Matthew R. Titchenal

Effects of high heel wear and increased weight on the knee during walking

Knee osteoarthritis (OA), a leading cause of disability, is more prevalent in women than men. Wearing high heeled shoes has been implicated as a potential contributing factor for the higher lifetime risk of osteoarthritis in women. This study tests the hypotheses that changes to knee kinematics and kinetics observed during high heeled walking increase in magnitude with increasing heel height and are accentuated by a 20% increase in weight. Fourteen healthy females were tested using marker‐based gait analysis in combinations of footwear (flat athletic shoe, 3.8 cm and 8.3 cm heeled shoes) and weight (with and without 20% bodyweight vest). At preferred walking speed, knee flexion angle at heel‐strike and midstance increased with increasing heel height and weight. Maximum knee extension moment during loading response decreased with added weight; maximum knee extension moment during terminal stance decreased with heel height; maximum adduction moments increased with heel height. Many of the changes observed with increasing heel height and weight were similar to those seen with aging and OA progression. This suggests that high heel use, especially in combination with additional weight, may contribute to increased OA risk in women.

Early Changes in Knee Center of Rotation During Walking After Anterior Cruciate Ligament Reconstruction Correlate With Later Changes in Patient-Reported Outcomes

Background: Altered knee kinematics after anterior cruciate ligament injury and reconstruction (ACLR) have been implicated in the development of posttraumatic osteoarthritis (PTOA), leading to poor long-term clinical outcomes. Purpose: This study was conducted to determine (1) whether the average knee center of rotation (KCOR), a multidimensional metric of knee kinematics, of the ACL-reconstructed knee during walking differs from that of the uninjured contralateral knee; (2) whether KCOR changes between 2 and 4 years after surgery; and (3) whether early KCOR changes predict patient-reported outcomes 8 years after ACLR. Study Design: Descriptive laboratory study. Methods: Twenty-six human participants underwent gait analysis with calculation of bilateral KCOR during walking at 2 and 4 years after unilateral ACLR. Knee injury and Osteoarthritis Outcome Score (KOOS) and Lysholm score results were collected at 2, 4, and 8 years after ACLR in 13 of these participants. Results: The ACL-reconstructed knee showed greater medial compartment motion because of pivoting about a more lateral KCOR (P = .03) than the contralateral knee at 2 years. KCOR became less lateral over time (P = .047), with values approaching those of the uninjured knee by 4 years (P = .55). KCOR was also more anterior in the ACL-reconstructed knee at 2 years (P = .02). Between 2 and 4 years, KCOR moved posteriorly in 16 (62%) and anteriorly in 10 (38%) participants. Increasing the anterior position of KCOR in the ACL-reconstructed knee from 2 to 4 years correlated with worsening clinical outcomes at 4 years (KOOS–Quality of Life, R2 = 0.172) and more strongly at 8 years (Lysholm score, R2 = 0.41; KOOS-Pain, R2 = 0.37; KOOS-Symptoms, R2 = 0.58; and KOOS–Quality of Life, R2 = 0.50). Conclusion: The observed changes to KCOR during walking between 2 and 4 years after ACLR show progressive improvement toward kinematic symmetry over the 2-year follow-up. The correlation between increasingly abnormal kinematics and worsening clinical outcomes years later in a subset of participants provides a potential explanation for the incidence of PTOA after ACLR.

Cartilage Subsurface Changes to Magnetic Resonance Imaging UTE-T2* 2 Years After Anterior Cruciate Ligament Reconstruction Correlate With Walking Mechanics Associated With Knee Osteoarthritis:

Background: Anterior cruciate ligament (ACL) injury increases risk for posttraumatic knee osteoarthritis (OA). Quantitative ultrashort echo time enhanced T2* (UTE-T2*) mapping shows promise for early detection of potentially reversible subsurface cartilage abnormalities after ACL reconstruction (ACLR) but needs further validation against established clinical metrics of OA risk such as knee adduction moment (KAM) and mechanical alignment. Hypothesis: Elevated UTE-T2* values in medial knee cartilage 2 years after ACLR correlate with varus alignment and higher KAM during walking. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Twenty patients (mean age, 33.1 ± 10.5 years; 11 female) 2 years after ACLR underwent 3.0-T knee magnetic resonance imaging (MRI), radiography, and gait analysis, after which mechanical alignment was measured, KAM during walking was calculated, and UTE-T2* maps were generated. The mechanical axis and the first and second peaks of KAM (KAM1 and KAM2, respectively) were tested using linear regressions for correlations with deep UTE-T2* values in the central and posterior medial femoral condyle (cMFC and pMFC, respectively) and central medial tibial plateau (cMTP). UTE-T2* values from ACL-reconstructed patients were additionally compared with those of 14 uninjured participants (mean age, 30.9 ± 8.9 years; 6 female) using Mann-Whitney U and standard t tests. Results: Central weightbearing medial compartment cartilage of ACL-reconstructed knees was intact on morphological MRI. Mean UTE-T2* values were elevated in both the cMFC and pMFC of ACL-reconstructed knees compared with those of uninjured knees (P = .003 and P = .012, respectively). In ACL-reconstructed knees, UTE-T2* values of cMFC cartilage positively correlated with increasing varus alignment (R = 0.568). Higher UTE-T2* values in cMFC and cMTP cartilage of ACL-reconstructed knees also correlated with greater KAM1 (R = 0.452 and R = 0.463, respectively) and KAM2 (R = 0.465 and R = 0.764, respectively) and with KAM2 in pMFC cartilage (R = 0.602). Conclusion: Elevated deep UTE-T2* values of medial knee cartilage 2 years after ACLR correlate with 2 clinical markers of increased risk of medial knee OA. These results support the clinical utility of MRI UTE-T2* for early diagnosis of subsurface cartilage abnormalities. Longitudinal follow-up of larger cohorts is needed to determine the predictive and staging potential of UTE-T2* for posttraumatic OA.

Mechanically stimulated biomarkers signal cartilage changes over 5 years consistent with disease progression in medial knee osteoarthritis patients

Using serum biomarkers to assess osteoarthritis (OA) disease state and risks of progression remain challenging. This study tested the hypothesis that changes to serum biomarkers in response to a mechanical stimulus in patients with medial knee OA signal cartilage thickness changes 5 years later. Specifically, serum concentrations of a collagen degradation marker (C1,2C) and a chondroitin sulfate synthesis marker (CS846) were measured 0.5 and 5.5 hours after a 30‐min walk in 16 patients. Regional cartilage thickness changes measured from magnetic resonance images obtained at study entry and at 5‐year follow‐up were tested for correlations with baseline biomarker changes after mechanical stimulus, and for differences between groups stratified based on whether biomarker levels increased or decreased. Results showed that an increase in the degradation biomarker C1,2C correlated with cartilage thinning of the lateral tibia (R = −0.63, p = 0.009), whereas an increase in the synthesis marker CS846 correlated with cartilage thickening of the lateral femur (R = 0.76, p = 0.001). Changes in C1,2C and CS846 were correlated (R2 = 0.28, p = 0.037). Subjects with increased C1,2C had greater (p = 0.05) medial tibial cartilage thinning than those with decreased C1,2C. In conclusion, the mechanical stimulus appeared to metabolically link the biomarker responses where biomarker increases signaled more active OA disease states. The findings of medial cartilage thinning for patients with increases in the degradation marker and correlation of cartilage thickening in the less involved lateral femur with increases in the synthetic marker were consistent with progression of medial compartment OA. Thus, the mechanical stimulus facilitated assessing OA disease states using serum biomarkers.

MRI UTE-T2* Shows High Incidence of Cartilage Subsurface Matrix Changes 2 Years After ACL Reconstruction: MRI UTE-T2* 2 years post-ACLR

Alteration of deep cartilage matrix has been observed following anterior cruciate ligament (ACL) injury, evidenced by elevated MRI UTE‐T2* values measured in small, 2‐D cartilage regions of interest. This Level I diagnostic study seeks to more thoroughly evaluate deep cartilage matrix changes to medial tibiofemoral UTE‐T2* maps 2 years after ACL reconstruction and examine the relative utilities of 3‐D compared to 2‐D assessments of cartilage UTE‐T2* maps. Thirty‐eight ACL‐reconstructed and 20 uninjured subjects underwent MRI UTE‐T2* mapping. “Small” single mid‐sagittal 2‐D and larger 3‐D “tread mark” regions of interest were manually segmented and found to be correlated in medial cartilage (r > 0.58, p < 0.005). 3‐D analyses of UTE‐T2* maps showed differences to medial tibial cartilage between ACL‐reconstructed and uninjured subjects (p = 0.007) that were not detected by smaller 2‐D regions (p > 0.46). Quantitative comparisons show 14/38 (37%) ACL‐reconstructed subjects have values >2 standard deviations higher than uninjured controls. Among a subset of ACL‐reconstructed subjects with no morphologic MRI evidence of medial tibiofemoral cartilage or meniscal pathology (n = 12), elevated UTE‐T2* values in “small” 2‐D femoral (p = 0.011), but not larger 3‐D tread mark regions of interest (p > 0.13), were observed. These data show the utility of 2‐D UTE‐T2* assessments of mid‐sagittal weight‐bearing regions of medial femoral cartilage for identifying subclinical deep cartilage matrix changes 2 years after ACLR. Clinical Significance: Mid‐sagittal single slice 2‐D UTE‐T2* mapping may be an efficient means to assess medial femoral cartilage for subsurface matrix changes early after ACL reconstruction while 3‐D assessments provide additional sensitivity to changes in the medial tibial plateau.

O’Donoghue Award Winner Early Changes in the Knee Joint Center of Rotation during Walking Following Anterior Cruciate Ligament Reconstruction Correlate with Later Changes in Patient Reported Outcomes

Background: Altered knee kinematics after anterior cruciate ligament injury and reconstruction (ACLR) have been implicated in the development of premature osteoarthritis (OA), leading to poor long term clinical outcomes. Purpose: This study was performed to determine (1) whether average knee center of rotation (KCOR), a multidimensional metric of knee kinematics, of the ACLR knee during walking differs from that of the contralateral uninjured knee, (2) whether KCOR changes between 2 and 4 years after surgery, and (3) whether early KCOR changes predict patient reported outcomes 8 years after ACLR. Study Design: Prospective Clinical Study. Methods: Twenty-six human subjects underwent gait analysis with calculation of bilateral KCOR during walking at 2 and 4 years after unilateral ACLR. Knee injury and Osteoarthritis Outcome Scores (KOOS) and Lysholm scores were collected at 2, 4, and 8 years after ACLR in 13 of these subjects. Results: The ACLR knee showed greater medial compartment motion due to pivoting about a more lateral KCOR (P=0.03) than the uninjured contralateral knee at 2 years. KCOR moved medially over time (P=0.047), with values approaching those of the uninjured knee by 4 years (P=0.55). KCOR was also more anterior in the ACLR knee at 2 years (P=0.02). Between 2 and 4 years, KCOR moved posteriorly in 16 (62%) and anteriorly in 10 (38%) subjects. Increasing anterior position of KCOR in the ACLR knee from 2 to 4 years showed no correlation with clinical outcomes at 4 years but correlated with worsening clinical outcomes at 8 years: Lysholm (R2=0.41); KOOS pain (R2=0.37), symptoms (R2=0.58), and quality of life (R2=0.50). Conclusions: The observed changes to KCOR during walking between 2 and 4 years after ACLR show progressive improvement suggestive of continued graft maturation and neuromuscular recovery. The finding of increasingly abnormal kinematics correlating with reduced clinical outcomes years later in a subset of subjects provides a potential explanation for the incidence of premature OA following ACLR. These findings support progressing to more comprehensive studies of larger cohorts examining the predictive potential of KCOR for OA risk as measured by advanced quantitative imaging and radiographs. Clinical Relevance: These results suggest that changes to KCOR during walking as derived from gait analysis, a clinically available metric, may provide early warning of deteriorating knee function after ACLR years before the onset of clinical symptoms.