CHILDREN’S ORTHOPAEDICS
The transverse Vulpius gastrocsoleus recession for equinus gait in children with cerebral palsy A. Tinney, P. Thomason, M. Sangeux, A Khot, H. K. Graham From Royal Children's Hospital, Victoria, Australia
We report the results of Vulpius transverse gastrocsoleus recession for equinus gait in 26 children with cerebral palsy (CP), using the Gait Profile Score (GPS), Gait Variable Scores (GVS) and movement analysis profile. All children had an equinus deformity on physical examination and equinus gait on three-dimensional gait analysis prior to surgery. The preoperative and post-operative GPS and GVS were statistically analysed. There were 20 boys and 6 girls in the study cohort with a mean age at surgery of 9.2 years (5.1 to 17.7) and 11.5 years (7.3 to 20.8) at follow-up. Of the 26 children, 14 had spastic diplegia and 12 spastic hemiplegia. Gait function improved for the cohort, confirmed by a decrease in mean GPS from 13.4° pre-operatively to 9.0° final review (p < 0.001). The change was 2.8 times the minimal clinically important difference (MCID). Thus the improvements in gait were both clinically and statistically significant. The transverse gastrocsoleus recession described by Vulpius is an effective procedure for equinus gait in selected children with CP, when there is a fixed contracture of the gastrocnemius and soleus muscles. Cite this article: Bone Joint J 2015;97-B:564–71.
A. Tinney, BioMedsci, Research Assistant The University of Melbourne, Flemington Road, Parkville, Victoria 3052, Australia. P. Thomason, B Phty, M Physio, Senior Physiotherapist, Manager M. Sangeux, MSc, PhD, Biomedical Engineer The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia. A Khot, MB, BS, FRCS(Tr&Orth), FRACS, Orthopaedic Surgeon Royal Children’s Hospital, Flemington Road, Parkville, Victoria 3052, Australia. H. K. Graham, MD, FRCS(Ed), FRACS, Professor of Orthopaedic Surgery Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia. Correspondence should be sent to Professor H. K. Graham; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B4. 34887 $2.00 Bone Joint J 2015;97-B:564–71. Received 17 August 2014; Accepted after revision 22 December 2014
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The muscles of children with cerebral palsy (CP) are smaller compared with unaffected children. Growth of the muscle tendon units lags behind growth of long bones, resulting in deforming contractures. The most common deformity is equinus.1,2 Reduced ankle dorsiflexion and equinus gait is frequently seen in children with spastic hemiplegia and diplegia.3-6 Equinus gait results in functional problems including reduced foot clearance in swing phase, tripping and falling. There is increased loading of the metatarsal heads and with time, breaching of the mid-foot and pes valgus.7 In younger children equinus deformity is predominantly spastic and management is often a combination of injections of botulinum toxin A (BoNT-A), ankle-foot-orthoses (AFOs) and physiotherapy.2,4,8 If fixed contractures develop surgery may be indicated.9-11 Surgery for equinus may be indicated as single level surgery in type II hemiplegia,12 as unilateral single event multilevel surgery (SEMLS) for children with type IV hemiplegia12 or as bilateral SEMLS for many children with diplegia.2,13-18 Three-dimensional gait analysis (3DGA) combined with physical examination has been shown to provide benefit in surgical planning and evaluation of outcomes.19-22 In recent years knowledge about surgical procedures for equinus and the expected outcomes have improved, due to studies in human cadavers,
clinical outcome studies and systematic reviews.23-27 There are multiple surgical procedures described for lengthening the gastrocsoleus muscle tendon unit (MTU) within its three anatomical zones. Zone 1 extends from the origin of the gastrocnemius muscle to the most distal fibres of the medial belly. Zone 2 extends from the distal extent of the medial gastrocnemius muscle belly to the most distal fibres of the soleus. Zone 3 is the Achilles tendon. Figure 1 depicts the three zones of the gastrocsoleus MTU and provides reference for the location of the transverse Vulpius gastrocsoleus recession (GSR).10,11,28 The transverse Vulpius GSR is a Zone 2 procedure which lengthens the gastrocnemius and soleus muscles equally. It is nonselective, meaning that gastrocnemius and soleus MTUs are both lengthened.23 It is, however, stable in cadaver simulations, suggesting that weight bearing can be safely initiated soon after surgery with no risk of disruption23 (Fig. 1). Although Vulpius described the transverse GSR28 more than a century ago there have been few clinical reports. There are no reports including outcome measures from gait analysis and summary statistics of gait.
Patients and Methods The aim of this study is to examine the outcome of the transverse Vulpius GSR in children with CP who have either spastic hemiplegia or THE BONE & JOINT JOURNAL
THE TRANSVERSE VULPIUS GASTROCSOLEUS RECESSION FOR EQUINUS GAIT IN CHILDREN WITH CEREBRAL PALSY
Fig. 1a
Fig. 1b
Line drawing showing a) the anatomical three zone division of the gastrocnemius soleus muscle tendon unit. The location of the transverse Vulpius gastrocsoleus recession is shown with complete division of the conjoined tendon and midline raphé prior to dorsiflexion (with the foot still in equinus) and b) the apparent lengthening attained following dorsiflexion.
diplegia. We selected outcome measures focused on gait function and dynamic ankle function derived from three dimensional kinematic studies. We assessed surgical complications and gait complications including the recurrence of equinus deformity or post-operative calcaneus gait. This was a retrospective analysis of gait laboratory data from a consecutive cohort of children with spastic CP who underwent surgery between January 2004 and December 2013. The data were collected prospectively, before and after surgery, according to standardised protocols.29 The study was approved under the audit provision of the Human Research Ethics Committee in our institution, number 34039 A. Prior to surgery informed, written consent was obtained from parents or legal guardians. No external funding was received in support of this study. Inclusion criteria for this study were children undergoing unilateral or bilateral transverse Vulpius GSR for an equinus gait secondary to CP. We included children with Gross Motor Function Classification System (GMFCS) Levels of I to III.30 We excluded children with GMFCS Level IV and those who did not have a full gait laboratory assessment before and after surgery. Over the study period 26 children (20 boys, six girls) met the inclusion criteria. The mean age at surgery was 9.2 years (5.1 to 17.7); 14 children had spastic diplegia and 12 children had spastic hemiplegia according to the Winters, Gage, and Hicks classification, types II or IV.12 Gait laboratory protocols involved the collection of patient demographics including gender, age, height, weight, body mass index, GMFCS and Functional Mobility Scale (FMS).31 A standardised physical examination was VOL. 97-B, No. 4, APRIL 2015
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performed on both occasions by an experienced physiotherapist using protocols with acceptable reliability.29,32 3DGA data was collected using a Vicon motion analysis system (Oxford Metrics Group, Oxford, United Kingdom) and at least two AMTI force plates (AMTI, Watertown, Massachusetts). A reflective marker set was applied to the children by an experienced physiotherapist using standardised procedures. Software used in the calculation of kinematic and kinetic data included Plug-in-Gait (Oxford Metrics Group) modeling software. Kinematic data was captured during barefoot walking at a self-selected speed. Kinematic data included the Gait Profile Score (GPS) and the Gait Variable Scores (GVS) for nine kinematic parameters; pelvic tilt, pelvic obliquity, pelvic rotation, hip flexion, hip abduction, hip rotation, knee flexion, ankle dorsiflexion and foot progression. For each child the GPS and GVS were calculated for the lower limb undergoing transverse Vulpius GSR The GPS and nine GVS scores formed the movement analysis profile (MAP)33-35 (Fig. 2). For both GPS and GVS, the units are degrees and a decrease indicates an improvement.34 The transverse Vulpius GSR was conducted as either single level surgery (spastic hemiplegia) or as part of SEMLS (spastic diplegia). The indications for GSR were symptomatic fixed equinus deformity of more than 25° with the knee extended and 15° with the knee flexed. Symptoms referable to equinus gait included parental concerns regarding toe walking, tripping, falling, difficulty with shoe-wear and forefoot pain. Objectively, on gait analysis, the indication was equinus deformity during gait, with ankle dorsiflexion in late stance greater than two standard deviations (SD) below the mean for typically developing children.35 Additional indications were during surgical procedures to stabilise the mid-foot (calcaneal lengthening osteotomy or subtalar fusion), when pre-operative examination indicated an equinus deformity and the intra-operative Silfverskiöld test10,11,36 confirmed fixed equinus affecting both the gastrocnemius and soleus. The final surgical decision to perform a Vulpius procedure was with the patient anaesthetised, when all children had a careful examination including a Silfverskiöld test. The management of the contralateral side of children included in the study with diplegia and asymmetric equinus deformities was according to the intra-operative findings. This included BoNT-A for spastic equinus, a Strayer distal gastrocnemius recession37 (an isolated transverse division of the gastrocnemius aponeurosis, immediately before the layers fused to form the conjoined tendon), a Vulpius GSR or lengthening of the Achilles tendon (TAL). Transverse Vulpius GSR was performed under general anaesthesia. Children undergoing SEMLS received supplementary epidural analgesia. The transverse GSR was performed as previously described.23,27,28 A 2 cm vertical, posteromedial incision was made in Zone 2. The deep fascia was divided to expose the conjoined aponeurosis of the gastrocsoleus. A right angled Langenbeck retractor was inserted
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30
Pre-operative Post-operative Norm
Degrees
20
10
0
Pel tilt
Hip flex
Knee Ank flex dors
Pel obl
Hip abd
Pel rot
Hip rot
Foot prog
GPS
Fig. 2 Pre- and post-operative movement analysis profile (MAP) for the nine unilateral kinematic Gait Variable Scores (GVS) with the Gait Profile Score (GPS) shown as mean values with standard deviation (error bars). Normal laboratory values35 are shown for comparison (Pel tilt, pelvic tilt; hip flex, hip flexion; knee flex, knee flexion; ank dors, ankle dorsiflexion; pel obl, pelvic obliquity; hip abd, hip abduction; pel rot, pelvic rotation; hip rot, hip rotation; foot prog, foot progression).
between the superficial and deep fascia to allow protection of the sural nerve and short saphenous vein. The sural nerve was not identified in all cases, presumably due to anatomical variations. In these cases, division of the conjoined aponeurosis was performed under direct vision with good retraction and did not result in any sural nerve injuries. The conjoined tendon was divided transversely, from medial to lateral, under direct vision, with a dorsiflexion force applied to the sole of the foot. The gastrocsoleus was stretched until a 10 mm to 15 mm gap opened up and the range of ankle dorsiflexion was checked. The midline raphé was then divided and a second dorsiflexion stretch was applied to the ankle. When, with the knee in extension, 10° of ankle dorsiflexion was achieved, no further dorseflexion stretching was undertaken. The incision was closed in layers and a below knee plaster cast applied with the foot plantigrade. Post-operative care allowed early mobilisation with immediate weight bearing as tolerated. Children who also had bony surgery were encouraged to bear weight one to three weeks following surgery according to the surgeon’s assessment of stability and healing. Casts were changed at three weeks when moulds were also taken for new AFOs. Six weeks after surgery casts were removed and replaced with solid AFOs. AFOs were recommended to be worn for a minimum of 12 months after surgery, until the postoperative 3DGA had confirmed they were no longer required biomechanically. A video-based gait analysis was conducted at three, six and nine months after surgery, with a repeat 3DGA after 12 months that was used for the analysis.2 The post-operative rehabilitation programme has been published in detail.38,39 The indications for the additional surgical procedures performed as part of SEMLS have previously been summarised.2
Statistical analysis. The GPS was calculated from the preand post-operative gait analysis for each patient. The nine GVS measures were calculated for the lower limb undergoing transverse Vulpius GSR. In cases of diplegia receiving bilateral GSR, one lower limb was included by random selection. Pre- and post-operative difference in the GPS and each GVS were assessed for significance by paired t-tests with a 95% confidence interval. All results were uploaded into an Excel spreadsheet (Window, Redmond, Oregon) and statistical analysis was performed using the Statistical Package for the Social Sciences version 18 (SPSS Inc, Chicago, Illinois). Paired t-tests, paired variance not assumed were conducted. Recurrent equinus was defined as ankle dorsiflexion more than two SDs below the mean for typically developing children.35 Calcaneus gait was defined as ankle dorsiflexion more than two SDs above the mean.5,15,40
Results All but one of the children had previously been treated for spastic equinus with injections of BoNT-A. The mean follow-up was 2.4 years (1 to 6). The demographics and GMFCS levels are found in Table I. There were 30 transverse GSR procedures performed in total. Four of these procedures were performed following insufficient Strayer procedures based on an intra-operative Silfverskiöld test. Four patients had bilateral transverse GSR procedures. Three patients had unilateral GSR procedures and alternative contralateral surgery, one Strayer procedure and two TALs. The remaining 19 patients had unilateral GSR procedures. A total of 107 concomitant procedures were performed across the entire cohort; 80 soft tissue procedures and 27 THE BONE & JOINT JOURNAL
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Table I. Pre- and post-operative patient demographics and Gross Motor Function Classification System (GMFCS) levels. Mean interval between assessments was 2.4 years (1 to 6). Pre-operative
Post-operative
Diagnosis
Spastic hemiplegia: n = 12 Spastic diplegia n = 14
Spastic hemiplegia: n = 12 Spastic diplegia: n = 14
Mean age (yrs) (range) Mean height (cm) (range) Mean weight (kg) (range) Mean BMI (kg/m2) (range) GMFCS level Ankle foot orthoses: (no, %)
9.2 (5.1 to 17.7) 130.4 (98.4 to 167.2) 28.5 (13.2 to 53.8) 16.1 (12.6 to 26.7) I = 5, II = 19, III = 2 18 (69)
11.5 (7.3 to 20.8) 141.7 (121.1 to 173.4) 36.7 (19.9 to 80.9) 17.5 (12.7 to 29.0) I = 8, II = 16, III = 2 21 (81)
BMI, body mass index
Table II. Operative procedures performed as part of single event multilevel surgery Procedure
Number performed
Transverse vulpius GSR Strayer and soleal fascial lengthening White slide TAL Hoke TAL Psoas over the brim lengthening Adductor release Hamstring lengthening Semitendinosus transfer Femoral derotation osteotomy Supramalleolar osteotomy tibia Tibialis posterior lengthening Split anterior tibialis tendon transfer Calcaneal lengthening osteotomy Subtalar fusion Peroneus brevis lengthening Plantar fascia release Total
30 5 1 1 3 13 10 1 18 4 10 3 1 4 2 1 107
GSR, gastrocsoleus recession; TAL, Achilles tendon lengthening
bony procedures. Procedures performed as part of SEMLS are summarised in Table II. Gait function improved for the whole cohort, as confirmed by a mean decrease in GPS from 13.4° (7.13° to 22.18°) before surgery to 9.0° (5.86° to 14.84°) more than one year after surgery (p < 0.001). This is also a clinically significant improvement; the decrease in mean GPS of 4.4° is 2.8 times the minimal clinically important difference (MCID = 1.6°).41 The mean improvement in GPS was smaller in children with hemiplegia, 11.8° (7.41° to 17.11°) to 9.0° (5.91° to 12.07°) (p = 0.016) than in those with diplegia, 14.7° (7.13° to 22.18°) to 9.1° (5.86° to 14.84°) (p < 0.001). However, this improvement is still greater than the MCID. For the whole cohort, all nine GVS improved significantly, as illustrated by the MAP (Fig. 2). For children with diplegia, seven of the nine GVS measures (pelvic tilt, pelvic obliquity, hip abduction, hip rotation, knee flexion, ankle dorsiflexion and foot progression) improved significantly. For children with hemiplegia, four of nine GVS measures (pelvic rotation, hip flexion, hip rotation, and ankle dorsiflexion) improved significantly. In both groups the mean ankle GVS improved significantly. In VOL. 97-B, No. 4, APRIL 2015
children with hemiplegia the mean ankle GVS improved from 16.4° (5.3° to 24.9°) to 8.1° (5.2° to 12.2°). In children with diplegia the mean ankle GVS improved from 21.3° (5.8° to 34.3°) to 7.2° (3.4° to 12.7°). (Table III). Maximum ankle dorsiflexion in stance increased in both groups as illustrated in Figure 3. It was also noted that there was a decrease in the range and variability of dynamic gastrocsoleus length following surgery. Two of the 14 children with diplegia and two of 12 children with hemiplegia had persistent or recurrent spastic equinus (> 2SDs below mean). One child with diplegia and two with hemiplegia had calcaneus at the ankle. (> 2SDs above the mean). These children are currently managed in solid AFOs and as yet do not have evidence of progressive crouch gait. There were no superficial or deep wound infections and no haematomas or injuries to the sural nerve. One child with hemiplegia has required revision surgery for recurrent equinus deformity.
Discussion Surgery in children with CP for equinus deformity must strike a balance between over correction resulting in
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Table III. Mean differences in Gait Profile Score (GPS) and Gait Variable Scores (GVS) pre-operatively (pre-op) and post-operatively (post-op) for the entire cohort Cohort GPS (°) Hemiplegia Diplegia Total GVS Sagittal pelvis Hemiplegia Diplegia Total Coronal pelvis Hemiplegia Diplegia Total Transverse pelvis Hemiplegia Diplegia Total Sagittal hip Hemiplegia Diplegia Total Coronal hip Hemiplegia Diplegia Total Transverse hip Hemiplegia Diplegia Total Sagittal knee Hemiplegia Diplegia Total Sagittal ankle Hemiplegia Diplegia Total Foot progression Hemiplegia Diplegia Total
Difference in means (pre-op to post-op)
95% CI
p-value (t-test)
Subjects improved (%)
2.8° 5.6° 4.4°
0.61 to 5.05 1.30 to 2.99 2.56 to 6.14
0.016 < 0.001 < 0.001
100 86 92
2.5° 3.5° 3.0°
-1.07 to 5.99 0.12 to 6.84 0.67 to 5.35
0.162 0.043 0.013
75 79 77
0.5° 1.8° 1.2°
-1.41 to 2.34 0.40 to 3.10 0.07 to 2.25
0.609 0.013 0.038
83 79 81
5.0° 1.8° 3.3°
0.77 to 9.28 -1.27 to 4.88 0.72 to 5.87
0.023 0.238 0.014
92 71 77
5.4° 3.0° 4.1°
0.35 to 10.37 -1.53 to 7.42 0.85 to 7.27
0.037 0.186 0.015
75 57 65
2.3° 2.4° 2.3°
-1.21 to 5.74 1.04 to 0.25 0.44 to 4.24
0.190 0.030 0.017
58 71 65
7.0° 8.9° 8.0°
2.35 to 2.03 2.93 to 14.80 4.2 to 11.83
0.009 0.005 < 0.001
83 79 81
2.5° 5.9° 4.3°
1.93 to -1.49 0.27 to 11.47 0.76 to 7.88
0.207 0.041 0.018
67 86 77
8.3° 14.1° 11.4°
2.28 to 3.39 9.44 to 18.69 8.03 to 14.76
0.003 < 0.001 < 0.001
83 93 88
1.5° 8.1° 5.0°
-5.58 to 8.53 0.73 to 15.38 0.03 to 10.01
0.669 0.032 0.049
50 86 69
CI, confidence interval
calcaneus or crouch gait and under correction leading to recurrent equinus and the need for revision surgery. There are important differences in the surgical procedures for equinus deformity in terms of their anatomy, biomechanics and clinical outcomes.36,42,43 Proximal zone procedures such as the Strayer gastrocnemius recession are selective, stable and associated with low rates of over correction and crouch gait at the expense of significant rates of recurrent equinus.15,40 Distal Zone 3 procedures such as slide lengthening of the Achilles tendon, are useful for severe equinus deformities in spastic hemiplegia but cause unacceptable rates of calcaneus and crouch gait in spastic diplegia.26,44,45 Recent long-term outcome studies of Zone 1 procedures confirm their safety and efficacy in children with spastic
diplegia.40 However, some children with diplegia and most children with hemiplegia present with a more severe degree of fixed equinus than can be corrected by either a Strayer or Baumann procedure.10,11,27,44 The current literature does not confirm which is the optimum procedure for children with a moderate fixed equinus affecting both the gastrocnemius and soleus. There is clearly a need for an evidencebased procedure which addresses the equinus deformity which is too severe for correction by a Zone 1 procedure but not sufficiently severe to require a Zone 3 procedure. In general, surgical outcomes following gait improvement surgery should be separated for children with spastic hemiplegia and spastic diplegia. However in this study we feel it is reasonable to consider both groups in the same THE BONE & JOINT JOURNAL
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Maximum ankle dorsiflexion (°)
30
20
+2SD +1SD
10
MEAN -1SD -2SD
0
-10
-20
Hemiplegia Diplegia
-30 Pre-operative
Post-operative Time Fig. 3
Box and whisker plot depicting the maximum ankle dorsiflexion in stance pre- and postoperatively. The horizontal line within each box is the median, with the top and bottom lines delineating the inter-quartile range. The whiskers plot the extremes of the data range. The solid horizontal reference line is the normal mean of maximum ankle dorsiflexion and the dashed lines above and below indicate 1 and 2 standard deviations (SD) either side.
study cohort as we are assessing a single operative procedure. In this study the Zone 2 transverse Vulpius GSR resulted in a clinical and statistically significant improvement for children with both spastic hemiplegia and spastic diplegia equinus gait (ankle GVS) as well as gait function in general (GPS). The GPS for the entire cohort improved by 2.8 times the MICD.41 Greater improvements were found in the GPS of children with diplegia who had SEMLS compared with children with hemiplegia who had single level surgery. The improvements in ankle GVS were greater in children with diplegia than those with hemiplegia because they had more severe fixed equinus at baseline. The transverse Vulpius GSR is now our principal procedure for the majority of children with spastic hemiplegia who have equinus gait, with the White slide TAL reserved for severe neglected equinus.46 It is gratifying to note that single-level surgery in Type II hemiplegia12 results in significant improvements not only at the ankle level, but also in an additional three GVS measures: pelvic rotation, hip flexion and hip rotation. The majority of children who present with fixed equinus deformity have had prior treatment with BoNT-A, AFOs and physiotherapy. Although nonoperative treatment does not prevent equinus deformity it may slow the progression and reduce severity.2,7,13 Surgical lengthening after the age of six years has a more predictable outcome with a lower prevalence of both recurrent equinus and calcaneus.46 VOL. 97-B, No. 4, APRIL 2015
We wish to emphasise that the Strayer gastrocnemius recession remains our index procedure, as part of SEMLS, for the management of equinus in children with spastic diplegia.15,38 We reserve the transverse Vulpius GSR specifically for children with a fixed equinus deformity affecting the gastrocnemius and soleus. To qualify for a Vulpius procedure, children with diplegia must have at least 15° of equinus deformity with the knee flexed when examined under anaesthesia at the time of surgery. In addition, there should be no more than a 15° increase in equinus, when the knee is extended. We consider a difference in equinus of more than 15° to be an indication for a distal gastrocnemius recession (Strayer) combined with a soleal fascial lengthening.10,11 As with all procedures for equinus gait, selecting the correct surgical ‘dose’ is important and the rates of both under correction and over correction were significant even at short-term follow up. Hence our recommendation to ‘fine tune’ the choice of surgery for equinus deformity at the time of examination under anaesthetia using the Silfverskiöld test. Under correction or recurrent equinus is preferred to any degree of over correction and calcaneus gait.15,47 Persistent or recurrent equinus is relatively easily treated by an additional procedure but calcaneus may lead to crouch gait and can be very difficult to salvage.44 The definitions of equinus and calcaneus used in this study are rigorous and permit comparison with previous
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work.15,40 To date, apart from one patient requiring a revision procedure, no other child is symptomatic or likely to require a revision procedure in the foreseeable future. The remainder have spastic equinus well managed in AFOs. To date no child has developed crouch gait. Those with mild over correction are managed in solid AFOs and remain under close follow-up. It is our experience that in children with mild over correction, protection of the gastrocsoleus in a solid AFO combined with longitudinal growth of the tibia will allow ‘re-tensioning’ to occur and prevent the development of progressive crouch gait.39 In this study strong plantar flexion and knee extension coupling was maintained in most children despite substantial increases in height and weight between the baseline evaluation and follow-up. Children maintained or improved both their GMFCS level and FMS grades and gait as a whole was improved, according to GPS scores. The criteria for selecting the appropriate surgery for equinus deformity and equinus gait in children with CP are becoming more stringent and more specific.23 In randomised studies in the formalin preserved human cadaver, the amount of lengthening of the MTU increases from proximal to distal.23,27 Even within Zone 2, differences exist between the amount of lengthening following a high transverse section of the conjoined tendon when compared with a low division of the conjoined tendon with division of the midline raphé as an additional variable.27 It is hoped that information from cadaver models may help refine surgical techniques in children to further reduce the rates of both over correction and under correction. The strengths of this study are the use of a standardised surgical approach for the correction of equinus deformity, standardised post-operative care and carefully monitored rehabilitation, uniform selection criteria, pre- and postoperative gait analysis, rigorous definitions of over correction and under correction and clearly defined outcome criteria for both the equinus component of gait (GVS) and overall gait function (GPS). The weaknesses of this study are the variable surgical SEMLS prescription and the shortterm follow-up. In addition, both the GPS and ankle GVS are clearly affected by the concomitant procedures, which represent a significant and uncontrolled confounding variable in this study. In conclusion, the short term results of the transverse Vulpius GSR as a single level surgery are encouraging for children with hemiplegia in equinus gait. It may also have a role for a highly selected subgroup of children with spastic diplegia as part of SEMLS. Longer term follow-up to skeletal maturity will be required to establish the true rates of recurrent equinus, calcaneus and crouch gait. Supplementary material A summary of indications for equinus gait surgery and combined procedures as part of single event multilevel surgery (SEMLS) in patients with cerebral palsy; hemiplegia and diplegia GMFCS I-III including rehabilitation protocols,
is available with the online version of this article at www.bjj.boneandjoint.org.uk Author contributions A. Tinney: Data collection. Data analysis, Writing of paper. P. Thomason: Data collection, Analysis and interpretation, Writing of paper. M. Sangeux: Data collection and analysis. A. Khot: Performed surgery, Writing of paper. H. K. Graham: Performed surgery, Writing of paper. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by E. Moulder and first proof edited by G. Scott.
References 1. Agarwal A, Verma I. Cerebral palsy in children: An overview. J Clin Orthop Trauma 2012;3:77–81. 2. Bache CE, Selber P, Graham HK. The management of spastic diplegia. Curr Orthop 2003;17:88–104. 3. Sheean G. The pathophysiology of spasticity. Eur J Neurol 2002;9:3–9. 4. Rodda J, Graham HK. Classification of gait patterns in spastic hemiplegia and spastic diplegia: a basis for a management algorithm. Eur J Neurol 2001;8:98–108. 5. Jahn J, Vasavada AN, McMulkin ML. Calf muscle-tendon lengths before and after Tendo- Achilles lengthenings and gastrocnemius lengthenings for equinus in cerebral palsy and idiopathic toe walking. Gait Posture 2009;29:612–617. 6. Fry NR, Gough M, McNee AE, Shortland AP. Changes in the Volume and Length of the Medial Gastrocnemius After Surgical Recession in Children With Spastic Diplegic Cerebral Palsy. J Pediatr Orthop 2007;27:769–774. 7. Goldstein M, Harper DC. Management of cerebral palsy: equinus gait. Dev Med Child Neurol 2001;43:563–569. 8. Corry IS, Cosgrove AP, Duffy CM, et al. Botulinum toxin A compared with stretching casts in the treatment of spastic equinus: a randomised prospective trial . J Pediatr Orthop 1998;18:304–311. 9. Lykissas MG, McCarthy JJ. Lower extremity management in cerebral palsy. Current Orthopaedic Practice 2013;24:334–339. 10. Graham HK. Cerebal Palsy. In: McCarthy JJ, Drennan JC, eds. Drennan's The Child's Foot & Ankle. Second ed. Philadelphia: Lippincott Williams & Wilkins, 2009:188–218. 11. Graham HK, Thomason P, Novacheck T. Cerebral Palsy. In: Lovell & Winter's Pediatric Orthopaedics. Seventh ed. Philadelphia:Lippincott, Williams & Wilkins, 2010:188–218. 12. Winters TF Jr, Gage JR, Hicks R. Gait patterns in spastic hemiplegia in children and young adults. J Bone Joint Surg [Am] 1987;69-A:437–441. 13. Cobeljic G, Bumbasirevic M, Lesic A, Bajin Z. The management of spastic equinus in cerebral palsy. Orthopaedics & Trauma 2009;23:201–209. 14. Graham HK, Baker R, Dobson F, Morris ME. Multilevel orthopaedic surgery in group IV spastic hemiplegia. J Bone Joint Surg [Br] 2005;87-B:548–555. 15. Firth GB, Passmore E, Sangeux M, et al. Multilevel surgery for equinus gait in children with spastic diplegic cerebral palsy: medium-term follow-up with gait analysis. J Bone Joint Surg [Am] 2013;95-A:931–938. 16. Etnyre B, Chambers CS, Scarborough NH, Cain TE. Preoperative and postoperative assessment of surgical intervention for equinus gait in children with cerebral palsy. J Pediatr Orthop 1993;13:24–31. 17. Karol LA. Surgical management of the lower extremity in ambulatory children with cerebral palsy. J Am Acad Orthop Surg 2004;12:196–203. 18. Steinwender G, Saraph V, Zwick E- B, Uitz C, Linhart W. Fixed and Dynamic Equinus in Cerebral Palsy: Evaluation of Ankle Function After Multilevel Surgery. J Pediatr Orthop 2001;21:102–107. 19. Molenaers G, Desloovere K, Fabry G, De Cock P. The effects of quantitative gait assessment and botulinum toxin a on musculoskeletal surgery in children with cerebral palsy. J Bone Joint Surg [Am] 2006;88-A:161–170. 20. Gage JR. The role of gait analysis in the treatment of cerebral palsy. J Pediatr Orthop 1994;14:701–702. 21. Saraph V, Zwick EB, Zwick G, et al. Multilevel surgery in spastic diplegia: evaluation by physical examination and gait analysis in 25 children. J Pediatr Orthop 2002;22:150–157. 22. Zwick EB, Leistritz L, Milleit B, et al. Classification of equinus in ambulatory children with cerebral palsy-discrimination between dynamic tightness and fixed contracture. Gait Posture 2004;20:273–279. 23. Firth GB, McMullan M, Chin T, et al. Lengthening of the gastrocnemius-soleus complex: an anatomical and biomechanical study in human cadavers. J Bone Joint Surg [Am] 2013;95-A:1489–1496.
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24. Blitz NM, Eliot DJ. Anatomical Aspects of the Gastrocnemius Aponeurosis and Its Insertion: a Cadaveric Study. J Foot Ankle Surg 2007;46:101–108. 25. Blitz NM, Eliot DJ. Anatomical Aspects of the Gastrocnemius Aponeurosis and its Muscular Bound Portion: A Cadaveric Study—part II. J Foot Ankle Surg 2008;47:533– 540. 26. Shore BJ, White N, Graham HK. Surgical correction of equinus deformity in children with cerebral palsy: a systematic review. J Child Orthop 2010;4:277–290. 27. Tinney A, Khot A, Eizenberg N, Wolfe R, Graham HK. Gastrocsoleus recession techniques: an anatomical and biomechanical study in human cadavers. Bone Joint J 2014;96-B:778–782. 28. Vulpius O, Stoffel A. Tenotomie der end schnen der mm. Gastrocnemius el soleus mittels rutschenlassens nach. Orthopadische Operationslehre 192029–31. 29. Keenan WN, Rodda J, Wolfe R, et al. The static examination of children and young adults with cerebral palsy in the gait analysis laboratory: technique and observer agreement. J Pediatr Orthop B 2004;13:1–8. 30. Palisano R, Rosenbaum P, Walter S, et al. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol 1997;39:214–223. 31. Graham HK, Harvey A, Rodda J, Nattrass GR, Pirpiris M. The Functional Mobility Scale (FMS). J Pediatr Orthop 2004;24:514–520. 32. Harvey AR, Morris ME, Graham HK, Wolfe R, Baker R. Reliability of the functional mobility scale for children with cerebral palsy. Phys Occup Ther Pediatr 2010;30:139–149. 33. Tirosh O, Baker R, McGinley J. GaitaBase: Web-based repository system for gait analysis. Comput Biol Med 2010;40:201–207. 34. Baker R, McGinley JL, Schwartz MH, et al. The gait profile score and movement analysis profile. Gait Posture 2009;30:265–269. 35. Pinzone O, Schwartz MH, Thomason P, Baker R. The comparison of normative reference data from different gait analysis services. Gait & Posture 2014;40:286–290. 36. Strayer LM Jr. Recession of the gastrocnemius; an operation to relieve spastic contracture of the calf muscles. J Bone Joint Surg [Am] 1950;32-A:671–676.
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37. Pinney SJ, Sangeorzan BJ, Hansen ST Jr. Surgical anatomy of the gastrocnemius recession (Strayer procedure). Foot Ankle Int 2004;25:247–250. 38. Thomason P, Baker R, Dodd K, et al. Single-event multilevel surgery in children with spastic diplegia: a pilot randomized controlled trial. J Bone Joint Surg [Am] 2011;93-A:451–460. 39. Thomason P, Graham HK. Rehabilitation of children with cerebral palsy after Single Event Multilevel Surgery. In: Iansek R, Morris ME, eds. Rehabilitation in Movement Disorders. Cambridge University Press, 2013:203–216. 40. Dreher T, Buccoliero T, Wolf SI, et al. Long-term results after gastrocnemiussoleus intramuscular aponeurotic recession as a part of multilevel surgery in spastic diplegic cerebral palsy. J Bone Joint Surg [Am] 2012;94-A:627–637. 41. Baker R, McGinley JL, Schwartz M, et al. The minimal clinically important difference for the Gait Profile Score. Gait Posture 2012;35:612–615. 42. Baker LD. A rational approach to the surgical needs of the cerebral palsy patient. J Bone Joint Surg [Am] 1956;38-A:313–323. 43. White JW. Torsion of the achilles tendon: Its surgical significance. Arch Surg 1943;46:784–787. 44. Borton DC, Walker K, Pirpiris M, Nattrass GR, Graham HK. Isolated calf lengthening in cerebral palsy. Outcome analysis of risk factors. J Bone Joint Surg [Br] 2001;83-B:364–370. 45. Segal LS, Thomas SE, Mazur JM, Mauterer M. Calcaneal gait in spastic diplegia after heel cord lengthening: a study with gait analysis. J Pediatr Orthop 1989;9:697– 701. 46. Graham HK, Fixsen JA. Lengthening of the calcaneal tendon in spastic hemiplegia by the White slide technique. A long-term review. J Bone Joint Surg [Br] 1988;70B:472–475. 47. Joseph B, Reddy K, Varghese RA, Shah H, Doddabasappa SN. Management of severe crouch gait in children and adolescents with cerebral palsy. J Pediatr Orthop 2010;30:832–839.
The transverse Vulpius gastrocsoleus recession for equinus gait in children with cerebral palsy A. Tinney, P. Thomason, M. Sangeux, A Khot, H. K. Graham From Royal Children's Hospital, Victoria, Australia
We report the results of Vulpius transverse gastrocsoleus recession for equinus gait in 26 children with cerebral palsy (CP), using the Gait Profile Score (GPS), Gait Variable Scores (GVS) and movement analysis profile. All children had an equinus deformity on physical examination and equinus gait on three-dimensional gait analysis prior to surgery. The preoperative and post-operative GPS and GVS were statistically analysed. There were 20 boys and 6 girls in the study cohort with a mean age at surgery of 9.2 years (5.1 to 17.7) and 11.5 years (7.3 to 20.8) at follow-up. Of the 26 children, 14 had spastic diplegia and 12 spastic hemiplegia. Gait function improved for the cohort, confirmed by a decrease in mean GPS from 13.4° pre-operatively to 9.0° final review (p < 0.001). The change was 2.8 times the minimal clinically important difference (MCID). Thus the improvements in gait were both clinically and statistically significant. The transverse gastrocsoleus recession described by Vulpius is an effective procedure for equinus gait in selected children with CP, when there is a fixed contracture of the gastrocnemius and soleus muscles. Cite this article: Bone Joint J 2015;97-B:564–71.
A. Tinney, BioMedsci, Research Assistant The University of Melbourne, Flemington Road, Parkville, Victoria 3052, Australia. P. Thomason, B Phty, M Physio, Senior Physiotherapist, Manager M. Sangeux, MSc, PhD, Biomedical Engineer The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia. A Khot, MB, BS, FRCS(Tr&Orth), FRACS, Orthopaedic Surgeon Royal Children’s Hospital, Flemington Road, Parkville, Victoria 3052, Australia. H. K. Graham, MD, FRCS(Ed), FRACS, Professor of Orthopaedic Surgery Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia. Correspondence should be sent to Professor H. K. Graham; e-mail: [email protected] ©2015 The British Editorial Society of Bone & Joint Surgery doi:10.1302/0301-620X.97B4. 34887 $2.00 Bone Joint J 2015;97-B:564–71. Received 17 August 2014; Accepted after revision 22 December 2014
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The muscles of children with cerebral palsy (CP) are smaller compared with unaffected children. Growth of the muscle tendon units lags behind growth of long bones, resulting in deforming contractures. The most common deformity is equinus.1,2 Reduced ankle dorsiflexion and equinus gait is frequently seen in children with spastic hemiplegia and diplegia.3-6 Equinus gait results in functional problems including reduced foot clearance in swing phase, tripping and falling. There is increased loading of the metatarsal heads and with time, breaching of the mid-foot and pes valgus.7 In younger children equinus deformity is predominantly spastic and management is often a combination of injections of botulinum toxin A (BoNT-A), ankle-foot-orthoses (AFOs) and physiotherapy.2,4,8 If fixed contractures develop surgery may be indicated.9-11 Surgery for equinus may be indicated as single level surgery in type II hemiplegia,12 as unilateral single event multilevel surgery (SEMLS) for children with type IV hemiplegia12 or as bilateral SEMLS for many children with diplegia.2,13-18 Three-dimensional gait analysis (3DGA) combined with physical examination has been shown to provide benefit in surgical planning and evaluation of outcomes.19-22 In recent years knowledge about surgical procedures for equinus and the expected outcomes have improved, due to studies in human cadavers,
clinical outcome studies and systematic reviews.23-27 There are multiple surgical procedures described for lengthening the gastrocsoleus muscle tendon unit (MTU) within its three anatomical zones. Zone 1 extends from the origin of the gastrocnemius muscle to the most distal fibres of the medial belly. Zone 2 extends from the distal extent of the medial gastrocnemius muscle belly to the most distal fibres of the soleus. Zone 3 is the Achilles tendon. Figure 1 depicts the three zones of the gastrocsoleus MTU and provides reference for the location of the transverse Vulpius gastrocsoleus recession (GSR).10,11,28 The transverse Vulpius GSR is a Zone 2 procedure which lengthens the gastrocnemius and soleus muscles equally. It is nonselective, meaning that gastrocnemius and soleus MTUs are both lengthened.23 It is, however, stable in cadaver simulations, suggesting that weight bearing can be safely initiated soon after surgery with no risk of disruption23 (Fig. 1). Although Vulpius described the transverse GSR28 more than a century ago there have been few clinical reports. There are no reports including outcome measures from gait analysis and summary statistics of gait.
Patients and Methods The aim of this study is to examine the outcome of the transverse Vulpius GSR in children with CP who have either spastic hemiplegia or THE BONE & JOINT JOURNAL
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Fig. 1a
Fig. 1b
Line drawing showing a) the anatomical three zone division of the gastrocnemius soleus muscle tendon unit. The location of the transverse Vulpius gastrocsoleus recession is shown with complete division of the conjoined tendon and midline raphé prior to dorsiflexion (with the foot still in equinus) and b) the apparent lengthening attained following dorsiflexion.
diplegia. We selected outcome measures focused on gait function and dynamic ankle function derived from three dimensional kinematic studies. We assessed surgical complications and gait complications including the recurrence of equinus deformity or post-operative calcaneus gait. This was a retrospective analysis of gait laboratory data from a consecutive cohort of children with spastic CP who underwent surgery between January 2004 and December 2013. The data were collected prospectively, before and after surgery, according to standardised protocols.29 The study was approved under the audit provision of the Human Research Ethics Committee in our institution, number 34039 A. Prior to surgery informed, written consent was obtained from parents or legal guardians. No external funding was received in support of this study. Inclusion criteria for this study were children undergoing unilateral or bilateral transverse Vulpius GSR for an equinus gait secondary to CP. We included children with Gross Motor Function Classification System (GMFCS) Levels of I to III.30 We excluded children with GMFCS Level IV and those who did not have a full gait laboratory assessment before and after surgery. Over the study period 26 children (20 boys, six girls) met the inclusion criteria. The mean age at surgery was 9.2 years (5.1 to 17.7); 14 children had spastic diplegia and 12 children had spastic hemiplegia according to the Winters, Gage, and Hicks classification, types II or IV.12 Gait laboratory protocols involved the collection of patient demographics including gender, age, height, weight, body mass index, GMFCS and Functional Mobility Scale (FMS).31 A standardised physical examination was VOL. 97-B, No. 4, APRIL 2015
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performed on both occasions by an experienced physiotherapist using protocols with acceptable reliability.29,32 3DGA data was collected using a Vicon motion analysis system (Oxford Metrics Group, Oxford, United Kingdom) and at least two AMTI force plates (AMTI, Watertown, Massachusetts). A reflective marker set was applied to the children by an experienced physiotherapist using standardised procedures. Software used in the calculation of kinematic and kinetic data included Plug-in-Gait (Oxford Metrics Group) modeling software. Kinematic data was captured during barefoot walking at a self-selected speed. Kinematic data included the Gait Profile Score (GPS) and the Gait Variable Scores (GVS) for nine kinematic parameters; pelvic tilt, pelvic obliquity, pelvic rotation, hip flexion, hip abduction, hip rotation, knee flexion, ankle dorsiflexion and foot progression. For each child the GPS and GVS were calculated for the lower limb undergoing transverse Vulpius GSR The GPS and nine GVS scores formed the movement analysis profile (MAP)33-35 (Fig. 2). For both GPS and GVS, the units are degrees and a decrease indicates an improvement.34 The transverse Vulpius GSR was conducted as either single level surgery (spastic hemiplegia) or as part of SEMLS (spastic diplegia). The indications for GSR were symptomatic fixed equinus deformity of more than 25° with the knee extended and 15° with the knee flexed. Symptoms referable to equinus gait included parental concerns regarding toe walking, tripping, falling, difficulty with shoe-wear and forefoot pain. Objectively, on gait analysis, the indication was equinus deformity during gait, with ankle dorsiflexion in late stance greater than two standard deviations (SD) below the mean for typically developing children.35 Additional indications were during surgical procedures to stabilise the mid-foot (calcaneal lengthening osteotomy or subtalar fusion), when pre-operative examination indicated an equinus deformity and the intra-operative Silfverskiöld test10,11,36 confirmed fixed equinus affecting both the gastrocnemius and soleus. The final surgical decision to perform a Vulpius procedure was with the patient anaesthetised, when all children had a careful examination including a Silfverskiöld test. The management of the contralateral side of children included in the study with diplegia and asymmetric equinus deformities was according to the intra-operative findings. This included BoNT-A for spastic equinus, a Strayer distal gastrocnemius recession37 (an isolated transverse division of the gastrocnemius aponeurosis, immediately before the layers fused to form the conjoined tendon), a Vulpius GSR or lengthening of the Achilles tendon (TAL). Transverse Vulpius GSR was performed under general anaesthesia. Children undergoing SEMLS received supplementary epidural analgesia. The transverse GSR was performed as previously described.23,27,28 A 2 cm vertical, posteromedial incision was made in Zone 2. The deep fascia was divided to expose the conjoined aponeurosis of the gastrocsoleus. A right angled Langenbeck retractor was inserted
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30
Pre-operative Post-operative Norm
Degrees
20
10
0
Pel tilt
Hip flex
Knee Ank flex dors
Pel obl
Hip abd
Pel rot
Hip rot
Foot prog
GPS
Fig. 2 Pre- and post-operative movement analysis profile (MAP) for the nine unilateral kinematic Gait Variable Scores (GVS) with the Gait Profile Score (GPS) shown as mean values with standard deviation (error bars). Normal laboratory values35 are shown for comparison (Pel tilt, pelvic tilt; hip flex, hip flexion; knee flex, knee flexion; ank dors, ankle dorsiflexion; pel obl, pelvic obliquity; hip abd, hip abduction; pel rot, pelvic rotation; hip rot, hip rotation; foot prog, foot progression).
between the superficial and deep fascia to allow protection of the sural nerve and short saphenous vein. The sural nerve was not identified in all cases, presumably due to anatomical variations. In these cases, division of the conjoined aponeurosis was performed under direct vision with good retraction and did not result in any sural nerve injuries. The conjoined tendon was divided transversely, from medial to lateral, under direct vision, with a dorsiflexion force applied to the sole of the foot. The gastrocsoleus was stretched until a 10 mm to 15 mm gap opened up and the range of ankle dorsiflexion was checked. The midline raphé was then divided and a second dorsiflexion stretch was applied to the ankle. When, with the knee in extension, 10° of ankle dorsiflexion was achieved, no further dorseflexion stretching was undertaken. The incision was closed in layers and a below knee plaster cast applied with the foot plantigrade. Post-operative care allowed early mobilisation with immediate weight bearing as tolerated. Children who also had bony surgery were encouraged to bear weight one to three weeks following surgery according to the surgeon’s assessment of stability and healing. Casts were changed at three weeks when moulds were also taken for new AFOs. Six weeks after surgery casts were removed and replaced with solid AFOs. AFOs were recommended to be worn for a minimum of 12 months after surgery, until the postoperative 3DGA had confirmed they were no longer required biomechanically. A video-based gait analysis was conducted at three, six and nine months after surgery, with a repeat 3DGA after 12 months that was used for the analysis.2 The post-operative rehabilitation programme has been published in detail.38,39 The indications for the additional surgical procedures performed as part of SEMLS have previously been summarised.2
Statistical analysis. The GPS was calculated from the preand post-operative gait analysis for each patient. The nine GVS measures were calculated for the lower limb undergoing transverse Vulpius GSR. In cases of diplegia receiving bilateral GSR, one lower limb was included by random selection. Pre- and post-operative difference in the GPS and each GVS were assessed for significance by paired t-tests with a 95% confidence interval. All results were uploaded into an Excel spreadsheet (Window, Redmond, Oregon) and statistical analysis was performed using the Statistical Package for the Social Sciences version 18 (SPSS Inc, Chicago, Illinois). Paired t-tests, paired variance not assumed were conducted. Recurrent equinus was defined as ankle dorsiflexion more than two SDs below the mean for typically developing children.35 Calcaneus gait was defined as ankle dorsiflexion more than two SDs above the mean.5,15,40
Results All but one of the children had previously been treated for spastic equinus with injections of BoNT-A. The mean follow-up was 2.4 years (1 to 6). The demographics and GMFCS levels are found in Table I. There were 30 transverse GSR procedures performed in total. Four of these procedures were performed following insufficient Strayer procedures based on an intra-operative Silfverskiöld test. Four patients had bilateral transverse GSR procedures. Three patients had unilateral GSR procedures and alternative contralateral surgery, one Strayer procedure and two TALs. The remaining 19 patients had unilateral GSR procedures. A total of 107 concomitant procedures were performed across the entire cohort; 80 soft tissue procedures and 27 THE BONE & JOINT JOURNAL
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Table I. Pre- and post-operative patient demographics and Gross Motor Function Classification System (GMFCS) levels. Mean interval between assessments was 2.4 years (1 to 6). Pre-operative
Post-operative
Diagnosis
Spastic hemiplegia: n = 12 Spastic diplegia n = 14
Spastic hemiplegia: n = 12 Spastic diplegia: n = 14
Mean age (yrs) (range) Mean height (cm) (range) Mean weight (kg) (range) Mean BMI (kg/m2) (range) GMFCS level Ankle foot orthoses: (no, %)
9.2 (5.1 to 17.7) 130.4 (98.4 to 167.2) 28.5 (13.2 to 53.8) 16.1 (12.6 to 26.7) I = 5, II = 19, III = 2 18 (69)
11.5 (7.3 to 20.8) 141.7 (121.1 to 173.4) 36.7 (19.9 to 80.9) 17.5 (12.7 to 29.0) I = 8, II = 16, III = 2 21 (81)
BMI, body mass index
Table II. Operative procedures performed as part of single event multilevel surgery Procedure
Number performed
Transverse vulpius GSR Strayer and soleal fascial lengthening White slide TAL Hoke TAL Psoas over the brim lengthening Adductor release Hamstring lengthening Semitendinosus transfer Femoral derotation osteotomy Supramalleolar osteotomy tibia Tibialis posterior lengthening Split anterior tibialis tendon transfer Calcaneal lengthening osteotomy Subtalar fusion Peroneus brevis lengthening Plantar fascia release Total
30 5 1 1 3 13 10 1 18 4 10 3 1 4 2 1 107
GSR, gastrocsoleus recession; TAL, Achilles tendon lengthening
bony procedures. Procedures performed as part of SEMLS are summarised in Table II. Gait function improved for the whole cohort, as confirmed by a mean decrease in GPS from 13.4° (7.13° to 22.18°) before surgery to 9.0° (5.86° to 14.84°) more than one year after surgery (p < 0.001). This is also a clinically significant improvement; the decrease in mean GPS of 4.4° is 2.8 times the minimal clinically important difference (MCID = 1.6°).41 The mean improvement in GPS was smaller in children with hemiplegia, 11.8° (7.41° to 17.11°) to 9.0° (5.91° to 12.07°) (p = 0.016) than in those with diplegia, 14.7° (7.13° to 22.18°) to 9.1° (5.86° to 14.84°) (p < 0.001). However, this improvement is still greater than the MCID. For the whole cohort, all nine GVS improved significantly, as illustrated by the MAP (Fig. 2). For children with diplegia, seven of the nine GVS measures (pelvic tilt, pelvic obliquity, hip abduction, hip rotation, knee flexion, ankle dorsiflexion and foot progression) improved significantly. For children with hemiplegia, four of nine GVS measures (pelvic rotation, hip flexion, hip rotation, and ankle dorsiflexion) improved significantly. In both groups the mean ankle GVS improved significantly. In VOL. 97-B, No. 4, APRIL 2015
children with hemiplegia the mean ankle GVS improved from 16.4° (5.3° to 24.9°) to 8.1° (5.2° to 12.2°). In children with diplegia the mean ankle GVS improved from 21.3° (5.8° to 34.3°) to 7.2° (3.4° to 12.7°). (Table III). Maximum ankle dorsiflexion in stance increased in both groups as illustrated in Figure 3. It was also noted that there was a decrease in the range and variability of dynamic gastrocsoleus length following surgery. Two of the 14 children with diplegia and two of 12 children with hemiplegia had persistent or recurrent spastic equinus (> 2SDs below mean). One child with diplegia and two with hemiplegia had calcaneus at the ankle. (> 2SDs above the mean). These children are currently managed in solid AFOs and as yet do not have evidence of progressive crouch gait. There were no superficial or deep wound infections and no haematomas or injuries to the sural nerve. One child with hemiplegia has required revision surgery for recurrent equinus deformity.
Discussion Surgery in children with CP for equinus deformity must strike a balance between over correction resulting in
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Table III. Mean differences in Gait Profile Score (GPS) and Gait Variable Scores (GVS) pre-operatively (pre-op) and post-operatively (post-op) for the entire cohort Cohort GPS (°) Hemiplegia Diplegia Total GVS Sagittal pelvis Hemiplegia Diplegia Total Coronal pelvis Hemiplegia Diplegia Total Transverse pelvis Hemiplegia Diplegia Total Sagittal hip Hemiplegia Diplegia Total Coronal hip Hemiplegia Diplegia Total Transverse hip Hemiplegia Diplegia Total Sagittal knee Hemiplegia Diplegia Total Sagittal ankle Hemiplegia Diplegia Total Foot progression Hemiplegia Diplegia Total
Difference in means (pre-op to post-op)
95% CI
p-value (t-test)
Subjects improved (%)
2.8° 5.6° 4.4°
0.61 to 5.05 1.30 to 2.99 2.56 to 6.14
0.016 < 0.001 < 0.001
100 86 92
2.5° 3.5° 3.0°
-1.07 to 5.99 0.12 to 6.84 0.67 to 5.35
0.162 0.043 0.013
75 79 77
0.5° 1.8° 1.2°
-1.41 to 2.34 0.40 to 3.10 0.07 to 2.25
0.609 0.013 0.038
83 79 81
5.0° 1.8° 3.3°
0.77 to 9.28 -1.27 to 4.88 0.72 to 5.87
0.023 0.238 0.014
92 71 77
5.4° 3.0° 4.1°
0.35 to 10.37 -1.53 to 7.42 0.85 to 7.27
0.037 0.186 0.015
75 57 65
2.3° 2.4° 2.3°
-1.21 to 5.74 1.04 to 0.25 0.44 to 4.24
0.190 0.030 0.017
58 71 65
7.0° 8.9° 8.0°
2.35 to 2.03 2.93 to 14.80 4.2 to 11.83
0.009 0.005 < 0.001
83 79 81
2.5° 5.9° 4.3°
1.93 to -1.49 0.27 to 11.47 0.76 to 7.88
0.207 0.041 0.018
67 86 77
8.3° 14.1° 11.4°
2.28 to 3.39 9.44 to 18.69 8.03 to 14.76
0.003 < 0.001 < 0.001
83 93 88
1.5° 8.1° 5.0°
-5.58 to 8.53 0.73 to 15.38 0.03 to 10.01
0.669 0.032 0.049
50 86 69
CI, confidence interval
calcaneus or crouch gait and under correction leading to recurrent equinus and the need for revision surgery. There are important differences in the surgical procedures for equinus deformity in terms of their anatomy, biomechanics and clinical outcomes.36,42,43 Proximal zone procedures such as the Strayer gastrocnemius recession are selective, stable and associated with low rates of over correction and crouch gait at the expense of significant rates of recurrent equinus.15,40 Distal Zone 3 procedures such as slide lengthening of the Achilles tendon, are useful for severe equinus deformities in spastic hemiplegia but cause unacceptable rates of calcaneus and crouch gait in spastic diplegia.26,44,45 Recent long-term outcome studies of Zone 1 procedures confirm their safety and efficacy in children with spastic
diplegia.40 However, some children with diplegia and most children with hemiplegia present with a more severe degree of fixed equinus than can be corrected by either a Strayer or Baumann procedure.10,11,27,44 The current literature does not confirm which is the optimum procedure for children with a moderate fixed equinus affecting both the gastrocnemius and soleus. There is clearly a need for an evidencebased procedure which addresses the equinus deformity which is too severe for correction by a Zone 1 procedure but not sufficiently severe to require a Zone 3 procedure. In general, surgical outcomes following gait improvement surgery should be separated for children with spastic hemiplegia and spastic diplegia. However in this study we feel it is reasonable to consider both groups in the same THE BONE & JOINT JOURNAL
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Maximum ankle dorsiflexion (°)
30
20
+2SD +1SD
10
MEAN -1SD -2SD
0
-10
-20
Hemiplegia Diplegia
-30 Pre-operative
Post-operative Time Fig. 3
Box and whisker plot depicting the maximum ankle dorsiflexion in stance pre- and postoperatively. The horizontal line within each box is the median, with the top and bottom lines delineating the inter-quartile range. The whiskers plot the extremes of the data range. The solid horizontal reference line is the normal mean of maximum ankle dorsiflexion and the dashed lines above and below indicate 1 and 2 standard deviations (SD) either side.
study cohort as we are assessing a single operative procedure. In this study the Zone 2 transverse Vulpius GSR resulted in a clinical and statistically significant improvement for children with both spastic hemiplegia and spastic diplegia equinus gait (ankle GVS) as well as gait function in general (GPS). The GPS for the entire cohort improved by 2.8 times the MICD.41 Greater improvements were found in the GPS of children with diplegia who had SEMLS compared with children with hemiplegia who had single level surgery. The improvements in ankle GVS were greater in children with diplegia than those with hemiplegia because they had more severe fixed equinus at baseline. The transverse Vulpius GSR is now our principal procedure for the majority of children with spastic hemiplegia who have equinus gait, with the White slide TAL reserved for severe neglected equinus.46 It is gratifying to note that single-level surgery in Type II hemiplegia12 results in significant improvements not only at the ankle level, but also in an additional three GVS measures: pelvic rotation, hip flexion and hip rotation. The majority of children who present with fixed equinus deformity have had prior treatment with BoNT-A, AFOs and physiotherapy. Although nonoperative treatment does not prevent equinus deformity it may slow the progression and reduce severity.2,7,13 Surgical lengthening after the age of six years has a more predictable outcome with a lower prevalence of both recurrent equinus and calcaneus.46 VOL. 97-B, No. 4, APRIL 2015
We wish to emphasise that the Strayer gastrocnemius recession remains our index procedure, as part of SEMLS, for the management of equinus in children with spastic diplegia.15,38 We reserve the transverse Vulpius GSR specifically for children with a fixed equinus deformity affecting the gastrocnemius and soleus. To qualify for a Vulpius procedure, children with diplegia must have at least 15° of equinus deformity with the knee flexed when examined under anaesthesia at the time of surgery. In addition, there should be no more than a 15° increase in equinus, when the knee is extended. We consider a difference in equinus of more than 15° to be an indication for a distal gastrocnemius recession (Strayer) combined with a soleal fascial lengthening.10,11 As with all procedures for equinus gait, selecting the correct surgical ‘dose’ is important and the rates of both under correction and over correction were significant even at short-term follow up. Hence our recommendation to ‘fine tune’ the choice of surgery for equinus deformity at the time of examination under anaesthetia using the Silfverskiöld test. Under correction or recurrent equinus is preferred to any degree of over correction and calcaneus gait.15,47 Persistent or recurrent equinus is relatively easily treated by an additional procedure but calcaneus may lead to crouch gait and can be very difficult to salvage.44 The definitions of equinus and calcaneus used in this study are rigorous and permit comparison with previous
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A. TINNEY, P. THOMASON, M. SANGEUX, A KHOT, H. K. GRAHAM
work.15,40 To date, apart from one patient requiring a revision procedure, no other child is symptomatic or likely to require a revision procedure in the foreseeable future. The remainder have spastic equinus well managed in AFOs. To date no child has developed crouch gait. Those with mild over correction are managed in solid AFOs and remain under close follow-up. It is our experience that in children with mild over correction, protection of the gastrocsoleus in a solid AFO combined with longitudinal growth of the tibia will allow ‘re-tensioning’ to occur and prevent the development of progressive crouch gait.39 In this study strong plantar flexion and knee extension coupling was maintained in most children despite substantial increases in height and weight between the baseline evaluation and follow-up. Children maintained or improved both their GMFCS level and FMS grades and gait as a whole was improved, according to GPS scores. The criteria for selecting the appropriate surgery for equinus deformity and equinus gait in children with CP are becoming more stringent and more specific.23 In randomised studies in the formalin preserved human cadaver, the amount of lengthening of the MTU increases from proximal to distal.23,27 Even within Zone 2, differences exist between the amount of lengthening following a high transverse section of the conjoined tendon when compared with a low division of the conjoined tendon with division of the midline raphé as an additional variable.27 It is hoped that information from cadaver models may help refine surgical techniques in children to further reduce the rates of both over correction and under correction. The strengths of this study are the use of a standardised surgical approach for the correction of equinus deformity, standardised post-operative care and carefully monitored rehabilitation, uniform selection criteria, pre- and postoperative gait analysis, rigorous definitions of over correction and under correction and clearly defined outcome criteria for both the equinus component of gait (GVS) and overall gait function (GPS). The weaknesses of this study are the variable surgical SEMLS prescription and the shortterm follow-up. In addition, both the GPS and ankle GVS are clearly affected by the concomitant procedures, which represent a significant and uncontrolled confounding variable in this study. In conclusion, the short term results of the transverse Vulpius GSR as a single level surgery are encouraging for children with hemiplegia in equinus gait. It may also have a role for a highly selected subgroup of children with spastic diplegia as part of SEMLS. Longer term follow-up to skeletal maturity will be required to establish the true rates of recurrent equinus, calcaneus and crouch gait. Supplementary material A summary of indications for equinus gait surgery and combined procedures as part of single event multilevel surgery (SEMLS) in patients with cerebral palsy; hemiplegia and diplegia GMFCS I-III including rehabilitation protocols,
is available with the online version of this article at www.bjj.boneandjoint.org.uk Author contributions A. Tinney: Data collection. Data analysis, Writing of paper. P. Thomason: Data collection, Analysis and interpretation, Writing of paper. M. Sangeux: Data collection and analysis. A. Khot: Performed surgery, Writing of paper. H. K. Graham: Performed surgery, Writing of paper. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by E. Moulder and first proof edited by G. Scott.
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