Long-term clinical and radiological outcome in patients with severe Legg-Calvé-Perthes disease after Chiari pelvic osteotomy: a mean of 14 years follow-up

Introduction: The Chiari pelvic osteotomy (CPO) has been recommended as a salvage procedure to improve head coverage in case of hip joint incongruence in paediatric hip disease. In this study, we aimed to assess the long-term results of CPO for severe Legg-Calvé-Perthes disease (LCPD). Methods: A total of 39 patients who underwent a CPO at our department between 1995 and 2010 were prospectively followed both radiologically (Stulberg classification) and clinically (Harris Hip Score [HHS], conversion into total hip arthroplasty). In this study, we retrospectively reviewed the cases of 12 hips (12 patients, 3 girls, 8 left hips) treated by CPO for severe LCPD (Catterall grade 3 or 4) with hip joint incongruence. Mean follow-up was 14.0 (range 7.6–21.3) years. Results: Mean age at surgery was 10.2 (range 8.2–17.8) years. Additional femoral osteotomy was performed in 8 patients. A good radiological result (Stulberg I or II) was achieved in 2 patients, a fair result (Stulberg III) in 4 patients, and a poor outcome (Stulberg IV or V) in 6 patients. Mean postoperative HHS averaged 93 (range 65–100) points. An excellent functional outcome (HHS 90–100 points) was achieved in 9 patients. No patient underwent total hip arthroplasty during follow-up. Postoperative limb-length discrepancy was found in 3 patients. Conclusions: CPO for severe LCPD with hip joint incongruence resulted in good long-term clinical outcome in about ⅔ of our patients after a mean of 14 years. Our results suggest that CPO can still be considered as a salvage joint-conserving procedure in this selected group of younger patients.

Relationship Between Middle Facet Peritalar Subluxation and the Severity of Flatfoot Deformity

Category: Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Recent literature has established the middle facet of the subtalar joint as a reliable and accurate marker of pronounced peritalar subluxation (PTS) in Adult Acquired Flatfoot Deformity (AAFD) patients. The Foot and Ankle Offset (FAO) has also been accepted as a more complete and three-dimensional (3D) measurement of foot collapse and hindfoot valgus. To date, no assessment has been made regarding the relationship between the severity of the AAFD and the amount PTS measured at the middle facet. The objective of this study was to investigate the correlation between these variables. We hypothesized that direct positive linear correlation would be found, with significantly increased middle facet joint incongruence and subluxation in patients with more pronounced hindfoot valgus and foot collapse. Methods: In this IRB-approved retrospective comparative study, we included 76 feet (42 left, 35 right) with symptomatic AAFD who underwent standing weightbearing CT (WBCT) as standard baseline assessment of their foot deformity. One blinded fellowship-trained foot and ankle surgeon with more than 10 years of experience performed measurements using multiplanar reconstruction (MPR) WBCT images. Manual measurements of subluxation and incongruence of the middle facet were performed at the anteroposterior midpoint of the articular facet. Semiautomatic calculation of the FAO was performed after 3D coordinate harvesting of the weightbearing points of the first, fifth metatarsal and calcaneus as well as the center of the ankle. Correlation of FAO severity and subluxation/incongruence of the middle facet was assessed by Spearman’s correlation and bivariate analysis. Paired Wilcoxon was utilized to compare FAO values in congruent (0% subluxation), subluxated (1-99% subluxation) and dislocated middle facets. P-values <0.05 were considered significant. Results: No significant direct correlation was observed between FAO and Middle Facet Incongruence angle (p=0.12). However, positive linear correlation was found between middle facet subluxation and FAO (Spearman’s 0.54, R2 0.29, p<0.0001). The subluxation of the middle facet was found to increase by 3.5% for every one-point FAO increase (Middle Facet Subluxation (%) = 6.903202 + 3.5452074*Foot and Ankle Offset). Mean values and confidence intervals (CI) of FAO were significantly different depending on the congruency of the middle facet (p=0.0003): congruent, 5.2 (CI, 3.4 to 7.0), subluxated, 8.7 (CI, 6.8 to 9.0) and dislocated, 12.9 (CI, 9.8 to 15.9). Similarly, middle facet subluxation was also found to progressively and significantly increase when FAO values were staged from zero (normal alignment) to four (FAO>20) (p<0.0001). Conclusion: This study is the first to compare and correlate measurements regarding the amount of subluxation of middle facet with the severity of AAFD, when measured by the foot and ankle offset (FAO). We found a significant, positive and linear correlation between the amount of subluxation of the middle facet and FAO measurements. No correlation was found between the incongruence angle of the facet and FAO. Our results support the concept of using the subluxation of the middle facet of the subtalar joint as a key marker of early and progressive deformity in patients with AAFD.

TL 18111 - Rate of unsatisfactory syndesmotic reduction according to a postoperative tomographic study

Objective: To analyze the rate of unsatisfactory reduction of syndesmosis injuries through a postoperative tomographic study. Methods: This is a prospective study conducted from March to December 2017. In total, 30 patients with syndesmosis injury were selected, and ankle tomography was performed during the first postoperative period. A form developed for the study was used to collect demographic data (sex and age in years) and postoperative data (operated side, Weber classification, computed tomography results and need for surgical reoperation). The images were evaluated using tomographic criteria. The intraoperative analysis was based on the results of radioscopy and direct visualization of syndesmosis. Results: Most of the patients were male (56.7%), and their ages ranged from 17 to 51 years. A total of 53.3% of the patients underwent treatment of the left side, 66.7% of patients were classified as type C, and 66.7% of patients did not undergo reoperation. The rate of unsatisfactory syndesmosis reduction was 25.9% based on analyses of the established variables. Although 74.1% of the criteria presented satisfactory outcomes, criterion B had a significant rate (37%) of unsatisfactory outcomes. Conclusion: Tomographic analysis showed a high percentage of unsatisfactory reductions of syndesmosis injuries. Accordingly, despite the use of correct fixation techniques and adequate intraoperative scopic monitoring, postoperative tomography identified cases of distal tibiofibular joint incongruence.

Middle Subtalar Joint Facet Subluxation as a Marker of Collapsing Flatfoot Deformity: A Case-Control Study

Category: Hindfoot Introduction/Purpose: Peritalar subluxation comprises part of the three-dimensional and complex distortion that occurs in patients with adult-acquired flatfoot deformity (AAFD) and is characterized by subluxation of the hindfoot through the triple joint complex. It is traditionally graded on weightbearing computed tomography (WBCT) coronal plane images, depending upon the degree of angulation and subluxation of the posterior facet of the subtalar joint. In this case-control study, we describe a new marker of peritalar subluxation represented by the amount of subluxation and joint incongruence of the middle facet of the subtalar joint. We hypothesized that the amount of joint subluxation and incongruence at the middle facet would be significantly increased in patients with AAFD when compared to controls. Methods: Case-control study, we included 30 patients with stage II AAFD (19 females/11 males), mean age 52.2 (range, 29 to 81) years, and 30 controls (18 females/12 males), mean age 49.3 (range, 28 to 83) years, that underwent WBCT as part of the evaluation of their foot condition. Age and gender were statistically similar in both groups. The amount of subluxation of the subtalar joint at the middle facet (% of uncoverage) and angle of joint incongruence, both measured at the midpoint of its longitudinal length, was measured in coronal WB CBCT images by two independent and blinded fellowship-trained foot and ankle surgeons. A second set of measurements was performed after one month (wash-out period). Intra- and interobserver reliability were assessed by Pearson/Spearman’s and Intraclass Correlation Coefficient (ICC), respectively. Comparison was performed using Paired Student T-Test or each pair Wilcoxon rank sum test. P-values lower than 0.05 were considered significant. Results: We found overall good to excellent intra- (range, 0.90-0.95) and interobserver reliability (range, 0.75-0.93) for the measurements. We found significantly increased subluxation of the subtalar joint at the middle facet in patients with AAFD, with a mean value for middle facet uncoverage of 45.3% (95% CI, 40.5% to 50.1%), when compared to 4.8% (95% CI, 0% to 9.6%) in controls (p<0.0001). Significant differences were also found for middle facet subtalar joint incongruence angle, with a mean value of 17.3 degrees (95% CI, 15.5 to 19.1) in AAFD patients and 0.3 degrees (95% CI, -1.5 to 2.1) in controls (p<0.0001). Conclusion: We described the use of the subtalar joint middle facet as a marker for peritalar subluxation in patients with AAFD. We found significant and marked differences in the percentage of joint uncoverage and incongruence when compared to controls. Hopefully, the use of the middle facet as an indicator for peritalar subluxation can potentially help in the early detection of high- risk AAFD patients for progressive collapse and development of sinus tarsi and subfibular impingement, as well as arthritic degeneration of the subtalar joint. Future longitudinal and prospective studies are needed.

Rate of unsatisfactory syndesmotic reduction by means of a postoperative tomographic study

Objective: To analyse the rate of unsatisfactory reduction in syndesmosis injuries by means of a postoperative tomographic study. Methods: This was a prospective study conducted from March to December 2017. Thirty patients with syndesmosis injury were selected, and ankle tomography was performed during the first postoperative period. A form developed for the study was used to collect demographic data (sex and age in years) and postoperative data (operated side, Weber classification, computed tomography results and need for surgical reoperation). The images were evaluated using tomographic criteria. The intraoperative analysis was performed through radioscopy and by direct visualization of the syndesmosis. Results: The majority of the patients were male (56.7%), ranging in age from 17 to 51 years; 53.3% of the patients were operated on the left side; 66.7% were classified as type C; and 66.7% did not undergo reoperation. Regarding the rate of unsatisfactory syndesmosis reduction, it was foundthat 25.9% of the analyses of the established variables presented unsatisfactory results. It was observed that 74.1% of the criteria presented satisfactory results; however, criterion B presented a significant rate (37%) of unsatisfactory results. Conclusion: Based on the computed tomographic scans, there was a high percentage of unsatisfactory reductions in syndesmosis injuries. Thus, it was concluded that, even using the correct fixation techniques and adequate intraoperative scopic monitoring, distal tibiofibular joint incongruence can still be observed when investigated using postoperative tomography. Level of Evidence II; Diagnostic Studies.