900 Archives ofDisease in Childhood 1991; 66: 900-903

PERSONAL PRACTICE Arch Dis Child: first published as 10.1136/adc.66.7.900 on 1 July 1991. Downloaded from

Use of movement analysis in understanding abnormalities of gait in

J H Patrick

Orthopaedic surgeons and paediatricians rarely walking potential. This is now a fine art, done use gait laboratory studies to assist decision best by skilled physiotherapists during a session making in the treatment of walking diplegic of play, observation, and exercise usually patients with cerebral palsy. This is now chang- undertaken during the first two years of life. In ing because of a realisation that operations for some areas of the country physiotherapists then cerebral palsy can be vastly improved using remain at the forefront of physical management such analysis. policy for that child. Orthopaedic surgeons and An unlikely stimulus came in spring 1990 paediatricians usually accept this, as the attain- from the media. BBC television showed a film ment of walking is usually the province of phy- about the progress of a spastic boy from south siotherapists and parents. Occasionally ortho- London who visited a movement analysis labor- paedic surgeons are asked to lengthen a tendon atory at Newington Children's Hospital, Con- or muscle (usually at the groin or ankle), but the necticut, USA. There he was assessed using child grows and learns without much medical VICON kinematics, electromyography, and advice. Most children whose is con- forceplate measurements. He then underwent fined to the legs, do walk; the more severely surgery and physiotherapy. The results of the affected require wheelchairs, but there is a operations were not spectacular, but the tech- group for whom walking becomes increasingly nology and the touching pictures of a coura- difficult because of high energy costs of particu- geous boy with cerebral palsy were more impor- lar deformities which deleteriously affect walk- tant than 'results'. ing. Doctors and therapists have been stimulated Until recently we have been unable to analyse to think of improvements in diagnostic methods why some children apparently do well after

and ways of achieving a better understanding of operations, for example lengthening of the http://adc.bmj.com/ the biomechanics of walking in individual heel cord. Others, seemingly identical, adopt a patients. A case is made here for reconsidering the place of surgery for many patients with cere- bral palsy by undertaking bony procedures and release or lengthening of tendons after gait analysis has been carried out, on more mature

children aged from 7-8 years. on September 29, 2021 by guest. Protected copyright. Although the television commentary did not mention the source of the equipment, that used in this patient's analysis was British; such sys- tems are no longer just research tools, as is shown by the work of our laboratory. Accurate three dimensional data about limb movements in space can be obtained and viewed at leisure by rerunning video film after conventional examination of the patient has identified some of the problems in the lower limbs. Such equip- ment, together with synchronous electromyog- raphic recordings of muscle activity and kinetic force estimations in the lower limb, can now be used to measure each ambulatory spastic child. Movement analysis is now more than an Orthotic Research interesting research tool, because it permits and Locomotor accurate diagnosis of the causes and effects of Assessment Unit, deformity in cerebral palsy. Consequently, (ORLAU), Robert Jones and treatment possibilities suggest themselves: phy- Agnes Hunt Orthopaedic siotherapy, orthoses, or operation. Hospital, Figure I Left mid-stance phase in ORLA U movement Oswestry, analysis laboratory. Ground reaction vector line (representing Shropshire SYIO 7AG body weight passing throughforce platform) shown as an Traditional treatment regimen extending moment to the left knee. Note slight equinus and J H Patrick lumbar lordosis caused by increased gastrocnemius and psoas Correspondence to: For spastic children traditional methods of muscle tone. (Figure is a polaroid photograph takenfrom a Mr Patrick. treatment have all included an assessment of moving video film.) Use ofmovement analysis in understanding abnormalities ofgait in cerebral palsy 901

crouch position after such operations. Why? unfairly brought into disrepute if the biomecha- Movement analysis now provides the answer nics of that child are not known. Furthermore,

(fig 1). A single frame photograph shows the neuromotor control is constantly maturing, and Arch Dis Child: first published as 10.1136/adc.66.7.900 on 1 July 1991. Downloaded from body weight vector as a 'white line', accurately surgical intervention can be mistimed in grow- giving the position and direction of the body ing children leading to bizarre gait problems in weight force as it is being applied to a Kistler already handicapped spastic patients. force platform. Clearly, in this case, if the child has the heel cord lengthened then the ground reaction force vector may come to lie behind the OTHER PROBLEMS IN MANAGEMENT OF DIPLEGIC knee (as in fig 2) unless the quadriceps can pro- CHILDREN vide an opposing moment to straighten the Sutherland and Hagys2 and Beals3 have knee. Often patients with cerebral palsy have pointed out that all diplegic children with cere- quadriceps that are so weak that a 'crouch' is the bral palsy who can walk, mature at a slow but only result of heel cord lengthening. This poor definite rate, following the developmental pat- result (for some children) can now reliably be tern of neuromuscular control in their normal predicted, so the benefits of the analysis are peers, but less efficiently. By the age of 7 years explicit. both groups have matured maximally, so surgeons should if possible wait until the pla- teau of maximum control has been reached Current problems before operating. We propose that no operation Many children have heel cord operations that should be undertaken until movement analysis produce this 'crouch' position, because kinetic has been made at the age of about 7-8 years. If a examinations such as ours are not generally disabling dynamic deformity is present earlier available. The flexed knee and hip posture per- than this, then it is probably the result of sists in spite of intense postoperative phy- increased tone in the lower limbs. Oppenheim siotherapy. Often surgical release of the flexion has shown that in some patients selective rhizo- contracture of the knee is the next stage, and tomy may be helpful, although experience of this has been called the 'birthday syndrome' this is still limited.4 because the child then undergoes still more physiotherapy, perhaps for another 6-12 months, until the surgeon releases the flexed Optimum management hips of the 'crouch'.' This last operation may If clinical maturation levels off during the destroy the flexor power of the limb (which is seventh year it should be easy to analyse which necessary to initiate the swing phase of gait) if mechnical faults are present in an individual the psoas tendon and muscle retract into the child. Sensible treatment is then possible. The pelvis, their insertion into the femur having gait analysis, preceded by traditional history been lost. Surgical intervention is therefore not taking and static examination, is followed by always a success and some patients are made kinematic analysis to show how the child walks. http://adc.bmj.com/ cosmetically worse. Surgical treatment is We can note in slow motion the action and dura- tion of the stance and swing phases, we can see objectively the limitations of movement in indi- vidual joints, and we can compare these with normal gait performance. Electromyographic examination may be helpful as cooperation is

quite possible in this age group. Energy studies on September 29, 2021 by guest. Protected copyright. to assess the work being done have important prognostic value, as high values will suggest eventual limitation of activity and the necessity for confinement to a wheelchair.

ANALYSIS OF LIMBS SEGMENTS In many diplegic children with cerebral palsy the hip flexors, hamstrings and rectus femoris muscles (at the front of the knee) are too tight; the Achilles tendon has increased tone, and the adductor musculature contributes to excessive internal rotation at the hip. The classic 'diplegic walk' is the result: the child moves on tiptoe with the knees permanently bent to about 400, with relative fixity of knee and hip motion dur- ing the swing phase.

Knees Figure 2 Right mid-stance on theforce platform in ORLA U movement analysis laboratory. This girl has had Gage et al have shown that stiff knees are often her achilles tendon lengthened. Theflexing moment to the caused by inappropriate contraction of the rec- knee is compensatedfor by quadriceps contraction-ifthis muscle weakensfurther she will 'crouch' byflexing hip and tus femoris muscle; dynamic electromyographs knee. (Figure is a polaroid photograph takenfrom a moving can be made in the gait laboratory to show this. videofilm.) If confirmed, release or transfer of the rectus 902 Patrick

muscle tendon just above the knee is suggested. pitch of an ankle foot orthosis (below knee Knee motion during the swing phase is restored splint) can dramatically change the walk of a

and elaborate, energy wasting swinging of the diplegic child. If the body weight vector is made Arch Dis Child: first published as 10.1136/adc.66.7.900 on 1 July 1991. Downloaded from limb from the hip (circumduction) is elimin- to pass anterior to the knee, the weak quadri- ated. ceps are strengthened. If the pitch is wrong, the ankle foot orthosis 'doesn't work', and the knee flexes more. This is confusing for child, parent, Hips and orthotist. If the body weight forces are The internal rotation of the femur at the hips is correctly distributed, walking is successful. conventionally said to be the result of adductor These kinetic examinations can fine tune the overactivity, but kinematic and electromyog- ankle foot orthosis. raphic analysis has shown that often iliopsoas or gracilis tightness are responsible. It is salutary Energy expenditure to speculate how many adductor releases and Surgery has been useful to many children with rotatory femoral osteotomies have been done cerebral palsy, but measurement of the results without simultaneous muscle balancing proce- has been inadequate. McGregor has shown that dures, or because of lack of understanding of estimating changes in heart rate during walking the cause of the internal rotation. Kinematic and relating them to walking speed provides a study can show internal rotation occurring after simple, non-invasive and accurate method of initial foot contact under the influence of evaluating treatment7 8 This has been con- gracilis and medial hamstring overactivity. An firmed by Rose et al.9 An index of the physio- electromyographic analysis will confirm the logical cost (PCI) is derived in the laboratory point and permit accurate diagnosis, with a dis- during five timed walks on the gait track. The tinction being made between this type of inter- resting heart rate is subtracted from the exercis- nal rotation and the adduction/internal rotation ing heart rate and divided by the speed. In our of true adductor muscle spasticity. orginal group of nine patients with cerebral A component of the 'crouch gait' is a dyna- palsy who underwent movement analysis and mic, end stance-phase hip flexion. This is then appropriate operation as indicated by the usually caused by psoas muscle spasticity and is assessment (AV Nene, GA Evans. Spastic seldom noticed by the untrained eye. Static diplegia: a functional assessment of simulta- examination is often unhelpful, but kinematic neous multiple surgical procedures to assist and kinetic analysis can show simply the end of walking. Paper presented to British Ortho- stance for, say, the left hip. If the iliopsoas mus- paedic Association, September 1990.), we were cle keeps the hip flexed at this moment, then pleased that eight had significant drops in their left hip extension is prevented as the trunk PCI. moves forwards (with the swinging leg) over the This seems to confirm that if gait analysis is stance hip. The result of this is a diminution of used preoperatively to indicate appropriate sur- right step length, understandable by readers if gical management, then overall functional http://adc.bmj.com/ they stand on the left leg keeping the left hip benefit occurs when these patients are reviewed bent, and then reach forwards with the swing- two years or more after treatment is completed. ing right leg. The foot contact point ahead is shorter than if we stand normally and allow the left stance hip to extend. Conclusion The deforming psoas muscle should not be Improvement in treatment for quadriplegic and

released from its lesser trochanteric insertion. If diplegic patients, of whatever ability, who are on September 29, 2021 by guest. Protected copyright. there is psoas over activity, the tendon can ret- able to walk, does not depend solely on their ract into the pelvis and the important dynamic 'determination' or their placement in different function of the muscle (as an accelerator and therapeutic environments, or even on therap- initiator of hip and thigh motion forwards) is ists' opinions, but on certain mechanical facts lost. This can be disabling for normal children; deduced by movement analysis. If the for those with cerebral palsy it greatly lessens biomechanical 'milieu' is abnormal then deci- their motor abilities. Gage showed that an intra- sions can be made about how the mechanics of abdominal, extraperitoneal lengthening of the that child's walk can be improved. Much has psoas tendon at the pelvic brim overcomes this been made here of surgical treatment, but potential complication of operation, but allows clearly the analysis may suggest that splinting hip extension so increasing step length.6 After with orthoses or plaster, or physiotherapy the operation the physiotherapist and patient targetted at one particular joint, is more approp- can develop this muscle action in a more normal riate. fashion. Whatever the outcome of the assessment, a regimen of treatment can be suggested to the parents and therapists; it is important that the Ankles decision to proceed remains with them. We Additional kinetic examinations can increase believe that this concept is new, is as yet the understanding of mechanical problems in unproved, but seems overwhelmingly sensible disabled walkers. A force plate examination car- in theory. Longitudinal study of such patients is ried out synchronously with the orthogonal required, and represents a clear but identifiable walks can show the position of the ground reac- opportunity to audit carefully the walking prog- tion vector (fig 2). The length of the vector line ress of a group of children in the expectation represents the direction and quantity of the that progress is real, if our experience is to be force. In the simplest example, altering the believed. Use ofmovement analysis in understanding abnormalities ofgait in cerebral palsy 903

1 Rang M, Silver R, de la Garza J. Cerebral palsy. In: Lovell help hip flexion as well as to prevent excessive WW, Winter RB, eds. Pediatric orthopedics. Vol 1. 2nd Ed. Philadephia: Lippincott, 1986:345-%. knee flexion. If the rectus is active in stance

2 Sutherland DH, Hagys JL. Measurement of gait movements also, and the problem is excessive hip flexion in Arch Dis Child: first published as 10.1136/adc.66.7.900 on 1 July 1991. Downloaded from from motion picture film. J Bone joint Surg 1990;54A: 787-97. standing, proximal release is logical. If, 3 Beals RK. Spastic paraplegia and diplegia: an evaluation of however, there is activity after early swing and non-surgical and surgical factors influencing the prognosis for ambulation. J Bone joint Surg 1%6;48A:827-46. the problem is excessive extension leading to a 4 Oppenheim WL. Selective posterior rhizotomy for spastic stiff gait distal release or transfer is a better cerebral palsy. Clin Orthop 1990;253:20-9. 5 Gage JR, Perry J, Hicks R, Koop S, Werntz JR. Rectus option. femoris transfer to improve knee function of children with It is still an article of faith that better planned cerebral palsy. Dev Med Child Neurol 1987;29:159-66. 6 Gage JR. Gait analysis for decision making in cerebral palsy. surgery will yield better results. This is entirely Bulletin Hosp Jt Dis Orthop Inst 1983;43:147-63. reasonable as, unlike dystonia, weak muscles in 7 MacGregor J. The objective measurement of physical performance with long term ambulatory physiological spastic disorders remain weak after surgery. surveillance equipment (LAPSE). In: Stott FD, Raftery Over active muscles remain strong. EB, Goulding L, eds. Proceedings of 3rd International Symposium on Ambulatory Monitoring. London: Academic Great caution must be exercised, therefore, in Press 1979:29-39. extending this analysis to children with extrapy- 8 MacGregor J. The evaluation of patient performance using long-term ambulatory monitoring technique in the ramidal involvement. Comparison of results of domiciliary environment. Physiotherapy 1981;67:30-3. procedures based on gait analysis with results of 9 Rose J, Gamble JG, Burgos A, Medeiros J, Haskell WL. Energy expenditure index of walking for normal children clinically based procedures will not be easy but and for children with cerebral palsy. Dev Med Child Neurol will be necessary to convince sceptics, and this 1990;32:333-40. includes funding authorities. As with all such surgery, the role of a physiotherapist throughout is crucial. Commentary The picture of practice that has emerged in Gait laboratory analysis is a welcome attempt to the United States where several gait laboratories introduce some science into a difficult and have developed considerable experience is for highly specialised area. Much orthopaedic recommendations to be made to the referring energy has been directed to improve walking in clinician. It is for those who know the child and children with or hemiplegia. family best to decide with them whether in this Even in the. most experienced hands the results particular child in his particular social and of surgery after careful clinical assessment are educational setting, this particular procedure sometimes unpredictable and undesired. will be appropriate. Clinical judgments have not Some reasons are not far to find. For exam- been replaced by gait analysis. Instead, I hope ple, intoeing is usually due to over activity of they will become directed to more logically the medial hamstrings-and is corrected by relevant questions. lateral transfer of the semitendinosus. However, the psoas or other hip internal rotator may be R 0 ROBINSON responsible. The distinction can be made by Newcomen Centre,

analysis of the electromyogram during the walk- Guy's Hospital, http://adc.bmj.com/ St Thomas Street, ing cycle. Similarly analysis of the function of London SEI 9RT muscles which cross two joints such as the rectus femoris can assist operative decisions.' 1 Perry J. Distal rectus femoris transfer. Dev Med Child Neurol Normally the rectus is active in early swing to 1987;27:153-8. on September 29, 2021 by guest. Protected copyright.