The Immediate Effects of Plantar Massage and Textured Insoles On Gait In Patients Following ACL Reconstruction
Introduction: Gait impairments, notably reduced knee flexion angle and external knee flexion moment, are common following anterior cruciate ligament reconstruction (ACLR) and may contribute to reinjury or future osteoarthritis development. Recently, plantar cutaneous sensation deficits have been reported following ACLR. It is likely that these sensory deficits influence gait and may represent a mechanism through which gait can be improved. Objective: To examine the efficacy of two sensory interventions, plantar massage and textured insoles, at altering plantar sensation and improving gait in patients after ACLR. Methods: Fourteen recreationally active adults with a history of ACLR participated in this study. Participants completed two testing sessions, each of which consisted of a baseline gait and plantar cutaneous sensation analysis, followed by completion of an intervention (massage or textured insole), and repeated gait and plantar cutaneous sensation assessment. Gait analysis was completed via 3D motion capture synchronized with force plate data collection while participants walked at standard gait speed (1.4 m/s ± 5%). Sagittal and frontal plane knee joint biomechanics were extracted from gait analysis using a standard inverse dynamics approach. Plantar cutaneous sensation analysis was conducted with Semmes Weinstein Monofilaments (SWM) with a 4-2-1 stepping algorithm at the plantar aspect of the head of the first metatarsal, base of the fifth metatarsal, and the medial and lateral malleoli. The plantar massage intervention consisted of a single, five-minute massage targeting the entire plantar surface of both feet, combining effleurage and petrissage techniques. For the textured insoles intervention, the participant was given textured insoles made from coarse grit sandpaper to place into his or her neutral athletic shoes to be worn during gait analysis. Gait data were analyzed using limb X time X condition repeated measures ANOVAs. T-tests were utilized to make all post hoc comparisons. Plantar cutaneous sensation data were analyzed via Wilcoxon Signed Rank tests to compare differences between limbs, conditions, and time. Effect sizes were calculated using Cohen’s d. Statistical analysis was performed using SPSS (v. 21, IBM SPSS, IBM Corp, Armonk, NY) and Microsoft Excel (v. 2011, Microsoft Corp., Redmond, WA). Alpha was set a priori at P< 0.05.Results: There was a significant limb x condition interaction for sagittal plane knee rotation Post hoc analyses revealed no differences between limbs or conditions (P>0.05). There was a significant main effect of limb for knee frontal plane rotation, suggesting the ACLR limb was more abducted during walking than the contralateral limb (P=0.028) regardless of time or condition. No significant interactions or main effects were observed for knee joint moments. There were no statistically significant differences between pre-massage and pre-textured insoles sessions within limbs pre-intervention. Comparing sensation between limbs prior to massage, the 5th metatarsal (P=0.016), medial malleolus (P=0.028), and lateral malleolus (P=0.046) demonstrated poorer sensation in the ACLR compared to the contralateral limb. Prior to receiving the textured insoles, participants demonstrated differences in sensation over the 5th metatarsal (P=0.031), with the ACLR limb having worse sensation. Massage improved sensation over the 1st metatarsal head (P=0.026), base of the 5th metatarsal (P=0.039), medial malleolus (P=0.035), and lateral malleolus (P=0.043) in the ACLR limb. No changes in sensation occurred as a result of massage in the contralateral limb. Following textured insoles application, sensation improved over the 1st metatarsal (P=0.027), 5th metatarsal (P=0.011), and medial malleolus (P=0.007) of the ACLR limb. No changes in sensation were observed as a result of textured insoles in the contralateral limb.Conclusions: Plantar massage and textured insoles improved plantar cutaneous sensation in the involved limb following ACLR. Both somatosensory interventions had minimal effects on gait biomechanics. Further investigation of other sensory interventions such as visual-spatial targeted interventions, should be implemented to improve gait biomechanics following ACLR.