Level IV, prospective case series.

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BackgroundThere is increased evidence of first metatarsal hyperpronation in patients with hallux valgus, but its impact on the stability of the first metatarsophalangeal and metatarsosesamoid joints is unknown. A previous biomechanical study showed that an increase in hallucal pronation might lead to medial soft tissue failure of the first metatarsophalangeal joint. Conversely, dynamic studies on hallux valgus have shown that the first tarsometatarsal joint moves in supination during weightbearing, and supination was associated with an increase in the intermetatarsal angle (IMA) and hallux valgus angle (HVA).Questions/purposes(1) Does an increase in first metatarsal pronation cause an increase in hallucal pronation? (2) Can an intrinsic increase in first metatarsal pronation lead to first ray supination during weightbearing? (3) Can a combination of intrinsic first metatarsal hyperpronation and first metatarsophalangeal medial soft tissue failure increase supination of the first ray during weightbearing? (4) Is first ray supination during weightbearing associated with an increase in the IMA and HVA?MethodsTwelve transtibial, nonpaired cadaver specimens without deformities were used. Each specimen underwent six weightbearing CT scans under different conditions. The first three CT examinations were performed without any osteotomy of the first metatarsal. The first was a simulated nonweightbearing condition. The second was a simulated weightbearing condition. The third was a simulated weightbearing condition with medial soft tissue release. Subsequentially, a 30° pronation osteotomy of the first metatarsal was performed, and the same sequence of weightbearing CT images was obtained. On each weightbearing CT image, the HVA, IMA, sesamoid rotation angle, metatarsal pronation angle (MPA), metatarsosesamoid rotation angle, and hallucal pronation (HP) were measured. Motions were calculated based on the differential values of these angular measurements produced by the six different conditions (weightbearing, medial soft tissue release, 30° pronation osteotomy, and combinations of these conditions). We compared means using a t-test for normally distributed variables and the Mann-Whitney U test for nonnormally distributed variables. Correlations were assessed with Pearson product-moment correlation coefficients.ResultsWe found that 30° pronation osteotomy of the first metatarsal increased the MPA and HP by 28° ± 4° and 26° ± 6°, respectively, in the nonweightbearing condition. No differences between the increase in MPA and the increase in HP were noted (mean difference 2° [95% CI -1° to 5°]; p = 0.20). Therefore, an increase in first metatarsal pronation caused an increase in hallucal pronation. When a 30° pronation osteotomy of the first metatarsal was performed, the first ray motion during weightbearing went from pronation to supination (4° ± 2° in pronation without osteotomy versus 4° ± 2° in supination after the osteotomy, mean difference 8° [95% CI 6° to 9°]; p < 0.001). Therefore, an intrinsic increase in prona...

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n ABSTRACTFrom 1989 until the end of 1993, 73 Ramses Total Ankle Arthroplasty (Ramses TAA) procedures were performed by the surgeons of the Talus Group. It was the beginning of our experience with this implant. We evaluated the long-term clinical results in 69 cases, after 10 years to 14 years postoperatively. Out of 57 cases the result was good for 40 cases, fair for 14 cases, and poor for 3 cases. Arthroplasties were considered to be a failure with removal of the implant and arthrodesis done in 7 cases: 4 for pain without loosening and 3 for clinical and radiographic loosening. Twenty-three complications occurred on these 12 cases: 3 malposition, 3 with significant instability, 1 progressive misplacement in varus, 4 medial malleolar fractures, 6 submalleolar syndromes, and 6 with evidence of clinical loosening. We had to do a second operation in 12 cases: 2 revisions with a larger mobile disk, 7 arthrodeses for failure, 3 revisions to another ankle arthroplasty without cement. The cumulative rate of survival after Ramses TAA was not influenced by age, sex, or weight. On the other hand, previous operative treatment, and especially the range of dorsiflexion postoperatively, significantly affected the rate of survival. The long-term results of Ramses TAA appear more promising. On the basis of these findings, this implant appears promising. It is essential that there be an appropriate liberation of malleoli. The Achilles lengthening appears to be important to achieve adequate postoperative dorsiflexion. The surgical technique is uncomplicated. The Ramses prosthesis is a semiconstrained prosthesis allowing, with congruence, flexion-extension, AP translation, and valgus and varus.

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