Abstract We tested the hypothesis that the DYT1 genotype is associated with a disorder of anatomical connectivity involving primarily the sensorimotor cortex. We used diffusion tensor magnetic resonance imaging (DTI) to assess the microstructure of white matter pathways in mutation carriers and control subjects. Fractional anisotropy (FA), a measure of axonal integrity and coherence, was reduced ( p < 0.005) in the subgyral white matter of the sensorimotor cortex of DYT1 carriers. Abnormal anatomical connectivity of the supplementary motor area may contribute to the susceptibility of DYT1 carriers to develop clinical manifestations of dystonia. Ann Neurol 2004
Hip resurfacing has enjoyed a resurgence in popularity as an alternative to total hip replacement (THR) for the treatment of end-stage arthritis in younger, active patients. However, technical difficulties in implant positioning have been realized, as the procedure has been introduced amongst surgeons new to the concept. Furthermore, as the follow-up interval increases beyond the short-term, it is evident that certain issues with the metal-on-metal bearing surface may lead to complications. These 5 points on hip resurfacing are selected to highlight the factors that will help ensure an optimal outcome.
Object. Short-term benefit from unilateral subthalamotomy for advanced Parkinson disease (PD) is associated with metabolic alterations in key targets of subthalamic nucleus (STN) and globus pallidus (GP) output. In this study positron emission tomography (PET) scanning was used to assess these changes and their relation to long-term benefits of subthalamotomy. Methods. To determine whether the early postoperative changes persisted at longer-term follow up, the authors assessed six patients with advanced PD by using [ 18 F]fluorodeoxyglucose—PET at 3 and 12 months postsurgery. The authors compared each of the postoperative images with baseline studies, and assessed interval changes between the short- and long-term follow-up scans. Clinical improvement at 3 and 12 months was associated with sustained metabolic decreases in the midbrain GP internus (GPi), thalamus, and pons of the lesioned side (p < 0.01). The activity of a PD-related multiregional brain network, which correlated with bradykinesia and rigidity, was reduced at both postoperative time points (p < 0.05). Comparisons of 3- and 12-month images revealed a relative metabolic increase in the GP externus (GPe) (p < 0.001), which was associated with worsening gait, postural stability, and tremor at long-term follow up. Conclusions. These findings indicate that subthalamotomy may have differential effects on each of the functional pathways that mediate parkinsonian symptomatology. Sustained relief of akinesia and rigidity is associated with suppression of a pathological network involving the GPi and its output. In contrast, the recurrence of tremor may relate to changes in the function of an STN—GPe oscillatory network.
Total hip arthroplasty is associated with extensive blood loss, which is often corrected using allogeneic blood transfusions. However, Jehovah's Witnesses often refuse allogeneic blood transfusions or certain types of autologous blood transfusions due to their religious beliefs. This may represent a tremendous challenge for the orthopaedic surgeon and their team. Performing a total hip arthroplasty on a Jehovah's Witness patient requires a well-trained group of physicians willing to pre-operatively optimize the patient, attempt to minimize the blood loss during the surgery, adequately manage the post-operative period, and be aware of which of the life-saving strategies can be used in these patients during an emergency situation. Ultimately, physicians should be prepared to deal with marked blood loss and respect the patients' wishes, values, and beliefs. This review focuses on studies where primary or revision total hip arthroplasty was performed in Jehovah's Witness patients. Therefore, we will illustrate that with a prepared team and an optimized patient, it is potentially quite safe to perform total hip arthroplasties in Jehovah's Witness patients.
Surface hip replacement (SHR) is generally used in younger, active patients as an alternative conventional total hip replacement in part because of the ability to preserve femoral bone. This major benefit of surface replacement will only hold true if revision procedures of SHRs are found to provide good clinical results. A retrospective review of SHR revisions between 2007 and 2012 was presented, and the type of revision and aetiologies were recorded. There were 55 SHR revisions, of which 27 were in women. At a mean follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical reasons, nine for impingement, 13 for metallosis, nine for unexplained pain and one for sepsis. Of the type of revision surgery performed, 14 were femoral-only revisions; four were acetabular-only revisions, and 37 were complete revisions. We did not find that clinical scores were significantly different between gender or different types of revisions. However, the mean post-operative HHS was significantly lower in patients revised for unexplained pain compared with patients revised for mechanical reasons (86.9 (66 to 100) versus 99 (96 to 100); p = 0.029). There were two re-revisions for infection in the entire cohort. Based on the overall clinical results, we believe that revision of SHR can have good or excellent results and warrants a continued use of the procedure in selected patients. Close monitoring of these patients facilitates early intervention, as we believe that tissue damage may be related to the duration of an ongoing problem. There should be a low threshold to revise a surface replacement if there is component malposition, rising metal ion levels, or evidence of soft-tissue abnormalities.
Stiffness after total knee replacement (TKR) is a frustrating complication that has many possible causes. Although the definition of stiffness has changed over the years, most would agree that flexion <75 degrees and a 15 degrees lack of extension constitutes stiffness. This study will focus on the potential causes of a stiff TKR, intraoperative tips to avoid this complication, the postoperative evaluation and management, surgical exposure of a stiff TKR, and the results of revision for this problem. The management of this potentially unsatisfying situation begins preoperatively with guidance of the patient's expectations; it is well-known that preoperative stiffness is strongly correlated with postoperative lack of motion. At the time of surgery, osteophytes must be removed and the components must be properly sized and aligned and rotated. Soft tissue balancing must be attained in both the flexion/extension and varus/valgus planes. One must avoid overstuffing the tibiofemoral and/or patellofemoral compartments with an inadequate bone resection. Despite these surgical measures and adequate pain control and rehabilitation, certain patients will continue to frustrate our best efforts. These patients likely have a biological predisposition for formation of scar tissue. Other potential causes for the stiff TKR include complex regional pain syndrome or joint infection. Close follow-up of a patient's progress is crucial for the success in return of range of motion. A patient should be evaluated early and frequently if motion appears to be reaching a plateau early in the recovery phase. In this situation, a manipulation under anesthesia can be very beneficial. At our institution, most manipulations are performed within 3-months postoperatively under an epidural anesthetic; patients will stay overnight for continuous epidural pain relief and immediate aggressive physical therapy. The surgical exposure of a stiff TKR can be challenging. Additional soft tissue releases often must be performed to allow for subluxation/eversion of the patella. This includes a lateral retinacular release and rectus snip. If these measures are not sufficient to gain exposure, one must consider a tibial tubercle osteotomy or quadriceps turndown. The results of reoperations for a stiff TKR are variable due to the multiple etiologies. A clear cause of stiffness such as component malposition, malrotation or overstuffing of the joint has a greater chance of regaining motion than arthrofibrosis without a clear cause. Although surgical treatment with open arthrolysis, isolated component, or complete revision can be used to improve TKR motion, results have been variable and additional procedures are often necessary.
