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7 Gait analysis in pes cavus
Abstracts
El
GAIT ANALYSIS M PES CAWS Benedetti M.G., Cat& F., Ceccarelli F., Simondni L., Giaunini S., Leardini Biomechanics Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy
A.
Introduction From a biomechanical point of view the aim of the treatment of the essential and symptomatic pas cavns is to recreate a plantigrade foot to improve load distribution and increase stability. The foot misalignment caused by the metatarsal head depression in relation to the hittdfoot produces a reduction of support area with consequent metatarsal mechanical overload and instability of the hindfoot. Usually the foot laxity allows the metatarsal depression to be compensated by increasing ankle dorsi tlexion In these patients we have a ‘bompensated caves”, generally asymptomatic and not requiring any surgical correction. The ~ttset of anterior metatarsalgia could be related not only to the degree of cavus deformity but also to the foot’s ability to correct itself during weight-bearing. We can measure the compensation ability of the foot trough the tibial-sole angle or ‘bquinus anple” formed by the intersection of lines drawn along the long axis of the tibia and of the sole (Kumtner, 1991). If this angle is neutral or up to IO0 of equinus, pes caves deformity results asymptomatic, while if the equinus is IS” or more, anterior metatarsalgia develops and gait performance can be severely impaired Gait analysis is the most appropriate technique to detine mechanical compensation of the foot during gait and to establish clinical-timctronal relationships for surgical correction. Methodology Nine patients suffering from essential pes caves were examined in the Movement Analysis Lab of Riuoli Institute. Mean age of the patients was of 29.7 years (max.49-min. IS), 6 male and 3 female. For 6 patients Iimctional assessment was performed in pre-operating period, for 3 patients post-operatively with a mean follow up of 8.3 years. Two patients of the first goup were treated with foot insoles and for these subjects the evaluation was performed in the same session with and without shoes and insoles Data acquisition was made by ELITE System for kinematic variables and by two Kistler platforms for recording foot-ground reaction forces. Both the determination of anatomical landmark position during movement and the anatomical reference system were obtained by “Calibrated Anatomical System Technique” (CAST) experimental protocol, according to Cappozzo, 1995 The study was completed by evaluation of surface EMG using the TELEMG. Data collected from the patient group were compared with a control population of 10 healthy subjects matched for age and sex Results I) Functional results were similar in 4 subjects examined pre-operatively These patients complained of mild pain. A tipical barefoot gait pattern was observed in this group. Kinematics were characterized by an increased flexion of the knee and an increased ankle dorsi flaxion during the stance phase Ankle dorsi flexion is sustained by an evident prolonged activation of the tibialis anterior during mid and late stance aimed at increasing the progression of the tibia on the foot during the ‘Second foot rocker”in order to compensate metatarsal equinus and aid push off and foot clearance. 2) Two patients with the most severe anterior metatarsalgia had a different barefoot gait pattern. In these eases marked abnQmtahties in tiediatan$e paraJ@ers and- ap hyperexstension of the knee during stance ware present. Also if tibialis anterior activity was prolonged throughout the whole stance phase the mechanical compensation at the ankle was not adequate in this case to reduce pain. Gait pattern was improvad by the use of insoles and shoes. The loading redistribution on a wider plantar surface and a metatarsal unloading ahow a painless and more physiological rocker on the support foot during gait. 3) Patients surgically treated had a normal kinematic and EMG pattern. Only time distance parameters were abnomtal with velocity reduction due to stride length. Diicussion In pes caws painiitl anterior metatarsalgia depends on the relationship of the metatarsah to each other in the sagittaI plane and with bindfoot or tibia. This relationship can be well estimated by means of gait analysis considering the ankle angle of dorsigexion during gait (“equinus angle’) Our preliminary study demonstrates how this biomechanical approach is important to evaluate the pathological timction of the pes caves and to individuate the appropriate surgical or conservative treatment.
1) Cappozzo A. et al., Clin. Biomech., Vol.10, 171-178, 1995. 2) Grood E.S.et al, J Biomech Eng; 105, 136-144, 1983. 3) Kummer F.J.et al, in Jahss Disorders of the Foot and Ankle, Saunders Company, Phyladelphia, 1991 4) Perry J., Gait Analysis, SLACK Incorporated, NY, 1992 The kinematic El
and kinetic effects of simulated anklefaot-orthosis
mA. D. Casey Kerrigau MD,MS,*” Charlene Cbiang, BS**, Joel Stein MD”’ l Spaulding Rehabilitation Hospital AH~ard Medical School Departtneot of Physical Medicine **Harvard Medical School
Chapt.21,
poor fit witI+
Robert
pp.541-563,
an
Krug, MD,*”
and Rehabilitation
Introduction Ankle-foot otthoses (AFO) are commonly prescribed in patients with upper and lower motor neuron lesions. Theoretically an AFO which reduces ankle plantar flexion and/or dorsiflexion will act to change the bending moments in the knee during mid- and terminal
169
stance by changing the position of the knee with regard to both the ground reaction force and time to foot-flat. Heel cord contractnres or increased ankle plantar flexor tone can often lead to difficulties in maintaining the correct position of the foot and shank within the brace. Inability to maintain the proper position within an AFO may lead to abnormal and possibly damaging moments at the knee. In order to examine tbe effect of an incorrect tit within an AFO kinematics and kinetics at the kuee and ankle of the braced limb were examined. Subjects wearing an B AFO and an AFO with a one inch heel wedge (Figure 1) placed below the heel inside the AFO (to simulate poor tit) were examined % and compared to nomud gait values. Figure 1 Methodology Kinematic and kinetic data were collected from seven able-bodied subjects (6 males, I female) at the Spaulding Rehabilitation Hospital Gait Laboratory. The meao age was 28.1 years. Three dimensionaI kinematic data were collected using an optoelectronic camera system (Bioengineering Technology Systems, Milan, Italy) at a sampling rate of 100 Hz.. Two AMTI forceplates were used to measure ground reaction fortes. A commercialized protocol (Satlo) was used to calculate kinematics and kinetics. Kinetic and kinematic data in the sag&al plane were analyzed. Three walking trials were collected for each of the following conditions: I) barefoot 2) with a solid AFO fixed at neutral and 3) with a one inch wedge placed inside the AFO below the heel, Subjects walked at a self-determined pace for all conditions. Maximum and minimutn knee and ankle flexion/extension angle, as well as knee and ankle flexion/extension moment for the three walking conditions were compared using two-way repeated analysis of variance tests, A total of six parameters were examined at the knee and ankle. A t-test @=0.05) for the braced and wedge conditions was then conducted on parameters showing any differences. ReSUlti hitid Statistical testing found differences in five of the of the six kinetic aud kinematic parameters However, post-hoc comparisons between the two AFO condition showed no statistical differences. The knee flexor moment at midstance was &o redwed to the point of becoming a small extensor moment (Figure 2), but resulta comparing the three conditions were not significant @=0.06).
0.2 f
Knee
Moment
0.1
Discussion The lack of difference between tbe braced and heel wedge condition may aileviate some of the concern that heel cord contracture and/or increased ankle plantar flexor tone, may cause damaging extensor moments at the knee. The increased extensor moment at the knee during terminal stance did not show a statistical difference between the AFO and simulated poor fit conditions. The increased extensor moment, when compared to normal, during terminal stance for the two AFO conditions is in agreement with the findings of Lebmatm (1982). By placing the subjects in a brace and fixing the ankle at neutral, subjects’ available dorsiflexion is limited during terminal stance and in effect creates a situation similar to that of a placing the foot in plantar flexion. It should be noted that the heel wedge does not perfectly mimic the situation of excessive ankle plantar flexion within the AFO since some body weight undoubtedly is transferred through the wedge, and thus the center of pressure may not progress as rapidly to tbe forefoot in the simulated as compared to the actual scenario.
Lehmann Lehmann Sutherland
References J.F., Arch Phys Mad Rehab. 60: 200-207, 1979. J.F., Arch Phys Med Rehab. 63: 345-351,1982. D.H., et al. Journal of Bone and Joint Surgery. 62-A:
EFFECTS *Pennsylvania
OF FOOT TYPE ON DIABETIC College
L&ttg’+, of Podiatric Medicine,
NEUROPATHIC
II. Hillstrom’r tDrexel University
354-363,198O.
FOOT FUNCTION , Philadelphia
PA.
El
GAIT ANALYSIS M PES CAWS Benedetti M.G., Cat& F., Ceccarelli F., Simondni L., Giaunini S., Leardini Biomechanics Laboratory, Istituto Ortopedico Rizzoli, Bologna, Italy
A.
Introduction From a biomechanical point of view the aim of the treatment of the essential and symptomatic pas cavns is to recreate a plantigrade foot to improve load distribution and increase stability. The foot misalignment caused by the metatarsal head depression in relation to the hittdfoot produces a reduction of support area with consequent metatarsal mechanical overload and instability of the hindfoot. Usually the foot laxity allows the metatarsal depression to be compensated by increasing ankle dorsi tlexion In these patients we have a ‘bompensated caves”, generally asymptomatic and not requiring any surgical correction. The ~ttset of anterior metatarsalgia could be related not only to the degree of cavus deformity but also to the foot’s ability to correct itself during weight-bearing. We can measure the compensation ability of the foot trough the tibial-sole angle or ‘bquinus anple” formed by the intersection of lines drawn along the long axis of the tibia and of the sole (Kumtner, 1991). If this angle is neutral or up to IO0 of equinus, pes caves deformity results asymptomatic, while if the equinus is IS” or more, anterior metatarsalgia develops and gait performance can be severely impaired Gait analysis is the most appropriate technique to detine mechanical compensation of the foot during gait and to establish clinical-timctronal relationships for surgical correction. Methodology Nine patients suffering from essential pes caves were examined in the Movement Analysis Lab of Riuoli Institute. Mean age of the patients was of 29.7 years (max.49-min. IS), 6 male and 3 female. For 6 patients Iimctional assessment was performed in pre-operating period, for 3 patients post-operatively with a mean follow up of 8.3 years. Two patients of the first goup were treated with foot insoles and for these subjects the evaluation was performed in the same session with and without shoes and insoles Data acquisition was made by ELITE System for kinematic variables and by two Kistler platforms for recording foot-ground reaction forces. Both the determination of anatomical landmark position during movement and the anatomical reference system were obtained by “Calibrated Anatomical System Technique” (CAST) experimental protocol, according to Cappozzo, 1995 The study was completed by evaluation of surface EMG using the TELEMG. Data collected from the patient group were compared with a control population of 10 healthy subjects matched for age and sex Results I) Functional results were similar in 4 subjects examined pre-operatively These patients complained of mild pain. A tipical barefoot gait pattern was observed in this group. Kinematics were characterized by an increased flexion of the knee and an increased ankle dorsi flaxion during the stance phase Ankle dorsi flexion is sustained by an evident prolonged activation of the tibialis anterior during mid and late stance aimed at increasing the progression of the tibia on the foot during the ‘Second foot rocker”in order to compensate metatarsal equinus and aid push off and foot clearance. 2) Two patients with the most severe anterior metatarsalgia had a different barefoot gait pattern. In these eases marked abnQmtahties in tiediatan$e paraJ@ers and- ap hyperexstension of the knee during stance ware present. Also if tibialis anterior activity was prolonged throughout the whole stance phase the mechanical compensation at the ankle was not adequate in this case to reduce pain. Gait pattern was improvad by the use of insoles and shoes. The loading redistribution on a wider plantar surface and a metatarsal unloading ahow a painless and more physiological rocker on the support foot during gait. 3) Patients surgically treated had a normal kinematic and EMG pattern. Only time distance parameters were abnomtal with velocity reduction due to stride length. Diicussion In pes caws painiitl anterior metatarsalgia depends on the relationship of the metatarsah to each other in the sagittaI plane and with bindfoot or tibia. This relationship can be well estimated by means of gait analysis considering the ankle angle of dorsigexion during gait (“equinus angle’) Our preliminary study demonstrates how this biomechanical approach is important to evaluate the pathological timction of the pes caves and to individuate the appropriate surgical or conservative treatment.
1) Cappozzo A. et al., Clin. Biomech., Vol.10, 171-178, 1995. 2) Grood E.S.et al, J Biomech Eng; 105, 136-144, 1983. 3) Kummer F.J.et al, in Jahss Disorders of the Foot and Ankle, Saunders Company, Phyladelphia, 1991 4) Perry J., Gait Analysis, SLACK Incorporated, NY, 1992 The kinematic El
and kinetic effects of simulated anklefaot-orthosis
mA. D. Casey Kerrigau MD,MS,*” Charlene Cbiang, BS**, Joel Stein MD”’ l Spaulding Rehabilitation Hospital AH~ard Medical School Departtneot of Physical Medicine **Harvard Medical School
Chapt.21,
poor fit witI+
Robert
pp.541-563,
an
Krug, MD,*”
and Rehabilitation
Introduction Ankle-foot otthoses (AFO) are commonly prescribed in patients with upper and lower motor neuron lesions. Theoretically an AFO which reduces ankle plantar flexion and/or dorsiflexion will act to change the bending moments in the knee during mid- and terminal
169
stance by changing the position of the knee with regard to both the ground reaction force and time to foot-flat. Heel cord contractnres or increased ankle plantar flexor tone can often lead to difficulties in maintaining the correct position of the foot and shank within the brace. Inability to maintain the proper position within an AFO may lead to abnormal and possibly damaging moments at the knee. In order to examine tbe effect of an incorrect tit within an AFO kinematics and kinetics at the kuee and ankle of the braced limb were examined. Subjects wearing an B AFO and an AFO with a one inch heel wedge (Figure 1) placed below the heel inside the AFO (to simulate poor tit) were examined % and compared to nomud gait values. Figure 1 Methodology Kinematic and kinetic data were collected from seven able-bodied subjects (6 males, I female) at the Spaulding Rehabilitation Hospital Gait Laboratory. The meao age was 28.1 years. Three dimensionaI kinematic data were collected using an optoelectronic camera system (Bioengineering Technology Systems, Milan, Italy) at a sampling rate of 100 Hz.. Two AMTI forceplates were used to measure ground reaction fortes. A commercialized protocol (Satlo) was used to calculate kinematics and kinetics. Kinetic and kinematic data in the sag&al plane were analyzed. Three walking trials were collected for each of the following conditions: I) barefoot 2) with a solid AFO fixed at neutral and 3) with a one inch wedge placed inside the AFO below the heel, Subjects walked at a self-determined pace for all conditions. Maximum and minimutn knee and ankle flexion/extension angle, as well as knee and ankle flexion/extension moment for the three walking conditions were compared using two-way repeated analysis of variance tests, A total of six parameters were examined at the knee and ankle. A t-test @=0.05) for the braced and wedge conditions was then conducted on parameters showing any differences. ReSUlti hitid Statistical testing found differences in five of the of the six kinetic aud kinematic parameters However, post-hoc comparisons between the two AFO condition showed no statistical differences. The knee flexor moment at midstance was &o redwed to the point of becoming a small extensor moment (Figure 2), but resulta comparing the three conditions were not significant @=0.06).
0.2 f
Knee
Moment
0.1
Discussion The lack of difference between tbe braced and heel wedge condition may aileviate some of the concern that heel cord contracture and/or increased ankle plantar flexor tone, may cause damaging extensor moments at the knee. The increased extensor moment at the knee during terminal stance did not show a statistical difference between the AFO and simulated poor fit conditions. The increased extensor moment, when compared to normal, during terminal stance for the two AFO conditions is in agreement with the findings of Lebmatm (1982). By placing the subjects in a brace and fixing the ankle at neutral, subjects’ available dorsiflexion is limited during terminal stance and in effect creates a situation similar to that of a placing the foot in plantar flexion. It should be noted that the heel wedge does not perfectly mimic the situation of excessive ankle plantar flexion within the AFO since some body weight undoubtedly is transferred through the wedge, and thus the center of pressure may not progress as rapidly to tbe forefoot in the simulated as compared to the actual scenario.
Lehmann Lehmann Sutherland
References J.F., Arch Phys Mad Rehab. 60: 200-207, 1979. J.F., Arch Phys Med Rehab. 63: 345-351,1982. D.H., et al. Journal of Bone and Joint Surgery. 62-A:
EFFECTS *Pennsylvania
OF FOOT TYPE ON DIABETIC College
L&ttg’+, of Podiatric Medicine,
NEUROPATHIC
II. Hillstrom’r tDrexel University
354-363,198O.
FOOT FUNCTION , Philadelphia
PA.