François Lintz

Management of Long-Term Sequelae of Compartment Syndrome Involving the Foot and Ankle:

Background: Lower leg compartment syndrome can lead to severe sequelae affecting patient autonomy. Ischemic muscle fibrosis and retraction result in foot and ankle deformities ranging from claw toes to complex multiplanar dislocations with soft tissue impairment requiring amputation. Although these deformities have been reported in relation to compartment syndrome, they have rarely been discussed specifically in the light of a long term follow up. Materials and Methods: Between 1981 and 2006, 151 patients were treated in our hospital for compartment syndrome of the lower limb. Ten of them later required further surgery to treat sequelae on the foot and ankle and were followed up prospectively. Personal data and surgical events were recorded, as well as potential risk factors for sequelae and functional outcome. The data was analyzed and compared to that available in previous literature. We analyzed and describe the different surgical procedures available for the management of this condition including arthroscopic ankle arthrodesis which could be a less invasive and efficient technique in mild equinus deformities. Results: All ten patients were diagnosed late for compartment syndrome. The anterior and lateral compartments were most often involved but rarely accounted for late sequelae. The deep posterior compartment seems to be the key element in generating after effects. Functional results were good in eight patients. Two required amputation after failed secondary surgery. Conclusion: The late, post-compartment syndrome affecting the foot and ankle can be treated efficiently provided surgery is performed acurately, taking into account the multiplanar deformity. However, the best treatment for this condition remains prevention. Level of Evidence: IV, Retrospective Case Series

Safety and Efficiency of a 2-Portal Lateral Approach to Arthroscopic Subtalar Arthrodesis: A Cadaveric Study

PURPOSE To investigate the safety and efficiency of a 2-portal lateral (anterior and middle) approach to arthroscopic subtalar arthrodesis. METHODS A cadaveric study was performed on 30 feet of 15 fresh cadaveric bodies (15 right and 15 left; 21 female specimens and 9 male specimens). The mean age at death was 78 ± 6.7 years. The procedure was performed with the specimen in the supine position through 2 lateral (anterior and middle) sinus tarsi portals by use of a 4.0-mm arthroscope. A 3.5-mm synovial shaver was used for debridement, and a 4.5-mm shielded bur was used to resect posterior subtalar facets. The feet were then dissected. The primary outcomes were the percentage of resected joint surface and the distances between portals and both sural and superficial peroneal nerves. The secondary outcomes were injury of sinus tarsi ligaments and lateral arterial network, calcaneofibular ligament, peroneal tendons, flexor hallucis longus tendon, and posterior tibial neurovascular bundle. RESULTS The mean percentages of resected talar and calcaneal posterior subtalar facets were 94% ± 7.2% and 91% ± 6.8%, respectively. The minimum distance of either subtalar portal to the nerves was 4 mm. No nerve injury was observed. In 28 of 30 cases, the lateral sinus tarsi arterial network was found intact. In all cases the inferior retinaculum extensor was transfixed by the portals. In all cases both cervical and interosseous talocalcaneal ligaments were found intact. In 3 cases a shaving lesion was observed on the peroneus brevis tendon. CONCLUSIONS According to this cadaveric study, more than 90% freshening of the posterior subtalar articular facets can be achieved through a 2-portal lateral (anterior and middle) approach. This technique is reproducible and safe with regard to the surrounding nerves. CLINICAL RELEVANCE The 2 lateral portals may offer a safe and effective alternative approach for arthroscopic arthrodesis of the posterior subtalar joint.

Critical study of resection margins in adult soft-tissue sarcoma surgery.

INTRODUCTION Resection margins constitute a recognized risk factor for local recurrence, but their impact on survival is less clear. HYPOTHESIS Infiltrative proliferation and satellite nodules are prognostic factors for local and systemic aggressiveness. TYPE OF STUDY Retrospective cohort study. PATIENTS AND METHODS In 105 patients under curative treatment, resection quality was assessed on UICC criteria (R0/R1) and on a modified version (R0M/R1M) taking account of proliferation contours and satellite nodules for narrow margins (<1mm). Uni- and multi-variate analysis was performed, and Kaplan-Meier survival curves were compared on log-rank. RESULTS Mean 5-year local recurrence-free survival (LRFS) was 0.64 [0.52-0.76] after R1 surgery, 0.9 [0.85-0.95] after R0, 0.64 [0.519-0.751] after R1M and 0.92 [0.87-0.96] after R0M. Resection type according to R classification correlated with disease-free survival (DFS) (P=0.028), but not with metastasis-free survival (MFS) (P=0.156). Resection type according to RM classification correlated with DFS and MFS. Multivariate analysis disclosed correlations between LRFS rate and RM resection type (HR 6.77 [1.78-25.7], P=0.005), DFS rate and RM resection type (HR 2.83 [1.47-5.43], P=0.001) and grade (HR=3.17 [1.38-7.27], P=0.003), and MFS and grade (HR=3.96 [1.50-10.5], P=0.006). DISCUSSION The microscopic aspect of the proliferation contours and presence of satellite nodules were confirmed as prognostic factors for local and systemic aggressiveness. They impact both disease-free survival and metastasis-free survival in case of margins less than 1mm. Their systematic consideration may help identify patients with elevated systemic risk. LEVEL OF EVIDENCE IV.

3D Biometrics for Hindfoot Alignment Using Weightbearing CT

Background: Hindfoot alignment on 2D radiographs can present anatomical and operator-related bias. In this study, software designed for weightbearing computed tomography (WBCT) was used to calculate a new 3D biometric tool: the Foot and Ankle Offset (FAO). We described the distribution of FAO in a series of data sets from clinically normal, varus, and valgus cases, hypothesizing that FAO values would be significantly different in the 3 groups. Methods: In this retrospective cohort study, 135 data sets (57 normal, 38 varus, 40 valgus) from WBCT (PedCAT; CurveBeam LLC, Warrington, PA) were obtained from a specialized foot and ankle unit. 3D coordinates of specific anatomical landmarks (weightbearing points of the calcaneus, of the first and fifth metatarsal heads and the highest and centermost point on the talar dome) were collected. These data were processed with the TALAS system (CurveBeam), which resulted in an FAO value for each case. Intraobserver and interobserver reliability were also assessed. Results: In normal cases, the mean value for FAO was 2.3% ± 2.9%, whereas in varus and valgus cases, the mean was −11.6% ± 6.9% and 11.4% ± 5.7%, respectively, with a statistically significant difference among groups (P < .001). The distribution of the normal population was Gaussian. The inter- and intraobserver reliability were 0.99 +/- 0.00 and 0.97 +/-0.02 Conclusions: This pilot study suggests that the FAO is an efficient tool for measuring hindfoot alignment using WBCT. Previously published research in this field has looked at WBCT by adapting 2D biometrics. The present study introduces the concept of 3D biometrics and describes an efficient, semiautomatic tool for measuring hindfoot alignment. Level of Evidence: Level III, retrospective comparative study.

Ground Reaction Force Calcaneal Offset: A new measurement of hindfoot alignment

BACKGROUND The tibio-calcaneal angle (TCA) does not measure individual forefoot contributions to the overall foot balance. Using standard radiographs we calculated the ideal hindfoot alignment based on ground reaction force (GRF), independently from the tibial axis. METHODS Thirty-six patients (40ft.) were included. Mean age was 56. Weight bearing radiographs were taken. Calcaneal offsets were measured using tibio-calcaneal angles and GRF algorithms. Measurements were compared using the Bland-Altman method. FINDINGS Both methods agreed (p>0.05) but individual discrepancies were found. Mean measured offsets were -11.5mm (SD: 10.2) using TCA and -8mm (SD: 9.3) using GRF. Mean bias between the methods was -0.88mm. INTERPRETATION The GRF algorithm successfully measured hindfoot alignment. The absence of a previous gold standard and radiographic variability are a limit. The TCA underestimated calcaneal offset. Discrepancies showed that forefoot position data provided increased accuracy. This could be of particular relevance for surgical planning.

Weightbearing computed tomography of the foot and ankle : emerging technology topical review

In the last decade, cone-beam computed tomography technology with improved designs allowing flexible gantry movements has allowed both supine and standing weight-bearing imaging of the lower extremity. There is an increasing amount of literature describing the use of weightbearing computed tomography in patients with foot and ankle disorders. To date, there is no review article summarizing this imaging modality in the foot and ankle. Therefore, we performed a systematic literature review of relevant clinical studies targeting the use of weightbearing computed tomography in diagnosis of patients with foot and ankle disorders. Furthermore, this review aims to offer insight to those with interest in considering possible future research opportunities with use of this technology. Level of Evidence: Level V, expert opinion.

Influence of lower limb rotation on hindfoot alignment using a conventional two-dimensional radiographic technique

BACKGROUND Rotation is one of the variables explaining lack of reproducibility in assessing hindfoot alignment. The hypothesis for this study was that a mathematical model predicts how this modifies radiographic hindfoot alignment measurements. METHODS A cadaveric lower limb, disjointed at knee level, was used. Sagittal and coronal planes were fixed using a custom clamp. Standard AP views were shot every five degrees and measured hindfoot alignments were compared to theoretical values obtained from a mathematical simulation. RESULTS Hindfoot angle was 7.04° at 0° rotation and 2.11° at -90°. Intra-class and inter-investigator correlation was 0.863. The t-test showed no significant difference (p=0.73). Intra-investigator correlation was 0.957. The R2 correlation index was 0.852. CONCLUSIONS The mathematical model accurately predicted the variations of the hindfoot angle which was maximum when the foot was aligned with the X-rays source. It then decreased when the foot rotated away, following a parabolic curve.

Weight-bearing cone beam CT scans in the foot and ankle

The 3D anatomical complexity of the foot and ankle and the importance of weight-bearing in diagnosis have required the combination of conventional radiographs and medical CT. Conventional plain radiographs (XR) have demonstrated substantial limitations such as perspective, rotational and fan distortion, as well as poor reproducibility of radiographic installations. Conventional CT produces high levels of radiation exposure and does not offer weight-bearing capabilities. The literature investigating biometrics based on 2D XR has inherent limitations due to the technology itself and thereby can focus only on whether measurements are reproducible, when the real question is whether the radiographs are. Low dose weight-bearing cone beam CT (WBCT) combines 3D and weight-bearing as well as ‘built in’ reliability validated through industry-standardized processes during production and clinical use (quality assurance testing). Research is accumulating to validate measurements based on traditional 2D techniques, and new 3D biometrics are being described and tested. Time- and cost-efficient use in medical imaging will require the use of automatic measurements. Merging WBCT and clinical data will offer new perspectives in terms of research with the help of modern data analysis techniques. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170066

Influence of investigator experience on reliability of adult acquired flatfoot deformity measurements using weightbearing computed tomography

BACKGROUND Our purpose was to assess the reliability of measurements of adult-acquired flatfoot deformity (AAFD) taken by investigators of different levels of clinical experience using weightbearing computed tomography (WBCT). METHODS Nineteen AAFD patients underwent WBCT. Three investigators with different levels of clinical experience made AAFD measurements in axial, coronal, and sagittal planes. Intra- and interobserver reliability were assessed. Mean values for each measurement were compared between investigators. RESULTS After a training protocol, substantial to perfect intra- and interobserver reliability was observed for most measures, regardless of the investigators experience level. Significant differences between investigators were observed in 2 of 21 measured parameters: medial cuneiform-first metatarsal angle (P=0.003) and navicular-medial cuneiform angle (P=0.001). CONCLUSIONS AAFD radiographic measurements can be performed reliably by investigators with different levels of clinical experience using WBCT. LEVEL OF EVIDENCE Level II, prospective comparative study.

Tendoscopy of Achilles, peroneal and tibialis posterior tendons: An evidence-based update

BACKGROUND Tendoscopy has been proposed in treating several conditions affecting tendons around the ankle. We reviewed literature to investigate the efficacy of Achilles, peroneal and tibialis posterior tendoscopy. METHODS Following the PRISMA checklist, the Medline, Scopus and EMBASE databases were searched, including studies reporting patients affected by disorders of Achilles, peroneal and tibialis posterior tendons and treated by tendoscopy (or tendoscopic-assisted procedures). The tendoscopic technique, rehabilitation protocol, clinical scores, patient satisfaction, success and failure rates and complications were evaluated. RESULTS Sixteen studies (319 procedures) dealt with Achilles tendoscopy, nine (108) and six (78) about peroneal and tibialis posterior, respectively. Wound healing, cosmetic results, complication rate, work and sport resumption delay were satisfactory. Clinical scores, classification methods and rehabilitation protocols adopted were heterogeneous. CONCLUSIONS The recent scientific evidence suggests that tendoscopy and endoscopic-assisted percutaneous procedures are a safe and effective treatment in chronic and acute disorders of tendons around the ankle.