Total ankle arthroplasty is used as a treatment for end stage arthritis of the ankle.

Surgical techniques highlight risk of injury to anterior neurovascular structures. No literature highlights injury risk to the posterior neurovascular structures in ankle replacement surgery. Current literature consists of cadaveric study in relation posterior ankle arthroscopy.

A retrospective review was done of ankle MRI's, performed by the senior author in his practice. Studies were included in the study where there was no pathology of the posterior ankle present. Axial, coronal and sagital T1 weighted films were reviewed and measurements of the posterior neurovascular structures and tendons were made in relation to the posterior tibia and medial malleolus in relation to planned tibial and talar cutting planes.

A total of seventy-eight MRI's were included in the study (ages ranged from 22 to 78 years). There were 40 females and 38 males. At the level of the tibial cut the tibial nerve and artery were between two to six millimeters from the posterior surface of the tibia. The flexor hallucis longus (FHL) is located in the midline between the medial malleolus and fibula, closely related to the posterior tibial surface. The flexor digitorum longus (FDL) tendon is located in the posterior medial corner of the ankle. There is a window approx ten millimeters wide between where the neurovascular structures lie between the FDL and FHL tendons. At the level of the talus cut the tibial nerve and artery were between five to 11 mm from the posterior body of the talus.

A similar window is present at this level where the neurovascular structures lie between the FDL and FHL tendons.

The neurovascular structures of the ankle are potentially at risk during the tibial and talar bone resection. They are most at risk with the transverse cut of the tibia. This may be decreased by preventing direct pressure over these structures during bone resection.

AIM

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.

Repetitive manual handling caused 31% of all work related musculoskeletal disorders in 2015, with the back being the site of injury 38% of the time. Despite its high resilience, studies have shown that intervertebral discs can be damaged during repetitive loading at physiological motions, causing cumulative damage and disc herniation. To understand the mechanism of disc injury resulting from repetitive lifting, it is important to measure disc deformations/strains accompanied by MRI imaging to identify disc tissue damage. Therefore, the aim of this study was to examine associations between the magnitude of 3D internal strains, tissue damage and macroscopic evidence of disc injury after simulated repetitive lifting on normal human lumbar discs. Sixteen cadaver lumbar functional spinal units (FSUs) were subjected to pre-test MRI. Eight FSUs (control) underwent 20,000 cycles or until failure (5 mm displacement) of loading under compression (1.7 MPa – to simulate lifting a 20 kg weight) + flexion (13°) + right axial rotation (2°) using a novel Hexapod Robot. The remaining eight FSUs (experimental) had a grid of tantalum wires inserted, and stereoradiographs were taken to track internal disc displacements at increasing cyclic intervals. Maximum shear strains (MSS) were calculated from the displacements using radiostereometric analysis at cycle 1 and 20,000 cycles (or failure). Post-test MRI was conducted to determine the extent of tissue damage and associated with regions of highest MSS. A repeated measures ANOVA was performed on MSS with a within–subjects factor of cycle number (cycle 1 and failure cycle) and a between subjects-factor of disc region and failure type (p < 0 .05). Pfirrmann grading revealed mostly normal discs [I (N=2), II (N=13), and III (N=1)]. No significant difference in MSS between control and experimental groups was found for number of cycles to failure (p=0.279). Pre and post-test MRI analysis revealed that 13 specimens were injured after repetitive lifting with either an endplate failure (N=9) or disc bulge (N=4), and two specimens did not fail. Failure strain was significantly greater than cycle 1 in all regions except posterior, left/right posterolateral (p>0.109). Largest MSS at failure was seen in the anterior (60%), and left/right posterolateral regions (64% and 70%, respectively). MSS at failure for the endplate failure group was significantly larger than the no injury group in all regions except right lateral and nucleus (p>0.707). Disc bulge group MSS was significantly larger than the no injury group in the anterior, right anterolateral, and left/right posterolateral regions (p < 0 .027). Simulated repetitive lifting led to largest shear strains in the anterior, left and right posterolateral regions that corresponded to annular tears or annular protrusion. The no injury group shear strain was less than 50% in all regions, indicating there may be a threshold that could be associated with tissue damage linked with injuries such as disc bulge and endplate failure. There was no evidence of disc herniation in normal discs, agreeing with current clinical knowledge. These results may be indicative of the effects of repetitive manual handling on normal discs of younger patients

Surgeon-performed periarticular injection and anesthesiologist-performed femoral nerve or adductor canal block with local anesthetic have been used in multimodal pain management for total knee arthroplasty (TKA) patients. Anesthesiologist-performed adductor canal blocks are costly, time consuming, and may be unreliable. We investigated the feasibility of a surgeon-performed saphenous nerve (“adductor-canal”) block from within the knee joint. A retrospective analysis of 94 thigh-knee MRI studies was performed to determine the relationship between the width of the distal femur at the epicondylar axis and the proximal location of the saphenous nerve after its exit from the adductor canal and separation from the superficial femoral artery. After obtaining these data, TKA resections and trial component implantation were performed, using a medial parapatellar approach, in 11 fresh cadaveric lower extremity specimens. Using a blunt tip 1.5cm needle, we injected 10 ml each of two different colored solutions at two different intra-articular medial injection locations, and after 30 minutes, dissected the femoral and saphenous nerve and femoral artery from the hip to the knee to determine the location of the injections. Based upon the MRI analysis, the saphenous nerve was located (and had exited the adductor canal) at a mean of 1.5 times the epicondylar width in females, and mean 1.3 times the epicondylar width in males, proximal to the medial epicondyle. After placement of TKA trial components and injection, the proximal injection site solution bathed the saphenous nerve in 8 of 11 specimens. The proximal blunt needle and solution was adjacent, but did not puncture, the femoral artery and vein in only one specimen. This study suggests that a surgeon-performed injection of the saphenous nerve from within the knee is a feasible procedure. This technique may be a useful alternative to ultrasound guided block. A trial comparing surgeon and anesthesiologist-performed nerve block should be considered to determine the clinical efficacy of this procedure. Our anecdotal use of this intra-articular injection over the past year has been favorable. Newer, extended release anesthetic agents should be investigated with this technique

An ACL reconstruction is designed to restore the normal knee function and prevent the onset and progression of degenerative changes such as osteoarthritis. However, contemporary literature provides limited consensus on whether knee degeneration can be attenuated by the reconstruction procedure. The aim of this pilot study was to identify the presence of early osteoarthritis after ACL reconstruction using MRI analysis. 19 patients who had undergone an ACL reconstruction (9 isolated ACL rupture, 8 ACL rupture and meniscectomy, 2 ACL rupture and meniscal repair) volunteered for this study. MRI's were collected preoperatively and postoperatively for analysis with a mean follow up of 23 months. The Boston-Leeds Osteoarthritis Knee Score (BLOKS) was used for the analysis of the articular cartilage by a consultant orthopaedic surgeon. Scores ranged from 0–3, with 0 being total coverage and thickness of the cartilage and 3 being no coverage. Qualitative analysis was then conducted on each patient to determine if the articular cartilage improved, degenerated, or did not change between preoperative and follow-up scans. All patients with isolated ACL rupture were found to either have no change or improved articular cartilage scores in their follow up scans compared preoperatively. In contrast, patients with a meniscal repair displayed worse cartilage scores postoperatively. Lastly, of the patients who had an associated meniscectomy, 6 had worse follow-up results, with the remaining patients showing no change or improved cartilage scores. The present results indicate that patients with an isolated ACL rupture have a reduced risk of developing OA compared to those with associated meniscal injuries. This has implications for analysing the outcome of current ACL reconstruction techniques and in predicting the likelihood of patients developing OA after ACL reconstruction. Future work will involve confirming this pattern in a larger patient sample, as well as exploring additional factors such as time to surgery delay and rehabilitation strategy

In the large majority of cases of knee osteoarthritis (OA), total knee replacement (TKA) is the selected treatment, due to its proven durability, satisfactory function and familiarity of surgeons. However in recent years there has been an increase in the numbers of uni-compartmental knees used (UKA), due to more favorable follow-up, improved designs and techniques, quicker and better patient recovery, and less hospitalization costs. Designs have been produced for even lesser invasive components than UKA, including simple spacers, with mixed results. Recently, several studies have been carried out on the wear patterns on the femoral and tibial condyles in OA, showing that the main areas of cartilage loss occur on the distal end of the femur, that area engaged in walking activities, and over a large proportion of the tibial plateau. A study we carried out on the bone pieces resected at TKA surgery showed that no less than 22% of the cases could have been done with a device which resurfaced only the medial side. That figure would have been higher if the patients had been treated earlier, before cartilage wear and deformation had progressed. In a more recent study, we showed the progress of the wear of OA by analyzing MRI scans of 50 patients at various stages of OA. The cartilage wear occurred on areas which were initially the thickest on both the femur and the tibia. This was evidently associated with excessive contact stresses, while the menisci, if they had previously been spreading the load over a large area of the cartilage surfaces, were no longer functional. In this paper it is proposed that the treatment modality of OA could be carried out on a sliding scale, based on MRI analysis together with clinical factors including pain and disability. Early Intervention devices, including UKA, could be used much more frequently if the surgical technique was developed to be reliable, simple and reproducible. Specifically there is space for an Early Intervention device (EI) where only the distal end of the femur and the tibial surface are resurfaced. A design has been produced where a pocket is milled into the distal end of the femur to house a plastic runner, and a thin layer is resected from the proximal tibia for a metal plate with a special keel design. The advantages of such a design are ease of exposure, accurate and simple surgery, minimal tibial resection for long term fixation, reduced wear, and ease of restoration of the original joint line. The wear is assessed using a custom-made wear machine, while fixation is evaluated using FEA. It is proposed that such a device would add a valuable option for the treatment of symptomatic early OA where the functional level of the patient can be maintained, and the progress of OA possibly arrested

Aims

The aticularis genu (AG) is the least substantial and deepest muscle of the anterior compartment of the thigh and of uncertain significance. The aim of the study was to describe the anatomy of AG in cadaveric specimens, to characterize the relevance of AG in pathological distal femur specimens, and to correlate the anatomy and pathology with preoperative magnetic resonance imaging (MRI) of AG.

Introduction. Pseudotumors have been reported following metal-on-metal total hip arthroplasty (THA); however, the natural history and longitudinal imaging findings of pseudotumors have yet to be fully analyzed. Our hypothesis was that pseudotumor size might change over time following metal-on-metal THA. This hypothesis was studied longitudinally using magnetic resonance imaging (MRI). Materials and Methods. Screening for pseudotumors was performed using MRI after large-diameter metal-on-metal THA. Initial MRI was conducted at a mean of 36 months postoperatively. Follow-up MRI was performed at a mean of 20 months after the detection of 24 pseudotumors in 20 asymptomatic patients. Pseudotumors were classified as cystic, solid, and mixed types. Fourteen hips were characterized as cystic type and 10 hips were defined as mixed type. There were three men and 17 women with a mean age of 63 years. Pseudotumor size was determined on MRI by manually outlining the greatest size of the mass. Serum cobalt and chromium ion levels were measured in nine patients with unilateral THA at the time of MRI. Statistical analysis was performed using the Kruskal-Wallis test and chi square test to compare age, gender, BMI, head diameter, cup inclination, cup anteversion, and pseudotumor type among changes of pseudotumor size. We compared the pseudotumor size for the three groups (increase in size, no change, decrease in size) using Kruskal-Wallis test and Mann-Whitney U test. Wilcoxon signed-rank test was used to compare median serum metal ion levels over time. A p value < 0.05 was considered significant. This study was approved by the ethics committee of our institution, and all patients provided informed consent. Results. The mean pseudotumor size changed from 729 mm. 2. to 877 mm. 2. Among the 24 hips, pseudotumors increased in size (Fig. 1) in eight (three cystic and five mixed) and decreased in size in six (four cystic and two mixed). Ten hips showed no changes in size (seven cystic and three mixed). We found no significant differences between changes of pseudotumor size and patient characteristics. The mean initial size of pseudotumor was bigger in pseudotumors with increased in size (1002 ± 309 mm. 2. ) than in those with decreased in size (542 ± 295 mm. 2. , p = 0.020) or no change (622 ± 448 mm. 2. , p = 0.041). The median cobalt ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 1.8 µg/L, respectively. The median chromium ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 3.1 µg/L, respectively. No significant differences were observed between the levels of either metal at initial and subsequent MRI. Conclusions. The present results suggest that pseudotumors frequently change in size in asymptomatic patients, and our hypothesis was verified. The initial size of pseudotumor was bigger in pseudotumors with increased in size than in those with decreased in size or no change. And we might predict that bigger pseudotumors would tend to increase in size