Sciatic nerve injury (SNI) is a rare and potentially devastating complication after total hip arthroplasty (THA). Neural monitoring has been found in several studies to be useful in preventing SNI, but can be difficult to practically implement during surgery. In this study, we examine the results of using a handheld nerve stimulator for intraoperative sciatic nerve monitoring during complex THA requiring limb lengthening and/or significant manipulation of the sciatic nerve. We retrospectively reviewed a consecutive series of 11 cases (9 patients, 11 hips) with either severe developmental dysplasia of the hip (Crowe 3–4) or other underlying conditions requiring complex hip reconstruction involving significant leg lengthening and/or nerve manipulation. Sciatic nerve function was monitored intra-operatively with a handheld nerve stimulator by obtaining pre- and post-reduction conduction thresholds during component trialling. The results of nerve stimulation were then used to influence intraoperative decision- making (downsizing components, shortening osteotomy).Intro
Methods
Several studies have shown that Is there a specific patient population at increased risk of Background
Study Question
Tibial component design has be been scrutinized in a number of studies in an attempt to improve tibial coverage in total knee arthroplasty. However, very few have controlled for both component rotation and resultant changes to posterolateral tibial tray overhang and posteromedial underhang. We hypothesize that asymmetrical tibial components can provide greater coverage than symmetrical trays without increasing overhang. The 6 most commonly used tibial trays on the Australian Joint Registry (2009) were superimposed on MRI slices of normal knees to assess tibial component overhang, underhang and percent coverage. Rotational alignment in this analysis was based upon the line joining the junciton of the medial and middle 1/3 of the patellar tendon and the PCL insertion.AIM
METHODS
Total knee arthroplasty is a painful operation. Peri-articular local anesthetic injections reduce post-operative pain and assist recovery. It is inconclusive whether intra-operative injections of peri-articular corticosteroids are of benefit. A prospective, randomized, double-blinded study was undertaken to assess the efficacy of adding peri-articular corticosteroids to intra-operative, peri-articular high volume local anaesthetic in post-operative pain management following TKA. 127 patients were randomised into three groups receiving local anaesthetic alone (control) or either low dose (40 mg) or high dose (80 mg) peri-articular corticosteroid plus local anaesthetic. Primary outcomes included ROM and visual analog pain scores (VAS). Pain was defined as the worst pain lasting for more than 20 minutes, measured at both rest (RVAS) and during activity (AVAS).Introduction
Methods
It is widely accepted that computer navigation more reliably restores neutral mechanical alignment than conventional instrumentation in total knee arthroplasty (TKA) surgery. Recently, magnetic resonance (MR) based instrumentation has been introduced to the market with a rapid growth in usage. However, a paucity of comparative data still exists on the precision of magnetic resonance (MR) based instruments in achieving acceptable lower limb alignment when compared to other validated techniques. In this analysis, we compare the radiographic outcomes of 3 techniques to achieve satisfactory prosthetic alignment by 2 surgeons using the same prosthesis and surgical technique. A series of 180 patients who had undergone TKA surgery were included in this study. Two fellowship-trained knee surgeons performed all surgeries using the same cemented, posterior stabilized implants (NexGen, Zimmer, Warsaw, In). Patients were stratified in to 3 groups according to the technique used to align the knee; 1. Conventional Intra-medullary Instrumentation, 2. Computer Navigation (Orthosoft), and 3. MR-based guides (Zimmer PSI). All patients underwent a post-operative CT Perth Protocol to assess coronal, sagittal and rotational alignment of the femoral and tibial implants. A radiographer who was blinded to the alignment technique used performed all radiographic measurements. Outliers were defined at a deviation of more than 3 degrees from the mechanical axis in all planes of motion.Introduction
Methods
Cementless prosthesis is one of the major bone-implant interface fixation methods in total joint replacement. Grit blasted surface, hydroxyapatite coated surface and plasma sprayed metallic porous coating have been popularly used. The latter has demonstrated higher bone implant mechanical stability in previous laboratory study in early and middle stages. However, question remains what the mechanism is to make it performing better and how to improve them further. This study is designed to examine the mode of failure in bone-implant interface in a sheep model. Plasma sprayed porous coated (TiPL); hydroxyapatite (HA) coated and and grit blasted (TiGB) titanium implants were examined in the study. Each type has 36 specimens. Implants were inserted into cortical bones in a press-fit fashion in a total of 22 sheep bilateral hind limbs. Specimens were retrieved at 4 weeks and 12 weeks. Push- out testing was performed to just reach ultimate failure. Failed bone-implant interface were investigated by histology and BSEM. The percentage of failure at bone-coating interface, bone itself fracture, coating itself failure, and coating-substrate dissociation were measured by BSEM.Aim
Method
This study was performed to compare the mechanism of bone-implant integration and mechanical stability among three popularly used cementless implant surfaces. Plasma sprayed porous surface (TiPL), grit-blasted rough surface (TiGB), and hydroxyapatite coated implant surface (HA) were tested in a sheep model at 4 and 12 weeks. The integration patterns were investigated using histology, histomorphometry, and mechanical strength by push-out test. All three groups demonstrated early bone ongrowth on their surfaces, with much of the ongrowth resembling contact osteogenesis. TiPL group showed bone anchorage into porous coating with new bone ingrowth into the pores. HA group revealed small cracks at its coating at 12 weeks time point. Plasma sprayed porous surface also demonstrated its superior mechanical stability maybe reinforced by its bone anchorage, whearas, HA surface exhibited higher osteoconductivity with highest ongrowth rate.
Intravenous administration of tranexamic acid (TXA) has been shown to be effective in reducing blood loss and transfusion requirements in total knee arthroplasty (TKA). However, concern exists that I.V. TXA may heighten the risk of venous thrombo-embolism. The intra-articular administration of TXA is an attractive and simple option to deliver this agent locally with minimal systemic effects on inducing hypercoagubale states. In this study, we analysed the effect of varying dosages of intra-articular tranexamic acid on blood loss in TKA. 176 patients who underwent a unilateral TKA for osteoarthritis were retrospectively analysed. Patients were excluded if they underwent a revision knee arthroplasty, concurrent removal of hardware, extensive synovectomy, or lateral patellar retinacular release. All patients underwent a primary cemented posterior stabilised TKA by 2 surgeons using a medial parapatellar approach. Tourniquet was only inflated for initial exposure and intra-articular drains were not used. Patients were separated into three groups; a control group (n=56) who did not receive TXA, and 2 treatment groups who received intra-articular TXA with doses of 1500 mg (n=60) or 3000 mg (n=60). Once the wound was closed, tranexamic acid was injected intra-articularly via an epidural pain catheter. Haemoglobin (Hb) levels were taken pre-operatively and on post-operative days 1 and 2. The primary outcome measure was mean difference in Hb drop between the three groups.Introduction & Aims
Methods
Fibrocartilaginous entheses are formed through endochondral ossification and characterized by four zones morphologically separated into tendon, uncalcified fibrocartilage, calcified fibrocartilage and bone [1]. These zones are not successfully regenerated following surgical repair. Demineralized Bone (DBM) presented at the tendon bone interface may improve healing between tendon and bone. Fifty six female nude rats were randomly allocated into either a control reconstruction or treatment group (DBM at the tendon-bone healing site). A modified rodent model of anterior cruciate ligament reconstruction was adopted [2]. Animals were sacrificed at 2, 4 and 6 weeks following surgery. Four rats per group were prepared for histology at each time point while eight rats were culled for biomechanical testing at 4 and 6 week time points. ANOVA and post hoc tests were used to examine differences which were considered significant at p < 0.05. The surgical procedure was well tolerated. Macroscopic dissection did not reveal any infection and all joint surfaces appeared normal. An intra-articular graft between the femur and tibia was present in all specimens. Mechanical differences were noted between groups. Peak loads were significantly higher in treatment group at 4 and 6 weeks (6.0 ± 3.6N and 9.1 ± 2.6 N, respectively) compared to controls (2.9 ± 1.9 N and 5.8 ± 2.7 N). No statistical differences were found in graft stiffness between the groups at 4 or 6 week time points. Histology showed an initial influx of inflammatory cells coupled with formation of a loose disorganized fibrovascular interface layer between tendon and bone in both groups. By the 6 weeks the interface layer in the DBM group fused into the newly formed bone to create a continuum between the tendon and bone, in an interdigitated fashion, containing Sharpy's like fibres. In the control group the continuum was less apparent with evidence of large areas of discontinuity between the two zones. A thicker region of newly formed woven bone with increased osteoblast activity along the bone tunnel was evident in the DBM group. DBM has the potential to increase the quality of repair following surgical procedures involving reattachment of tendon to bone.
The diagnosis and treatment of disorders of the long head of the biceps tendon remains controversial. There is uncertainty as to the role of the long head of biceps and it can be difficult to determine whether the patient's pathology is coming from the biceps or other adjacent structures. In addition, the appropriate type of treatment remains controversial. We retrospectively reviewed the files of the senior author's experience in over 4000 arthroscopic shoulder procedures. We examined cases involving isolated biceps pathology, excluding those patients with rotator cuff tears and labral pathology, involving 92 biceps tenotomies and 103 biceps tenodeses. Our analysis supports the benefit of clinical examination over all types of radiological investigations. The benefits and technique of biceps tenodesis is described including surgical technique. Irritation by PLA interference screw is examined. A paradigm is put forward to help in diagnosis and management of these lesions. Long head of biceps pathology is a significant cause of shoulder pain in association with other shoulder problems and in isolation. Biceps tenodesis and tenotomy is an efficacious way of dealing with this pathology.
