The Effect Of The Forefoot Plantar Pressure Distribution Of Hallux Valgus After Ludloff Osteotomy

ObjectiveTo investigate the distribution of plantar pressure after Ludloff osteotomy,and to study its features and indications. Materials and MethodsSubject: 11 patients (15 feet, age 24 to 65, mean: 43years) were treated by modified Ludloff osteotomy on the first metatarsal and release on the lateral of the first metatarsophalangeal joint in the department of orthopedic, Beijing Tongren hospital,from May.2004 to Oct.2004. The control: 11 healthy persons (16 feet, age 24 to 53, mean: 35years), All of the persons were measured in dynamic state by Tekscan-system (Footscan software5.03, Tekscan international) before operation and 6 months later, so there were 3 groups we had studied. Five anatomical pressure areas were identified by the researcher, based on the peak pressure footprint and standing anteroposterior radiograph of the foot. These areas were defined as metatarsal heads1-5(M1, M2, M3, M4 and M5); Peak force(PF) and Total force(F) of the regions were used respectively.Results(1) Radiological Analysis and AOFAS Score 3 months went after the operation, the mean Hallux valgus angle (HVA) reduced from 38°to 14.5°, the meanⅠ/Ⅱintermetatarsal angle (IMA) reduced from 17.5°to 8.5°, and the forefoot score of American Orthopedics Foot and Ankle Society (AOFAS) improved from 52 to 85.(2) The analysis of plantar pressureF and Ratios of F analysisbefore operation, when the load of the 1st metatarsal got the max in gait, the load of the 2nd was the largest among 5 metatarsals, the 1st followed it. After operation, the load of the 1st was the largest, the 2nd, 3rd, 4th, 5th followed one by one. Comparing three groups, the ratios of the M1/M1~5,M1/M2,M1/M3, only were found no significant differences between the post-operative and the healthy; the ratios of the M2/M1~5, M2/M3, only were found no significant differences between the pre-operative and the healthy; the ratios of the M3/M1~5, weren't found significant differences among three groups; the ratios of the M4/M1~5, M1~2/M1~5 and M4~5/M1~5, only no significant differences was found between the pre-operative and the post-operative; the ratio of the M5/M1~5, only were found significant differences between the post-operative and the healthy. PF and Ratios of PF analysisthe PF of the M2,M1(M3),M4,M5 decreased one by one in the pre-operative and the healthy; the PF of the M1(M2,M3),M4,M5 decreased one by one. The ratios of the M1/M3 weren't found significant differences among the three groups. The ratios of the M1/M2, M2/M3, only were found significant differences between the pre-operative and the post-operative.Conclusion(1) As the differences of the equipments, conditions, methods and the content of analysis, now there are no consensuses in the plantar pressure.(2) Hallux valgus deformity really exhibited a typical loading pattern of forefoot characterized by a medio-lateral transfer from the 1st metatarsal to the 4th, 5th metatarsals in this study.(3) The Ludloff osteotomy can reconstruction"the transverse arch of the forefoot".(4) Ludloff osteotomy only changes the load of the 1st and 2nd metatarsals, has nosignificant effect on the 3rd, 4th and 5th metatarsals. Comparing the subject and the control, we found the fore-plantar pressure distribution of the postoperative was similar to the control.(5) The methods in the study can successfully be applied in the hallux valgus.In one word, Ludloff osteotomy can successfully deal with such problems as the forefoot deformity, selecting shoes, delay even avoid transferring metatarsalgia. Without dealing with medio-lateral transferring of the loading, but it make planter pressure of forefoot moderate.