Modular neck (MN) components in total hip arthroplasty (THA) offer intraoperative flexibility, but adverse local tissue reactions (ALTR) due to tribocorrosion at modular junctions are a potential complication of such designs. Serum ion levels and metal artifact reduction sequence (MARS) MRI are used to assess ALTR following modular THA. This study investigates serum ion levels and MARS MRI findings in a series of hips with MN components and differing articulating surfaces. We retrospectively evaluated a cohort of 184 primary THAs in 159 patients implanted with a dual modular femoral stem by one surgeon from 2005–2013. 121 THAs had a cobalt-chromium neck component and non-metal-on-metal articulation, while 63 THAs had a titanium neck component and metal-on-metal (MoM) articulation. Serum ion levels were recorded for all patients. MARS MRI scans were read by musculoskeletal-trained radiologists. Pseudotumor grade and location were measured.Introduction
Methods
To determine the preferable treatment for congenital pseudarthrosis of the tibia, we retrospectively reviewed 19 patients (20 limbs) treated consecutively over a 22 year period (1988–2007). Fifteen were followed up to maturity. The patients were assessed for union, leg length discrepancy (LLD), ankle valgus, range of ankle movement and distal tibial physeal injury. The median age at surgery was 3 years. At surgery nineteen of the tibiae had a dysplastic constriction with a fracture (Crawford II-C or Boyd II) lesion. To obtain union in the 20 tibiae, 29 procedures were done. Nine failed primarily and required a second procedure to obtain union. Older patients (≥ 5 years) had a significantly higher success rate. Excision, intramedullary rodding and bone graft (IMR) was done in 14 tibiae: 10 (71.4%) were successful. Six of 10 primary operations and all 4 secondary operations after a previous failed procedure were successful. Ipsilateral vascularized fibula transfer (IVFT) was successful in 5 tibiae (3 primary and 2 secondary). Ilizarov with bone transport only, failed in two patients. Ilizarov with excision, intramedullary rodding and bone graft with lengthening was successful in 2 of 5 cases (40%); two sustained fractures at the proximal lengthening site. A median leg length discrepancy (LLD) of 3 cms occurred post surgery which was treated with contralateral epiphysiodesis. At maturity 3 patients had a LLD of ≥ 2cms. Six limbs had ankle valgus and were treated with stapling and tibio-fibular syndesmosis. Decreased range of movement of the ankle (< 50%) occurred in 7 patients. Distal tibial physeal injury occurred in 4 patients and was associated with repeated rodding.Aim
Results
A rotational limit for screw insertion may improve screw purchase and plate compression by reducing stripping, as compared to a torque based limit. Over-tightening screws results in inadvertent stripping of 20% of cortical bone screws. The current method of “two-fingers tight” to insert screws relies on the surgeon receiving torque feedback. Torque, however, can be affected by screw pitch, bone density and bone-thread friction. An alternative method of tightening screws is the “turn-of-the-nut” model, commonly used in engineering applications. In the “turn-of-the-nut” method, nuts used to fasten a joint are rotated a specific amount in order to achieve a pre-specified bolt tension. When applied to orthopaedics, bone assumes the role of the nut and the screw is the bolt. The screw is turned a set angular rotation that is independent of torque feedback. Potentially the “turn-of-the-nut” method provides an easier way of screw insertion that might lessen inadvertent screw stripping. The purpose of the current study was to use the “turn-of-the-nut” method to determine the angular rotation that results in peak plate compression and peak screw pullout force.Summary
Introduction
We reviewed ninety-three civilian transpelvic gunshot wounds from 1998 to date. The patients were all recruited through our Trauma Unit. The first sixty were seen on a referral basis, yet for the subsequent patients we were informed on admission. Based on our earlier findings we promoted bullet tract washout, bullet removal when passed through hollow viscus, rectal stump washout and early removal of juxta-articular bullets. We review the nature of associated injuries and outcomes in relation to osteitis, osteoarthritis, nerve injuries and vascular injuries. Fifty-seven patients had an entry wound in the buttock. This is associated with a high incidence of sciatic nerve damage (14%), extra peritoneal rectal injury (21%), juxta-articular bullets (73%) and osteitis (12%). There were fifty patients with hollow viscus injuries in various combinations. Thirteen patients overall developed osteitis (14%), of these twelve had hollow viscus injuries. Of these extra-peritoneal rectal injuries carry the highest proportion of osteitis (33%) as a complication, followed by colonic injuries (25%) and bladder (21%). Small bowel injuries (29) were not associated with any osteitis. Peri and intra-articular injuries were grouped together totalling fifty-nine. Seven of these developed osteitis, leading to secondary osteoarthritis in all. The sciatic nerve was damaged in nine patients, and only three recovered fully. There were two femoral nerve injuries with no significant sequelae. In extra-peritoneal rectal injuries those who had early rectal stump wash-out (5/12) did not develop osteitis and yet of those not washed (5/12) three developed osteitis (60%). Tract washout has similar results. Of bullets that passed through a hollow viscus and were removed late 45% (8/18) were infected. Our preliminary results suggest that all missile tracts should be washed out and debrided, that all bullets traversing a hollow viscus should be removed, that all peri-articular bullets be removed, and that the rectal stump be washed out in extra-peritoneal rectal injuries.
