Kajetan Klos

Short-Term Outcome of Retrograde Tibiotalocalcaneal Arthrodesis with a Curved Intramedullary Nail

Background: The aim of this study was to investigate the potential clinical benefit of tibiotalocalcaneal arthrodesis (TTCA) with an intramedullary nail with a valgus curve, two compression options, and angle-stable locking. Material and Methods: Patients who had undergone TTCA at two tertiary hospitals were eligible. Patients who had undergone TTCA before the beginning of the study were evaluated retrospectively, then all following patients were examined prospectively. There were 59 TTCAs; 55 patients were available for analysis. Twenty-eight were evaluated retrospectively, 27 prospectively. Main Outcome Measures were an SF-36, Mazur-, and AOFAS ankle-hindfoot rating scores and radiographic examination. Results: Bony union was obtained in 53 patients. Fifty-one patients were satisfied with the outcome. Fifty-one patients had marked subjective improvement in mobility. The mean AOFAS score of the 55 patients at the latest followup was 66.8 (range, 38 to 86). The mean Mazzur score was 68.0 (range, 30 to 83). In the prospective group, the scores were significantly improved: AOFAS score by an average of 39.6 points (p < 0.001); Mazur score by an average of 43 points (p < 0.001); SF-36 physical component summary score (p < 0.001) and mental component summary score also improved (p < 0.048). Radiology showed good hind-foot alignment. The complication rate was 25%. Conclusion: Compared with the literature, the data obtained in this study show a good outcome and a high rate of bony union, with comparable complication rates. Patient satisfaction was good. However, the patients still had limitations. The clinical benefit of the nail used was confirmed. Level of Evidence: IV, Case Series

Stability of Medial Locking Plate and Compression Screw Versus Two Crossed Screws for Lapidus Arthrodesis

Background: Lapidus (first metatarsocuneiform joint) arthrodesis is an established procedure for the management of hallux valgus. This study investigated the utility of fixation with a medial locking plate with adjunct compression screw versus fixation with two crossed screws. Materials and Methods: Eight pairs of fresh-frozen human specimens were used in a matched pair test. Bone mineral density (BMD) was measured with peripheral quantitative computed tomography (pQCT). Fixation with two 4-mm-diameter crossed screws was compared versus a medial locking plate (X-Locking Plate 2.4/2.7; Synthes, Solothurn, Switzerland) with adjunct 4-mm-diameter compression screw. The specimens were tested in a four-point bending test. Parameters obtained were initial stiffness; plantar joint-line gapping after one cycle, 100 and 1000 cycles; and number of cycles to failure. Failure was defined as more than or equal to 3 mm plantar gapping. Results: The groups did not differ significantly with regard to BMD (p = 0.866) and initial stiffness (p = 0.889). The plate-and-screw construct showed significantly less movement during testing, and significantly (p = 0.001) more cycles to failure than did the crossed-screw construct. There was a significant correlation (crossed-screw construct: p = 0.014; plate-and-screw construct: p = 0.010) between BMD and the number of cycles to failure. Conclusion: Under cyclic loading conditions, the construct using a medial locking plate with adjunct compression screw was superior to the construct using two crossed screws. Clinical Relevance: The medial locking-plate technique described could help shorten the period of nonweightbearing and reduce the risk of non-union.

2D-fluoroscopic navigated percutaneous screw fixation of pelvic ring injuries - a case series

BackgroundScrew fixation of pelvic ring fractures is a common, but demanding procedure and navigation techniques were introduced to increase the precision of screw placement. The purpose of this case series was the evaluation of screw misplacement rate and functional outcome of percutaneous screw fixation of pelvic ring disruptions using a 2D navigation system.MethodsBetween August 2004 and December 2007, 44 of 442 patients with pelvic injuries were included for closed reduction and percutaneous screw fixation of disrupted pelvic ring lesions using an optoelectronic 2D-fluoroscopic based navigation system. Operating and fluoroscopy time were measured, as well as peri- and postoperative complications documented. Screw position was assessed by postoperative CT scans. Quality of live was evaluated by SF 36-questionnaire in 40 of 44 patients at mean follow up 15.5 ± 1.2 month.Results56 iliosacral- and 29 ramus pubic-screws were inserted (mean operation time per screw 62 ± 4 minutes, mean fluoroscopy time per screw 123 ± 12 seconds). In post-operative CT-scans the screw position was assessed and graded as follows: I. secure positioning, completely in the cancellous bone (80%); II. secure positioning, but contacting cortical bone structures (14%); III. malplaced positioning, penetrating the cortical bone (6%). The malplacements predominantly occurred in bilateral overlapping screw fixation. No wound infection or iatrogenic neurovascular damage were observed. Four re-operations were performed, two of them due to implant-misplacement and two of them due to implant-failure.Conclusion2D-fluoroscopic navigation is a safe tool providing high accuracy of percutaneous screw placement for pelvic ring fractures, but in cases of a bilateral iliosacral screw fixation an increased risk for screw misplacement was observed. If additional ramus pubic screw fixations are performed, the retrograde inserted screws have to pass the iliopubic eminence to prevent an axial screw loosening.

Angle-stable and Compressed Angle-stable Locking for Tibiotalocalcaneal Arthrodesis with Retrograde Intramedullary Nails: Biomechanical Evaluation

BACKGROUND Retrograde intramedullary nailing is an established procedure for tibiotalocalcaneal arthrodesis. The goal of this study was to evaluate the effects of angle-stable locking or compressed angle-stable locking on the initial stability of the nails and on the behavior of the constructs under cyclic loading conditions. METHODS Tibiotalocalcaneal arthrodesis was performed in fifteen third-generation synthetic bones and twenty-four fresh-frozen cadaver legs with use of retrograde intramedullary nailing with three different locking modes: a Stryker nail with compressed angle-stable locking, a Stryker nail with angle-stable locking, and a statically locked Biomet nail. Analyses were performed of the initial stability of the specimens (range of motion) and the laxity of the constructs (neutral zone) in dorsiflexion/plantar flexion, varus/valgus, and external rotation/internal rotation. Cyclic testing up to 100,000 cycles was also performed. The range of motion and the neutral zone in dorsiflexion/plantar flexion at specific cycle increments were determined. RESULTS In both bone models, the intramedullary nails with compressed angle-stable locking and those with angle-stable locking were significantly superior, in terms of a smaller range of motion and neutral zone, to the statically locked nails. The compressed angle-stable nails were superior to the angle-stable nails only in the synthetic bone model, in external/internal rotation. Cyclic testing showed the nails with angle-stable locking and those with compressed angle-stable locking to have greater stability in both models. In the synthetic bone model, compressed angle-stable locking was significantly better than angle-stable locking; in the cadaver bone model, there was no significant difference between these two locking modes. During cyclic testing, five statically locked nails in the cadaver bone model failed, whereas one nail with angle-stable locking and one with compressed angle-stable locking failed. CONCLUSIONS Regardless of the bone model, the nails with angle-stable or compressed angle-stable locking had better initial stability and better stability following cycling than did the nails with static locking.

Comparison of Two Intramedullary Nails for Tibiotalocalcaneal Fusion: Anatomic and Radiographic Considerations:

Background: Retrograde intramedullary nailing is an established procedure for tibiotalocalcaneal arthrodesis. This study was conducted to see whether, and if so to what extent, nail design modifications would influence the risk to anatomic structures and the bony coverage of the nail base. Methods: Six pairs of thawed fresh-frozen cadaver legs received two different intramedullary nails (N1: straight nail, lateral-medial tip locking; N2: valgus-curved nail, medial-lateral tip locking) under simulated operative conditions. The specimens were dissected; distances between the at-risk structures and the hardware were measured. The hindfoot axis and the volume of the intracalcaneal nail portion were determined with CT. Results: At the plantar entry site, N2 was significantly farther from the flexor hallucis longus tendon (p = 0.047), the medial plantar artery (p = 0.026), and the lateral plantar nerve (p = 0.026) than N1. The lateral-medial calcaneal locking screw of N1 damaged significantly more often the peroneus brevis tendon (p = 0.03) than N2. The proximal tip-locking screw, N2, was significantly farther from the anterior tibial artery (p = 0.075) and the deep (p = 0.047) and superficial peroneal nerves (p = 0.009) than N1; N1 was significantly farther from the great saphenous vein (p = 0.075) than N2. The distal tip-locking screw, N1. damaged significantly more often the extensor digitorum longus (p = 0.007), the anterior tibial artery(p = 0.04), and the deep and superficial peroneal nerves (p = 0.03) than N2. CT did not show any significant changes in the hindfoot axis with either device; intracalcaneal nail volumes were similar. Conclusions: A curved nail can increase the distance to at-risk plantar structures. Medial-lateral nail-tip locking appears to have less risk to neurovascular structures. Clinical Relevance: Safer retrograde intramedullary nailing for tibiotalocalcaneal fusion requires knowledge of the structures at risk and appropriate operative technique.

Screw placement for acetabular fractures: which navigation modality (2-dimensional vs. 3-dimensional) should be used? An experimental study.

Objectives: Screw navigation techniques with different image guidance [2-dimensional (2D) vs. 3-dimensional (3D) fluoroscopy] were evaluated for acetabular fracture surgery. Methods: Two-dimensional and 3D navigation images were analyzed for visualization of different osseous corridors: supra-acetabular, anterior column, posterior column, and infra-acetabular. Forty guide wires per group were placed in synthetic pelvis with a prefabricated soft tissue envelope (10 per group) using a 2D or 3D fluoroscopic navigation procedure. Duration of the single steps for each procedure and of cumulative fluoroscopy time was measured. The accuracy of guide wire placement was evaluated visually and in 3D cone-beam scans. Results: The overall procedure time per pelvis was significantly reduced in the 3D group compared with the 2D group [mean ± standard error (SE) (minutes): 50.11 ± 1.38 vs. 63.42 ± 2.32; P < 0.0001]. A trend to reduction in image acquisition time [mean ± SE (minutes): 12.37 ± 1.34 vs. 15.43 ± 1.03; P = not significant] and significant increase in the cumulative fluoroscopy time [mean ± SE (seconds): 64 ± 9 vs. 13 ± 1.3; P < 0.0001) was measured in the 3D compared with the 2D group, caused by the 3D scan. Intra-articular misplacements were not observed in both the groups, but an increased accuracy could be achieved using the 3D image–based navigation procedure (perfect placement: 37 vs. 29; secure placement: 2 vs. 7; misplacement: 1 vs. 4). Conclusions: Both navigation procedures securely prevent an intra-articular penetration during drilling, but the 3D image–based navigation procedure increases the overall accuracy compared with the 2D image–based navigation technique (misplacement rates of 2.5% vs. 10%). Especially, in very narrow corridors (as the infra-acetabular screw path), the use of 3D navigation should be preferred.

Comparison of Calcaneal Fixation of a Retrograde Intramedullary Nail with a Fixed-Angle Spiral Blade Versus a Fixed-Angle Screw

Background: Retrograde intramedullary nailing is an established technique for tibiotalocalcaneal arthrodesis (TTCA). In poor bone stock (osteoporosis, neuroarthropathy), device fixation in the hindfoot remains a problem. Fixed-angle spiral-blade fixation of the nail in the calcaneus could be useful. Materials and Methods: In seven matched pairs of human below-knee specimens, bone mineral density (BMD) was determined, and TTCA was performed with an intramedullary nail (Synthes Hindfoot Arthrodesis Nail HAN Expert Nailing System), using a conventional screw plus a fixed-angle spiral blade versus a conventional screw plus a fixed-angle screw, in the calcaneus. The constructs were subjected to quasi-static loading (dorsiflexion/plantarflexion, varus/valgus, rotation) and to cyclic loading to failure. Parameters studied were construct neutral zone (NZ) and range of motion (ROM), and number of cycles to failure. Results: With dorsiflexion/plantarflexion loading, the screw-plus-spiral-blade constructs had a significantly smaller ROM in the quasi-static test (p = 0.028) and early in the cyclic test (p = 0.02); differences in the other parameters were not significant. There was a significant correlation between BMD and cycles to failure for the two-screw constructs (r = 0.94; p = 0.002) and for the screw-plus-spiral-blade constructs (r = 0.86; p = 0.014). Conclusion: In TTCA with a HAN Expert Nailing System, the use of a calcaneal spiral blade can further reduce motion within the construct. This may be especially useful in poor bone stock. Clinical Relevance: Results obtained in this study could be used to guide the operating surgeons TTCA strategy.

Evaluation of a polyaxial angle-stable volar plate in a distal radius C-fracture model – A biomechanical study

INTRODUCTION Polyaxial angle-stable plating is thought to be particularly beneficial in the management of complex intra-articular fractures of the distal radius. The purpose of the present study was to investigate whether the technique provides stability to match that of conventional (fixed-angle) angle-stable constructs. MATERIAL AND METHODS In seven pairs of human cadaver radii, an Arbeitsgemeinschaft für Osteosynthese (AO) 23 C2.1 intra-articular fracture was created. One radius of each pair received a juxta-articular 2.4-mm locking compression plate (LCP) Volar Distal Radius Plate, whilst the contralateral one received a 2.4-mm Variable Angle Locking Compression Plate (LCP) Two-Column Volar Distal Radius Plate (both plates: Synthes, Oberdorf, Switzerland). Parameters tested were construct stiffness (static axial loading with 150 N), range of motion and secondary loss of reduction (dynamic 150 N axial loading over 5000 cycles). Stiffness and range of motion were measured both pre- and post-cycling. RESULTS The polyaxial constructs were significantly stiffer, both before and after cyclic testing. However, the two-column plates showed a significant loss of stiffness during cyclic testing. The range of motion was significantly greater, both initially and at the end of cyclic testing, in the fixed-angle constructs. The conventional constructs had significantly greater secondary loss of reduction. CONCLUSION The polyaxial two-column plate tested in this study provides a biomechanically sound construct for the management of intra-articular fractures of the distal radius.

Arthroscopic-Controlled Navigation for Retrograde Drilling of Osteochondral Lesions of the Talus

Background: Retrograde drilling of symptomatic osteochondral lesions (OCL) is usually controlled by fluoroscopy. Due to the limited visualization of the OCLs in the acquired images and the narrow access to the talar dome, this approach can be demanding. Several navigation procedures have been reported (2D- or 3D- fluoroscopy or intraoperative CT-based) to increase the accuracy and reduce the radiation exposure. We developed a new arthroscopic-controlled navigation procedure which is free of radiation exposure and free of a reference base rigidly fixed to the bone. 17 We hypothesized that this procedure (Fluoro-Free) is at least as precise as the standard 2D-Fluoro navigation (2D-Fluoro). Furthermore, our first clinical experiences are described and discussed. Material and Methods: Sixteen drillings per group (standard 2D-Fluoro vs. Fluoro-Free) were performed in artificial sawbones. Times for the different steps of each drilling procedure were recorded and the precision evaluated by measuring the deviation and depth of drilling. Results: The accuracy of the Fluoro-Free navigation was as precise as the standard 2D-Fluoro based navigation (axis deviation of drill tip to the target point: 1.07 ± 0.11 versus 1.14 ± 0.15 mm). Due to the simplified workflow without radiation exposure and fixation of a reference base, the Fluoro-Free procedure was significantly faster (mean procedure time per drilling: 23.7 ± 11.6 versus 165 ± 9 seconds) and easy to use. Its clinical usefulness was demonstrated during three retrograde drillings of a talar OCL in a 16-year-old patient. Conclusion: The Fluoro-Free navigation procedure is a simplified approach for retrograde drilling of OCL in the talus under arthroscopic control without radiation exposure and without the need for fixation of a dynamic reference base to the bone. Level of Evidence: V, Expert Opinion

Modified Lapidus arthrodesis with plantar plate and compression screw for treatment of hallux valgus with hypermobility of the first ray: A preliminary report

BACKGROUND TMT-1 arthrodesis is an established method in hallux valgus surgery, but it is technically demanding and typically calls for a period of postoperative immobilization. METHODS In this cohort study, initial experience with a plantar plate is described. 58 patients (59 arthrodesis) were included. RESULTS The mean duration of protected full weight bearing was 7 weeks. 94.12% patients were satisfied with the results, bony union was achieved in 98.31%. The Foot Function Index improved by 33 to a mean of 8 (p<.001). The postoperative Mayo Clinic Forefoot Score was excellent in 47.04 and good in 47.04%. The mean hallux valgus angle improved by 24.4-13.2° (p<.001). The mean first intermetatarsal angle improved by 11.2-5.2° (p<.001). CONCLUSION Initial experience with this form of fixation appears to provide suitable stability, allow early-protected weight bearing, with an acceptable level of complications.