Purpose The Cobb angle as an objective measure is used to determine the progression of deformity, and is the basis in the planning of conservative and surgical treatment. However, studies have shown that the Cobb angle has two limitations: an inter- and intraobserver variability of the measurement is approximately 3–5 degrees, and high variability regarding the definition of the end vertebra. Scoliosis is a three-dimensional (3D) pathology, and 3D pathologies cannot be completely assessed by two-dimensional (2D) methods, like 2D radiography. The objective of this study was to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using X-rays and 3D computer tomography (CT) reconstructions in scoliotic spines. Methods To assess interoberver variation the Cobb angle and the end vertebra were assessed by five observers in 55 patients using X-rays and 3D CT reconstructions. Definition of end vertebra and measurement of the Cobb angle was repeated two times with a three-week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits were provided for measurement errors. Results Intraclass correlation coefficient (ICC) showed excellent reliability for both methods. The measured Cobb angle was on average 9.2 degrees larger in the 3D CT group (72.8°, range 30–144) than on 2D radiography (63.6°, range 24–152). Conclusions In scoliosis treatment it is very essential to determine the curve magnitude, which is larger in a 3D measurement compared to 2D radiography.
The scarf osteotomy is a well-established surgical method for correcting a hallux valgus deformity. It is often combined with an Akin osteotomy. However, clear guidelines defining indication criteria are missing. The purpose of this study was to analyze the radiological outcome after scarf osteotomy in dependence of additional Akin osteotomy. This study included 184 patients in whom a hallux valgus deformity was corrected with a scarf osteotomy (group S), and 63 patients in whom an additional Akin osteotomy was performed (group SA). Weight-bearing radiographs were evaluated preoperatively, postoperatively, after 6 weeks, after 3 months and at a follow-up with a mean of 45.4 months. Analysis was made for the following radiological parameters: the intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), the proximal to distal phalangeal articular angle (PDPAA), and the position of the sesamoids as well as the joint congruity. Radiographic recurrence (HVA > 20°) was detected in 1 patient (1.6% of recurrence) in the SA group, and in 27 patients in the S group (14.7% of recurrence) at follow-up. Outcome between the two groups differed significantly showing reduced loss of HVA correction in the SA group (p < 0.001). The subgroup with a preoperative PDPAA above eight degrees showed significant inferiority of outcome for the S group compared to the SA group. Radiological outcome after scarf osteotomy is superior with concomitant Akin osteotomy. A preoperative PDPAA above eight degrees makes additional Akin osteotomy recommendable. Therapeutic, Level III, retrospective comparative series
Recurrence after hallux valgus correction is a relatively frequent occurrence. Little is known about the importance of initial correction on radiologic outcome. The objective of our study was to determine postoperative radiologic parameters correlating with loss of correction after scarf osteotomy and the combined scarf/akin osteotomy, respectively. Loss of correction was evaluated based on a group of 53 feet with isolated scarf osteotomy (S group) and a group of 17 feet with combined scarf and akin osteotomy (SA group) in a retrospective analysis. The intermetatarsal angle (IMA), the hallux valgus angle (HVA), the distal metatarsal articular angle (DMAA), the proximal to distal phalangeal articular angle (PDPAA), the position of the sesamoids, and joint congruity were measured in weight-bearing radiographs preoperatively and postoperatively throughout a mean follow-up of 44.8 ± 23.6 months. Loss of correction was comparable between the S and the SA group (P > .05). In contrast, we found higher loss of HVA correction in the S subgroup with a preoperative PDPAA above 8 degrees (P = .011), whereas loss of correction in the S subgroup below 8 degrees of PDPAA was comparable to the SA group. In the S group, loss of correction showed significant correlation with postoperative IMA (P = .015) and PDPAA (P = .008), whereas in the SA group a correlation could be detected for IMA only (P = .045). In cases with a PDPAA above 8 degrees, we recommend a combined scarf/akin osteotomy to diminish the potential for loss of correction. Level III, therapeutic, retrospective comparative series.