Septic arthritis in an in vivo murine model induced by Staphylococcus aureus : a comparison between actions of the haemolysin toxin and the effects of the host immune response.

AIMS: Staphylococcus aureus is a major cause of septic arthritis, and in vitro studies suggest α haemolysin (Hla) is responsible for chondrocyte death. We used an in vivo murine joint model to compare inoculation with wild type S. aureus 8325-4 with a Hla-deficient strain DU1090 on chondrocyte viability, tissue histology, and joint biomechanics. The aim was to compare the actions of S. aureus Hla alone with those of the animal's immune response to infection. METHODS: Adult male C57Bl/6 mice (n = 75) were randomized into three groups to receive 1.0 to 1.4 × 107 colony-forming units (CFUs)/ml of 8325-4, DU1090, or saline into the right stifle joint. Chondrocyte death was assessed by confocal microscopy. Histological changes to inoculated joints were graded for inflammatory responses along with gait, weight changes, and limb swelling. RESULTS: Chondrocyte death was greater with 8325-4 (96.2% (SD 5.5%); p < 0.001) than DU1090 (28.9% (SD 16.0%); p = 0.009) and both were higher than controls (3.8% (SD 1.2%)). Histology revealed cartilage/bone damage with 8325-4 or DU1090 compared to controls (p = 0.010). Both infected groups lost weight (p = 0.006 for both) and experienced limb swelling (p = 0.043 and p = 0.018, respectively). Joints inoculated with bacteria showed significant alterations in gait cycle with a decreased stance phase, increased swing phase, and a corresponding decrease in swing speed. CONCLUSION: Murine joints inoculated with Hla-producing 8325-4 experienced significantly more chondrocyte death than those with DU1090, which lack the toxin. This was despite similar immune responses, indicating that Hla was the major cause of chondrocyte death. Hla-deficient DU1090 also elevated chondrocyte death compared to controls, suggesting a smaller additional deleterious role of the immune system on cartilage.Cite this article: Bone Joint Res 2022;11(9):669-678.

Imaging of occult hip fractures: CT or MRI?

OBJECTIVES: Patients presenting with hip pain but normal plain radiographs may ultimately be shown on further investigation to have suffered an occult hip fracture (OHF). This diagnosis can be made with CT or MRI. Traditionally MRI has been considered a superior modality. We performed a retrospective review of all patients presenting to our service with a suspected OHF over a four-year period, investigated with either CT or MRI. DESIGN: Retrospective review. SETTING: Urban trauma centre. PATIENTS: Patients with suspected hip fractures and negative radiographs. INTERVENTION: CT or MRI. MAIN OUTCOME MEASURES: Detection rate; delay in request for further imaging; delay to theatre; re-presentations with missed fractures. RESULTS: A total of 179 patients were investigated, with a mean age of 82±13 years. The ultimate diagnosis was of an OHF in 71 cases and pelvic or acetabular fracture in 34. The average time from presentation plain radiograph to further imaging was 2.0±2.7 days, but was significantly shorter for CT. No patient re-presented with unidentified fractures or other localised hip pathology within a 12-month period. CONCLUSIONS: Modern imaging technology does not appear to miss clinically significant fractures. As CT is usually more accessible than MRI, the results of our study should encourage surgeons to consider CT as a first line investigation for occult hip fractures. We advocate a high index of suspicion and early imaging referral for elderly patients presenting with non-specific hip pain following a fall. Level 3 Evidence.

Trabecular Metal Use in Paprosky Type 2 and 3 Acetabular Defects: 5-Year Follow-Up.

BACKGROUND: The reconstructive challenge of achieving a stable acetabulum in revision total hip arthroplasties in the presence of major osteolytic lesions has led to debate about the most appropriate surgical strategy to minimize implant-related failures. Trabecular metal (TM) implants have become popular but ongoing surveillance of their performance is required. METHODS: We reviewed the clinical and radiological outcome of a consecutive series of 52 patients (55 hips) who had undergone revision total hip arthroplasty for Paprosky type 2 or 3 acetabular defects with TM revision acetabular shells between 2002 and 2008. RESULTS: Four implant failures occurred (2 infections and 2 dislocations). Eleven patients from this cohort died (representing 12 hips) before the 5-year follow-up period giving us a follow-up of 78.2%. Implant survival at 5 years was 92% (95% confidence interval: 80.2%-96.9%). There were no cases of radiological loosening. The mean Oxford hip score was 34 (range, 5-48) at a mean follow-up of 63 months (range, 34-105 months). CONCLUSIONS: We conclude that the use of TM revision shells for complex acetabular reconstruction yields satisfactory results.

Frozen shoulder : long-term outcome following arthrographic distension.

Arthrographic distension of the glenohumeral joint was adopted as a mainstream treatment for frozen shoulder before any randomised controlled trials were performed. Interpretation of the effectiveness of this procedure rests mostly on data from cohort studies of which there are few of high quality. Papers reporting long-term results have either excluded diabetic patients or failed to report patient orientated outcomes. The authors present a long-term prospective cohort study of 51 patients (12 diabetics and 39 non-diabetics), with 53 frozen shoulders, who had an arthrographic distension performed by a single radiologist as a primary intervention. Oxford shoulder score (OSS), visual analogue pain score (VAS), and range of movement (ROM) were recorded pre-distension, at 2 days and 1 month post-distension. OSS and VAS were recorded again at a mean of 14 months post distension (range : 8-26 months). OSS improved from a pre-distension mean of 22.3 by 16.9 points at final follow-up (p < 0.001, 2 tailed paired samples t-test) whilst VAS improved from a mean pre-distension value of 7.1 by -3.5 (p < 0.001). ROM improved by a mean of 39.3 degrees in flexion, 55.2 degrees in abduction and 19.5 degrees in external rotation at one month (p < 0.001 for all). The outcome in diabetic patients was the same as in non-diabetic patients. Arthrographic distension is a safe and effective treatment for frozen shoulder; it is also effective in diabetic patients. It gives long-term improvement. The authors believe that the low number of patients requiring a secondary procedure makes arthrographic distension preferable to manipulation under anaesthesia.

Surgical training 2.0: How contemporary developments in information technology can augment surgical training.

BACKGROUND: The current surgical trainee is faced with reduced training time compared to predecessors as a result of changes in working practices. The past decade has seen marked developments in the information technology sector. This editorial will review how modern technological innovations could augment current surgical training. METHODS: We review the literature and summarize important developments in information technology that could assist the modern surgical trainee. We also look at some of the challenges faced by use of this technology. FINDINGS: Developments in mobile internet connectivity will improve access to online resources for the surgical trainee. Web 2.0 will revolutionise the way trainees interact with textbooks, journals, webpages and each other. Simulators could help to fill gaps created by reduced operating hours. To maximize the effectiveness of these resources they need to be accessible and incorporated into training in a structured way, ensuring patient safety and accuracy of information. CONCLUSION: Contemporary developments in technology offer benefits to the surgical trainee and could fill gaps left by reduced operating times. In order to ensure efficient use of technology and patient safety, bodies such as the Royal Colleges and Training Programmes must embrace these developments.

Pure robotic retrocaval ureter repair.

PURPOSE: To demonstrate the feasibility of pure robotic retrocaval ureter repair. MATERIALS AND METHODS: A 33 year old female presented with right loin pain and obstruction on intravenous urography with the classical "fish-hook" appearance. She was counseled on the various methods of repair and elected to have a robot assisted repair. The following steps are performed during a pure robotic retrocaval ureter repair. The patient is placed in a modified flank position, pneumoperitoneum created and ports inserted. The colon is mobilized to expose the retroperitoneal structures: inferior vena cava, right gonadal vein, right ureter, and duodenum. The renal pelvis and ureter are mobilized and the renal pelvis transected. The ureter is transposed anterior to the inferior vena cava and a pyelopyelostomy is performed over a JJ stent. RESULTS: This patient was discharged on postoperative day 3. The catheter and drain tube were removed on day 1. Her JJ stent was removed at 6 weeks postoperatively. The postoperative intravenous urography at 3 months confirmed normal drainage of contrast medium. CONCLUSION: Pure robotic retrocaval ureter is a feasible procedure; however, there does not appear to be any great advantage over pure laparoscopy, apart from the ergonomic ease for the surgeon as well the simpler intracorporeal suturing.

Pure robotic retrocaval ureter repair

PURPOSE: To demonstrate the feasibility of pure robotic retrocaval ureter repair. MATERIALS AND METHODS: A 33 year old female presented with right loin pain and obstruction on intravenous urography with the classical "fish-hook" appearance. She was counseled on the various methods of repair and elected to have a robot assisted repair. The following steps are performed during a pure robotic retrocaval ureter repair. The patient is placed in a modified flank position, pneumoperitoneum created and ports inserted. The colon is mobilized to expose the retroperitoneal structures: inferior vena cava, right gonadal vein, right ureter, and duodenum. The renal pelvis and ureter are mobilized and the renal pelvis transected. The ureter is transposed anterior to the inferior vena cava and a pyelopyelostomy is performed over a JJ stent. RESULTS: This patient was discharged on postoperative day 3. The catheter and drain tube were removed on day 1. Her JJ stent was removed at 6 weeks postoperatively. The postoperative intravenous urography at 3 months confirmed normal drainage of contrast medium. CONCLUSION: Pure robotic retrocaval ureter is a feasible procedure; however, there does not appear to be any great advantage over pure laparoscopy, apart from the ergonomic ease for the surgeon as well the simpler intracorporeal suturing.