physiotherapy, D ecem ber 1983, vol 39, no 4 93 THE EFFECTS OF MENISECTOMY A FOLLOW-UP STUDY OF THE EFFECTS OF MENISECTOMY ON LOWER LIMB MUSCLE STRENGTH, A N D ON KNEE JOINT FUNCTION. JO A N N E ENSL1N: B.Sc. (Physiotherapy) W itw atersrand. B.Sc, (Med) (H ons) Sport Science* SUMMARY The object of this study was to determine the l ong t e r m r e s u l t s of u n c o m p l i c a t e d menisectomies in 16 patients who were at least 8 months post-operative. The average age of the patients was 25 years and all had right dominant legs. Seven of the subjects had undergone right knee surgery, and the remaining eight left knee surgery. Questionnaires were answered to determine the patients’ current symptoms and functional ability. Fifteen patients attended a physical examination to assess quadriceps and hamstring muscle strength. The findings were compared to a control group of subjects who had not undergone knee surgery. This study1 shows that: (i) Sixty percent of the patients had some symptoms such as stiffness, swelling, pain or discomfort, locking, weakness and instability. Seventy-five percent of the patients had some functional limitations during for example squatting, kneeling, climbing stairs, walking on rough ground etc, and half of these surgical patients had some pain and discomfort, as well as-:difficulty in squatting ■ and kneeling. (ii) Eight months after surgery, the patients had still not regained full muscle strength despite having undergone n o rm a l rehabilitation procedures. Iso k in e tic muscle testing showed a decrease! in quadriceps muscle strength in the right-operated leg, the left- 'operated leg and the right unoperated leg. There was also an increase in right hamstring muscle strength in the right-operated leg. T h e s e f i n d i n g s s u g g e s t t h a t e v e n uncomplicated menisectomy is not a trivial procedure and that current practices in muscle rehabilitation following menisectomy are not adequate. There should be routine procedures whereby all patients can receive appropriate and adequate muscle rehabilitation after knee surgery. From : the M etropolitan Sport Science C entre, D epartm ent o f Physiology, University o f Cape Town Medical School O bservatory. 7925 RSA. Address for Correspondence: Miss J Enslin' PO Box 68170 BRYANSTON 2021 OPSOM MING | Die doel van hierdie studie was om die langtermyn resultate van ongekompliseerde menisektomies te bepaal in 16 pasiente wat ten minste agt maande post-operatief was. Die gemiddelde ouderdom van hierdie pasiente was 25 jaar en almal het regterbeen dominansie 1 vertoon. Sewe van hulle het operasies op hulle regter kniee ondergaan, en die oorblywende agt op hulle linker kniee. Vraelyste is beantwoord om die pasiente se huidigesim ptom eenfunksionelevermoeevaste i ste.l. Vyftien het 'n fisiese ondersoek ondergaan • om die krag van hulle agterdyspiere en ! quadricepsspiere vas te stel. Die bevindings is j vergelyk met ’n kontrole groep van gevalle wat i nie knie operasies ondergaan het nie. Hierdie bevindings toon aan dat:- , (i) Sestig persent van die pasiente het simptome , vertoon soos styfheid, swelling, pyn of ongemak, swakheid en onstabiliteit. Vyf en sewentig persent het 'n mate van funksionele b e p e r k i n g s o n d e r v i n d g e d u r e n d e byvoorbeeld hurk, kniel, trapklim, stap oor I ongelyke grond ens., en helfte van hierdie I chirurgiese pasiente het 'n mate van pyn en ongemak ondervind sowel as probleme met hurk en kniel. (ii) Agt maande na hulle operasies het die pasiente nog steeds nie algehele spierkrag herwin nie tenspyte daarvan dat hulle norm ale rehabilitasie prosedure ondergaan het. Iso kinetiese spiertoetsing het 'n vermindering vertoon van quadricepsspier sterkte in die regter ge-opereerde been, die linker ge-opereerde been en die regter onge- opereerde been. Daar was ook 'n toename van sterkte in die regter agterdyspier in die regter ge-opereerde been. Hierdie bevindinge doen aan die hand dat selfs | o n g e k o m p l i s e e r d e m e n i s e k t o m i e nie 'n | kleinigheid is nie en dat huidige praktyke in spier rehabilitasie wat volg op menisektomie nie I toereikend is nie. Daar behoort roetine prosedures te wees waar volgens alle pasiente toepaslike en doeltreffende spier rehabilitasie na | knie chirurgie kan ontvang. IN TRO D U C TIO N Any sporting injury to the knee that requires surgery is a potentially serious injury, because it may leave the sportsm an with persistent knee problems such as instability, R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) 94 Fisioterapie, D esem ber 1983, deeI 39, n o 4 pain on w eight-bearing and swelling, in spite o f early diagnosis and ap p ro p riate tre a tm e n t.1 M enisectomy is one o f the m ost com m on procedures perform ed by orthopaedic surgeons, and between 28-69% of meniscus injuries are reported to have been sustained in sp o rt.2,3 There is much controversy over the results of surgery, so th a t the orthopaedic literature is replete with contradictory statem ents regarding the long-term results in patients who have undergone menisectomies. F or example H enderson'1 and W ynn Parry et al.3 have reported th at 75% or more o f their patients had relatively norm al knees when evaluated up to eight years after surgery, whereas H uckell5 reported that only 26% o f their patients had relatively norm al knees when studied sixteen years after menisectomy. A recent study on the longterm results o f menisectomy in athletes6, found th a t 27% had stopped o r restricted their athletic activities as a result of surgery. C om m on com plaints included swelling, instability, pain, locking etc. These com plaints started im mediately after surgery in 79% o f the patients, the m ajor com plaints being a feeling o f instability and pain on weight bearing. In a sim ilar study Yocum et a l.7 found th at only 50% o f their subjects felt that they had returned to a satisfactory level o f com petition, l ‘/ 2 years after menisectomy. In this paper, the subjective and clinical end-results in a group o f subjects who had undergone uncom plicated menisectomies were analyzed in order to evaluate:- (i) T he effects o f m enisectom y in lim iting sp o rts participation and knee function (in squatting, kneeling, climbing stairs etc.), as well as the presence o f sym ptom s (such as stiffness, swelling, pain, locking etc.). (ii) Lower limb muscle strength during isom etric, slow speed and fast speed isokinetic muscle contractions. MATERIALS AND M E T H O D S Subjects: Q uestionnaires were sent to patients who had had menisectomy perform ed e ith e ra t G roote Schuur H ospital or by a private orthopaedic surgeon. All patients were at least eight m onths postoperative. Patients who had evidence o f other injuries such as osteochondritis dissecans, loose bodies, degenerative arthritis, chondrom alacia patellae or torn ligaments at the time o f operation were excluded. The questionnaire was designed to determ ine the p atien t’s current sym ptom s, the level o f his recreational physical activity, and the presence o f any disability related to his injured knee. O f the tw enty questionnaires sent, sixteen were completed and returned. One patient was om itted due to the presence of degenerative arth ritis prior to surgery. Fifteen o f these patients were evaluated at the S.A.B. Sports Injury Clinic at the University o f Cape Town. Two o f the subjects were female and thirteen were male, and their ages ranged between tw enty-tw o and fifty-three years. T heir ages at the time o f operation ranged from seventeen to fifty years (average age twenty-five years). Eight of the subjects had undergone left knee surgery and the rem aining seven had undergone right knee surgery. The time delay between the initial injury and surgery ranged from seven days to eleven years. In the latter subject, surgery was the result of a second injury. ANALYSIS O F TH E Q UESTIO N N A IR E DATA: The p atien t’s current sym ptom s and disability related to his knee were graded from the questionnaire, according to the following scale: 1. E X C E L L E N T : The patient had no sym ptom s and no disability related to his knee. The patient had any o f the following sym ptom s but only once a m onth: stiffness, swelling, pain, weakness and instability. There was some lim itation in the following activities: squatting, kneeling, climbing stairs, walking on rough ground and changing direction whilst running/w alking. The patient had the above sym ptom s not more than once a week and had m arked disability in the above activities. The patient had constant sym ptom s and was unable to perform the above activities. PH YSICA L EXAMINATION Each patient was examined in the following m anner: - Thigh circumference measured with a tape m easure at three different positions —6 cm , 12 cm, and 18 cm above the apex of the patellae. - Range o f Jo in t m ovem ent m easured with a goniom eter. - Muscle strength. The o rth o tro n 11 isokinetic dynam om eter was used to measure the torque o u tp u t o f the quadriceps and ham string muscle groups (in footpounds). M aximal reciprocal contractions o f the quadriceps and ham string muscles for both extremities were perform ed at test speeds o f OVs, 60°/s, and 300°/s. Each subject was positioned on the O rthotron with his o r her back fully supported with hips in 75-80 degrees o f flexion. The thigh was stabilized with a Velcro strap and the subject’s knee was concentrically aligned with the dynam om eter input shaft. The tibial pad was placed on the distal third o f the tibia and held firmly in place with an o th er Velcro strap. Each subject then perform ed a series o f 10 subm axim al muscle contractions at 120°/s in order to ‘warm u p ’ and to become accustom ed to the equipm ent. A rest period o f ninety seconds followed before the actual testing comm enced. Two testing sequences were used to dim inish the variability that might have been caused by either learning or fatigue. H alf of the subjects were tested in a ‘slow ’ sequence using 3 sets of 10 isokinetic contractions in sequence a t the following speeds — 60°/s, 300°/s, 0°/s. The rem aining half were tested in a ‘fa st’ sequence using the reverse o rder — 300°/s, 60°/s, 0 °/s. A ninety second rest period was allowed between each set. Isokinetic extension pow er (isokinetic contraction speed equals OVs) was recorded with the knee in 65 degrees flexion, and isometric flexion with the knee in 45 degrees flexion. Only the peak torques generated at the various velocities were recorded. A control group o f eleven subjects aged between twenty and twenty-five years was also tested in an identical manner. These d ata were analysed to determ ine: 1. The difference in knee torques during both flexion and extension, in the dom inant and non-dom inant legs of the o perated subjects. Lower extrem ity dom inance was defined as the foot the subject used to kick a football. (Only right d o m in an t subjects participated in this study). 2. The difference in knee torques during both flexion and extension in the dom inant and non-dom inant legs o f the control subjects. 3. The percentage differences in knee torques during flexion and extension in the dom inant and non-dom inant legs of 2. G O O D : 3. FA IR : 4. PO OR : R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) physiotherapy, D ecem ber 1983, vol 39, no 4 95 the operated subjects were com pared with those o f the control subjects. A. RESU LTS O F Q U ESTION NA IRE 1. Cause of Injury 82% of the patients sustained meniscal injury during sporting activity. The others sustained their injuries during norm al every day activity. 2. Presence of Rehabilitation All subjects had either undergone physiotherapy or had designed their own exercise program m es, but the intensity and nature o f such program m es could not be accurately assessed. 3. Subjective and Functional Results after Menisectomy Table l details the incidence and severity o f reported sym ptom s in the 16 subjects. H alf o f the patients had some pain and discom fort, and 38% of the patients had stiffness and weakness o f their knee, which was present a t least once every m onth. The functional results following menisectomy (Table 2) indicate th at the vast m ajority o f the subjects had some difficulty in kneeling , and squatting following menisectomy. Climbing stairs, Walking on rough ground, and changing direction whilst running caused problem s in fewer subjects. 4. Influence of menisectomy on sports participation: Ten o f the sixteen patients who had undergone knee surgery said that their sporting activity had been altered following surgery. Three of the patients gave up contact sports due to the feeling o f instability in the o perated leg, and three patients were now playing less vigorous sports. O ther alterations included reducing the time spent on sport, and not playing as much com petitive sport. B. RESU LTS O F PHYSICAL EXAMINATION Fifteen right-legged dom inant subjects were examined. Seven o f the subjects had undergone right knee surgery and eight, left knee surgery. 1. Thigh Circumference: Ten o f the subjects had a decrease, and five an increase in thigh circumference. It has been show n that c o n c o m i t a n t w ith m u s c le a t r o p h y a f t e r im m obilization following surgery, there is an increase o f subcutaneous tissue so that the m easurem ent of limb circumference may not reveal the true degree of muscle atro p h y .8 Right operated knee Left operated knee (7) (8) Thigh Circumference Increase Decrease Increase Decrease N um ber of Subjects 2 5 3 5 2. Range of Joint Motion: No significant difference was noted in range o f joint movem ent between the operated an d non-operated knees. 3. Muscle Strength: The peak static (0°/s) and isokinetic torque values m easured during knee flexion and extension a t 300°/s and 60°/ s fo r the right operated and left operated leg are given in T ables 3 and 4 below. The percentage by which the values for the right leg exceed those o f the left leg are also included. It should be noted th at in the right-operated-leg-subjects, only the isometric strength o f the right ham strings was Table 1 SUMMARY O F C OM PLA IN TS O F PATIENTS FO LL O W IN G M EN ISECTO M Y C O M PL A IN T E X C E LL E N T G O O D FA IR PO OR (None) (M onthly) (Weekly) (Daily) Stiffness 10 (63%) 3 (19%) 2 (13%) 1 (6%) Swelling 11 (69%) 3 (19%) 1 ( 6%) 1 (6%) Pain o r discom fort 8 (50%) 5 (31%) 3 (19%) 0 Locking 14 (88%) 2 (13%) 0 0 Weakness 10 (63%) 3 (19%) 3 (19%) 0 Instability and giving way 12 (75%) 3 (19%) 0 1 . (6%) Table 2 SUMMARY O F LIM ITA TION S O F ACTIVITIES O F PATIENTS FO LL O W IN G M EN ISECTO M Y A CT IV IT Y E X C E L L E N T G O O D FA IR POOR 1 N o difficulty. Some difficulty. Extreme difficulty. Inability to Squatting 8 (50%) 7 (44%) 1 (6%) perform activity. 0 Kneeling 6 (38%) 8 (50%) 1 (6%) 1 (6%) Clim bing stairs 14 (88%) 2 (13%) 0 0 W alking on rough ground 14 (88%) 2 (13%) 0 0 C hanging direction whilst running 11 (69%) . ' 3 (19%) 2 (13%) 0 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) 96 Fisioterapie, D esem ber 1983, dee! 39, no 4 significantly g reater than the left ham strings (by 22%). The quadriceps in the right-operated-leg showed no significant increase in muscle strength when com pared w ith the left leg. (Table 3). Table 4 shows that m aximal torque values during low speed a n d iso m etric q u a d ric e p s c o n tra c tio n were significantly lower in the left-operated limbs (com pared with the right). C ontrol subjects show significantly greater peak torque values fo r the right dom inant leg during isometric q u a d ric e p s c o n tra c tio n a n d high speed h am strin g contractions. (Table 5) This indicates that leg dom inance influences muscle strength so that leg dom inance must be considered in any evaluation o f the effects o f surgery and rehabilitation o f muscle strength. F urtherm ore, it is also of interest that the quadriceps produced a higher torque than did the ham strings at each o f the three test speeds, but the torque difference decreased as the test speed increased. This phenom enon is well docum ented. In o rder to draw some conclusions ab o u t the influence leg dom inance has on muscle strength afte r surgery, Figure 1 has been draw n. It shows the percentage difference in peak torque values between right and left legs during isometric and low speed quadriceps contractions, and isometric and high speed ham string contraction. Only these d ata are presented as they were the only ones in which statistically significant differences were found. D ata for control subjects, left operated legs and right operated legs are presented separately. The relevant findings are the following: 1. During isometric quadriceps contraction: The right quadriceps o f the control group produced a 25% greater torque than did th at o f the left leg. The subjects with left operated legs showed a 16% greater right quadriceps torque com pared with the left leg, whereas the subjects with right knee operations had equal isom etric quadriceps torque o u tp u t on both sides. These results therefore indicate th at the right quadriceps o f people with right leg dom inance are Table 3 PEAK T O R Q U E VALUES (F O O T PO UN DS) AT TH REE D IFFEREN T ISO K IN ETIC CONTRACTION SPE E D S FOR RIG HT O PERATED LEG S. Muscle group and contraction speed Isom etric Q uadriceps (0°/s) High Speed Q uadriceps (300°/s) Low Speed Q uadriceps (60°/s) Isom etric H am strings (OVs) Highspeed H am strings (300°/s) Low Speed H am strings (60°/s) Mean values, standard error or the mean (S.D), percentage difference between right (operated) and left sides (% R > L), and significant levels between paired observations are given. Isom etric quadriceps contraction was perform ed at a jo in t angle o f 65° o f flexion, whereas isom etric ham string was perform ed at 45° o f flexion. Peak Torque Percentage Difference Between Right and Left Sides (% R > L) P Value (Students t-test) Right (operated) 201 + 46 Left Leg 201 ± 42 0% NS 108 ± 46 110 ± 40 0% NS 157 ± 50 167 ± 55 -6% NS 154 ± 28 120 ± 19 22% 0.001* 106 ± 45 93 ± 39 11% NS 159 ± 32 142 ± 32 11% NS Table 4 PEAK VALUES (FO O T PO U N D S) AT 3 D IFFEREN T ISO K IN ETIC CONTRACTION SPE E D S FOR LEFT OPERATED LEG S. Muscle G ro u p and C ontraction Speed. Isom etric Q uadriceps (OVs) Highspeed Q uadriceps (300°/s) Low speed Q uadriceps (60°/s) Isom etric H am strings (OVs) High Speed H am strings (300Vs) Low Speed H am strings (6 0 % ) Peak Torque Percentage Difference Between Right and Left Sides (% R > L) P Value (Students t-test) Left (O perated) 148 ± 37 Right 170 ± 45 18% <0.001* 83 ± 37 99 ± 47 16% NS 142 ± 49 165 ± 52 14% <0.05* 109 ± 41 116 ± 39 6% NS 114 + 38 93 ± 44 -18% NS 118 ± 34 130 ± 34 9% NS Mean values, standard erro r o f the mean (S.D ) percentage difference between right and left sides (% R > L), and significant levels between paired observations are given. Isom etric quadriceps contraction was perform ed at a jo in t angle o f 65° o f flexion, whereas isom etric ham string contraction was perform ed at 45° o f flexion. R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Physiotherapy, D ecem ber 1983, vol 39, no 4 97 Table 5 PEAK VALUES (F O O T PO UN DS) AT 3 DIFFEREN T ISO K IN ETIC CONTRACTION SPE ED S FOR C O N T RO L SU BJEC TS. Muscle group and C ontraction Percentage Difference Between Left an d Right Sides P Value (Students Speed Peak torque (% R > L) t test) Right Leg Left Leg Mean Mean Isom etric Q uadriceps ( 0 % ) 175 ± 62 118 ± 32 25% <0.05* High Speed Quadriceps (3 0 0 % ) 192 ± 42 180 ± 34 6% NS Low Speed Q uadriceps (60°/s) 218 ± 47 198 ± 48 9% NS Isom etric H am strings (0°/s) 128 ± 34 120 ± 28 6% NS High Speed H am strings (300°/s) 151 ± 35 133 ± 24 13% < 0.01 * Low Speed H am strings (60°/s) 135 ± 28 125 ± 26 7% NS Mean values, standard erro r o f the mean (S.D ) percentage difference between right and left sides (% R > L), and significant levels between paired observations are given. Isometric quadriceps contraction was perform ed at a jo in t angle o f 65° o f flexion, whereas isometric ham string contraction was perform ed at 45° o f flexion. stronger than their left quadriceps, and that right knee surgery causes a decrease in right quadriceps strength, whereas left knee surgery causes a decrease in both left and right quadriceps strength. This suggests th at causes o th er than th at o f the effects o f surgery must play a role in prom oting muscle weakness. A reduction in general physical activity after surgery could be one such factor. 2. During low speed quadriceps contraction: ■ The controls had a 9% greater torque o u tp u t with the right leg than the left leg. The left operated leg subjects had a 14% greater right quadriceps strength, com pared with the operated leg, and the right operated leg subjects, only a 6% greater right quadriceps torque than the unoperated leg. These results show that surgery causes a decrease in low speed quadriceps muscle strength on the side on which it was perform ed. 3. During isometric H am string contraction: Subjects whose right knees had been operated on, had a 21% greater muscle strength in their right than their left hamstrings. In the control group, and the left-operated group, this difference was only 6%. This result indicates an increase in right ham string muscle strength following right knee surgery, which may be a com pensatory result in o rder to prom ote right do m in a n t leg stability. 4. During high speed hamstring contraction: The subjects whose left legs had been operated on had an 18% greater muscle strength in their right Ham strings than in their left legs, w hereas in the controls this difference was only 12%. This result suggests th a t left ham string muscle strength may be reduced following left knee surgery. D ISC U SSIO N The menisci in the knee are know n to perform several im portant functions, in p articu lar they act as load- transm itting and energy-absorbing structures inside the joint. The forces between the menisci and articu lar surfaces o f the tibia and fem ur are greatly increased in any activity causing an increase in weight bearing across the knee as in running, w alking and jum ping, but also in squatting and kneeling. The stresses across the jo in t are significantly increased after m enisectom y1 for a given load transm itted across the jo in t. A fter menisectomy, the am o u n t o f compressive deform ation is approxim ately twice that measured in the intact joint. Therefore, the menisci serve the im p o rtan t function o f reducing the com pression o f the a rticu lar cartilage and subchondral bone an d menisectomy w ould be expected to alter and load-bearing ability of the jo in t quite substantially. F urtherm ore, menisci play a role in the stability o f the knee, and the increased instability following knee surgery may be a contributing cause to the high incidence o f new knee injuries after menisectom y.6 In this study, h alf o f the subjects experienced occasional pain and discom fort on norm al activity, as well as difficulty in squatting and kneeling, and 62% had altered their sports participation in some way following menisectomy. This serves to indicate the im portance o f the meniscus in the norm al function of the knee joint. Besides the effects th at are a direct result o f removal o f the menisci, surgery causes muscle atrophy and muscle weakness ’ '6. Ten o f the subjects had a decrease in thigh circumference when evaluated more than eight m o n th sp o st- operatively, but five subjects had an increase. This result was not influenced by the side o f the knee surgery, and showed no correlation with muscle strength. It should be noted that during the im m obilization following surgery, there is an increase in subcutaneous fat tissue and this obscures muscle atro p h y and could explain these apparently strange results8. Previous w orkers have reported a decrease in muscle strength after knee surgery11,12 but they have not considered the im portance o f leg dom inance. In o u r control group the right leg was stronger than the left leg, particularly during isometric quadriceps contraction, b u t in the test group (after menisectomy) the following was found: 1. D uring isometric quadriceps contraction, quadriceps pow er in the right (unoperated leg) was significantly greater than th at in the left (operated) leg. This suggests R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) % di ff er en ce be tw ee n R. a nd L .s id es (* /iR > L ) 98 Fisioterapie, D esem ber 1983, dee! 39, no 4 th at knee surgery causes a long term im pairm ent in muscle strength. However, the relative isometric quadriceps strength o f the right leg also decreased (in com parison to the left leg) following left knee surgery. This is unexpected, but may be due to a general decrease in the level of physical activity. A dditional evidence for this is the finding th at 62% o f the patients in this study had altered their sports participation in some way following menisectomy. Similar results have been found by other researchers. Sonne-H olm 6 showed that 27% o f his subjects stopped or restricted their sporting activities after menisectomy, and Yocum et a l.7 found th at only h alf o f their subjects returned to their previous level of com petition one-and-a-half years after knee surgery. 2. The quadriceps of the operated leg regardless of side showed a decrease in low speed torque when com pared to findings in control subjects. There are a num ber of explanations for this: There may be long-term im pairm ent o f m otor unit recruitm ent at m aximal effort or im pairm ent o f contractile properties o f the muscle following knee surgery and im m obilization, o r b o th 9. control. 35 right operated leg. * * 30 _ 2 5 2 0 15 10 □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ • * □ □ A A □ □ n n • • □ □ • • □ □ • • □ □ • • □ □ • • □ □ 1 - 1. □ □ * * * * * * □ □ * * □ □ * * □ □ * * □ □ * * □ □ * * • • □ □ * * • • □ □ * * * * • • □ □ * * * * • • □ □ l—i i-i * * * * • • U l—l □ □ * * □ □ * * • • □ □ * * □ □ * * • • □ □ * * □ □ * * • • □ □ * * □ □ * * • • □ □ * * □ □ • • □ □ JJL I sometrie Quadriceps Contraction Low Speed Quadriceps Contraction Isometric Hamstring Contraction High Speed Hamstring Contraction Fig. 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) physiotherapy, D ecem ber 1983, vol 39, no 4 99 (i) Tourniquet-induced Muscle damage D uring isometric muscle contraction, the slow twitch fibres are recruited first, and as more tension is required, more fast twitch fibres are recruited1. Studies using muscle biopsies have show n th at after sports injuries and im m obilization o f the knee jo in t, it is mainly the type 1 fibres (slow tw itch) that a tro p h y 10. H aggm ark et a l.8 and Booth et a l.13 have shown that this type 1 fibre atro p h y occurs very rapidly after im m obilization o f the knee jo in t, within the first six hours to first week following im mobilization. Besides atrophy, there might also be a change in fibre type com position, that is, a change in the relative pro p o rtio n o f type 1 and type 11 fibres. It was also found th at the extensor muscles and the more tonic muscles with higher tension and higher percentage o f type I fibres showed m ore pronounced signs o f atrophy4. Thus the difference in isom etric muscle strength could be due to selective atro p h y o f type 1 fibres ’ . (ii) The effects of immobilization in the extended knee position It has been fo u n d th a t w hen low er lim b im m obilization is in a position where the muscle is on tension, there are no signs o f a tro p h y .10,9 An explanation for this w ould be th at the muscle spindles within the muscle relax when there is no tension and the impulses returning to the extrafusal muscle fibre via the m onosynaptic reflex arc disappear, and the afferent impulses to the tonic type 1 fibres cease. The knee is im mobilized in an alm ost straight position after surgery, relaxing the quadriceps muscle which could have contributed to the atro p h y found in this study. (iii) Tourniquet-induced nerve damage A large percentage o f surgery for sports injuries is perform ed under tourniquet to ensure a bloodless surgical field. Some au th o rs suggest th at tourniquet- induced ischaemia causes both muscle dam age and damage to the peripheral nerves. Im paired nerve function measured electro-m yographically has been reported in as many as 71 % o f p a tie n ts '1 and involves the following nerves in the following sequence: The p o s t e r io r tib ia l n e rv e w hich s u p p lie s th e gastrocnem ius muscle is affected first, followed by the fem oral nerve supplying the quadriceps, and lastly the sciatic nerve supplying the ham strings. This may indicate th at the fem oral nerve is affected more than the sciatic nerve by the pneum atic tourniquet, thus resulting in a greater loss o f muscle strength in the quadriceps than in the ham strings. This would be in keeping with our finding that the quadriceps strength decreases after surgery whereas ham string strength was unaltered o r increased. (iv) The effects of pain M oderate pain first inhibits the nerve supply to type 1 muscle fibres which have a low activation threshold, whereas severe pain inhibits all m otor nerve activity to the muscles8. Early post-operative pain relief by continuous epidural analgesia may allow muscle activity to resume shortly after surgery and could possibly prevent muscle w asting10. 3. D uring isom etric ham string contraction, there was a very m arked (fourfold) increase in the right ham string strength after right knee surgery, but no such change in left ham string strength after left knee surgery. This strange finding seems to have no simple explanation, but was also found by D u ffin '4. The increase in ham string strength may be a com pensatory mechanism to increase knee stability in the right d o m in an t leg. Alternatively, the increase may just be a peculiarity o f this small subject group and may not be o f any practical significance. 4. We found th a t in the control group the d o m in an t knee produces a significantly greater torque o u tp u t than the non-dom inant knee. The clinician should therefore be concerned with lower extrem ity dom inance and should strengthen an affected dom inant knee until its torque o u tp u t exceeds that o f the unaffected non-dom inant leg. C O N C LU SIO N S AND RECO M M EN DA TION S This study shows th a t menisectomy is not a benign procedure th at allows the p atient to return to previous activities w ithout any long-term ill effects. Few patients in this study had good muscle function on follow -up at least eight m onths after surgery despite having undergone ‘n o rm al’ rehabilitative procedures. This indicates that current rehabilitative practices after menisectomy are inadequate and do not restore full muscle strength after surgery. The following guidelines are suggested for correcting this: 1. T ourniquet application during surgery: It has been show n that there is a large individual variation in the susceptibility to ischaemia. It would therefore be advantageous to perform surgical procedures for sports injuries w ithout the use o f a tourniquet, o r to have careful m onitoring of the tourniquet pressure and time of application ’ 2. This study indicates th a t spontaneous activity, including athletic training, may not be sufficient to restore and m aintain m uscular function in most subjects. Therefore we suggest th at post operative strength training should begin with im m ediate muscle training a few hours after surgery (in the operating room ) under the supervision of a physiotherapist. C ontinued intensive physiotherapy should be given, the muscles being strengthened at all training speeds (slow, m edium and fast velocities) so that the operated leg is fully rehabilitated at all contractile velocities. This will also ensure th at all muscle fibre types are recruited and trained. It should be noted that Yocum et a l.7, showed th at patients regained 75% o f the pre­ operative muscle strength six m onths after surgery. Very few p a ti e n ts sh o w e d f u r th e r m u sc le s tre n g th im provem ent beyond six m onths post-operatively despite continuous training. This may indicate the need fo r early intensive rehabilitation for up to six m onths following knee surgery. This m ay only be practical in com pletely m otivated athletes and not in sedentary individuals. 3. Strict criteria should be applied before athletes are allowed to return to sport. Isokinetic muscle strength should be evaluated and should include testing at slow, m edium and fast speeds o f both the ham strings and quadriceps. The d o m in an t leg should be strengthened so th at it is able to produce a significantly greater torque o u tp u t than the non-dom inant leg. The quadriceps should produce a greater torque than the ham strings at each o f the three test speeds. The patient m ust also be tested to ensure that he has sufficient muscle flexibility, muscle endurance and co-ordination to protect the post- surgical knee and prevent re-injury during competitive sport. R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) 100 Fisioterapie, D esem ber 1983, deeI 39, no 4 The d uration of rehabilitation depends on the rate of recovery and the desired muscle strength. Thus, where desired strength is greater (in athletes), intensive rehabilitation for up to 6 m onths is suggested, but in sedentary individuals rehabilitation need only aim at returning the patient to norm al daily activities. References 1. K rause, W. R., Pope, M. H ., Johnson, R. J. and Wilder, D. G. Mechanical Changes in the Knee After M enisectom y. J Bone Joint Surg 1976 58-A: 599-603. 2. A ppel, H. Late results after menisectomy in the knee jo in t. A clinical a n d ro en tg en o lo g ic follow -up investigation. (1970;). Acta Orthop Scand Suppl 133. 3. Wynn Parry, C. B., N ichols, P. J. R., and Lewis, N. R. Menisectomy: A Review o f 1723 Cases. Ann Phys Med (1958;) 4; 201-215. 4. H enderson, M. S. P osterolateral Incision for the Removal o f Loose Bodies from the Posterior C om partm ent o f the Knee Joint. Proc Mayo Clin (1934;). 9: 65. 5. H uckell, J. R. Is M enisectomy a benign procedure? Can J Surg (1965;) 8: 254-268. 6. Sonne-H olm , S., Fledelius, I. and A hn, N. C. N. Results after M enisectomy in 147 Athletes. Acta Orthop Scand (1980;) 51: 303-309. 7. Y ocum, L. A., B achm an, D. C., Bates Noble, H. and H oover, R. L., The deranged knee: R estoration of function! Am J Sports M ed (1978;) 6: 51-53. 8. H aggm ark, T., Jansson, E. and Erikssen, E. Fibre Area and M etabolic Potential o f the Thigh Muscle in Man After Knee Surgery and Im m obilisation. Int J Sports M e d ( m \ ; ) 2: 12-21. 9. Coyle, E. F., Feiring, D. C., T. C., Cote, R. W., Robe, F. B., Lee, W. and W ilmore, J. H. Specificity o f power im provem ents through slow and fast isokinetic training. J Appl Physiol. (1981;) 51: 1437-1442. 10. Eriksson, E. R ehabilitation of Muscle Function After Sport Injury — M ajor Problem in Sports Medicine. Int J Sports M ed (1981;) 2: 1-6. 11. D obner, J. J. and Nitz, A. K. Post Menisectomy tourniquet palsy and functional sequelae. Am J Sports M ed ( m i , ) 10: 211-214. 12. M acD ougall, J. D ., Elder, G. C. B., Sale, D. G. et al. Effects o f strength training and im m obilisation of hum an muscle fibres. Eur J Appl Physiol (1980;). 43:25- 34. 13. B ooth, F. W. The effect of limb im m obilisation on skeletal muscle. J Appl Physiol (1982); 52: 1113-1118. 14. D uffin, D. Knee Strength and F unction following M enisectomy. Physio (1977;) 63: 362-363. 15. R orabeck, C. H. and Kennedy, J. C. T ourniquet- induced nerve ischemia com plicating knee ligament surgery. Am J Sports M ed (1980;) 8: 98-102. 16. S herm an, W. M., Pearson, D. R., Plyley, M. J., Costill, D. L., H abansky, A. J. and Voegelgesang, D. A. Isokinetic rehabilitation after surgery. A review of f a c to r s w hich a re i m p o r t a n t fo r d e v e lo p in g physiotherapeutic techniques after knee surgery. Am J Sports M ed (\9&2\) 10: 155-161. 17. W yatt, M. P., and Edw ards, A. M. C om parison o f Q uadriceps and H am string Torque Values during Isokinetic Exercise. J Orth Sports Phys Therapy (1981;) 3: 49-56. Pezzi Balls Swiss Vinyl Balls —Bobath Balls--------- • OUTDOOR GAMES • DIDACTICS • GYMNASTICS • PHYSIOTHERAPY • REHABILITATION A ll the products designed by Dr. H orst Maurer. Pezzi Balls, Gymnastlk Balls and Physioballs • 42cm0 YELLOW • 53 cmo ORANGE • 65 cmo GREEN • 95 cmo RED • 120 cmo ORANGE Heavy Balls — weighted balls with handles. Medicine Balls, all weights and sizes. Pon Pon Balls and Bouncing Balls. Available from: LUNBA (PTY) LTD. 706 - 6th Street, Wynberg SANDTON P.O. 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