- Email: [email protected]
Severity of acl injury affects functional performance 2 years after surgery
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Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534
uncover mechanisms by which function is maintained during walking. The purpose was to determine whether muscle activation levels are immediately altered after a 1 and 3 cm medial and lateral walkway surface perturbations during gait in individuals with moderate knee OA. Methods: 12 participants with unilateral symptomatic moderate knee OA, defined on functional and radiographic criteria, were recruited and provided informed consent. Surface electromyograms (EMG) were acquired from lateral (LG) and medial (MG) gastrocnemius, vastus lateralis (VL), medialis (VM), and rectus femoris (RF), lateral (LH) and medial (MH) hamstrings using an AMT-8™ EMG measurement system (Bortec Inc.). Retro-reflective markers were placed on lower limbs using standardized procedures to monitor knee joint motion. A dual-belt instrumented perturbation treadmill (R-Mill, MotekForcelink) was set to over-ground walking speed. Participants warmed up for 6 minutes followed by 3 blocks of randomized medial and lateral walkway surface perturbations at 1 and 3 cm in magnitude applied at speed (0.1m/s) occurring during the stance phase of symptomatic and asymptomatic limbs. Participants walked bare feet, perturbations were unexpected and separated by at least 40 unperturbed strides. Low pass filtered, time normalized EMG signals were amplitude normalized using the maximal voluntary isometric contraction method. Three strides before each perturbation were averaged (time 0) and the first and third stride after the perturbation was identified as time 1 and 3 respectively. Stance phase average EMG levels and sagittal plane knee range of motion measures were calculated. Analysis of Variance Models tested for main effects and interactions (alpha ¼ 0.05). Post hoc testing was employed using Bonferonni procedures. Results: Muscle main effects were found for each of the perturbation directions and magnitudes where VL > VM > RF and LH > MH. For the lateral 1cm perturbation, a muscle*time interaction was present where LG ¼ MG at time 0 and 3 (p > 0.05) and LG > MG for time 1 (p < 0.05). For lateral 1cm, 3cm and medial 3cm perturbations, quadriceps, gastrocnemii and hamstrings, time 1 was greater than time 0 (p < 0.05). For medial 1cm, time 1 was only greater than time 0 for the quadriceps (p < 0.05). Lateral 1cm (all muscles) and 3cm (quadriceps, gastrocnemii), medial 1cm (all muscles) and 3cm (gastrocnemii, quadriceps, hamstrings), time 3 was not different from time 0 (p > 0.05). For lateral 3cm, time 3 was still greater than time 0 for the hamstrings (p < 0.05). Knee range of motion differences were found for lateral 1 and 3 cm perturbations (p < 0.05) however the absolute differences were small ( < 2 degrees) with exception to the first stride after the lateral 3 cm perturbation where participants contacted the ground in approximately 3 more degrees of flexion compared to preperturbation (p < 0.001). Conclusions: Many individuals with knee OA report poor confidence in their knee and episodes of giving-way during walking. This novel investigation provides evidence that individuals with knee OA respond to unknown challenges through elevated muscle activation that does not result in significantly altered joint kinematics. With exception to hamstrings after the lateral 3cm perturbation, pre-perturbation levels were attained after 3 strides. Generally, this occurred regardless of perturbation direction and magnitudes, suggesting neuromuscular alterations to preserve joint function are transient, non-specific and important for the maintenance of joint function during walking in knee OA. These data have implications for understanding mechanisms of knee OA joint function preservation when walking dynamics are challenged.
however, these two pathologies have not been studied concurrently. The purpose of this study was to investigate the functional performance of ACL reconstructed knees at one and two years after surgery, its relationship to the severity of injury and its association with T1r and T2 relaxation times. Methods: 29 patients (Age ¼ 30.8 ± 8.2 years, BMI ¼ 23.62 ± 2.82 kg/ m2, 16 females) with acute unilateral ACL tears and no previous history of knee trauma or disease were recruited prior to surgery (i.e. baseline). Patients were scanned at baseline (BL), 1 year (1Y) and 2 year (2Y) follow-ups using a 3T MR scanner to acquire sagittal high resolution 3D fast spin-echo imaging (CUBE) and T1r and T2 sequences. Cartilage was segmented semi-automatically on CUBE images into six compartments [lateral femoral condyle, lateral tibia, medial femoral condyle, medial tibia, trochlea and patella], and further divided into 14 subcompartments. Functional performance was evaluated using the commercially available Y-Balance Test (YBT), single leg hop test for distance (SHD) and timed 6-meter hop test for both injured and contralateral (contra) knees. Performance values were obtained by averaging three trials for each assessment. Paired t-test was used to compare functional performance of injured and contra sides at 1Y and 2Y, and also to compare between 1Y and 2Y. Partial correlations controlling for age, gender, BMI and leg length determined whether BL T1r and T2 in the pLT, interpreted as an indicator of severity of injury, predicts functional performance at 2Y. Partial correlations were also used to determine cross-sectional correlations between functional performance and T1r and T2, and also to evaluate if functional performance at 1Y longitudinally affected T1r and T2 at 2Y. Significance was defined as p<0.05. Results: There was no significant difference in YBT performance between injured and contra sides at 1Y and 2Y, as well as between 1Y and 2Y. SHD on the injured side was significantly lower than contra at 1Y and 2Y (Figure 1A) (p<0.01). Timed 6-meter hop was significantly slower for the injured knee at 1Y (p<0.01), but not at 2Y (Figure 1B). No significant associations were identified between 2Y T1r and T2 with YBT, SHD, or timed 6-meter hop at 2Y or 1Y. Higher T1r and T2 in the pLT of the injured knee at BL was associated with decreased YBT distance in all three directions of both knees (Figure 2) (p<0.05, R ¼ 0.427). There was no association between 1Y functional performance with 2Y T1r or T2. Conclusions: The lack of significance between injured and contra 1Y and 2Y YBT performance suggests recovery of postural stability; however, the injured sides’ significantly decreased SHD at 1Y and 2Y and slower 6-meter hop at 1Y may be due to deficiency in strength and confidence in the affected limb. Although there is no significant difference between injured and contra sides of YBT as a group, there are individual variations, and BL T1r and T2 in pLT was correlated with YBT at 2Y. Because the pLT is a region of cartilage damaged by the pivoting mechanism during initial injury, the negative correlation between BL T1r and T2 in the pLT and YBT performance suggests that injury severity may affect postural stability at 2Y; this altered function may suggest abnormal kinematics in the knee joint and lead to long-term OA. Interestingly, we found similar correlations between T1r and T2 and YBT in the contra side as well, suggesting potential adaption of the uninjured side. Our next steps include using additional 2Y follow-ups to further assess long-term functional performance’s relationship with BL T1p and T2, as well as its relationship with biomechanical data and patient report outcomes. Acknowledgment: Funding was provided by NIH/NIAMS and AOSSM.
180 SEVERITY OF ACL INJURY AFFECTS FUNCTIONAL PERFORMANCE 2 YEARS AFTER SURGERY A.K. Li y, K. Amano z, M.S. Tanaka z, R. Souza z, X. Li z, C. Ma z. y Univ. of California, Berkeley, Berkeley, CA, USA; z Univ. of California, San Francisco, San Francisco, CA, USA Purpose: Anterior cruciate ligament (ACL) injury results in instability of the knee joint and early onset of osteoarthritis (OA) in more than half of the injured patients. This deterioration of cartilage can be monitored using quantitative MR, specifically T1r and T2. Immediately following injury, elevated T1r and T2 have been found in cartilage of the posterolateral tibia (pLT); this can be interpreted as an indicator of injury severity because the pivot shift injury mechanism results in the impaction of the lateral femoral condyle against the posterolateral tibial plateau. Additionally, postural stability and isokinetic strength may be decreased despite reconstruction’s partial restoration of kinematics;
Figure 1. (A) Injured limb's single leg hop distance was significantly shorter than the contra's side at 1Y and 2Y. (B) Injured side's timed 6-
Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534
meter hop was significantly slower than the contralateral side at 1 year, but not 2 year. (*P<0.05)
Figure 2. Baseline T1r relaxation time in the posterior lateral tibia is negatively correlated to all directions of Y-Balance Test performance at 2 years (only anterior direction is shown here). (P< 0.05, R ¼ -0.427) 181 IS RESTORATION OF HEALTHY GAIT BIOMECHANICS FOLLOWING TOTAL KNEE REPLACEMENT SURGERY REFLECTED IN PATIENT REPORTED OUTCOME MEASURES? P.R. Biggs y, P. Jones y, C. Wilson z, D. Watling y, G.M. Whatling y, C.A. Holt y. y Cardiff Univ., Cardiff, United Kingdom; z Cardiff and Vale Univ. Hlth.Board, Cardiff, United Kingdom Purpose: Total Knee Replacement (TKR), is a common procedure for patients with late stage osteoarthritis. Despite advancements in design and surgical technique, it is commonly reported that around 1 in 5 subjects are dissatisfied with their outcome; in comparison to closer to 1 in 15 in hip replacements. As with all interventions, one of the keys to maximising benefits is an understanding of which patients benefit the most. This requires the use of post-operative outcome measures to monitor improvement following surgery.However it is accepted that patient reported scoring is limited with respect to objective functional measures. This study aims to quantify restoration of biomechanical function following TKR surgery and compare it to the change in three commonly used patient reported outcome measures (PROMS), to determine which PROMS are most appropriate for measuring the restoration of biomechanical function. Methods: Motion analysis was initially performed on 27 healthy (NL) and 34 subjects with late stage knee osteoarthritis (OA), prior to having TKR surgery. Subjects were asked to fill out a number of PROMS, including the Oxford Knee Score (OKS), Knee Outcome Survey (KOS) and the Knee Injury and Osteoarthritis Outcome Survey (KOOS). Motion capture using an adapted Cleveland Clinic marker set was performed (9 cameras, 60 Hz, Qualisys, Sweden). Ground reaction forces (GRF) were measured (2 forceplates, 1,080 Hz, Bertec, USA). Subjects walked barefoot overground at a self-selected pace and kinematics and inverse dynamic calculations were performed for the hip, knee and ankle (Visual 3D, C-Motion, USA). Principle component analysis was performed to represent the greatest variance of each waveform as discrete variables. This data was used to train the Cardiff Classifier to characterise OA and healthy biomechanical knee function. This methodology was then repeated to quantify pre- and 1 year postoperative function of 13 TKR patients. Postoperative improvement in function was calculated as the absolute reduction of the percentage in the belief of OA. All PROMS were calculated as a percentage, where 0% is healthy, and 100% severely pathological. Statistical analysis was carried out in SPSS using a Pearson correlation and an alpha level of 0.05. Results: The classification accuracy of the training body was 100%; assessed using a leave-one-out cross validation algorithm. Of the 13 TKRs analysed at the 1 year follow up, the average belief of OA (B{OA}) was 85%, which reduced to 55% postoperatively. The change in B{OA} was not correlated to the OKS, KOS, or KOOS. When analysing the individual sections of the KOOS score; including “activities of daily
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living” and “symptoms, the change in B{OA} was again found not to correlate. There was a significant correlation (0.90, p<0.01) between change in OKS and KOS scores. There was no correlation between changes in KOOS score and changes in either OKS or KOS. Conclusions: The Cardiff Classifier was shown to accurately discriminate between the biomechanics of healthy and osteoarthritic gait. Surprisingly, restoration of healthy gait biomechanics following TKR surgery was not found to correlate with changes in either the KOS, KOOS, or OKS patient reported outcome measures. The biomechanics of gait has a major role in daily living and reflective of functional deficits such as quadriceps weakness, knee stiffness and joint pain which affect general function and quality of life. While the post-operative group was fairly small in this study, these preliminary findings suggest PROMS alone may not be sufficient at defining and monitoring functional improvements following TKR surgery, and objective functional outcome measures should be collected in clinic. 182 KNEE OSTEOARTHRITIS FUNCTIONAL CLASSIFICATION SCHEME e VALIDATION OF TIME DEPENDENT TREATMENT EFFECT. ONE YEAR FOLLOW-UP OF 518 PATIENTS A. Herman y, z, A. Mor x, G. Segal x, N. Shazar k, Y. Beer ¶, N. Halperin ¶, R. Debi #, A. Elbaz x. y Dept. of Orthopaedic Surgery,Sheba Med. Center, Tel Hashomer, Israel; z Talpiot Med. Leadership Program, Sheba Med. Center, Tel Hashomer, Israel; x AposTherapy Res. Group, Herzliya, Israel; k Dept. of Orthopaedic Surgery, Sheba Med. Center, Tel Hashomer, Israel; ¶ Dept. of Orthopedic Surgery, Assaf Harofeh Med. Ctr., Zerifin, Israel; # Dept. of Orthopedic Surgery, Barzliay Med. Menter, Ashkelon, Israel Purpose: The purpose of the current study was to validate time dependent changes of a recently published novel functional classification for patients with knee osteoarthritis (KOA), following a homebased biomechanical treatment (HBBT). Methods: A retrospective analysis of 518 patients with KOA was conducted. Patients were graded using a novel knee osteoarthritis functional grade (KOFG) classification for KOA, based on spatio-temporal gait analysis. Patients were re-classified after 3 months and 1 year of HBBT. The time dependent changes in the classification were compared to gold-standard self-assessment questionnaires, WOMAC and short form 36 (SF-36). Results: Change in KOFG were demonstrated over time. Most changes were observed after 3 months of treatment with consolidation of the effect at 12 months. For example, of 427 patients that were KOFG 2-4 at baseline 44.9% and 51.5% had lower (better) KOFG at 3 and 12 months of treatment, respectively. The changes in KOFG were validated with WOMAC and SF-36 questionnaires that showed similar trends. SF-36 pain sub-scale showed an improvement of 33.0% and 38.0% following 3 months and 12 months of treatment, respectively (p values <0.0001). Conclusions: The KOFG classification scheme offers an objective measurement tool for the assessment of function in KOA population and is also a valid tool to assess time-dependent treatment effect. 183 LOWER EXTREMITY KINEMATIC PROFILE OF GAIT OF PATIENTS POST ANKLE FRACTURE. A CASE CONTROL STUDY A. Elbaz y, A. Mor y, G. Segal y, D. Bar y, M.K. Monda z, B. Kish x, M. Nyska x, E. Palmanovich x. y AposTherapy Res. Group, Herzliya, Israel; z UCL Inst. of Orthopaedics and Musculoskeletal Sci., London, United Kingdom; x Dept. of Orthopedic Surgery, Meir Med. Ctr., Kfar-Saba, Israel Purpose: This study aims to examine the differences in lower extremity gait kinematic characterization profile of patients recovering from ankle fracture in comparison to healthy control. In addition it set out to inquire whether the profile is different between fracture severity groups Methods: Forty eight patients participated in this prospective, casecontrolled study. Twenty four patients recovering an ankle fracture injury and twenty four healthy matched control’s gait was examined using inertial measurement unit sensor system. The following gait parameters were evaluated: knee range of motion (ROM) during swing phase, maximum knee flexion angle during stance, thigh and calf ROM through a single gait cycle, and average stride duration.
Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534
uncover mechanisms by which function is maintained during walking. The purpose was to determine whether muscle activation levels are immediately altered after a 1 and 3 cm medial and lateral walkway surface perturbations during gait in individuals with moderate knee OA. Methods: 12 participants with unilateral symptomatic moderate knee OA, defined on functional and radiographic criteria, were recruited and provided informed consent. Surface electromyograms (EMG) were acquired from lateral (LG) and medial (MG) gastrocnemius, vastus lateralis (VL), medialis (VM), and rectus femoris (RF), lateral (LH) and medial (MH) hamstrings using an AMT-8™ EMG measurement system (Bortec Inc.). Retro-reflective markers were placed on lower limbs using standardized procedures to monitor knee joint motion. A dual-belt instrumented perturbation treadmill (R-Mill, MotekForcelink) was set to over-ground walking speed. Participants warmed up for 6 minutes followed by 3 blocks of randomized medial and lateral walkway surface perturbations at 1 and 3 cm in magnitude applied at speed (0.1m/s) occurring during the stance phase of symptomatic and asymptomatic limbs. Participants walked bare feet, perturbations were unexpected and separated by at least 40 unperturbed strides. Low pass filtered, time normalized EMG signals were amplitude normalized using the maximal voluntary isometric contraction method. Three strides before each perturbation were averaged (time 0) and the first and third stride after the perturbation was identified as time 1 and 3 respectively. Stance phase average EMG levels and sagittal plane knee range of motion measures were calculated. Analysis of Variance Models tested for main effects and interactions (alpha ¼ 0.05). Post hoc testing was employed using Bonferonni procedures. Results: Muscle main effects were found for each of the perturbation directions and magnitudes where VL > VM > RF and LH > MH. For the lateral 1cm perturbation, a muscle*time interaction was present where LG ¼ MG at time 0 and 3 (p > 0.05) and LG > MG for time 1 (p < 0.05). For lateral 1cm, 3cm and medial 3cm perturbations, quadriceps, gastrocnemii and hamstrings, time 1 was greater than time 0 (p < 0.05). For medial 1cm, time 1 was only greater than time 0 for the quadriceps (p < 0.05). Lateral 1cm (all muscles) and 3cm (quadriceps, gastrocnemii), medial 1cm (all muscles) and 3cm (gastrocnemii, quadriceps, hamstrings), time 3 was not different from time 0 (p > 0.05). For lateral 3cm, time 3 was still greater than time 0 for the hamstrings (p < 0.05). Knee range of motion differences were found for lateral 1 and 3 cm perturbations (p < 0.05) however the absolute differences were small ( < 2 degrees) with exception to the first stride after the lateral 3 cm perturbation where participants contacted the ground in approximately 3 more degrees of flexion compared to preperturbation (p < 0.001). Conclusions: Many individuals with knee OA report poor confidence in their knee and episodes of giving-way during walking. This novel investigation provides evidence that individuals with knee OA respond to unknown challenges through elevated muscle activation that does not result in significantly altered joint kinematics. With exception to hamstrings after the lateral 3cm perturbation, pre-perturbation levels were attained after 3 strides. Generally, this occurred regardless of perturbation direction and magnitudes, suggesting neuromuscular alterations to preserve joint function are transient, non-specific and important for the maintenance of joint function during walking in knee OA. These data have implications for understanding mechanisms of knee OA joint function preservation when walking dynamics are challenged.
however, these two pathologies have not been studied concurrently. The purpose of this study was to investigate the functional performance of ACL reconstructed knees at one and two years after surgery, its relationship to the severity of injury and its association with T1r and T2 relaxation times. Methods: 29 patients (Age ¼ 30.8 ± 8.2 years, BMI ¼ 23.62 ± 2.82 kg/ m2, 16 females) with acute unilateral ACL tears and no previous history of knee trauma or disease were recruited prior to surgery (i.e. baseline). Patients were scanned at baseline (BL), 1 year (1Y) and 2 year (2Y) follow-ups using a 3T MR scanner to acquire sagittal high resolution 3D fast spin-echo imaging (CUBE) and T1r and T2 sequences. Cartilage was segmented semi-automatically on CUBE images into six compartments [lateral femoral condyle, lateral tibia, medial femoral condyle, medial tibia, trochlea and patella], and further divided into 14 subcompartments. Functional performance was evaluated using the commercially available Y-Balance Test (YBT), single leg hop test for distance (SHD) and timed 6-meter hop test for both injured and contralateral (contra) knees. Performance values were obtained by averaging three trials for each assessment. Paired t-test was used to compare functional performance of injured and contra sides at 1Y and 2Y, and also to compare between 1Y and 2Y. Partial correlations controlling for age, gender, BMI and leg length determined whether BL T1r and T2 in the pLT, interpreted as an indicator of severity of injury, predicts functional performance at 2Y. Partial correlations were also used to determine cross-sectional correlations between functional performance and T1r and T2, and also to evaluate if functional performance at 1Y longitudinally affected T1r and T2 at 2Y. Significance was defined as p<0.05. Results: There was no significant difference in YBT performance between injured and contra sides at 1Y and 2Y, as well as between 1Y and 2Y. SHD on the injured side was significantly lower than contra at 1Y and 2Y (Figure 1A) (p<0.01). Timed 6-meter hop was significantly slower for the injured knee at 1Y (p<0.01), but not at 2Y (Figure 1B). No significant associations were identified between 2Y T1r and T2 with YBT, SHD, or timed 6-meter hop at 2Y or 1Y. Higher T1r and T2 in the pLT of the injured knee at BL was associated with decreased YBT distance in all three directions of both knees (Figure 2) (p<0.05, R ¼ 0.427). There was no association between 1Y functional performance with 2Y T1r or T2. Conclusions: The lack of significance between injured and contra 1Y and 2Y YBT performance suggests recovery of postural stability; however, the injured sides’ significantly decreased SHD at 1Y and 2Y and slower 6-meter hop at 1Y may be due to deficiency in strength and confidence in the affected limb. Although there is no significant difference between injured and contra sides of YBT as a group, there are individual variations, and BL T1r and T2 in pLT was correlated with YBT at 2Y. Because the pLT is a region of cartilage damaged by the pivoting mechanism during initial injury, the negative correlation between BL T1r and T2 in the pLT and YBT performance suggests that injury severity may affect postural stability at 2Y; this altered function may suggest abnormal kinematics in the knee joint and lead to long-term OA. Interestingly, we found similar correlations between T1r and T2 and YBT in the contra side as well, suggesting potential adaption of the uninjured side. Our next steps include using additional 2Y follow-ups to further assess long-term functional performance’s relationship with BL T1p and T2, as well as its relationship with biomechanical data and patient report outcomes. Acknowledgment: Funding was provided by NIH/NIAMS and AOSSM.
180 SEVERITY OF ACL INJURY AFFECTS FUNCTIONAL PERFORMANCE 2 YEARS AFTER SURGERY A.K. Li y, K. Amano z, M.S. Tanaka z, R. Souza z, X. Li z, C. Ma z. y Univ. of California, Berkeley, Berkeley, CA, USA; z Univ. of California, San Francisco, San Francisco, CA, USA Purpose: Anterior cruciate ligament (ACL) injury results in instability of the knee joint and early onset of osteoarthritis (OA) in more than half of the injured patients. This deterioration of cartilage can be monitored using quantitative MR, specifically T1r and T2. Immediately following injury, elevated T1r and T2 have been found in cartilage of the posterolateral tibia (pLT); this can be interpreted as an indicator of injury severity because the pivot shift injury mechanism results in the impaction of the lateral femoral condyle against the posterolateral tibial plateau. Additionally, postural stability and isokinetic strength may be decreased despite reconstruction’s partial restoration of kinematics;
Figure 1. (A) Injured limb's single leg hop distance was significantly shorter than the contra's side at 1Y and 2Y. (B) Injured side's timed 6-
Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534
meter hop was significantly slower than the contralateral side at 1 year, but not 2 year. (*P<0.05)
Figure 2. Baseline T1r relaxation time in the posterior lateral tibia is negatively correlated to all directions of Y-Balance Test performance at 2 years (only anterior direction is shown here). (P< 0.05, R ¼ -0.427) 181 IS RESTORATION OF HEALTHY GAIT BIOMECHANICS FOLLOWING TOTAL KNEE REPLACEMENT SURGERY REFLECTED IN PATIENT REPORTED OUTCOME MEASURES? P.R. Biggs y, P. Jones y, C. Wilson z, D. Watling y, G.M. Whatling y, C.A. Holt y. y Cardiff Univ., Cardiff, United Kingdom; z Cardiff and Vale Univ. Hlth.Board, Cardiff, United Kingdom Purpose: Total Knee Replacement (TKR), is a common procedure for patients with late stage osteoarthritis. Despite advancements in design and surgical technique, it is commonly reported that around 1 in 5 subjects are dissatisfied with their outcome; in comparison to closer to 1 in 15 in hip replacements. As with all interventions, one of the keys to maximising benefits is an understanding of which patients benefit the most. This requires the use of post-operative outcome measures to monitor improvement following surgery.However it is accepted that patient reported scoring is limited with respect to objective functional measures. This study aims to quantify restoration of biomechanical function following TKR surgery and compare it to the change in three commonly used patient reported outcome measures (PROMS), to determine which PROMS are most appropriate for measuring the restoration of biomechanical function. Methods: Motion analysis was initially performed on 27 healthy (NL) and 34 subjects with late stage knee osteoarthritis (OA), prior to having TKR surgery. Subjects were asked to fill out a number of PROMS, including the Oxford Knee Score (OKS), Knee Outcome Survey (KOS) and the Knee Injury and Osteoarthritis Outcome Survey (KOOS). Motion capture using an adapted Cleveland Clinic marker set was performed (9 cameras, 60 Hz, Qualisys, Sweden). Ground reaction forces (GRF) were measured (2 forceplates, 1,080 Hz, Bertec, USA). Subjects walked barefoot overground at a self-selected pace and kinematics and inverse dynamic calculations were performed for the hip, knee and ankle (Visual 3D, C-Motion, USA). Principle component analysis was performed to represent the greatest variance of each waveform as discrete variables. This data was used to train the Cardiff Classifier to characterise OA and healthy biomechanical knee function. This methodology was then repeated to quantify pre- and 1 year postoperative function of 13 TKR patients. Postoperative improvement in function was calculated as the absolute reduction of the percentage in the belief of OA. All PROMS were calculated as a percentage, where 0% is healthy, and 100% severely pathological. Statistical analysis was carried out in SPSS using a Pearson correlation and an alpha level of 0.05. Results: The classification accuracy of the training body was 100%; assessed using a leave-one-out cross validation algorithm. Of the 13 TKRs analysed at the 1 year follow up, the average belief of OA (B{OA}) was 85%, which reduced to 55% postoperatively. The change in B{OA} was not correlated to the OKS, KOS, or KOOS. When analysing the individual sections of the KOOS score; including “activities of daily
S117
living” and “symptoms, the change in B{OA} was again found not to correlate. There was a significant correlation (0.90, p<0.01) between change in OKS and KOS scores. There was no correlation between changes in KOOS score and changes in either OKS or KOS. Conclusions: The Cardiff Classifier was shown to accurately discriminate between the biomechanics of healthy and osteoarthritic gait. Surprisingly, restoration of healthy gait biomechanics following TKR surgery was not found to correlate with changes in either the KOS, KOOS, or OKS patient reported outcome measures. The biomechanics of gait has a major role in daily living and reflective of functional deficits such as quadriceps weakness, knee stiffness and joint pain which affect general function and quality of life. While the post-operative group was fairly small in this study, these preliminary findings suggest PROMS alone may not be sufficient at defining and monitoring functional improvements following TKR surgery, and objective functional outcome measures should be collected in clinic. 182 KNEE OSTEOARTHRITIS FUNCTIONAL CLASSIFICATION SCHEME e VALIDATION OF TIME DEPENDENT TREATMENT EFFECT. ONE YEAR FOLLOW-UP OF 518 PATIENTS A. Herman y, z, A. Mor x, G. Segal x, N. Shazar k, Y. Beer ¶, N. Halperin ¶, R. Debi #, A. Elbaz x. y Dept. of Orthopaedic Surgery,Sheba Med. Center, Tel Hashomer, Israel; z Talpiot Med. Leadership Program, Sheba Med. Center, Tel Hashomer, Israel; x AposTherapy Res. Group, Herzliya, Israel; k Dept. of Orthopaedic Surgery, Sheba Med. Center, Tel Hashomer, Israel; ¶ Dept. of Orthopedic Surgery, Assaf Harofeh Med. Ctr., Zerifin, Israel; # Dept. of Orthopedic Surgery, Barzliay Med. Menter, Ashkelon, Israel Purpose: The purpose of the current study was to validate time dependent changes of a recently published novel functional classification for patients with knee osteoarthritis (KOA), following a homebased biomechanical treatment (HBBT). Methods: A retrospective analysis of 518 patients with KOA was conducted. Patients were graded using a novel knee osteoarthritis functional grade (KOFG) classification for KOA, based on spatio-temporal gait analysis. Patients were re-classified after 3 months and 1 year of HBBT. The time dependent changes in the classification were compared to gold-standard self-assessment questionnaires, WOMAC and short form 36 (SF-36). Results: Change in KOFG were demonstrated over time. Most changes were observed after 3 months of treatment with consolidation of the effect at 12 months. For example, of 427 patients that were KOFG 2-4 at baseline 44.9% and 51.5% had lower (better) KOFG at 3 and 12 months of treatment, respectively. The changes in KOFG were validated with WOMAC and SF-36 questionnaires that showed similar trends. SF-36 pain sub-scale showed an improvement of 33.0% and 38.0% following 3 months and 12 months of treatment, respectively (p values <0.0001). Conclusions: The KOFG classification scheme offers an objective measurement tool for the assessment of function in KOA population and is also a valid tool to assess time-dependent treatment effect. 183 LOWER EXTREMITY KINEMATIC PROFILE OF GAIT OF PATIENTS POST ANKLE FRACTURE. A CASE CONTROL STUDY A. Elbaz y, A. Mor y, G. Segal y, D. Bar y, M.K. Monda z, B. Kish x, M. Nyska x, E. Palmanovich x. y AposTherapy Res. Group, Herzliya, Israel; z UCL Inst. of Orthopaedics and Musculoskeletal Sci., London, United Kingdom; x Dept. of Orthopedic Surgery, Meir Med. Ctr., Kfar-Saba, Israel Purpose: This study aims to examine the differences in lower extremity gait kinematic characterization profile of patients recovering from ankle fracture in comparison to healthy control. In addition it set out to inquire whether the profile is different between fracture severity groups Methods: Forty eight patients participated in this prospective, casecontrolled study. Twenty four patients recovering an ankle fracture injury and twenty four healthy matched control’s gait was examined using inertial measurement unit sensor system. The following gait parameters were evaluated: knee range of motion (ROM) during swing phase, maximum knee flexion angle during stance, thigh and calf ROM through a single gait cycle, and average stride duration.