Pascal Raffael Furrer

Background: With an ever-increasing population of elderly orthopedic patients experiencing co-morbidities and immune suppression, the proportion of postoperatively acquired surgical site infections (SSIs) may increase compared to prior decades, where the majority of SSIs were acquired intraoperatively. A comprehensive overview would aid in allocating resources under these conditions. Methods: We examined a prospective database containing data from four prospective randomized clinical interventional trials and surveillance registers. We concentrated on cases of acute SSIs with complete documentation from the 2019–2024 period, during which the number and proportion of clinically frail patients treated at our tertiary center increased significantly. In this assessment, surgeons and Infectious Physicians specialized in orthopedic infections evaluated each SSI episode clinically by searching medical and nursing notes for postoperative events that could possibly be associated with postoperative surgical site infection. Results: Among 370 SSI cases, we estimated that 241 infections (65%) were acquired intraoperatively and 129 (35%) postoperatively. The three most frequent reasons for postoperative SSIs were skin breakdowns, surgical complications (hematoma; dehiscence), and ischemic necrosis. These (new) risk associations differed significantly from the SSI risk reported in the literature on middle-aged orthopedic patients. Conclusions: According to our prospective evaluation, one-third of acute orthopedic SSIs in the last six years might be associated with a postoperative complication. We need to implement additional preventive measures in the postoperative period.

Background: Understanding syndesmotic injury in conjunction with lateral ligament disruption is essential for accurate diagnosis and treatment. Although the influence of deltoid ligament injury on syndesmotic evaluation during bilateral external torque computed tomography (BET-CT) has been examined, the effect of concurrent lateral ligament lesion remains unclear and is rarely examined in the literature. This leads to the question of whether a lateral ligament lesion influences the previously established measurement parameters of syndesmosis instability in BET-CT and whether it results in a quantifiable increase in tibiotalar instability. Methods: Seven paired cadaveric lower limbs (n = 14; mean age 78.6 years) with pre-existing iatrogenic syndesmotic transection underwent sequential lateral ligament sectioning: anterior talofibular (ATFL), calcaneofibular (CFL), and posterior talofibular ligaments (PTFL). BET-CT imaging was performed under applied external rotation torques of 0, 2.5, 5.0, and 7.5 Nm. Outcome measurements included the anterior tibiofibular distance, tibiofibular clear space, posterior tibiofibular distance, medial tibiotalar gutter angle, and lateral fibulotalar gutter angle for each ligament condition and torque level. Results: The anterior tibiofibular distance remained stable despite progressive lateral ligament dissection and increasing torque ( P > .05). Tibiofibular clear space and posterior distance measurements showed inconsistent trends and did not reach statistical significance. In contrast, the medial tibiotalar gutter angle increased significantly from 22.9° in isolated syndesmotic injury to 27.6° (±6.3°) following complete disruption of the lateral complex ( P < .001). Conclusion: Concurrent lateral ligament injury does not impair the assessment of syndesmotic widening in BET-CT, as tibiofibular alignment remains preserved. However, disruption of the lateral complex exacerbates rotational tibiotalar instability. Clinical Relevance: In this cadaveric model, BET-CT remains reliable for assessing syndesmotic lesions even in the presence of lateral ligament injury. However, the increase in rotational tibiotalar instability with combined injuries highlights the need for comprehensive evaluation of ankle ligament injuries, pending clinical validation.

Background: Accurate hindfoot alignment (HA) assessment is essential for surgical planning of foot and ankle procedures, as measurement errors may lead to inappropriate indication. Weight-bearing computed tomography (WBCT) enables HA assessment through coronal images, typically aligned perpendicular to the second ray. However, this forefoot-based reference may not be appropriate in all clinical scenarios, particularly when isolated hindfoot evaluation is required. This exploratory study sought to evaluate how 3 anatomical reference axes affect HA measurements in patients with different foot deformities. Methods: This retrospective cohort study examined 136 WBCT and standard foot radiographs of patients older than 18 years. HA was measured as hindfoot alignment angle (HAA) in coronal images perpendicular to (1) second ray, (2) ankle mortise (bisection of medial and lateral malleoli), and (3) forefoot midpoint (bisection of first and fifth metatarsal heads). Meary, Sgarlato, hallux valgus, and intermetatarsal I-II and I-V angles assessed foot morphology. Spearman correlation analysis was performed to assess relationships between 2-dimensional (2D) parameters and HAA measurements. Results: Median age was 50.3 years and 64% were female. HAA showed significant variations across different reference systems (second ray: 10.0 degrees, ankle mortise: 15.2 degrees, forefoot midpoint: 12.7 degrees; P < .01), with 20.6% of feet showing a discrepancy exceeding 10 degrees between the second ray and ankle mortise. Spearman correlation analysis showed correlation between HAA and Meary angle across all reference axes (ρ = −0.58 to −0.49, P < .01), and between HAA and Sgarlato angle with second ray referencing (ρ = −0.41, P < .01). Conclusions: Reference axis selection substantially influences 2D HA measurements on WBCT. The ankle mortise reference could provide isolated measurement of HA regardless of concurrent forefoot deformities. When using 2D measurement methods, reference system selection could be tailored to whether surgical planning requires comprehensive foot alignment assessment or isolated hindfoot evaluation. Level of Evidence: Level III, retrospective cohort study.

Background: The Hintermann osteotomy (HOT) is one type of calcaneal lengthening osteotomy during progressive collapsing foot deformity surgery. The entry point on the lateral wall of the calcaneus is critical because it affects the direction and depth of the osteotomy. Accurate osteotomy placement can be technically demanding, and joint facets can sustain damage in up to 50% of the cases. We hypothesize that the further posterior the osteotomy is performed, the greater the risk of facet injury. Methods: Twenty-two computed tomography–based 3-D models underwent simulated HOT at 5, 10, 15, 20 mm posterior to the calcaneocuboid joint. Primary outcomes were facet penetration rate and “safe-zone” angle; secondary outcomes were distance to the flexor hallucis longus (FHL) and anterior-facet translation. Results: Facet penetration increased from 0% (0/22) with entry points 5 to 15 mm posterior to the calcaneocuboid joint to 23% (5/22) at 20 mm. The safe-zone angle narrowed from 11 ± 2.6 degrees at 5 mm to 3.0 ± 6.5 degrees at 20 mm ( P < .01). Mean FHL clearance decreased from 44 ± 6 mm to 35 ± 6 mm (−20%, P < .05), and anterior-facet translation increased by 32% between the 5- and 20-mm cuts. Conclusion: The choice of the entry point is crucial. If an entry point is chosen 20 mm behind the calcaneocuboid joint, facet penetration is anatomically inevitable in 23% of cases. A more anterior entry point results in a longer distance between the lateral wall and the sensitive medial structures. Level of Evidence: Level IV, case series.

Background: Intra-articular malunions of the finger can lead to deformity and loss of function and can be treated with intra-articular corrective osteotomies. The aim of this study was to evaluate radiographic joint congruency, feasibility and functional outcome of three-dimensional (3D) printed patient-specific instrumentation (PSI) for corrective osteotomies at the trapeziometacarpal and finger joints. Methods: Computer-tomography (CT) scans were acquired preoperatively for standard 3D planning, which was followed by calculation of cutting planes and the design of individualized bone surface contact drilling, sawing and reposition guides. Follow-up CT scans and clinical examinations (range of motion, grip strength) were performed. Postoperative complications were documented and patient-reported outcome measurements were assessed (Single Assessment Numeric Evaluation (SANE) score, brief Michigan Hand Questionnaire (MHQ)). Results: Ten patients (mean age 28.4 ± 12.8,range 13.8–51.3) years) were included with a mean follow-up of 21 ± 18 (3–59) months including seven osteotomies at the trapeziometacarpal or metacarpophalangeal joints and three at the proximal interphalangeal joint (PIP). All radiographic follow-up examinations showed the planned correction with good joint congruency and regular osseous consolidation. At the latest follow-up, the range of motion (ROM) increased and the average grip strength recovered to the level of the contralateral side. No postoperative complication was detected. The mean SANE score improved from 44 ± 23 (0–70) to 82 ± 12 (60–90) after a mean of 72 ± 20 (44–114) months. The mean postoperative brief MHQ was 92 ± 8 (71–98). Conclusion: The use of 3D PSI in treating intra-articular malunions at the trapeziometacarpal and finger joints restored articular congruency accurately. ROM and grip strength improved postoperatively comparable to the healthy contralateral side and patient-reported outcome measures improved after medium-term follow-up.

A retrospective, single center, data analysis. Persistent pain and instability are common complications after distal ulnar head arthroplasty. One main reason may be the insufficient representation of the anatomical structures with the prosthesis. Some anatomical structures are neglected such as the ulnar head offset and the ulnar torsion which consequently influences the wrist biomechanics. CT scans of the ulnae of forty healthy and asymptomatic patients were analyzed in a three-dimensional surface calculation program. In the best fit principle, cylinders were fitted into the medullary canal of the distal ulna and the ulnar head to determine their size. The distance between the central axes of the two cylinders was measured, which corresponds to the ulnar offset, and also their rotational orientation was measured, which corresponds to the ulnar torsion. The mean medullary canal diameter was 5.8 mm (±0.8), and the ulnar head diameter was 15.8 mm (±1.5). The distance between the two cylinder axes was 3.89 mm (±0.78). The orientation of this offset was at an average of 8.63° (±15.28) of supination, reaching from 23° pronation to 32° supination. With these findings, a novel ulnar head prosthesis should have different available stem and head sizes but also have an existing but variable offset between these two elements. A preoperative three-dimensional analysis is due to the high variation of offset orientation highly recommended. These findings might help to better represent the patients natural wrist anatomy in the case of an ulnar head arthroplasty. III.

Case: We report the case of a 35-year-old patient who presented with a septic residual synovial cavity infection 8 weeks after a through-the-knee amputation because of a parosteal sarcoma. An endoscopic evacuation of the turbid fluid and synovial debridement through parapatellar portals as in a standard knee arthroscopy was performed, in conjunction with appropriate antibiotic therapy. One year postoperatively, there were no signs of residual infection. Conclusion: Endoscopic treatment of a septic stump infection of the residual synovial cavity after through-the-knee amputation is feasible. In our case, this approach resulted in rapid wound healing and early prosthesis mobility.