Kinematic modifications after surgical correction of equinovarus foot deformity in chronic hemiplegic adults

. Summary/conclusions Equinovarus foot is one of the most common deformity in chronic spastic hemiplegia of the adult. Gait analysis can be a powerful tool to assist clinicians in surgical decision and during the follow up, to provide objective, reliable and repetible data about outcome. In this retrospective study we have investigated 177 patients which underwent surgical treatment for spastic equinovarus foot deformity. Gait analysis provided a useful tool to objective outcome assessment. Data from a wide group of patients can make clinicians more confident with surgical treatment of this deformity. 2. Introduction Gait recovery is one of the most important goals in stroke rehabilitation. Achieving this goal is often made difficult by positive and negative upper motor neuron syndrome symptoms. Most frequently observed deformity at lower limb is equinovarus foot. Surgical correction of this deformity is known by several years [1], but the procedure is not widely used, mainly because of concern about predictability and relevance of functional outcomes. The impact of gait analysis in surgical planning is known [2], but its role in outcome assessment has not been already addressed in spastic hemiplegic adults. 3. Statement of clinical significance Gait analysis may provide a reliable and objective tool to assess gait after surgical treatment of equinovarus foot deformity in hemiplegic adults. Obtaining reliable and predictable results and using the suitable tool to assess them is fundamental in such a surgical and rehabilitative procedure. 4. Methods One hundred seventy-seven chronic (>12 months) hemiplegic stroke patients with static equinovarus foot deformity were recruited for this retrospective study. Foot could not be placed over neutral position with knee extended, confirming static equinus deformity. All patients underwent gait analysis (BTS GaitEliclinic 8 VCR, 2 Kistler force platforms) using S.A.F.Lo [3] protocol and dynamic poly-emg (BTS TeleEMG 8 channels) with both surface and fine-wire electrodes. Patients were required to walk at self-selected speed, barefoot, using their usually used assistive devices if needed. Surgical treatment was tailored according to clinical and instrumental data. All patients were evaluated before and 12 months after surgery. We investigated the following parameters, see Fig. 1: mean velocity (V), cadence (C), step width (StW), stride length (StrL), step length (StL), swing velocity (SwV), body speed advancement during omolateral swing phase (BSAOSw), ankle angle at heel strike (AAHS) and maximum ankle dorsiflexion during swing phase (AASw). SwV is defined as the mean velocity during swing phase of the marker placed on the lateral malleolus. BSAOSw was calculated as the mean velocity of the marker placed on sacrum during omolateral swing phase. All parameters except V, C and StW were calculated for paretic and healthy limb. Two-tailed Student's t-test with an ? error = 0.05 was utilized. Data are presented as mean ± 1S.D. Download : Download full-size image Fig. 1. (A) Ankle angle at heel strike (AAHS); (B) maximum ankle dorsiflexion during swing phase (AASw). Negative values represent plantarflexion. 5. Results All parameters showed a meaningful improvement, except for AAHS and AASw on sound side. Levels of significance were very high, with p-values ranging from 10-6 to 10-12. Data are summarized in Table 1. Table 1. V (m/s)C (step/min)StW (mm) MeanS.D.MeanS.D.MeanS.D. Before0.320.1962.919.74234.941.1 After0.4*0.268.31*18.26209.9*41.3 StrL (m)StL (m)SwV (m/s)BSAOSw (m/s)AAHS (degree)AASw (degree) MeanS.D.MeanS.D.MeanS.D.MeanS.D.MeanS.D.MeanS.D. Healthy Before0.590.220.260.121.160.390.320.195.877.075.536.83 After0.68*0.220.3*0.121.29*0.420.4*0.25.76.055.627.62 Paretic Before0.580.220.30.10.770.40.320.18-0.778.97-6.0711.2 After0.67*0.220.35*0.10.9*0.420.4*0.192.44*7.084.28*10 * p < 0.05. 6. Discussion One year after treatment our patients were able to walk faster, with longer strides and steps, and with a more narrow base of support. These data have never been previously reported on a so wide sample [4]. Also ankle kinematics on operated feet showed a clear trend towards normalization. Results of combined surgical and rehabilitative treatment for equinovarus foot deformity can be divided in two categories: stance phase results and swing phase results. During stance phase the treatment allowed a better prepositioning of the paretic foot at initial contact, as demonstrated by the improvement of AAHS. Furthermore during stance phase the patients are more stable, as evident from the meaningful reduction of StW. Another result is the better capacity of advancement over paretic foot during stance. In fact, the improvement of healthy limb BSAOSw represents the amelioration of rolling over the paretic foot during stance phase. This can be possible only if the foot is more stable during stance (i.e. more plantigrade position and less varus) and resistances on the posterior side of the leg (caused by plantarflexor muscles contracture) are reduced. During swing phase the treatment allowed a better capacity of clearance, as shown by the higher velocity during swing on paretic side accompanied by a meaningful improvement on dorsiflexion of the ankle. Since no treatment was done at hip or knee, results can be explained only in terms of distal modifications. References [1] B.A. Roper, et al. J Bone Joint Surg Br, 60-B (November (4)) (1978), pp. 533-535 View Record in Scopus [2] D.A. Fuller, et al. Foot Ankle Int, 23 (August (8)) (2002), pp. 738-743 CrossRefView Record in Scopus [3] C. Frigo, et al. Med Biol Eng Comput, 36 (March (2)) (1998), pp. 179-185 View Record in Scopus [4] M.S. Pinzur, et al. J Bone Joint Surg Am, 69 (8) (1986), pp. 1249-1257