Second-site prosthetic joint infection in patients with multiple prosthetic joints.

INTRODUCTION: Prosthetic joint infections (PJIs) are among the most serious complications in arthroplasty. A second-site PJI in patients with multiple prosthetic joints increases morbidity, with many requiring further revision procedures. We aimed to establish why some patients with multiple joints develop second-site infections. METHODS: Our institution's arthroplasty database was reviewed from 2004 to 2017. All PJIs were identified, and all patients with more than one prosthetic joint in situ were included. We recorded risk factors, causative organisms, number of procedures and length of stay. RESULTS: Forty-four patients meeting the criteria were identified. Four patients (9.1%) developed second-site infection. Eight patients (18.2%) developed re-infection of the primary PJI. Positive MRSA carrier status and PJI of a total knee replacement were associated with an increased risk of a second episode of infection. Patients who developed further infection had more frequent admission and longer lengths of stay than isolated PJIs. DISCUSSION: Higher morbidity and use of hospital resources are associated with this cohort of patients. PJIs in total knee replacements and positive MRSA status are associated with higher rates of second infection. Identifying this vulnerable cohort of patients at an early stage is critical to ensure measures are taken to reduce the risks of further infection.

Syndesmotic fixation in Weber B ankle fractures: A systematic review.

Weber Type B fractures often arise from external rotation with the foot supinated or pronated. Altered tibiofibular joint kinematics in Weber B fractures are responsible for syndesmotic damage seen in Weber B fractures. Weber B fractures are managed using open reduction and internal fixation if displaced. The syndesmosis is injured in up to 40% of cases resulting in an unstable injury with a syndesmotic diastasis. This systematic review aimed to evaluate the current literature on syndesmotic fixation in Weber B fractures, assess the outcomes and complications of syndesmotic fixation and assess the necessity of syndesmotic fixation in Weber B fractures. A search was carried out on the EMBASE, PubMed and CINAHL databases and eight studies assessing the outcomes of syndesmotic fixations versus no syndesmotic fixation with 292 Weber B ankle fractures were included in this systematic review. Results showed significant heterogeneity so a narrative review was conducted. Results of these studies showed that functional, radiological, and quality-of-life outcomes and incidences of post-traumatic osteoarthritis in patients with syndesmotic screws were similar to those of patients not managed with syndesmotic screws. Only one favoured syndesmotic fixation in all cases of diastasis. As such, syndesmotic fixation with screws may not be necessary in the management of Weber B fractures. Screws are also associated with breakage, loosening, local irritation and infections. Suture button devices and antiglide fixation techniques appear to be valid alternatives to syndesmotic screws. It was found that there was no need for routine hardware removal unless the hardware was causing significant side effects for the patient.

CT pulmonary arteriogram diagnosis of macroscopic fat embolism to the lung.

Pulmonary fat embolism (PFE) is a recognised complication of long bone fractures. The majority of cases represent microscopic embolism and are not detectable at CT pulmonary arteriography (CTPA). CT can be used to detect macroscopic fat based on Hounsfield attenuation. This case describes a case of macroscopic fat embolism to the pulmonary arteries which was confidently diagnosed at CTPA. Distinction from thromboembolism is important as treatment is supportive and may avoid risks of anticoagulation.

The role of preoperative cardiac investigation in emergency hip surgery.

BACKGROUND: Given the well recognized imperative to treat hip fractures as expeditiously as possible there can arise uncertainty regarding the balance between pre-operative medical optimization and delay of surgery. Echocardiography is often felt to considerably delay surgery with limited change to patient management. METHODS: We retrospectively reviewed forty-nine consecutive patients who had echocardiography prior to surgery for hip fracture and compared them to fifty-eight patients who did not have echocardiography. RESULTS: We found that those who had echocardiography were more likely to have medication changes (51.02% vs. 6.9%) but were unlikely to require angiography, bypass or valvular surgery prior to fracture fixation. Those undergoing echo had a longer time to surgery-3.30 days (SD=2.49) while those in the control group waited 1.5 days (SD=1.29), (p=0.005). Rates of spinal anaesthesia were similar in both groups. CONCLUSIONS: We feel that these results confirm the theory that echocardiography, as currently provided, significantly delays surgery for hip fracture and that this may negatively affect patient outcomes.

Surgical duration is associated with an increased risk of periprosthetic infection following total knee arthroplasty: A population-based retrospective cohort study.

BACKGROUND: Total knee arthroplasty (TKA) is one the most common elective procedures in the world. Post-operative infection is one of its most devastating complications, often necessitating multiple additional surgeries. We aimed to describe the relationship between surgical duration and risk of deep infection following primary elective TKA. METHODS: In this cohort study we analyses primary TKAs done between 2009 and 2016 in Ontario, Canada. We utilized restricted cubic splines to identify a threshold of surgical duration that was associated with an increased risk for infection requiring surgery. Patients with a 'short' duration of surgery were matched to those with a 'long' duration on patient age (±3 years), patient sex, severe obesity (BMI > 40), the primary surgeon, the hospital and the type of anesthetic. FINDINGS: In 92,343 primary TKAs, the median surgical duration was 106 min. We identified a cut-point of 100 min that was associated with an increased risk for infection. Subsequently, 17,815 TKA recipients with a 'long' procedure length were matched to those with a 'short' procedure length. 'Long' procedures had a higher rate of deep infection (1.1% versus 0.6%, p < 0.0001). This was equal to a relative risk of 1.81 (p < 0.0001). INTERPRETATION: In a cohort of TKA recipients, we found that procedure lengths longer than 100 min were associated with a significantly increased risk of deep infection requiring surgery. This time threshold serves a useful time-point to identify patients that require closer surveillance.

A Simple Approach to Assessment of a Total Knee Replacement's Rotationary Profile Using Computed Tomography.

Malrotation is a cause of persistent pain and poor functioning postoperatively in those who undergo a total knee replacement (TKR). The accurate measurement of malrotation is not routinely available in most hospital settings due to an absence of three-dimensional computed tomography (CT) software. An accessible, uncomplicated technique to demonstrate TKR prosthesis malrotation would be of benefit to orthopaedic surgeons worldwide. A patient was reviewed with persistent postoperative pain, having undergone a right TKR 3 years previously for progressive osteoarthritis. Postoperative prosthetic infection, instability, loosening, and fracture were ruled out as causes for the persistent pain. A two-dimensional CT scan was obtained of the patient's affected right knee. Adhesive pieces of paper (Post-it notes) were used to highlight the posterior tibial prosthesis axis, the tibial tuberosity axis, the posterior condylar axis of the femoral prosthesis and the femoral surgical transepicondylar axis, as per the technique described by Berger et al. A protractor was used to assess the degree of malrotation of the tibial and femoral prostheses. Allowing for human error and that of parallax, an immediate assessment was made of the patient's prosthesis using a readily available imaging modality, and malrotation was quickly identified using accessible, affordable everyday stationary equipment.

Fibrous Dysplasia of the Spine - A Case Involving Three Levels of Thoracic Spine.

INTRODUCTION: Involvement of the spinal column in either monostotic or polyostotic form is rare, with fewer than thirty-five cases discussed in the literature. Most of the cases of polyostotic fibrous dysplasia of spine have involvement of the appendicular skeleton. CASE REPORT: We report a case of a 74-year-old Irish man with a two month history of back pain. Investigations revealed a diagnosis of fibrous dysplasia involving three levels of the thoracic spine in isolation. The patient underwent T2-T9 stabilization and bone grafting. CONCLUSION: A case of fibrous dysplasia involving three levels of the thoracic spine in isolation has never previously been reported. The extreme rarity of this type of presentation can pose a diagnostic dilemma, and in cases with spinal involvement, a consensus of management has not yet been achieved.

Implant failure caused by non-union of bisphosphonate-associated subtrochanteric femur fracture.

Bisphosphonate use has been identified as a contributory factor in atypical subtrochanteric fracture of the femur. These fractures are commonly treated with an intramedullary device. We present a case of implant failure of an intrameduallary device caused by non-union of an atypical subtrochanteric fracture.

Recapitulating aspects of the oxygen and substrate environment of the damaged joint milieu for stem cell-based cartilage tissue engineering.

Human infrapatellar fat pad contains a source of mesenchymal stem cells (FPSCs) that potentially offer a novel population for the treatment of damaged or diseased articular cartilage. Existing cartilage repair strategies such as microfracture harness the presence of a low-oxygen microenvironment, fibrin clot formation at sites of microfracture, and elevations in growth factors in the damaged joint milieu. Bearing this in mind, the objective of this study was to determine the chondrogenic potential of diseased human FPSCs in a model system that recapitulates some of these features. In the first phase of the study, the role of transforming growth factor beta-3 (TGF-ß3) and fibroblast growth factor-2 (FGF-2), in addition to an altered oxygen-tension environment, on the colony-forming unit-fibroblast (CFU-F) capacity and growth kinetics of human FPSCs during monolayer expansion was evaluated. The subsequent chondrogenic capacity of these cells was quantified in both normoxic (20%) and low- (5%) oxygen conditions. Expansion in FGF-2 was shown to reduce CFU-F numbers, but simultaneously increase both the colony size and the cell yield compared to standard expansion conditions. Supplementation with both FGF-2 and TGF-ß3 significantly reduced cell-doubling time. Expansion in FGF-2, followed by differentiation at 5% oxygen tension, was observed to synergistically enhance subsequent sulfated glycosaminoglycan (sGAG) accumulation after chondrogenic induction. FPSCs expanded in FGF-2 were then encapsulated in either agarose or fibrin hydrogels in an attempt to engineer cartilaginous grafts. sGAG synthesis was higher in fibrin constructs, and was further enhanced by differentiation at 5% oxygen tension, accumulating 2.7% (ww) sGAG after 42 days in culture. These results indicate that FPSCs, a readily accessible cell population, form cartilage in an in vitro environment that recapitulates several key biological features of cartilage repair during microfracture and also point toward the potential utility of such cells when combined with fibrin hydrogel scaffolds.

The use of bone morphogenetic protein 7 in fracture non-unions.

OBJECTIVE: To assess the rate of clinical and radiological union with the use of bone morphogenetic protein 7 (BMP-7) in a range of fractures. METHODS: This case series retrospectively reviews a series of 16 fracture non-unions in 13 patients. These patients were treated with the commercially available BMP-7. Time to radiological and clinical union was assessed by serial out-patient follow-up. RESULTS: At nine months post-surgery in which BMP-7 was added, 12 of 16 non-unions had achieved clinical and radiographic union. Three patients required repeat grafting. The mean time to union was 5.1 ± 1.6 months after the application of BMP-7. CONCLUSION: The use of the osteo-inductive agent, BMP-7 results in good clinical and radiological outcomes which are not restricted to tibial non-unions.

Segmental fracture of the lumbar spine.

STUDY DESIGN: A case report is presented. OBJECTIVE: To describe a rare, previously undescribed pattern of spinal injury. SUMMARY OF BACKGROUND DATA: This seems to be a unique injury with no previously described injuries matching the fracture pattern observed. METHODS: This is a case report based on the experience of the authors. The discussion includes a short literature review based on pubmed searches. RESULTS: We report the case of a 26-year-old female cyclist involved in a road traffic accident with a truck resulting in complete disruption of the lumbar spine. The cyclist was caught on the inside of a truck turning left and seems to have passed under the rear wheels. She was brought to the local emergency department where, after appropriate resuscitation, trauma survey revealed spinal deformity with complete neurologic deficit below T12 and fractured pubic rami, soft tissue injuries to the perineum and multiple abrasions. Plain radiology showed a segmental fracture dislocation of her lumbar vertebrae, extending from the L1 superior endplate through to L4-L5 disc space. The entire segment was displaced in both anteroposterior and lateral planes. Computed tomography confirmed these injuries and ruled out significant visceral injury. She was transferred to the national spinal unit (author unit), where she underwent reduction and fixation with rods and screws from T9-S1, using one cross-link. After her immediate postoperative recovery, she was referred to the national rehabilitation unit. CONCLUSION: Although so-called "en bloc" lumbar fractures have been previously described, the authors were unable to find any injury of this degree in the literature. This rare injury seems to show a pattern of spinal injury previously undescribed.

The evaluation of the inverted supinator reflex in asymptomatic patients.

STUDY DESIGN: A prospective study was undertaken over a 6-month period to determine the incidence of the inverted supinator reflex in asymptomatic, neurologically normal individuals. OBJECTIVE: The objective of our study is to assess asymptomatic patients for the presence of the inverted radial reflex and to determine its clinical relevance. SUMMARY OF BACKGROUND DATA: The inverted radial reflex sign is commonly used in clinical practice to assess cervical myelopathy. It is unknown whether the sign correlates with the presence or severity of myelopathy, and no consensus exists regarding the significance of a positive sign in asymptomatic individuals. METHODS: Patients attending the Trauma Clinic at our institution were invited to participate. Each patient was examined neurologically and specifically for the presence or absence of the Babinski test, Hoffman's sign, the finger escape sign, static and dynamic Romberg's test, and the inverted supinator reflex. Patients were excluded if they had any history of neck pain, any history of neurosurgical procedure or spinal surgery, any known neurologic disorder or deficit, or if there was any outstanding medicolegal case. RESULTS: We examined 277 patients in 6-month period. The male to female ratio was 1.1:1. The mean age was 27 years (range, 16-78). The incidence of the inverted supinator reflex was 27.6% (75/271). Of the 75 positive patients, the inverted supinator reflex was present bilaterally in 39% (29/75). Nine of 75 patients (10%) had an associated positive Hoffman's sign but had no other signs suggestive of myelopathy. The proportion of patients with a positive inverted supinator reflex reduced with increasing age (Pearson correlation coefficient > 0.80). CONCLUSION: This study demonstrates that an isolated, inverted supinator reflex may be a variation of normal clinical examination. We believe that an isolated inverted supinator reflex, in the absence of other clinical findings, is not a reliable sign of cervical myelopathy; however, it must be interpreted with caution in the older patient.