Effect of Lateral Sliding Calcaneus Osteotomy on Tarsal Tunnel Pressure.

BACKGROUND: Lateral sliding calcaneus osteotomies are common procedures to correct hindfoot varus deformities. Shifting the calcaneal tuberosity laterally (lateralization) can lead to tarsal tunnel pressure increase and tibial nerve palsy. The purpose of this cadaveric biomechanical study was to investigate the correlation of lateralization and pressure increase underneath the flexor retinaculum. METHODS: The pressure in the tarsal tunnel of 12 Thiel-fixated human cadaveric lower legs was measured in different foot positions and varying degrees of calcaneal lateralization. RESULTS: The mean pressure increased from plantarflexion (PF) to neutral position (NP) and from NP to hindfoot dorsiflexion (DF), and with increasing amounts of lateralization of the calcaneal tuberosity. The mean baseline pressure in PF was 1.5, in NP 2.2, and in DF 6.5 mmHg and increased to 8.1 in PF, 18.4 in NP, and 33.1 mmHg with 12 mm of lateralization. The release of the flexor retinaculum significantly lowered the pressure. CONCLUSION: Increasing pressures were found in the tarsal tunnel with increasing lateralization of the tuberosity and with both dorsiflexion and plantarflexion of the ankle. CLINICAL RELEVANCE: A pre-emptive release of the flexor retinaculum for a lateralization of the calcaneal tuberosity of more than 8 mm should be considered, especially if specific patient risk factors are present. No tibial nerve palsy should be expected with 4 mm of lateralization.

Popliteal vessel trauma: Surgical approaches and the vessel-first strategy.

BACKGROUND: In this study, we analyzed long-term outcomes following treatment of traumatic popliteal vascular injuries in an urban level I trauma center, using a vessel-first approach in the case of combined vascular and bony/ligamentous injuries and discussing the relative merits of the medial and posterior approach to popliteal vessels. METHODS: Data including patient demographics, mechanism and type of injury, severity of limb ischemia, Injury Severity Score (ISS), limb ischemia time, time to revascularization from admission, treatment strategy, type of vascular reconstruction, limb salvage and mortality were retrospectively collected in patients treated for traumatic popliteal vessel lesions. All patients in this study were operatively treated using medial and posterior approaches. A vessel-first approach was used where possible. RESULTS: Twenty-four patients (13 male) with a median age of 45 years (range 21-88) and popliteal vessel injury after traumatic knee dislocation (n = 10, 42%), proximal tibia fracture (n = 5, 21%), distal femur fracture (n = 4, 17%), blunt popliteal injury (n = 3, 12%) and penetrating trauma (n = 2, 8%) were identified. Twelve (50%) patients were treated via a medial approach and 12 (50%) via a posterior approach. All had injury of the popliteal artery (15 complete transection, eight local intimal disruption and one pseudoaneurysm) with seven having additional popliteal vein and five with nerve injury. Nineteen patients (88%) presented with limb ischemia Rutherford category ≥II. Vessel reconstruction (four direct sutures, four patch plasties, 16 venous interposition/bypasses) was performed prior to bone/joint stabilization in 22 patients (92%). Thirty-day mortality was zero. Two above-knee amputations were performed within 30 days due to severe infection. During a median follow-up of 59 (range 12-143) months, there were no deaths and no amputations. At the end of follow-up, all patients denied claudication. CONCLUSIONS: The vessel-first strategy promises an excellent outcome, independent of the surgical approach needed to repair traumatic popliteal vessel injuries.

Analysis of Osteoclastogenesis/Osteoblastogenesis on Nanotopographical Titania Surfaces.

A focus of orthopedic research is to improve osteointegration and outcomes of joint replacement. Material surface topography has been shown to alter cell adhesion, proliferation, and growth. The use of nanotopographical features to promote cell adhesion and bone formation is hoped to improve osteointegration and clinical outcomes. Use of block-copolymer self-assembled nanopatterns allows nanopillars to form via templated anodization with control over height and order, which has been shown to be of cellular importance. This project assesses the outcome of a human bone marrow-derived co-culture of adherent osteoprogenitors and osteoclast progenitors on polished titania and titania patterned with 15 nm nanopillars, fabricated by a block-copolymer templated anodization technique. Substrate implantation in rabbit femurs is performed to confirm the in vivo bone/implant integration. Quantitative and qualitative results demonstrate increased osteogenesis on the nanopillar substrate with scanning electron microscopy, histochemical staining, and real-time quantitative reverse-transcription polymerase chain reaction analysis performed. Osteoblast/osteoclast co-culture analysis shows an increase in osteoblastogenesis-related gene expression and reduction in osteoclastogenesis. Supporting this in vitro finding, in vivo implantation of substrates in rabbit femora indicates increased implant/bone contact by ≈20%. These favorable osteogenic characteristics demonstrate the potential of 15 nm titania nanopillars fabricated by the block-copolymer templated anodization technique.