Postoperative fever: differences between elective vs. traumatic hip, knee and shoulder arthroplasty.

BACKGROUND: It is unclear whether there is a difference in the incidence of postoperative fever (POF) between hip, knee and shoulder arthroplasty. The influence of a trauma setting has not been investigated. METHODS: A retrospective review was performed on 675 joint replacement surgeries (hip, knee, shoulder arthroplasty) in an elective or trauma setting over a 2 year period (2016-2018). Patient demographics and perioperative/postoperative parameters were investigated. The fever curve was characterized. The results and costs of any fever-related diagnostic workup were reviewed. RESULTS: A total of 89 patients (13.2%) experienced a POF ≥ 38.0 °C, only 21 patients (3.1%) a POF ≥ 38.5 °C (of the latter: 4.6% of hip arthroplasties, 0.6% of knee arthroplasties, 0% of shoulder arthroplasties). There was a significantly greater risk (OR 3.88) for POF ≥ 38.5 °C in trauma total hip arthroplasty (THA) compared to elective THA (10.6 vs. 3.0%; p < 0.01). Differences in POF rate between the various joint areas were statistically insignificant when comparing only elective and trauma cases with each other, even though there was a trend for higher rates in hip surgery. Patients experiencing POF ≥ 38.5 °C were more often males (p < 0.01) and had an increased intraoperative blood loss (p = 0.03) and longer hospital stay (p < 0.01). There was only 1/89 POF patients developing an early periprosthetic joint infection. The cost of a positive fever workup (3/27 patients, 11.1%) leading to a new diagnosis and treatment was 2045 US$. CONCLUSION: POF ≥ 38.5 °C was more frequent in traumatic THA compared to elective THA. A trend of difference between POF rates between the different joint areas was statistically insignificant after separating elective and traumatic cases. The risk of developing an early periprosthetic joint infection was not increased in POF. A fever-related diagnostic workup was rarely helpful in the absence of clinical symptoms.

Novel measurement technique of the tibial slope on conventional MRI.

UNLABELLED: The posterior inclination of the tibial plateau, which is referred to as posterior tibial slope, is determined routinely on lateral radiographs. However, radiographically, it is not always possible to reliably recognize the lateral plateau, making a separate assessment of the medial and lateral plateaus difficult. We propose a technique to measure the plateaus separately by defining a tibial longitudinal axis on a conventional MRI. The medial plateau posterior tibial slope obtained from radiographs was compared with MR images in 100 consecutive patients with knee pain when ligament or meniscal injury was assumed. The posterior tibial slope on MRI correlated with those on radiographs. The mean posterior tibial slope was 3.4 degrees smaller on MRI compared with radiographs (4.8 degrees +/- 2.4 degrees versus 8.2 degrees +/- 2.8 degrees , respectively). The reproducibility was slightly better on radiographs than MRI (+/- 0.9 degrees versus +/- 1.4 degrees ). Twenty-one of the 100 cases had more than a 5 degrees difference (range, -8.7 degrees to 8.9 degrees ) between the medial and lateral plateaus. The proposed technique allows measurement of the posterior tibial slope of the medial and lateral plateaus on a standard knee MRI. By using this novel measurement technique, a reliable assessment of the medial and lateral tibial plateaus is possible. LEVEL OF EVIDENCE: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Expression of atrophy mRNA relates to tendon tear size in supraspinatus muscle.

Skeletal muscle atrophy and fatty infiltration develop after tendon tearing. The extent of atrophy serves as one prognostic factor for the outcome of surgical repair of rotator cuff tendon tears. We asked whether mRNA of genes involved in regulation of degradative processes leading to muscle atrophy, ie, FOXOs, MSTN, calpains, cathepsins, and transcripts of the ubiquitin-proteasome pathway, are overexpressed in the supraspinatus muscle in patients with and without rotator cuff tears. We evaluated biopsy specimens collected during surgery of 53 consecutive patients with different sizes of rotator cuff tendon tears and six without tears. The levels of corresponding gene transcripts in total RNA extracts were assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Supraspinatus muscle atrophy was assessed by MRI. The area of muscle tissue (or atrophy), decreased (increased) with increasing tendon tear size. The transcripts of CAPN1, UBE2B, and UBE3A were upregulated more than twofold in massive rotator cuff tears as opposed to smaller tears or patients without tears. These atrophy gene products may be involved in cellular processes that impair functional recovery of affected muscles after surgical rotator cuff repair. However, the damaging effects of gene products in their respective proteolytic processes on muscle structures and proteins remains to be investigated.

Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear.

Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARgamma, C/EBPbeta) and myogenic (myostatin, myogenin, Myf-5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARgammaã, myostatin, myogenin, Myf-5, and C/EBPbeta transcript levels was carried out with sheep muscle biopsy-derived total RNA. We found a significantly increased expression of Myf-5 and PPARgamma after tenotomy and a significant change for Myf-5 and C/EBPbeta after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARgamma, C/EBPbeta, and Myf-5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep.

Upregulation of alpha-skeletal muscle actin and myosin heavy polypeptide gene products in degenerating rotator cuff muscles.

Impaired function of shoulder muscles, resulting from rotator cuff tears, is associated with abnormal deposition of fat in muscle tissue, but corresponding cellular and molecular mechanisms, likely reflected by altered gene expression profiles, are largely unknown. Here, an analysis of muscle gene expression was carried out by semiquantitative RT-PCR in total RNA extracts of supraspinatus biopsies collected from 60 patients prior to shoulder surgery. A significant increase of alpha-skeletal muscle actin (p = 0.0115) and of myosin heavy polypeptide 1 (p = 0.0147) gene transcripts was observed in parallel with progressive fat deposition in the muscle, assessed on parasagittal T1-weighted turbo-spin-echo magnetic resonance images according to Goutallier. Upregulation of alpha-skeletal muscle actin and of myosin heavy polypeptide-1 has been reported to be associated with increased muscle tissue metabolism and oxidative stress. The findings of the present study, therefore, challenge the hypothesis that increased fat deposition in rotator cuff muscle after injury reflects muscle degeneration.

Elastic properties of an intact and ACL-ruptured knee joint: measurement, mathematical modelling, and haptic rendering.

An analytical, dynamic model of the human knee joint has been developed to simulate the unloaded knee joint behaviour in 6 degrees of freedom. It is based on extensive robot-based measurements of the elastic properties of a human cadaver knee joint. The measured data are compared with data from the literature to ensure that a proper database for modelling is used. The analytical modelling of the passive elastic joint properties is done with Local Linear Model Trees. The deduced knee joint model incorporates passive elastic properties of the internal knee joint structures, passive elastic muscle forces, damping forces, gravitational forces, and external forces. There are two sets of parameters, one simulating the movement of the intact knee joint, and a second simulating the knee joint with ruptured anterior cruciate ligament. The dynamic model can be easily processed in real-time. It is implemented in the haptic display of the Munich Knee Joint Simulator (MKS), which enables a person to move a plastic leg driven by a robot manipulator and feel the simulated knee joint force. Orthopaedic physicians judged the performance of the dynamic knee joint model by executing physical knee joint tests at the MKS.

Phantom-based multimodal interactions for medical education and training: the Munich Knee Joint Simulator.

Simulation environments based on virtual reality technologies can support medical education and training. In this paper, the novel approach of an "interactive phantom" is presented that allows a realistic display of haptic contact information typically generated when touching and moving human organs or segments. The key idea of the haptic interface is to attach passive phantom objects to a mechanical actuator. The phantoms look and feel as real anatomical objects. Additional visualization of internal anatomical and physiological information and sound generated during the interaction with the phantom yield a multimodal approach that can increase performance, didactic value, and immersion into the virtual environment. Compared to classical approaches, this multimodal display is convenient to use, provides realistic tactile properties, and can be partly adjusted to different, e.g., pathological properties. The interactive phantom is exemplified by a virtual human knee joint that can support orthopedic education, especially for the training of clinical knee joint evaluation. It is suggested that the technical principle can be transferred to many other fields of medical education and training such as obstetrics and dentistry.

The influence of right anterolateral thoracotomy in prepubescent female patients on late breast development and on the incidence of scoliosis.

BACKGROUND: It is assumed that a right anterolateral thoracotomy for correction of simple congenital cardiac defects (ie, atrial septal defect) achieves more favorable cosmetic results than a standard median sternotomy. METHODS: Ninety-five patients, 72 with right anterolateral thoracotomy and 23 with median sternotomy, who had corrective transatrial operations when they were younger than 12 years of age were contacted by questionnaire. The mean follow-up time was 23.1 years. Of these, 61 patients (46 thoracotomy and 15 sternotomy) were investigated clinically. Volume differences of the breasts were measured by 3-dimensional surface scanning. By using photographs of the upper chest, breast symmetry was described by an index. The degree of scoliosis was measured by clinical examination. RESULTS: According to the questionnaire analysis, 76% (thoracotomy group) versus 39% (sternotomy group) thought that the cosmetic result was excellent (P =.008). Breast volume measurement showed a volume difference greater than 20% (left side larger than right) in 55% (thoracotomy) versus 0% (sternotomy). With our index, asymmetry in the lower part of the right breast occurred in 61% (thoracotomy) versus 0% (sternotomy; P <.001). A total of 6.6% of the patients had scoliosis, without any differences between groups. CONCLUSIONS: Because our long-term follow-up in prepubescent female patients after right anterolateral thoracotomy revealed significantly impaired unilateral breast development, we propose to abandon right anterolateral thoracotomy in this subgroup of patients, although the subjective satisfaction with the cosmetic result was high. To avoid potential damage of future breast tissue, other surgical approaches, such as right posterior thoracotomy, should be considered. According to the orthopedic investigation, the surgical approach does not cause a higher rate of scoliosis.