An investigation of clinical tests for functional hallux limitus

Abstract

Aim: In clinical practice, various tests are routinely used to diagnose Functional Hallux Limitus, which to-date, have not been rigorously investigated. Thus, this study aimed to investigate the validity of the Non-Weightbearing Test (NWB), Hubscher’s manoeuvre (HM) and plantar pressure analysis, or any of their combinations, to represent first metatarsophalangeal joint (MPJ) dorsiflexion during gait. Methods: A comparative, non-experimental study design with a deductive approach was employed on 52 feet from 26 subjects. The NWB and HM were performed on the participants. Vicon® Nexus capture system with the Istituto Ortopedico Rizzoli model was used to acquire and analyse foot and ankle kinematics, whilst the TEKSCAN HR mat was used to measure peakpressures and pressure time integral for the plantar aspect of the foot. The pressure data was divided into three regions which included hallux, first metatarsal head and 2-5 metatarsal heads. Ratios between the hallux and first metatarsal head regions (HRPP and HRPTI), and between the lesser metatarsal heads and the first metatarsal head (LRPP and LRPTI) were created. Results: There was no significant difference in Maximum (p=0.296) or True (p=0.643) Hallux Dorsiflexion between participants that tested positively and negatively for the NWB test. There was also no significant difference in Maximum (p=0.528) or True p=(0.942) Hallux Dorsiflexion between participants that tested positively and negatively for the HM test. HRPP was found to have a correlation with Maximum Hallux Dorsiflexion (p=0.012). A cut-off point of 1.67, used to distinguish positive and negative scores, was found for HRPP. Whilst HRPTI was not found to have any correlations, LRPP was found to have a correlation with Maximum Hallux Dorsiflexion (p=0.033). A cut-off point of 2.60 was found for LRPP. LRPTI was found to have a correlation with Maximum Hallux Dorsiflexion (p=0.03). A cut-off point of 1.68 was found for LRPTI. The combination of HM and HRPP was found to have the most significant difference between positive and negative groups for Maximum Hallux Dorsiflexion (p=0.014). Conclusion: The HM and NWB tests are not valid tests that represent hallux dorsiflexion during gait. With regards to plantar pressure analysis, greater the peak pressures under the hallux and lesser metatarsals compared to the first metatarsal head, correlated to decreased Maximum Hallux Dorsiflexion. Greater pressure time integrals under the lesser metatarsals compared to the first metatarsal head, correlated to less Maximum Hallux Dorsiflexion. The combination of HM and HRPP tests showed a more significant difference between positive and negative groups for Maximum Hallux Dorsiflexion. No significant differences were noted when using True first MPJ dorsiflexion between midstance and toe-off. Hence the author cautions other researchers to specify how first MPJ dorsiflexion was calculated.