- ment of the joint surface. Perhaps a greater challenge is management of the osteoarthritic knee, particularly in older patients who wish to remain physically active. Modifying activity may be effective in the early stages of osteoarthritis, but this is often not well tolerated by athletes who want to continue rigorous activity. Abrasion chondroplasty and sub- chondral drilling of chondral defects was developed to promote vascular stimulus for the influx of primitive mesenchymal cells. 39 Subsequent histologic evaluation demonstrated fibrous metaplasia of the accumulat- ed clot that ultimately resulted in the formation of fibrocartilage. Rand 40 compared the results of abra- sion chondroplasty with débride- ment alone for full-thickness os- teoarthritic articular defects of the knee and documented a 77% initial improvement rate in the débride- ment group compared with only 39% in the chondroplasty group. Moreover, 32% of the chondroplasty group were worse at 3-year follow- up, with 50% eventually needing joint replacement with a prosthe- sis. 40 For these reasons, abrasion chon- droplasty and subchondral drilling has largely been supplanted by the microfracture technique. In this technique, subchondral penetration is accomplished with an awl, which is thought to be advantageous be- cause it causes less thermal necrosis of subchondral bone than drilling does. Thus, the architectural integri- ty (it is not just the strength but also the shape that is important) of the subchondral bone is maintained, bone loss decreased, and the sub- chondral osseous bed roughened for better clot adhesion. 41 The clot that forms has been shown to contain pluripotential cells that can differen- tiate according to signals elaborated by cells in the surrounding chondro- cytes. 38 Using the microfracture technique, Steadman et al 41 reported 75% improvement at 3- to 5-year follow-up in the general population. Valgus high tibial osteotomy is indicated primarily for active pa- tients with medial compar tment arthritis with medialization of the mechanical limb axis. Although tra- ditionally this procedure has been reserved for patients younger than age 60 years, it is now being per- formed on older, active patients of younger physiologic age. It is an excellent alternative to unicompart- mental knee replacement, which is indicated primarily for patients with relatively sedentary lifestyles. Sprenger and Doerzbacher 42 re- viewed the results of 76 high tibial osteotomies done over 18 years for the treatment of varus gonarthrosis; they reported 90% survivorship (the percent that remain successful at 10 years). However, Nagel et al 43 report- ed that, although 82% of patients (28/34) were satisfied after high tib- ial osteotomy, the average score on the Tegner and Lysholm activity scale dropped from 5.4 to 4.8. Hip arthroscopy has been used to address early osteoarthritis and la- bral tears. McCarthy et al 44 reported that in elite athletes, hip arthrosco- py could safely and reproducibly di- agnose and treat intra-articular hip disorders, including labral pathology, chondral lesions, and loose bodies. Hip arthroscopy may be indicated in older patients with osteoarthritis who are either unwilling to modify activities or who do not have suffi- cient degenerative changes to under- go prosthetic replacement. Arthros- copy of the hip is an evolving procedure with limited collective experience. Helenius et al 45 reported on 68 patients with mild to moder- ate osteoarthritis of the hip treated with arthroscopy. Three months af- ter the procedure, 72% reported de- Andrew L. Chen, MD, et al Volume 13, Number 6, October 2005 413 creased hip pain; however , by 1 year, this had declined to 26%. Repeat hip arthroscopy for recurrent symptoms resulted in no clinical benefit. The authors concluded that hip arthros- copy for the treatment of mild to moderate primary osteoarthritis of the hip is, at best, of only temporary benefit. 45 Joint Replacement In 1999, almost 550,000 knee and hip replacements were performed in the United States. 46 Although pros- thetic replacement of the shoulder is less commonly done than total hip or knee replacement, the number of shoulder arthroplasties performed likely will increase as experience and understanding of shoulder ar- throplasty expand. In 1998, 15,266 shoulder replacements were per- formed nationwide, including 8,556 hemiarthroplasties and 6,710 total shoulder replacements. 46 Whereas the traditional goal of prosthetic re- placement was satisfactory pain re- lief, the current measure of success is effective return to functional ac- tivities. Total joint arthroplasty for os- teoarthritis has been shown to pre- dictably relieve pain and restore functional mobility; today it is not uncommon for patients to remain athletically active after surgery (Table 4). Although most patients ultimately pursue lower-intensity, lower-impact activities (eg, golf, walking), many frequently inquire about high-intensity, high-impact activities (eg, alpine skiing, running) that may result in excessive implant wear or jeopardize implant fixation. There are a number of measures of success in prosthetic replacement, but the primary one is patient activ- ity level. Older athletes who have achieved high levels of skill or con- ditioning in a particular sport have the best chance of safely resuming such activities after prosthetic re- placement; patients who have not previously participated in a particu- lar sport (especially high-risk activi- Table 4 Athletic Activity After Joint Arthroplasty: Summary of the 1999 Surveys of the Hip Society, the Knee Society, and the American Shoulder and Elbow Society 46 Activity Hip Arthroplasty Knee Arthroplasty Shoulder Arthroplasty Aerobics–high impact – 0 0 Aerobics–low impact + ++ ++ Baseball/softball – 0 0 Basketball – – 0 Bicycling–road + + ++ Bicycling–stationary ++ ++ ++ Bowling + ++ ++ Canoeing + + ++ Croquet ++ ++ ++ Dancing–ballroom ++ ++ ++ Dancing–jazz 0 ++ ++ Dancing–square 0 ++ ++ Fencing 0 0 0 Football – – – Golf ++ ++ + Gymnastics – – – Handball – – 0 Hiking + + + Hockey – – – Horseback riding + ++ 0 Horseshoes ++ ++ ++ Ice skating 0 + + Jogging – – ++ Lacrosse – – 0 Racquetball – – 0 Rock climbing – – – Roller/in-line skating 0 0 0 Rowing 0 + 0 Shooting ++ ++ + Shuffleboard ++ ++ ++ Skiing–cross-country + + ++ Skiing–downhill 0 0 + Skiing–stationary (machine) 0 + ++ Soccer – – 0 Speed walking 0 + ++ Squash – – 0 Swimming ++ ++ ++ Tennis–doubles ++ + ++ Tennis–singles – – 0 Volleyball – – 0 Walking ++ ++ ++ Weightlifting–free-weights 0 0 0 Weightlifting–machines 0 + 0 ++ = allowed, + = allowed with experience,0=noconclusion, – = not recommended Orthopaedic Care of the Aging Athlete 414 Journal of the American Academy of Orthopaedic Surgeons ties, such as alpine skiing) are at increased risk for injury. 46 With new- found pain relief and mobility, such patients often place undue stresses on the implant and are at higher risk of injury because they lack sport- specific skills or muscular condi- tioning. Despite continued improvements in implant materials, design, and prosthetic technology, implant fixa- tion remains a critical factor limit- ing athletic activity after total joint arthroplasty. Youth, imparted load, and activity have been shown to in- crease the risk of failure; in patients older than 65 years, the critical fac- tor for implant survivorship is the quality of initial implant fixation. 46 Increased activity also results in in- creased cycling of the articular bear- ing surfaces and the inevitable wear and particle production. Moreover, sports participation places the older athlete at risk of traumatic compli- cations, such as dislocation, implant failure, and periprosthetic fracture, all of which are challenging to man- age successfully. Total joint arthro- plasty presents a unique challenge in the older athlete. From a technical standpoint, patient age, activity lev- el, and sport-specific requirements may affect implant selection, bear- ing surface, use of cement or supple- mental screw fixation, and measures to enhance prosthetic stability. In 1999, the Hip Society, the Knee Society, and the American Shoulder and Elbow Society all surveyed their members on athletic activity after joint arthroplasty 46 (Table 4). In general, these surgeons allowed pa- tients with total joint arthroplasties to take part in unrestricted low- impact activities, such as walking or stationary bicycling. For low-impact activities that may be deleterious to implant longevity, such as cross- country skiing, we prefer patients to have had preoperative experience with such activities to minimize the risk of falling. Patients should avoid athletic activity until adequate strength, balance, and coordination have returned. Hip replacement im- poses additional restrictions on cer- tain body positions that increase the risk of hip dislocation. Therefore, we are cautious about activities that place patients at risk of falling and allow return to participation in sports on a case-specific basis. We discourage participation in contact or high-impact sports, such as foot- ball or gymnastics. Summary Growth of our aging population will undoubtedly result in an increased number of musculoskeletal prob- lems. So-called normal age-related changes must be differentiated from pathologic ones. Treatment should be tailored to the specific functional requirements of the patient in the context of the individual’s general health and musculoskeletal com- plaints. Although nutritional supple- ments such as glucosamine, chon- droitin sulfate, and creatine have become popular, their effectiveness has not been established. 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