Nonrandom evolution of end-stage osteoarthritis of the lower limbs

OBJECTIVE: Patients with unilateral hip or knee replacements for end-stage osteoarthritis (OA) are at high risk for future progression of OA in other joints of the lower extremities, often requiring additional joint replacements. Although the risks of future surgery in the contralateral cognate joints (i.e., contralateral hip replacement after an initial hip replacement) have been evaluated, the evolution of end-stage hip OA to OA involving the knee joints, and vice versa (i.e., noncognate progression) has not been investigated. Because characterization of OA progression in noncognate joints may shed light on the pathogenesis of multijoint OA, we investigated the pattern of evolution of end-stage lower extremity OA in a large, clinical cohort. METHODS: Total joint replacement (TJR) was selected as a marker of end-stage OA, and a database comprising all lower extremity TJRs performed at a large referral center between 1981 and 2001 was accessed. Of the 5,894 patients identified, 486 patients with idiopathic OA who underwent hip replacement and 414 who underwent initial knee replacement were analyzed to determine the relative likelihood of subsequent TJRs. Patients with the systemic inflammatory arthropathy, rheumatoid arthritis (RA), were evaluated as a control population because RA progression is not considered to be a primarily mechanically mediated process. RESULTS: The contralateral cognate joint was the most common second joint to undergo replacement in both the OA and the RA groups. However, in OA patients for whom the second TJR was in a noncognate joint, that joint was >2-fold more likely to be on the contralateral limb than on the ipsilateral limb (hip to knee P < 0.001; knee to hip P = 0.013). In contrast, among the RA cohort, the evolution was random and no laterality for noncognate TJR was observed at either the hip or the knee (P = 0.782). CONCLUSION: This characterization of end-stage lower extremity OA demonstrates that the disease evolves nonrandomly; after 1 joint is replaced, the contralateral limb is significantly more likely to show progression of OA than is the ipsilateral limb. Thus, OA in 1 weight-bearing joint appears to influence the evolution of OA in other joints. The absence of such laterality in RA suggests that OA progression may be mediated by extrinsic factors such as altered joint loading.     

Effects of specialized footwear on joint loads in osteoarthritis of the knee

OBJECTIVE: Elevated dynamic joint loads have been associated with the severity and progression of osteoarthritis (OA) of the knee. This study compared the effects of a specialized shoe (the mobility shoe) designed to lower dynamic loads at the knee with self-chosen conventional walking shoes and with a commercially available walking shoe as a control. METHODS: Subjects with knee OA were evaluated in 2 groups. Group A (n = 28) underwent gait analyses with both their self-chosen walking shoes and the mobility shoes. Group B (n = 20) underwent gait analyses with a control shoe and the mobility shoe. Frontal plane knee loads were compared between the different footwear conditions. RESULTS: Group A demonstrated an 8% reduction in the peak external knee adduction moment with the mobility shoe compared with self-chosen walking shoes (mean +/- SD 49 +/- 0.80 versus 2.71 +/- 0.84 %BW x H; P < 0.05). Group B demonstrated a 12% reduction in the peak external knee adduction moment with the mobility shoe compared with the control shoe (mean +/- SD 2.66 +/- 0.69 versus 3.07 +/- 0.75 %BW x H; P < 0.05). CONCLUSION: Specialized footwear can effectively reduce joint loads in subjects with knee OA, compared with self-chosen shoes and control walking shoes. Footwear may represent a therapeutic target for the treatment of knee OA. The types of shoes worn by subjects with knee OA should be evaluated more closely in terms of their effects on the disease.     

Knee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis

OBJECTIVE: To compare the knee joint loading patterns in individuals with differing radiographic grades of knee osteoarthritis (OA) for characterization of the mechanical implications of different structural states, and to compare the knee adduction angular impulse, a measure of gait complementary to the commonly used peak knee adduction moment. METHODS: Asymptomatic subjects (those without knee OA) having a Kellgren/Lawrence (K/L) radiographic severity grade of 0 or 1 (n = 28) and subjects with symptomatic knee OA having K/L grades of 2 (n = 66) or 3 (n = 23) were recruited. Gait analysis was used to calculate the peak external knee adduction moment and the external knee adduction angular impulse for the whole stance and for the 4 subdivisions of stance. RESULTS: Both the peak knee adduction moment and the knee adduction angular impulse increased with K/L radiographic grade (P < 0.05). However, only the knee adduction angular impulse differed between subjects with moderate (grade 3) and those with mild (grade 2) radiographic knee OA (P < 0.05). CONCLUSION: The differences between mild and moderate symptomatic radiographic knee OA are not only structural but also functional, based on the magnitude of load in the medial knee joint. Moreover, knee adduction angular impulse provides additional information beyond that available from the peak knee adduction moment, and may therefore be an important gait parameter to include in OA research. These findings are important for our understanding of the pathophysiologic mechanisms of OA.     

Gait analysis in an osteoarthritis patient with restoration of the hip joint space following contralateral total hip arthroplasty: a case report

We present the case of a patient who, after undergoing unilateral total hip arthroplasty (THA), achieved pain reduction in the contralateral hip accompanied by restoration of the radiographic joint space. We conducted gait analysis to clarify the dynamic factors affecting the natural course of osteoarthritis (OA). Our findings revealed that the patient walked with exaggerated adduction of the hip following the contralateral THA, causing substantial regeneration of joint loading.     

Nonrandom evolution of end‐stage osteoarthritis of the lower limbs

Objective

Patients with unilateral hip or knee replacements for end‐stage osteoarthritis (OA) are at high risk for future progression of OA in other joints of the lower extremities, often requiring additional joint replacements. Although the risks of future surgery in the contralateral cognate joints (i.e., contralateral hip replacement after an initial hip replacement) have been evaluated, the evolution of end‐stage hip OA to OA involving the knee joints, and vice versa (i.e., noncognate progression) has not been investigated. Because characterization of OA progression in noncognate joints may shed light on the pathogenesis of multijoint OA, we investigated the pattern of evolution of end‐stage lower extremity OA in a large, clinical cohort.

Methods

Total joint replacement (TJR) was selected as a marker of end‐stage OA, and a database comprising all lower extremity TJRs performed at a large referral center between 1981 and 2001 was accessed. Of the 5,894 patients identified, 486 patients with idiopathic OA who underwent hip replacement and 414 who underwent initial knee replacement were analyzed to determine the relative likelihood of subsequent TJRs. Patients with the systemic inflammatory arthropathy, rheumatoid arthritis (RA), were evaluated as a control population because RA progression is not considered to be a primarily mechanically mediated process.

Results

The contralateral cognate joint was the most common second joint to undergo replacement in both the OA and the RA groups. However, in OA patients for whom the second TJR was in a noncognate joint, that joint was >2‐fold more likely to be on the contralateral limb than on the ipsilateral limb (hip to knee P < 0.001; knee to hip P = 0.013). In contrast, among the RA cohort, the evolution was random and no laterality for noncognate TJR was observed at either the hip or the knee (P = 0.782).

Conclusion

This characterization of end‐stage lower extremity OA demonstrates that the disease evolves nonrandomly; after 1 joint is replaced, the contralateral limb is significantly more likely to show progression of OA than is the ipsilateral limb. Thus, OA in 1 weight‐bearing joint appears to influence the evolution of OA in other joints. The absence of such laterality in RA suggests that OA progression may be mediated by extrinsic factors such as altered joint loading.

     

Relationship between pain and medial knee joint loading in mild radiographic knee osteoarthritis

OBJECTIVE: The relationship between knee pain and radiographic evidence of knee osteoarthritis (OA) is notoriously imperfect. In particular, conditions that distinguish individuals with symptoms from those with comparable radiographic involvement who remain asymptomatic are unclear. We investigated dynamic loading across the knee in individuals with mild radiographic OA who were distinguished by the presence or absence of knee pain. METHODS: Subjects were recruited into 3 groups: symptomatic with a Kellgren/Lawrence (K/L) grade of 2 (n = 52), asymptomatic with a K/L grade of 2 (n = 19), and asymptomatic with a K/L grade of 0 or 1 (n = 37), the latter representing a normal comparator group. Dynamic knee loading was assessed with gait analysis, and both the peak external knee adduction moment and the knee adduction angular impulse were determined. RESULTS: Peak knee adduction moment and knee adduction angular impulse were 19% and 30% higher, respectively, in symptomatic K/L grade 2 individuals than in asymptomatic individuals with the same radiographic grade (P < 0.05). Conversely, the asymptomatic K/L grade 2 group did not differ from the K/L grade 0-1 normal comparator group (P = 1.00). CONCLUSION: Among individuals with mild radiographic knee OA (K/L grade 2), those who are symptomatic have significantly higher medial compartment loads than those who are asymptomatic, whereas those who are asymptomatic do not differ from normal controls (asymptomatic K/L grade 0 or 1). These findings suggest a biomechanical component to the distinction between asymptomatic and symptomatic radiographic OA, which may be pathophysiologically important.     

Walking barefoot decreases loading on the lower extremity joints in knee osteoarthritis

OBJECTIVE: To evaluate the effects that modern shoes have on gait and lower extremity joint loads in osteoarthritis (OA). METHODS: Gait analyses were performed on 75 subjects with knee OA while they were wearing their everyday walking shoes and while they were walking barefoot. The trials involved optoelectronic detection of external markers during ambulation over a multicomponent force plate, and were matched for speed. Comparisons were made of gait parameters and joint loading during trials in which the subjects walked while wearing shoes and while barefoot. RESULTS: Peak joint loads at the hips and knees significantly decreased during barefoot walking, with an 11.9% reduction noted in the knee adduction moment. Stride, cadence, and range of motion at the lower extremity joints also changed significantly, but these changes could not explain the reduction in the peak joint loads. CONCLUSION: Shoes may detrimentally increase loads on the lower extremity joints. Once factors responsible for the differences in loads between with-shoe and barefoot walking are better delineated, modern shoes and walking practices may need to be reevaluated with regard to their effects on the prevalence and progression of OA in our society.     

Secondary gait changes in patients with medial compartment knee osteoarthritis: increased load at the ankle, knee, and hip during walking

OBJECTIVE: This study tested the hypothesis that gait changes related to knee osteoarthritis (OA) of varied severity are associated with increased loads at the ankle, knee, and hip. METHODS: Forty-two patients with bilateral medial compartment knee OA and 42 control subjects matched for sex, age, height, and mass were studied. Nineteen patients had Kellgren/Lawrence (K/L) radiographic severity grades of 1 or 2, and 23 patients had K/L grades of 3 or 4. Three-dimensional kinematics and kinetics were measured in the hip, knee, and ankle while the subjects walked at a self-selected speed. RESULTS: Patients with more severe knee OA had greater first peak knee adduction moments than their matched control subjects (P = 0.039) and than patients with less severe knee OA (P < 0.001). All patients with knee OA made initial contact with the ground with the knee in a more extended position than that exhibited by control subjects. An increased axial loading rate was present in all joints of the lower extremity. Patients with more severe knee OA had lower hip adduction moments compared with their matched control subjects. CONCLUSION: The secondary gait changes observed among patients with knee OA reflect a potential strategy to shift the body's weight more rapidly from the contralateral limb to the support limb, which appears to be successful in reducing the load at the knee in only patients with less severe knee OA. The increased loading rate in the lower extremity joints may lead to a faster progression of existing OA and to the onset of OA at joints adjacent to the knee. Interventions for knee OA should therefore be assessed for their effects on the mechanics of all joints of the lower extremity.     

Prevalence of generalised osteoarthritis in patients with advanced hip and knee osteoarthritis: the Ulm Osteoarthritis Study

OBJECTIVES: Different prevalences of generalised osteoarthritis (GOA) in patients with knee and hip OA have been reported. The aim of this investigation was to evaluate radiographic and clinical patterns of disease in a hospital based population of patient subgroups with advanced hip and knee OA and to compare the prevalence of GOA in patients with hip or knee OA, taking potential confounding factors into account. METHODS: 420 patients with hip OA and 389 patients with knee OA scheduled for unilateral total joint replacement in four hospitals underwent radiographic analysis of ipsilateral and contralateral hip or knee joint and both hands in addition to a standardised interview and clinical examination. According to the severity of radiographic changes in the contralateral joints (using Kellgren-Lawrence > or = grade 2 as case definition) participants were classified as having either unilateral or bilateral OA. If radiographic changes of two joint groups of the hands (first carpometacarpal joint and proximal/distal interphalangeal joints defined as two separate joint groups) were present, patients were categorised as having GOA. RESULTS: Patients with hip OA were younger (mean age 60.4 years) and less likely to be female (52.4%) than patients with knee OA (66.3 years and 72.5% respectively). Intensity of pain and functional impairment at hospital admission was similar in both groups, while patients with knee OA had a longer symptom duration (median 10 years) compared with patients with hip OA (5 years). In 41.7% of patients with hip OA and 33.4% of patients with knee OA an underlying pathological condition could be observed in the replaced joint, which allowed a classification as secondary OA. Some 82.1% of patients with hip and 87.4% of patients with knee OA had radiographic changes in their contralateral joints (bilateral disease). The prevalence of GOA increased with age and was higher in female patients. GOA was observed more often in patients with knee OA than in patients with hip OA (34.9% versus 19.3%; OR = 2.24; 95% CI: 1.56, 3.21). Adjustment for the different age and sex distribution in both patient groups, however, takes away most of the difference (OR = 1.32; 95% CI: 0.89, 1.96). CONCLUSION: The crude results confirm previous reports as well as the clinical impression of GOA being more prevalent in patients with advanced knee OA than in patients with advanced hip OA. However, these different patterns might be attributed to a large part to a different distribution of age and sex in these hospital based populations.     

Reducing joint loading in medial knee osteoarthritis: shoes and canes

OBJECTIVE: Increased medial knee loading is associated with a much higher risk of disease progression in knee osteoarthritis (OA). Interventions that can reduce medial knee joint load have the potential to slow disease progression over time. We evaluated the effects of shoes and a cane on knee load in people with knee OA. METHODS: Forty people with medial knee OA underwent 3-dimensional gait analysis to measure their peak knee adduction moment, an indicator of medial knee joint load. Results when walking in bare feet were compared with those obtained when walking in their own usual shoes. Twenty participants also underwent testing using a cane, and results were compared with walking unaided. RESULTS: Compared with barefoot, walking in shoes was associated with a significant increase in the peak knee adduction moment (mean +/- SD N x m/BW x H% 3.49 +/- 0.84 versus 3.77 +/- 0.90; P < 0.001), although there was considerable individual variation. The use of a cane resulted in a 10% decrease in the knee adduction moment (mean +/- SD N x m/BW x H% 3.76 +/- 0.95 versus 3.38 +/- 0.68; P = 0.001). CONCLUSION: Wearing shoes increases medial knee joint load compared with walking barefoot. Given the variable response to shoes observed, further research is required to ascertain which shoe types might be optimal for those with knee OA. The use of a cane significantly reduces medial knee loading and has the potential to reduce the risk of disease progression in knee OA.     

Individuals with severe knee osteoarthritis (OA) exhibit altered proximal walking mechanics compared with individuals with less severe OA and those without knee pain

Objective

To examine hip, pelvis, and trunk walking biomechanics in individuals with medial compartment knee osteoarthritis (OA) of varying radiographic disease severities and others without knee pain.

Methods

Hip, pelvis, and trunk kinematics and hip kinetics were assessed in 75 individuals with radiographically confirmed OA and 20 asymptomatic individuals. Differences in peak hip adduction and abduction angles, the amount of contralateral pelvic drop, and peak lateral trunk lean measured by 3‐dimensional gait analysis were examined using analyses of variance. Peak external hip abduction and adduction moments were compared using analyses of covariance, with gait speed as a covariate.

Results

Those with severe OA disease exhibited significantly less peak hip adduction (5.0°), but more ipsilateral trunk lean toward the study extremity (5.0°) than all other groups (P < 0.001). Those in the severe (1.1°) and asymptomatic (0.9°) groups also exhibited significantly less lateral trunk lean toward the non‐study extremity (P = 0.004). No significant differences in hip joint moments or contralateral pelvic drop were observed between the groups (P > 0.02).

Conclusion

Gait changes at the hip and trunk were evident across the groups based on radiographic disease severity and compared with those without knee pain. Although not conclusive from this cross‐sectional study design, the results provide initial evidence to support increased lateral trunk lean as being a compensatory response to the disease.     

Clinical epidemiology of hip and knee joint arthroses: an overview of the results of the "Ulm Osteoarthrosis Study"

AIM OF STUDY: To summarize the strategy of patient recruitment, applied methods and published results within the Ulm Osteoarthritis Study, a multicenter cross-sectional survey of patients with advanced hip and knee osteoarthritis. METHODS: 420 patients with hip OA and 398 patients with knee OA scheduled for unilateral total joint replacement in four hospitals in the southwestern part of Germany underwent detailed clinical investigations and a standardized interview in addition to radiographic analyses of ipsilateral and contralateral hip or knee joint and both hands. Odds ratios and 95% confidence intervals for the association of different possible risk factors with OA patterns (unilateral, bilateral and generalized OA) were calculated with logistic regression, adjusting for potential confounders. RESULTS: In 41.7% of patients with hip OA and 33.4% of patients with knee OA, an underlying pathological condition allowed a classification as secondary OA. 82.1% of patients with hip and 87.4% of patients with knee OA had bilateral disease. Generalized OA (GOA) was found in 19.3 and 34.9%, respectively (after adjustment for different age and sex distribution in the two patient groups; however, this difference was not any more significant). A positive association could be observed between hypercholesterolemia and GOA in knee OA patients as well as between serum uric acid and GOA in hip OA patients. Obesity and overweight were associated with bilateral knee OA, but not bilateral hip OA nor GOA. DISCUSSION: Our innovative study design allows the non-invasive investigation of patient subgroups with established disease and a testing of relevant hypotheses in an appropriate setting. The data add to the evidence regarding the independent role of different systemic risk factors for OA. In an ongoing study the natural course of the disease of the contralateral, unoperated joint is currently being investigated in all recruited patients.     

End-stage coxarthrosis and gonarthrosis. Aetiology, clinical patterns and radiological features of idiopathic osteoarthritis

OBJECTIVES: To determine and compare the aetiological background, clinical patterns and radiological features of idiopathic osteoarthritis (OA) of the hip and the knee warranting arthroplasty. METHODS: A total of 402 Caucasians consecutively undergoing total hip replacement (THR) or total knee replacement (TKR) for idiopathic OA at a major centre was surveyed. RESULTS: Previous joint injury was more common in the TKR group (P < 0.0001). However, both groups manifested a mixed occupational background, body mass indices similar to the general population and a predominance of females (F:M = 1.3-1.4:1). The TKR group had a significantly younger age of symptom onset (56 yr) than the THR group (61 yr) but both groups had a tendency to bilateral arthroplasty (33%), nodal involvement (54-59%), a significant excess of right-sided replacements (1.8:1, THR; 2.2:1, TKR) and similar levels of pre-operative pain and disability. Up to 40% of hips manifested acetabular dysplasia and 10% possible previous slipped upper femoral epiphyses. Eighty-five per cent with end-stage coxarthrosis or gonarthrosis had an identical pattern of radiographic disease contralaterally. CONCLUSIONS: Our data suggest the importance of a constitutional tendency to idiopathic, end-stage OA, a disorder traditionally associated with environmental factors leading to 'wear and tear'.     

Bone mineral density varies as a function of the rate of joint space narrowing in the hip

OBJECTIVE: To determine whether patients with a rapid rate of joint space narrowing (JSN) in the hip have higher initial bone mineral density (BMD) in the proximal femur and/or lumbar spine than corresponding patients with a slow rate of JSN. METHODS: Twenty-eight patients undergoing unilateral total hip replacement (THR) for osteoarthritis (OA), but whose contralateral hips were asymptomatic and had minimal or no radiographic OA, were evaluated. The contralateral proximal femur (i.e., non-operated hip) and lumbar spine were scanned by dual energy x-ray absorptiometry at baseline (prior to THR) and at 2 years. The rate of JSN was determined by serial longitudinal quantification of the joint spaces over the 2 year period following THR from conventional radiographs, and the patients were divided into a group with a slow rate of JSN (< or = 0.2 mm/yr, n = 20) and a group with a rapid rate of JSN (> 0.2 mm/yr, n = 8). RESULTS: The baseline BMD z and t scores at the femoral neck, Ward's triangle, and lumbar spine of the patients with subsequent rapid rates of JSN were significantly higher than those of patients with slower rates (p < 0.05). There was no difference between the rapid and slow narrowers at the greater trochanter (p > 0.2). Age, sex, weight, height, body mass index, Kellgren- Lawrence scores, and initial joint space width were not significantly different between the 2 groups. CONCLUSION: Patients with a rapid rate of JSN of the asymptomatic hip after unilateral THR are characterized by elevated local and remote BMD. The local elevation in BMD implies that increased local bone density may contribute to or serve as a marker for increased risk of development of OA (assuming that JSN can be used as a predictive marker). The presence of elevated BMD in the spine suggests that there are systemic as well as local aspects of OA pathogenesis, at least in patients with one THR and rapid JSN in the contralateral hip.     

The relationship between the knee adduction moment and knee pain in middle-aged women without radiographic osteoarthritis

OBJECTIVE:. An abnormally high knee adduction moment increases the medial tibiofemoral compartment load at the knee during gait, and is an important biomechanical marker of joint pathology. This cross-sectional study examines the relationship between the knee adduction moment and knee pain in middle-aged women without radiographic knee osteoarthritis (OA). METHODS: Three-dimensional Vicon gait analyses were performed on 20 women who had knee pain but no radiological evidence of joint pathology. RESULTS: In multivariate analysis, the peak knee adduction moment during the late stance phase of gait was inversely associated with knee pain [beta: -10.1 (95% CI -17.6, -2.7), p = 0.01] after adjustment for body mass index (BMI) and age. This explained that the knee adduction moment during late stance contributed 32% of the variance in knee pain. The peak knee adduction moment during early stance was not significantly associated with knee pain prior to and after adjustment for BMI and age. CONCLUSION: There is a significant inverse association between the peak knee adduction moment during late stance and the amount of knee pain experienced by women without radiographic evidence of joint pathology. This may represent a compensatory mechanism to reduce medial tibiofemoral joint load in the setting of knee pain.     

Dynamic load at baseline can predict radiographic disease progression in medial compartment knee osteoarthritis

OBJECTIVE: To test the hypothesis that dynamic load at baseline can predict radiographic disease progression in patients with medial compartment knee osteoarthritis (OA). METHODS: During 1991-93 baseline data were collected by assessment of pain, radiography, and gait analysis in 106 patients referred to hospital with medial compartment knee OA. At the six year follow up, 74 patients were again examined to assess radiographic changes. Radiographic disease progression was defined as more than one grade narrowing of minimum joint space of the medial compartment. RESULTS: In the 32 patients showing disease progression, pain was more severe and adduction moment was higher at baseline than in those without disease progression (n=42). Joint space narrowing of the medial compartment during the six year period correlated significantly with the adduction moment at entry. Adduction moment correlated significantly with mechanical axis (varus alignment) and negatively with joint space width and pain score. Logistic regression analysis showed that the risk of progression of knee OA increased 6.46 times with a 1% increase in adduction moment. CONCLUSIONS: The results suggest that the baseline adduction moment of the knee, which reflects the dynamic load on the medial compartment, can predict radiographic OA progression at the six year follow up in patients with medial compartment knee OA.     

Hip abduction moment and protection against medial tibiofemoral osteoarthritis progression

OBJECTIVE: To test the hypothesis that a greater peak internal hip abduction moment is associated with a reduced likelihood of ipsilateral medial tibiofemoral osteoarthritis (OA) progression. METHODS: Fifty-seven persons with knee OA (by definite osteophyte presence and symptoms) were evaluated. Baseline assessments included kinematic and kinetic gait parameters, obtained with an optoelectronic camera system and force platform, with inverse dynamics used to calculate 3-dimensional moments at the joints; pain, using a separate visual analog scale for each knee; and alignment, using full-limb radiographs. Radiographs of the knee in a semiflexed position, with fluoroscopic confirmation of tibial rim alignment, were obtained at baseline and 18 months later. Disease progression was defined as worsening of the grade of medial joint space narrowing. Logistic regression obtained with generalized estimating equations was used to estimate odds ratios (ORs) for progression per unit of hip abduction moment, after excluding knees with the worst joint space grade at baseline (which could not progress). RESULTS: The 57 participants (63% women) with mild to moderate OA had a mean age of 67 years and a mean body mass index of 29. A greater internal hip abduction moment during gait was associated with a reduced likelihood of medial tibiofemoral OA progression, with OR/unit hip abduction moment of 0.52 and a 95% confidence interval (95% CI) of 0.32-0.85. This protective effect persisted after adjustment for age, sex, walking speed, knee pain severity, physical activity, varus malalignment severity, hip OA presence, and hip OA symptom presence, with an adjusted OR of 0.43 a 95% CI of 0.22-0.81. CONCLUSION: A greater hip abduction moment during gait at baseline protected against ipsilateral medial OA progression from baseline to 18 months. The likelihood of medial tibiofemoral OA progression was reduced 50% per 1 unit of hip abduction moment.     

The effect of the knee adduction moment on tibial cartilage volume and bone size in healthy women

OBJECTIVES: There is considerable evidence that an abnormally high knee adductor moment is a characteristic of the gait patterns in people with knee osteoarthritis (OA). The aim of this study was to examine the relationship between the peak knee adduction moment during the early and late stance phases of gait, and medial and lateral tibial bone size and cartilage volume in healthy women. METHODS: Three-dimensional Vicon gait analyses and magnetic resonance imaging (MRI) were performed on 20 healthy women without knee OA. The external knee adduction moment was correlated with medial and lateral tibial bone size and cartilage volume for the dominant leg. RESULTS: The knee adduction moment significantly correlated with the bone size of the medial tibial plateau (r = 0.63, P < 0.005), but was not related to the bone size of the lateral plateau. No relationship was observed between the knee adduction moment and medial or lateral tibial cartilage volume. CONCLUSIONS: Although the knee adduction moment was positively associated with the bone size of the medial tibial plateau, it appeared to have little effect on cartilage volume in that compartment in healthy women. It may be that the effect of the knee adduction moment differs in healthy subjects compared with those with established knee OA.     

Effects of common footwear on joint loading in osteoarthritis of the knee

Objective

Elevated joint loads during walking have been associated with the severity and progression of osteoarthritis (OA) of the knee. Footwear may have the potential to alter these loads. This study compares the effects of several common shoe types on knee loading in subjects with OA of the knee.

Methods

Thirty‐one subjects (10 men, 21 women) with radiographic and symptomatic knee OA underwent gait analyses using an optoelectronic camera system and multicomponent force plate. In each case, gait was evaluated during barefoot walking and while wearing 4 different shoe types: 1) clogs, 2) stability shoes, 3) flat walking shoes, and 4) flip‐flops. Peak knee loads were compared between the different footwear conditions.

Results

Overall, the clogs and stability shoes resulted in a significantly higher (～15% higher) peak knee adduction moment (mean ± SD 3.1 ± 0.7 and 3.0 ± 0.7 divided by body weight [BW] × height [H] multiplied by 100, respectively; P < 0.05) compared with that of flat walking shoes (mean ± SD 2.8 ± 0.7 %BW × H), flip‐flops (mean ± SD 2.7 ± 0.8 %BW × H), and barefoot walking (mean ± SD 2.7 ± 0.7 %BW × H). There were no statistically significant differences in knee loads with the flat walking shoes and flip‐flops compared with barefoot walking.

Conclusion

These data confirm that footwear may have significant effects on knee loads during walking in subjects with OA of the knee. Flexibility and heel height may be important differentiating characteristics of shoes that affect knee loads. In light of the strong relationship between knee loading and OA, the design and biomechanical effects of modern footwear should be more closely evaluated in terms of their effects on the disease.     

Compensatory gait mechanics in patients with unilateral knee arthritis

OBJECTIVE: Few studies exist on gait adaptation caused by knee osteoarthritis (OA), and those have only explored adaptations of the kinematics and kinetics of the knee joint itself. We characterize ankle, knee, hip, and low back mechanical energy expenditures (MEE) and compensations (MEC) during gait in patients with knee OA. METHODS: Thirteen elderly patients with unilateral knee OA and 10 matched healthy elderly controls were studied during preferred and paced speed gait. Gait speed, step length, and lower extremity and low back joint MEE and MEC were compared between groups. RESULTS: Patients with knee OA had lower, but not significantly different, walking speed and step length compared to the controls, and had significantly different joint kinetic profiles. Patients had reduced ankle power at terminal stance, lacked a second positive peak in knee power, and had increased power absorption at the hip. Abnormal knee kinematics were exaggerated when walking at a paced speed, but hip kinetics normalized among patients with OA. CONCLUSION: Reduced ankle plantar-flexion power in patients with knee OA was probably due to disrupted transfer of energy through the knee. Lack of concentric knee power supports prior studies' conclusions that patients with knee OA avoid using their quadriceps to stabilize the knee, probably to reduce articular loads. Patients with knee OA increase eccentric hip power due to increased hip extension caused by abnormal knee kinematics, potentially increasing hip articular forces. This passive mechanism, however, may assist in the advancement of the leg into swing phase.