First Metatarsophalangeal Joint Range of Motion What is

First Metatarsophalangeal Joint Range of Motion: What is Necessary for Normal Gait? 20 08 Carl Kihm B. S. ¥, Zachary Ogden B. A. ¥, Craig Camasta D. P. M. * ¥ Temple University School of Podiatric Medicine, * Private Practice (Douglasville, GA) PURPOSE Figure 2 A This study reexamines the clinical premise that 65˚ of 1 st metatarsophalangeal joint (MTPJ) dorsiflexion is necessary for normal gait. Individuals with excessive pain at the 1 st MTPJ, often associated with a condition termed hallux limitus, undergo surgery to fuse the joint ( arthrodesis). Following surgery, Brodsky reported 96% of 45 arthrodesis patients studied could walk one to six blocks and 75% could return to jogging [1]. This study will compare the 1 st MTPJ motion of healthy, hallux limitus, and 1 st MTPJ arthrodesis populations and explore how subjects with limited 1 st MTPJ motion compensate for insufficient MTPJ joint motion in gait. Several studies have been conducted on hallux limitus, but definitions for classification and joint motion reporting conventions make comparison across studies difficult [2]. Joseph did an initial study looking at 1 st MTPJ motion and found healthy subjects’ 1 st MTPJ motion to be approximately 65°-75° [3]. Root cited this study to suggest the range of motion (ROM) that Joseph found was required for normal gait and that excessive motion at the hallux interphalangeal joint (IPJ) is a “major complication of the hallux limitus deformity” [4]. More recently, Dananberg proposed excessive midtarsal joint pronation is a compensation mechanism for hallux limitus, not a causative factor [5]. The wide variability of normal 1 st MTPJ dorsiflexion values (50°-90°) reported is believed to exist primarily due to the lack of a standard measuring technique; weightbearing status and the relative plane at which the angle is measured must be consistent to properly compare data [2]. The purpose of this pilot study is to estimate 1 st MTPJ motion in gait and to better understand how gait is affected in patients with limited 1 st MTPJ motion. Figure 2 B DISCUSSION Figure 2 C IPJ < MPJ < Figure 2. (A) Dots placed over the bisection of the distal phalanx of the hallux, the hallux IPJ, the first MTPJ and the base of the first metatarsal. (B) Four steps of the right foot were video recorded throughout the stance phase of gait. (C) Joint ROM determined using Dartfish Pro. Suite video analysis software. The video-based walking analysis showed the largest 1 st MTPJ ROM for the healthy subjects followed by the hallux limitus subjects and the arthrodesis subjects, as expected. The IPJ ROM was smallest for the healthy group and the arthrodesis subjects had the largest excursions. Arthrodesis subjects with a properly fused 1 st MTPJ were expected to have little to no 1 st MTPJ ROM, however, the 29° average 1 st MTPJ ROM seen for arthrodesis subjects may suggest a significant amount of skin movement or some possible bending of the MTPJ. As 1 st MTPJ ROM decreased, hallux IPJ ROM increased to provide adequate motion of the 1 st ray for propulsion. Hallux limitus and 1 st MTPJ arthrodesis populations surpassed the normal reported hallux IPJ dorsiflexion of 19° which was observed for the healthy population [6]. There was no significant difference in the summation of hallux IPJ and 1 st MTPJ ROM for the three populations. Larger arch drop measurements seen for the hallux limitus and arthrodesis groups, compared to the healthy group, support Dananberg’s proposed mechanism that midtarsal joint pronation is a compensatory mechanism for hallux limitus. The average velocity of gait for the healthy and hallux limitus populations both fell within the accepted normal range of gait velocity reported [7]. The arthrodesis subjects walked significantly slower and below the normal expected range but the difference is thought to be more related to the differences in the populations’ average and BMIs. The hallux limitus population had higher plantar pressures under the hallux than the 1 st metatarsal, however, arthrodesis patients did not demonstrate this trend presumably due to hallux’s fused dorsiflexed position. The unexpected 1 st MTPJ motion seen for the arthrodesis population accounts for the unexpected pressures under the joint. MATERIALS & METHODS Subject Population 1. Healthy foot motion (3 male/1 female, 25. 3 years old, 23. 8 kg/m 2 body mass index (BMI)) • Non-painful gait & passive 1 st MTPJ dorsiflexion of ≥ 35º when weightbearing 2. Hallux Limitus (6 male/4 female, 26. 5 years old, 24. 7 kg/m 2 BMI) • Clinical assessment of passive weightbearing 1 st MTPJ ROM, <35º dorsiflexion 3. 1 st MTPJ Arthrodesis (1 male/2 female, 52. 7 years old, 32. 7 kg/m 2 BMI) • Without hallux abducto valgus deformity or a condition causing inability to ambulate without a walking aid Data Collection 1. Barefoot plantar pressures during comfortable cadence; EMED (Novel GMBH, Germany); figure 1 A. 2. Temporal and spatial footfall parameters; Gait. Matt II system (E. Q. Inc. , Chalfont, PA). 3. 1 st MTPJ flexibility; figure 1 B. 4. Arch drop as measured by the difference in arch height in sitting and standing; figure 1 C. 5. Dynamic hallux IPJ and 1 st MTPJ ROM; 30 Hz video & Dartfish Pro. Suite (Dartfish, Switzerland) video analysis software; figure 2 A-2 C. Repeatability was shown as there was no significant difference between three independent measurements of joint motion. 6. Results were compared with an analysis of variance (ANOVA) at a significance level of 0. 05. RESULTS LIMITATIONS OF STUDY • Limited subjects were studied; more subjects with similar demographics would increase the power of our results. • Lack of radiographs to assess quality of the 1 st MTPJ for the purpose of subject categorization. • Video capture limited 3 D joint motion to 2 D and allowed for marker identification error. Figure 4. Average 1 st MTPJ motion captured with video and analyzed with Dartfish software. 44. 7 Figure 1 A Figure 1 B 18. 2 62. 9 40. 3 23. 2 63. 5 29. 1 28. 8 57. 9 Figure 1 C Figure 3. Dynamic ROM of the 1 st MTPJ and hallux IPJ. 1 st MTPJ arthrodesis subjects had significantly less 1 st MTPJ ROM than healthy and hallux limitus subjects. The 1 st MTPJ arthrodesis population had significantly more hallux IPJ ROM than the healthy group; the hallux limitus population was not significantly different from either group. Summation of 1 st MTPJ and hallux IPJ angles are not significantly different for any population. Figure 1. (A) Dynamic plantar pressures captured for each subject using an EMED pressure plate. (B) Animation depicting custom device to test first MTPJ flexibility. (C) Example of arch height measurement device. CONCLUSIONS • Healthy and hallux limitus subjects achieved normal gait without having 65° of 1 st MTPJ motion. • As 1 st MTPJ ROM decreased, hallux IPJ ROM increased as a compensatory mechanism to provide adequate motion of the toe for propulsion; summation of hallux IPJ and 1 st MTPJ motion was not significantly different for any population. • Plantar pressures did not follow the trend expected in subjects with limited 1 st MTPJ motion. • A further study is needed with a more rigorous subject classification method via radiographic findings and assessment of 1 st MTPJ motion in weightbearing and nonweightbearing conditions. REFERENCES Figure 5. Average 1 st hallux IPJ motion captured with video and analyzed with Dartfish software. Table 2. Average gait parameters for all populations studied. Letters (A, B, C) are listed to demonstrate which groups are statistically the same or different (p<0. 05). 1. Brodsky J, et al. FAI 26(2): 140 -6, 2005. 2. Nawoczenski D, et al. The Journal of Bone and Joint Surgery 81: 370 -6, 1999. 3. Joseph J. J Bone and Joint Surg 36 B(3): 450 -7, 1954. 4. Root M, et al. Clinical Biomechanics 2: 54 -60, 1977. 5. Dananberg HJ, et al. JAPMA 83: 433, 1993. 6. Salleh R, et al. Foot Ankle Clinic 10(1): 129 -40, 2005. 7. Bohannon R. Age and Ageing. 26: 15 -9, 1997. ACKNOWLEDGEMENTS Jinsup Song, D. P. M. , Ph. D. ; Benjamin Heilman, M. S. ; Jaminelli Liwanag, B. S. ; Emilie Zoltick, B. A. , Ji Su Yun, B. A.