CC BY
24
Russian Journal of Biomechanics
www.biomech.ac.ru
LOAD DISTRIBUTION TO VARIOUS HAND PARTS IN PATHOLOGICAL HAND
A.V. Novikov, N.V. Loskutova, G.V. Smirnov, M.N. Lavrov
Nizhny Novgorod Research Institute of Traumatology and Orthopaedics, 18, V. Volzskaya nab., 603155, Nizhniy Novgorod, Russia, e-mail: novik2@imail.ru
Abstract: The foot pressure analyser «F-Scan» is used to visualise and quantitatively analyse load distribution to hand parts. By this technique we examined the character and degree of pressure distribution among various hand parts during force (cylindrical) grip in some injuries and diseases. To perform the study a sensory element connected with computer by commutator and containing 980 microbarotransducers was applied to a cylinder of 65 mm diameter. The patient compressed the cylinder with maximally possible force while F-Scan recorded load distribution to the whole palm (including thenar), II - V fingers, the thumb (distal and proximal phalanges) and only the thenar. At first comparison was made between healthy and «pathologically deformable» (as a result of trauma, disease or operation) hands. The second investigation stage was devoted to identification of correlations between hand load degree with its character and pathology pattern. We studied pressure distribution in patients with flexor (20 persons) and extensor (8 persons) tendon injuries, hand tubular bone fractures (8 persons), associated traumas (12 persons), and Dupuytren's contracture (25 persons). Thus we resume that trauma and operative interference result in pressure redistribution to various hand parts: load to thumb and hypothenar increases while load to ll-V fingers and thenar goes down. Synergism disturbance of hand muscles necessitates the addressed hand muscle stimulation (especially thenar) and specific kinesiotherapy.
Key words: F-Scan, force (cylindrical) grip, pressure distribution
Introduction
In daily life and professional activities human beings commonly apply force and fine grips [3, 4, 7] that require muscle synergism be available. The above synergism may undergo disorders following trauma or disease [5]. In its turn, muscle disbalance provides load changes to different hand parts and it is necessary to consider in creating an adequate rehabilitation program.
Experiments
The foot pressure analyser «F-Scan» is used to visualise and quantitatively analyse load distribution to hand parts. This technique has been accepted to study weight to foot during walking [9] and now it is being applied in hand pathology [2, 6].
By this technique we examined the character and degree of pressure distribution among various hand parts during force (cylindrical) grip in some injuries and diseases. To perform the study a sensory element connected with computer by commutator and containing 980 microbarotransducers was applied to a cylinder of 65 mm in diameter (Fig. la). The
ADC
2 □ thenar
3 □ 11-V fingers
4 I.' i palm and hypothenar
Fig. 1: a) examination scheme; b) studied hand pressure zones (CD-R McGrouther and O' Higgins: The Interactive Hand.- Copyright © 1997.-Primal Pictures Ltd.); c) cylindrical grip muscles; d) pressure distribution to various hand parts (%) in healthy people.
patient compressed the cylinder with maximally possible force while F-Scan recorded load distribution to the whole palm (including thenar), II-V fingers, the thumb (distal and proximal phalanxes) and only the thenar. However, in processing the obtained results we paid attention to pressure distribution in the following areas of hand: II-V fingers, the thumb, the thenar and the middle palm with hypothenar (Fig. lb). The load that was experienced by the last zone [m.m. interossei, m.m. lumbricfles, hypothenar) was identified as a difference of pressure values to a palm and a thenar.
^-►
IBM PC XT
1 H l-st finger
Results and discussion
At first to calculate normal values of load distribution we examined both hands in 20 healthy men and 16 healthy women aged from 20 to 42 years [1] (Table 1).
Table 1. Normal load distribution values (%) to various hand parts in cylindrical grip.
Men Women
Right Left Right Left
1 finger 23.3±5.4% 21.8±4.8% 29.3±3.9% 29.0±5.3%
II-V fingers 48.7±5.0% 49.2±6.3% 43.2±3.5% 43.7±5.1%
Palm with hypothenar 28.0±6.1% 29.0±7.2% 27.5±4.4% 27.1+6.1%
Thenar 21.6±6.0% 23.5±7.0% 17.7±4.2% 18.7±7.0%
Significant distinctions (p > 0.1) of pressure distribution between different parts of both hands in men and women were not revealed. Therefore we counted unified values accepted as norm: the thumb - 25.4±0.7%, II-V fingers - 46.6±0.7%, the thenar - 20.7±0.8%, and the middle palm with hypothenar - 7.3±0.6% (Fig. Id).
Thus, II-V fingers and middle palm with hypothenar sustain a main load during cylindrical grip (53.9%) in healthy people. This occurs because m. flexor digitorumprofundus (Fig lc, 7) and mm. interossei palmares (Fig lc, 4) account for the strength of the grip, proximal and distal interfalangeal joints account for grip stabilising and hypothenar muscles take a final role in the grip performance [3].
Thumb and thenar bear 46.6% of all hand load with m. abductor pollicis brevis (Fig lc, 1), m.m. flexor pollicis brevis (Fig lc, 2) and longus implementing contrastress to II-V fingers and thenar muscles in particular m. adductor pollicis (Fig lc, 3) providing strength and stabilisation of grip.
We have studied load distribution and dynamics of load restoring during rehabilitation process in 73 patients with sequel of hand traumas and diseases. Examinations were carried out 2 weeks later trauma or the last surgical interference as well as a goniometry with measurements of overall range of active motions (RAM) in finger joints and an electromyography of hand muscles (thenar, hypothenar and forearm, m. digitorum superflciales and m. extensor digitorum).
At first comparison was made between healthy and «pathologically deformable» (as a result of trauma, disease or operation) hands (Fig. 2). A single united group without pathology was created for the second differentiation modelling.
As it was determined there was pressure-to-hand redistribution in the first month after injury or operation. Thumb and middle palm with hypothenar experienced zooming load (38.8 ±1.6 %;p < 0.0001 and 13.0±1.0%; p < 0.0001, respectively).
Because of decreasing load to thenar, which was 7.98±0.84% (p < 0.001), decreasing pressure to whole palm occurred (21.0±1.3%; /»<0.001). Load to II-V fingers became less provided injured (41.4±0.74%; p < 0.001) phalanxes were ruled out of grip. Pressure values for II-V fingers were at direct dependence (r = 0.86) on range of active motions in metacarpaphalangeal and interphalangeal joints. Mean RAM of finger joints was 566° ±44.10 or 45.7% of norm (Xn-v= ^40°) by the goniometry performed within this term. Influence
of the existing range of active motions in thumb joints on pressure expression of its phalanxes was not revealed.
Contractures even in both thumb joints minimally affected on thumb contrastress to other fingers. It should be noted that isolated little finger traumas practically unchanged pressure to II-V fingers (p > 0.1) in connection with its less participation in cylindrical grip in compared with other fingers. For the following 4 weeks 65 patients were showing positive dynamics in pressure distribution to various hand parts. We marked load decline on thumb
% 40 35 30 25 20 15 10 5 0
15-30 31 -45 46-60 61 -75 day day day day
I-St
% 25 20-I 15 10-5-
norm 15-30 31 -45 46-60 61 -75 day day day day
Thenar
% 50 45 40 35 30 25 20 15 10 5 0
norm
15-30 31 -45 46-60 61 -75 day day day day
II-V fingers
% 15
10
norm 15-30 31 -45 46-60 61 -75 day day day day
Palm with hypothenar
Fig. 2. Pressure distribution to various abnormal hand parts in rehabilitation process.
(31±1.0%) and also middle palm with hypothenar (11.5±0.8%) and load lift on II-V fingers (43.0+0.74%) and thenar (13.6±0.9%).
However, pressure-to-hand disorders still remained in 8 patients with associated hand and flexor tendon traumas 2-2.5 months after injury or operation. They had thumb pressure (26.2+2.1%) achieved norm (p> 0.2) but palm load (32.0±2.1%) stayed higher due to pressure growing to middle palm and hypothenar (14.9±2.4%). The pressure to thenar (17.2+ 1.1%) and II-V fingers (41.7±0.9%) was lower as well. In our view such remaining dynamics was justified by trauma severity and functional disturbances resulting from delay of rehabilitation procedures.
The second investigation stage was devoted to identification of correlations between hand load degree with its character and pathology pattern. We studied pressure distribution in patients with flexor (20 persons) and extensor (8 persons) tendon injuries, hand tubular bone fractures (8 persons), associated traumas (12 persons), and Dupuytren's contracture (25 persons).
For 30 days postoperatively flexor tendon injuries (Fig. 3) the significant (p < 0.001) pressure elevation to thumb (35.3±3.3%) and middle palm with hypothenar (13.3+2.3%) were observed, whereas thenar (9.4±1.5%), II-V fingers (42.6±1.7%), and whole palm demonstrated significant (p< 0.001) load decrease. At the end of the rehabilitation course (45-60 days) loads to thumb (27.1+1.4%), thenar (20.6+2.6%), and middle palm with hypothenar (8.7+0.9%) were within norm (p > 0.5). Nevertheless pressure to II-V fingers (43.6+1.5%; p < 0.05) was reduced because of insufficient restoration of active motions in the interphalangeal joints.
In extensor tendon injuries abnormalities of hand pressure distribution were less apparent (Fig. 4).
% 40i
%30!
30-20-10
20-
10-
% 50 40 30 20 10
norm 16-30 31 -45 46-60 day day day
I finger
norm 16- 30 31 -45 46-60 day day day
% 20
10
norm 16-30 31 -45 46-60 day day day
Thenar
norm 16-30 31 -45 46-60 day day day
II-V fingers Palm with hypothenar
Fig. 3. Dynamics of load changes to various hand parts in flexor tendon injury during rehabilitation.
% 30
20
10
% 50 40 30 20 10 0
16-30 31 -45 46-60 day day day
I finger
norm 16-30 31 -45 46-60 day day day
II-V fingers
%30
20
10
%30i 20 10 0
16-30 31 -45 46-60 day day day
Thenar
norm 16-30 31 -45 46-60 day day day
Palm with hypothenar
Fig. 4. Dynamics of load changes to various hand parts in extensor tendon injury during rehabilitation.
%30i
30 20 10 0
% 50 40 30 20' 10 0
norm 16-30 31 -45 46-60 day day day
I finger
20-10 o-
% 20 10
norm 16-30 31 -45 46-60 day day day
Thenar
norm 16 -30 31 -45 46 -60 day day day
norm 16-30 31 -45 46-60 day day day
II-V fingers Hypothenar
Fig. 5. Dynamics of load changes to various hand parts in hand tubular bone fractures during rehabilitation.
We marked less pressure elevation to thumb (up to 29.4±2.4%) in compared with flexor tendon injuries (p < 0.001) in early period after tendon suture. Loads to thenar (12.5± 1.9%) and II-V fingers (42.7±1.6%) were below norm (p< 0.001). Like that in the flexor tendon traumas, pressure to middle palm and hypothenar in these cases zoomed up to 15.4± 2.1% (p< 0.0001). Despite overall tendency to normalisation, the hand load distribution values still deviated from norm at the patient discharge moment. So load to thumb decreased to 24.9±2.1% and pressure to thenar enhanced to 13.1±2.6%. Decreasing pressure to II-V fingers (37.2±1.8%) contributed to pressure growing to hypothenar (21.8±1.4%) and therefore to the whole palm.
As to hand tubular bone fractures the pressure alteration dynamics was smoother (Fig. 5).
For the first month postinjury remarkable (p< 0.0001) pressure-to-thumb intensification (37.9±2.95%) was documented as well as pressure elevation to middle palm with hypothenar (13.9±2.8%). Loads to II-V fingers (39.7±1.8%) and thenar (8.7%±1.5%) were underneath norm (p < 0.001). At the end of the second month after fracture the pressure distribution was at norm. Load to thumb was 28.2±3.9% (> 0.5), to thenar - 18.7±2.9% (p > 0.2), to II-V fingers - 45.6±2.7% (p > 0.1), and to middle palm with hypothenar - 7.5±1.98% (P> 0.1).
When there were associated soft tissue trauma, tendon, bone injuries and phalanx avulsion the changes of load distributions in studied areas were especially significant (Fig. 6). So there was zooming (p < 0.0001) pressure to thumb (51.3±3.0%) for the first month after trauma. Within this term 6 patients were unable to load thenar during cylindrical grip (zero load). Mean pressure among patients with this pathology was 1.5±1.0%. Further, essentially decreasing load was observed at II-V fingers (33.1±3.1%). Subsequently abnormal values trended to normalisation. At the end of the second month loads to thumb and hypothenar declined to 31.5±3.4% and 10,3±1.6%, respectively, whereas pressures to II-V fingers and thenar came up (41.3±1.0% and 16.9±2.6%, respectively). However, 50% of patients
% 60 50 40 30 20 10 0
%50 40 30 20 10 0
% 30
20-
10-
norm 16 -30 31 -45 46-60 61 -75 day day day day
I finger
norm 16-30 31 -45 46-60 61 -75 day day day day
Thenar
% 20
10
norm 16- 30 31 -45 46 -60 61 -75 day day day day
norm 16- 30 31 -45 46-60 61 -75 day day day day
II-V fingers Hypothenar
Fig. 6. Dynamics of load changes to various hand parts in associated hand injury during rehabilitation.
demonstrated abnormal pressure distribution values at the end of the rehabilitation course on the 61-75th day after trauma with decreasing pressure to thumb up to 22,4±1.3% (p < 0.005) and normalising pressure to thenar - 20.9±2.0% (p> 0.1). Despite that patients had load to hypothenar and interosseus muscles enhanced to 13.7±2.9% (p < 0.001), whereas load to II-V fingers coincided to that in the previous study (43.1±1.2%).
In the case of operated Dupuytren's contracture tendency in pressure value dynamics was the same (Fig. 7).
There were increasing (p < 0.0001) load to thumb (39.6±2.2%) and middle palm with hypothenar (11.6±1.4%) and decreasing load to II-V fingers (39.5±0.9%) with thenar (8.0± 1.5%) for 30 days after palm aponeurosis excision. Two months later levelling the pressure-to-fingers (45.5±0.9%) «curves» to norm (p >0.1) appeared but load to thumb (32.4±1.4%) and hypothenar with m.m. interossei and m.m.lumbricales (10.1±0.87%) was above norm (p < 0.005). Load to thenar (12.0±1.7%) and the whole palm was kept underneath norm as well.
Conclusions
Thus we resume that trauma and operative interference result in pressure redistribution to various hand parts: load to thumb and hypothenar zooms while load to II-V fingers and thenar goes down. We assume the load decrease to II-V fingers to be explained by existing flexor and extensor contractures in interphalangeal and metacarpophalangeal joints whereas pressure redistribution to the rest zones allows supposition about hand muscle disbalance which, in our opinion, was confirmed by the electromyography data. By processing the above-mentioned data we made calculation of per cent ratio of bioelectrical activity (BA) values of affected hand muscles and contralateral hand muscles. All the patients showed sharp decrease of affected hand thenar BA-49.4±4.8%. Hypothenar muscles (BA= 60.2±5.5%), m.
% 40i
% 30 ■
30 20-10"
20"
10"
norm
% 50' 40 30 20 10 0-
16 -30 31 -45 46-60 day day day
I finger
norm 16 -30 31 -45 46-60 day day day
Thenar
%20
10
norm 16-30 31 -45 46-60 day day day
II-V fingers
norm 16-30 31 -45 46-60 day day day
Hypo thenar
Fig. 7. Dynamics of load changes to various hand parts in Dupuytren's contracture.
flexor digitorum superficialis (BA= 73.6±4.2%), m. extensor digitorum (BA=69.7±6.3%) suffered to a lesser extent.
Synergism disturbance of hand muscles necessitates the addressed hand muscle stimulation (especially thenar) and specific kinesiotherapy.
2.
4.
5.
6.
7.
9.
References
ЛОСКУТОВА H.B., НОВИКОВ A.B., СМИРНОВ Г.В. Некоторые характеристики цилиндрического схвата в норме. Тез. докл. IV Всерос. конф. по биомеханике. Н. Новгород, с. 161, 1998 (in Russian).
НОВИКОВ А.В., ЛОСКУТОВА Н.В. Перспективы применения F-SCAN в реабилитации больных с патологией кисти. Тез. докл. IV Всерос. конф. по биомеханике. Н. Новгород, с. 179, 1998 (in Russian).
МАТЕВ И., БАНКОВ С. Реабилитация при повреждениях руки. Пер. с болгар. София, Медицина и физкультура, 1981 (in Russian).
BENDZ P. The functional significance of the fifth metacarpus and hypothenar in two useful grips of the hand. Am J Phys Med Rehabil, 72(4): 210-213, 1993.
BRAND P.W. Biomechanics of balance in the hand. J Hand Ther, 6(4): 247-251, 1993.
PARLIITZ D., PESCHEL Т., ALTENMULLER E. Assessment of dynamic finger forces in pianists:
Effects of training and expertise. J Biomechanics, 31(11): 1063-1067, 1988.
MATHIOWETZ V., WEBER K., VOLLAND G„ KASHMAN N. Reliability and validity of grip and
pinch strength evaluations. J Hand Surg, 9A(2): 222-226, 1984.
THAYER D.T. Distal interphalangeal joint injuries. Hand Clin, 4(1): 1-4, 1988.
YOUNG C.R. The F-SCAN system of foot pressure analysis. Clin Podiatr Med Surg, 10(3): 455-
461, 1993.
РАСПРЕДЕЛЕНИЕ НАГРУЗКИ НА РАЗЛИЧНЫЕ ОТДЕЛЫ КИСТИ В
НОРМЕ И ПРИ ПАТОЛОГИИ
A.B. Новиков, Н.В. Лоскутова, Г.В. Смирнов, М.Н. Лавров (Нижний Новгород, Россия)
С помощью программно-аппаратного комплекса F-Scan (на основе технологии фирмы «Tekscan», США) проведено изучение характера и степени распределения нагрузки на различные отделы кисти во время силового (цилиндрического) захвата в норме, а также при некоторых травмах и заболеваниях. Учитывалось распределение давления на следующие отделы кисти: II-V пальцы, первый палец, область тенара и среднюю часть ладони с гипотенаром.
На первом этапе сравнивалась здоровая и «патологически измененная» в результате травмы, заболевания или операции кисть, изучены распределение нагрузки и динамика ее восстановления в процессе реабилитации.
На втором этапе исследования определялась зависимость степени и характера нагрузки на кисть от вида патологии - были обследованы пациенты с повреждениями сухожилий сгибателей и разгибателей, переломами трубчатых костей кисти, сочетанными травмами, контрактурами Дюпюитрена.
В результате проведенного исследования установлено, что травма и оперативное вмешательство приводят к перераспределению давления на различные зоны кисти: резко увеличивается нагрузка на первый палец и область гипотенара с мелкими мышцами, что сопровождается снижением ее на II-V пальцы и тенар. Это подтверждено и данными электромиографии.
Образование дисбаланса во взаимодействии мышц кисти, выраженность которого зависит от тяжести патологии, обуславливает необходимость включения в комплекс реабилитационных мероприятий направленной стимуляции мышц кисти (особенно тенара), а также подбор специфических упражнений двигательной терапии. Библ. 9.
Ключевые слова: распределение нагрузки, цилиндрический захват (схват), F-Scan, травмы и заболевания кисти
Received 15 June 2001
