Military Medicine International Journal of amsus raising the bar: extremity trauma care guest editors
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–61. 23. Wren TA, Rethlefsen S, Kay RM: Prevalence of speci fic gait abnor- malities in children with cerebral palsy: in fluence of cerebral palsy subtype, age, and previous surgery. J Pediatr Orthop 2005; 25(1): 79 –83.
24. Vaughan CL, O ’Malley MJ: Froude and the contribution of naval archi- tecture to our understanding of bipedal locomotion. Gait Posture 2005; 21(3): 350 –62. 25. Wilken JM, Rodriguez KM, Brawner M, Darter BJ: Reliability and minimal detectible change values for gait kinematics and kinetics in healthy adults. Gait Posture 2012; 35(2): 301 –7. 26. Holm S: A Simple sequentially rejective multiple test procedure. Scand J Stat 1979; 6(2): 65 –70.
27. Winter DA: Kinematic and kinetic patterns in human gait: variability and compensating effects. Hum Mov Sci 1984; 3: 51 –76. 28. Hansen AH, Meier MR, Sessoms PH, Childress DS: The effects of prosthetic foot roll-over shape arc length on the gait of trans-tibial pros- thesis users. Prosthet Orthot Int 2006; 30(3): 286 –99. 29. Norvell DC, Czerniecki JM, Reiber GE, Maynard C, Pecoraro JA, Weiss NS: The prevalence of knee pain and symptomatic knee osteo- arthritis among veteran traumatic amputees and nonamputees. Arch Phys Med Rehabil 2005; 86(3): 487 –93.
30. Rueda FM, Diego IM, Sanchez AM, Tejada MC, Montero FM, Page JC: Knee and hip internal moments and upper-body kinematics in the frontal plane in unilateral transtibial amputees. Gait Posture 2013; 37(3): 436 –9.
31. Gard SA, Konz RJ: The effect of a shock-absorbing pylon on the gait of persons with unilateral transtibial amputation. J Rehabil Res Dev 2003; 40(2): 109 –24.
32. Esposito ER, Rodriguez KM, Rabago CA, Wilken JM: Does unilateral transtibial amputation lead to greater metabolic demand during walk- ing? J Rehabil Res Dev 2014; 51(8): 1287 –96.
MILITARY MEDICINE, Vol. 181, November/December Supplement 2016 37 The Prevalence of Gait Deviations in Individuals With Transtibial Amputation MILITARY MEDICINE, 181, 11/12:38, 2016 A Narrative Review of the Prevalence and Risk Factors Associated With Development of Knee Osteoarthritis After Traumatic Unilateral Lower Limb Amputation Shawn Farrokhi, PT, PhD*†; Brittney Mazzone, PT, DPT*†‡; Adam Yoder, MS*†; Kristina Grant, BS*†; Marilynn Wyatt, PT, MA* ABSTRACT Introduction: Young military Service Members with traumatic unilateral lower limb amputations may be at a high risk for developing knee osteoarthritis (OA). There is growing evidence for potential in fluence and predictive value of nonsystemic risk factors on development and progression of primary knee OA in older adults. Proposed factors include chronic knee pain, obesity, abnormal knee joint mechanics, muscle weakness, previous knee trauma, and altered physical activity level. However, there is limited information available regarding whether such nonsystemic risk factors could also be responsible for the increased risk of knee OA after traumatic, unilateral lower limb amputation in young military Service Members. The purpose of this narrative review is to compile and present evidence regarding prevalence of nonsystemic and potentially modi fiable knee OA risk factors in Service Members with traumatic, unilateral lower limb amputation, and to identify potential strategies for intervention. Materials and Methods: A comprehensive literature search was performed in July 2015 using structured search terms related to nonsystemic risk factors for knee OA. Results: Current collective evidence does suggest an elevated prevalence of the nonsystemic knee OA risk factors in young military Service Members with unilateral lower limb amputation. In conclusion, the present state of the literature supports that young military Service Members with traumatic unilateral lower limb amputations may be at increased risk for develop- ing knee OA compared to nonamputees. Military Service Members injured at a young age have a long life expectancy, and thus require comprehensive rehabilitation programs to prevent or delay progression of knee OA. Given the lack of strong evidence, further clinical research is needed to determine whether early identi fication and modification of nonsystemic risk factors for knee OA could optimize long-term function and quality of life in young Service Members after traumatic, unilateral, limb amputations. BACKGROUND Young military Service Members who have sustained an amputation have unique long-term health care and rehabilita- tion needs. Traumatic limb amputations, in particular, represent an important source of chronic impairments and functional limitations that could signi ficantly impact returning to active duty, employment status and long-term quality of life (QOL) in young military Service Members. Although a signi ficant amount of resources have been focused on the immediate rehabilitation needs of young Service Members after amputa- tion, an important consideration is the early identi fication and modi
fication of potential risk factors responsible for long-term development of secondary health conditions such as knee osteoarthritis (OA). KNEE OA AFTER TRAUMATIC UNILATERAL LOWER LIMB AMPUTATION Individuals with traumatic, unilateral lower limb amputation are at a greater risk of developing knee OA compared to nonamputees. Melzer et al reported that the prevalence of contralateral knee OA was 66% in 32 individuals with lower limb amputation, which was signi ficantly greater than a 38% prevalence rate detected in an age- and body weight- matched control group consisting of 24 individuals without an amputation. 1 Similarly, Hungerford and Cockin 2 reported
knee OA prevalence rates of 63%, 41%, and 21% in trans- femoral amputees, transtibial amputees, and matched controls, respectively. Conversely, Norvel et al 3 reported that the prev- alence of symptomatic knee OA was 16% among 62 older amputees with no history of previous knee trauma as com- pared to an 11% rate in 94 elderly nonamputees. Exclusion of previous knee trauma, which is a strong risk factor for knee OA, could be partially responsible for the reports of lower contralateral knee OA by Norvel et al. 3 More recently, Struyf et al 4 reported knee OA prevalence rates of 27% for the intact limbs of 78 individuals with traumatic, unilateral lower limb amputation (mean age 60 years) that were con- siderably higher than the age- and gender-adjusted rates in the general population. The much lower knee OA prevalence rates after traumatic, unilateral limb amputation in this study compared to previous publications may be associated with advancements in prosthetic design and rehabilitation of indi- viduals with lower limb amputation over the past decade. Nevertheless, the current evidence suggests that the intact limbs of individuals with traumatic, unilateral lower limb amputation are at great risk for developing knee OA. Given *The Department of Physical and Occupational Therapy, Naval Medical Center San Diego, 34800 Bob Wilson Drive, San Diego, CA 92134. †Extremity Trauma & Amputation Center of Excellence, 2748 Worth Road, Suite 29, Fort Sam Houston, TX 78234. ‡BADER Consortium, University of Delaware, STAR Campus, 540 South College Avenue, Suite 102, Newark, DE 19713. doi: 10.7205/MILMED-D-15-00510 MILITARY MEDICINE, Vol. 181, November/December Supplement 2016 38
the importance of the intact limb for preservation of mobil- ity and functional independence in individuals with unilat- eral lower limb amputation, risk factor identi fication, and early disease detection appear to be of high importance for effective prevention and rehabilitation of knee OA in this patient population. KNEE OA PATHOMECHANICS AND RISK FACTORS The knee is one of the joints most commonly affected by OA with a 50% lifetime risk of developing symptomatic disease in the general population. 5 As there is no cure, conservative management of knee OA has traditionally focused on pain management and improving overall mobility. However, due to the degenerative nature of the disease, knee OA commonly progresses to a stage where joint replacement surgery may be the only viable option for alleviating symptoms and improving function and QOL. However, joint replacement surgery may not be a feasible option for some patients such as those with lower limb amputation or other concomitant comorbidities. Therefore, attempts are currently underway to identify potentially modi fiable risk factors and implement joint protective strategies that can result in favorable long- term outcomes. Although knee OA has long been viewed as a non- in flammatory “wear and tear” of the articular cartilage in older adults, this disease paradigm is rapidly changing. There is now mounting evidence that although OA is a mechani- cally driven condition, the disease process is chemically mediated through a complex interplay between systemic and nonsystemic factors. 6,7
Normal articular cartilage has a unique load-bearing mechanism capable of tolerating customary daily loads without sustaining injury that is determined through contributions from genetics, 8 as well as mechanical 9 and age-
related factors. 10 However, long-term exposure to excessive loads and other changes in joint mechanics, similar to those observed after lower limb amputation, 11 –14
can lead to adap- tive cellular responses and altered gene expressions that facili- tate the onset and progression of the disease. 7,15
Although systemic risk factors such as genetic predisposi- tion
16 may increase the risk of knee OA development after traumatic limb amputation through gene-speci fic and time- dependent alterations in gene expression, e.g., these factors are permanent and nonmodi fiable, which makes them unlikely as direct preventative or therapeutic targets. Conversely, pre- viously identi fied nonsystemic and potentially modifiable risk factors such as chronic knee pain, 17,18
obesity, 19,20
abnormal knee joint mechanics, 6,7 lower limb muscle weakness, 6,21 pre-
vious joint trauma, 22 and altered physical activity levels 23,24 are all modi fiable through preventative and rehabilitative strat- egies that could be applied to individuals with lower limb amputation. Therefore, the purpose of this narrative review is to organize the pertinent literature in an effort to identify nonsystemic, potentially modi fiable risk factors related to the development and progression of knee OA in the sound limbs of Service Members with traumatic amputations and identify possible prevention and treatment solutions. REVIEW CRITERIA Electronic searches of PubMed and EMBASE databases were performed in July 2015. MeSH terms for the initial search included “knee,” “OA,” “amputation,” and “trauma.” A com- prehensive search was performed for each nonsystemic, OA-related risk factor by combining the initial search strat- egy with the combination of the following keyword search terms:
“pain,” “obesity or body mass index or BMI,” “bio- mechanics or load or force or moment or rate, ” “muscle and (weakness or strength or symmetry), ” “acute joint injury or trauma,
” and “physical activity or sports participation.” All titles and abstracts were screened for content and pertinence to the purpose of the review. In cases where direct evidence was lacking, additional supplemental manual searches were performed for relevant articles based on reference lists of the retrieved articles or relevant published literature related to knee OA and its risk factors in the general population. CHRONIC KNEE PAIN Presence of chronic knee pain has been deemed as an early indicator of degenerative joint changes that may appear before evidence of radiographic knee OA in nonamputees. 17 The commonly used conventional radiographs are known to be insensitive to detecting early OA structural changes and are often only useful in measuring late-stage disease. 25 More
recently it has been suggested that symptoms often precede the appearance of radiographic abnormalities, implying the existence of a potentially detectable “prodromal phase” in the transition from preradiographic to radiographic stages of OA.
18 As such, knee pain with activities associated with higher dynamic knee loading such as climbing stairs has been suggested to help identify individuals with preclinical knee OA suitable for early intervention strategies. 17,18
Furthermore, presence of chronic knee pain has been identi fied as an early sign of future OA-related risk of functional decline. 26 After lower limb amputation, high knee pain prevalence rates of 50 to 55% and 36 to 38% have been reported in the intact limbs of individuals with unilateral transfemoral and transtibial amputations, respectively, compared to only a 20% prevalence rate among nonamputees. 3,27,28 Conversely, the residual knee on the side of a transtibial amputation has been reported to be five times less likely to be painful compared to matched knees in nonamputees. 3 Furthermore, Burke et al 29 reported a knee pain prevalence rate of 52% in the intact limbs of individuals with unilateral transtibial amputations as compared to no reports of pain in the resid- ual side knee. The higher prevalence of knee pain on the side of the intact lower limb in individuals with unilateral amputation is consistent with the patterns of knee OA reported in this patient population and may be a sign of MILITARY MEDICINE, Vol. 181, November/December Supplement 2016 39 Development of Knee Osteoarthritis After Unilateral Lower Limb Amputation underlying disease that could be used for initiation of early prevention and intervention strategies. OBESITY Obesity is a well-documented individual risk factor for pri- mary knee OA in older adults. To this end, a three-fold increase in risk of future knee OA development has been previously reported for young men between the ages of 20 and 29 years with BMI values between 24.7 and 37.6 kg/m 2 compared to their leaner counterparts with BMI values between 15.6 and 22.8 kg/m 2 . 19 Epidemiologic studies have previously demonstrated that obesity is linked to both the development and progression of knee OA 20 ; however, there is considerable debate about how obesity contributes to the onset and progression of the disease. Potential mechanisms for the contribution of obesity to knee OA include (1) a gen- eralized negative metabolic environment re flecting a sys- temic in
flammatory response to the products secreted by the adipose tissues; 30,31 (2) increased cumulative compressive loads experienced by the joint due to a greater body mass; 32 or (3) a combination of both metabolic and biomechanical factors. Currently, evidence in support of the metabolic explanation of the link between obesity and knee OA are mixed. Although some authors have suggested that meta- bolic factors associated with obesity contribute to the patho- genesis of knee OA, 30,31
others have not supported this premise.
33 On the other hand, the biomechanical theory explaining the potential link between knee OA and obesity is well supported by the contention that excessive body mass increases the loads placed on the knee joint. 32 For example, it has been reported that a weight increase of 1 kg can result in a four-fold (4 kg) increase in compressive knee joint loads per step during activities of daily living. 32 However, the potentially deleterious effects of greater joint loads due to an increase in body mass may be countered by the lower activity level, slower preferred walking speed, and less number of steps taken per day by individuals with higher body mass, therefore reducing the total knee joint loading exposure. Clinical observations suggest that individuals with traumatic lower limb amputation are at increased risk for weight gain and obesity. Kurdibaylo 34 reported higher fat content in body mass for individuals with transtibial (21%) and transfemoral amputations (23%) compared to age-matched controls (13%). Norvell et al 3 also reported signi ficantly higher average body weight and BMI for individuals with unilateral transtibial and transfemoral amputations compared to control subjects greater than 40 years of age. Younger individuals with amputations, in particular, are at high risk of obesity progression within their
first year status post amputation, mostly as a result of a sedentary lifestyle immediately after amputation but before prosthesis fitting.
34 Given that military standards for recruit- ment commonly exclude overweight volunteers, increased risk of obesity after lower limb amputation is most likely a consequence of the limb loss, which provides a great oppor- tunity for initiation of early weight management strategies. ABNORMAL KNEE JOINT MECHANICS Knee joint mechanics experienced over time create a cus- tomary joint loading history that helps to precondition the tissue to withstand repeated mechanical demands without sustaining injury. 35 However, joint damage may occur when the mechanical environment is signi ficantly altered, such that new patterns of cartilage stresses\strains outside a habituated envelope result. 35 This may be a concern after a traumatic, unilateral lower limb amputation, where the intact limb is challenged by increased demands for body support and for- ward progression. Several key reviews within the past decade have summarized the speci fic mechanical factors which in
fluence the onset and progression of compartment knee OA in the general population 9,36,37 and after lower limb amputations. 38,39
In both populations, the external knee adduction moment (KAM) has been the most frequently used surrogate measure for medial knee joint loading related to knee OA. The KAM may be roughly estimated by multi- plying the magnitude of the ground reaction force (GRF) in the frontal plane with the lever arm distance between the line of action of the GRF and the knee joint axis of rotation (Fig. 1). Individuals with knee OA characteristically demon- strate elevated peak KAM during walking that are strongly associated with severity of medial compartment knee OA, which is 10 times more prevalent in the general nonamputee population than lateral compartment knee OA. 9,36 Further-
more, for patients with existing medial knee OA, KAM magnitude at baseline has strong associations with baseline knee pain severity, and was shown to be longitudinally FIGURE 1. Schematic representation of intact limb knee adduction moment (KAM) during initial limb loading. Ground reaction force (GRF) magnitude, along with the perpendicular distance (white dotted line) between the GRF line of action and the frontal plane knee center of rotation approximates KAM magnitude, which is highly determinate of compressive load within the medial knee compartment. MILITARY MEDICINE, Vol. 181, November/December Supplement 2016 40 Development of Knee Osteoarthritis After Unilateral Lower Limb Amputation predictive of OA radiographic progression. 40 However, mea- sures useful in predicting progression of existing OA may dif- fer from those associated with initiation of OA. 40 Previous investigations of walking in individuals with transtibial amputations (mean age ranging 41.2 –56.3 years old) have reported 33 to 56% greater peak KAM on the intact limb than on the prosthetic limb, depending on walking speed and the type of prosthetic foot used in the study. 13,41
–44 While
this is greater relative to an asymmetry of ~10% in non- amputees, 45 the intact limb may not necessarily be overloaded in direct comparison to the limb of a speed-matched non- amputee. For example, Royer et al 44 found a 56% greater peak KAM on the intact limb relative to the prosthetic side in individuals with unilateral transtibial amputations, associated with a 45% greater tibial plateau bone mineral density on the intact limb, relative to the prosthetic side. However, neither peak KAM magnitude nor the bone mineral density for the intact limb were signi ficantly different from speed- and age- matched nonamputees. 44 In contrast, a number of other studies have instead found mechanical differences in the sagittal plane, reporting 48% greater peak external knee extension moments on the intact limb, relative to the prosthetic side. 12 –14 Higher-level analysis of net GRFs can also lend insight Yüklə 2,47 Mb. Dostları ilə paylaş:
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