Aslam Mohammed

Circulating Cytokines after Hip and Knee Arthroplasty: A Preliminary Study

Several studies show cytokine concentrations in the peripheral blood are associated with inflammatory activity and surgical trauma. Cytokine concentrations have more rapid increase and quicker return to normal values than either C-reactive protein or erythrocyte sedimentation rate – a matter of hours rather than weeks; some studies suggest they are better predictors of postoperative infection than C-reactive protein and erythrocyte sedimentation rate. Threshold levels of interleukin-6 after joint arthroplasty have been determined, but levels of other potentially useful cytokines (tumor necrosis factor-α, interleukin-8, interleukin-10, etc) are not known. We measured the serum levels of 25 different cytokines before and after hip and knee arthroplasties and identified those associated with surgical trauma. Peripheral venous blood samples (one preoperative and three postoperative) from 49 patients undergoing hip or knee arthroplasty were analyzed by laser chromatography. Three of the 25 cytokines had a relationship with postsurgical trauma, which included one deep infection. Serum levels of these three cytokines might be useful to identify periprosthetic infections during the early postoperative period when C-reactive protein and erythrocyte sedimentation rate remain elevated.Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The effect of tibial component sizing on patient reported outcome measures following uncemented total knee replacement

UNLABELLED When performing total knee replacement (TKR), surgeons are required to decide on the most appropriate size of tibial component. As implants are predominantly selected from incremental sizes of a preferred design, it may be necessary for a surgeon to slightly under or oversize the component. There are concerns that overhang could lead to pain from irritation of soft tissues, and an undersized component could lead to subsidence and failure. Patient reported outcome measures were recorded in 154 TKRs at one year postoperatively (in 100 TKRs) and five years post-operatively (in 54 TKRs) in 138 patients. The Oxford Knee Score (OKS), WOMAC and SF-12 were recorded, and a composite pain score was derived from the OKS and WOMAC pain questions. Tibial component size and position were assessed on scaled radiographs and implants were grouped into anatomic sized tibial component (78 TKRs), undersized component (48 TKRs), minor overhang one to three mm (10 TKRs) or major overhang ≥ 3 mm (18 TKRs). There was no statistically significant difference between the mean post-operative OKS, WOMAC, SF-12 or composite pain score of each group. Furthermore, localisation of the site of pain did not correlate with medial or lateral overhang of the tibial component. Our results suggest that tibial component overhang or undersizing is not detrimental to outcome measures or pain. LEVEL OF EVIDENCE II.

Does Orthopaedic Surgical Training Induce Hypertension? A Pilot Study

BackgroundElevated blood pressure (BP) is associated with increased cardiovascular risks manifested by ischemic heart disease and stroke. Studies of cardiothoracic surgeons and neurosurgeons suggest surgery induces a hemodynamic stress malresponse. However, it is unclear whether these occur in orthopaedic surgeons.Questions/PurposesWe measured the BP of surgeons during hallux valgus surgery, TKA, and THA with the: (1) trainee assisting the trainer, (2) the trainer assisting the trainee, (3) the trainee operating independently, and (4) compared the intraoperative changes in BP and heart rate of orthopaedic surgeons with those of a clinic day and during an exercise tolerance test.MethodsWe used an ambulatory BP monitor to measure the BP and heart rate of three consultants and their respective trainees during hallux valgus surgery, TKA, or THA. We noted if there were any differences in the stress response of the lead surgeon in comparison to when the same individual was assisting a trainee, and vice versa. Additionally, we recorded the trainee’s BP and heart rate when they were operating independently. The intraoperative changes in BP and heart rate of orthopaedic surgeons were compared with those measured during a clinic day and during an exercise tolerance test.ResultsWhen the trainer was leading the operation, their mean arterial pressure gradually increased to 105 (range, 102–109) until implant placement. However, when the trainee was operating and the trainer assisting, the trainer’s BP peaked (mean, 101; range, 95–111) at the beginning of the procedure and slowly declined as it progressed. The trainee’s BP remained elevated throughout. The highest peaks for trainees were noted during independent operating. All of the surgeons had higher average BP readings (mean, 100; range, 95–108) and heart rate (mean, 86; range, 57–117) on days when they did surgery compared with baseline.ConclusionsThe elective operations studied induced a hypertensive response. The response was more marked in trainees than in trainers, particularly if the trainee was operating independently.

Actinobacillus hominis osteomyelitis: First reported case in the English language medical literature

Introduction: Actinobacillus hominis is currently a rarely reported pathogen. It has previously been associated with respiratory tract infections and bacteraemia in debilitated patients. However, under-reporting may occur due to misidentification by commonly used laboratory bacterial identification systems. This case is, to the best of our knowledge, the first reported case of A. hominis osteomyelitis in the English language medical literature. Case presentation: A 37-year-old male presented with a painful foot. He had no previous foot problems, history of injury or animal contact. Osteomyelitis was confirmed by magnetic resonance imaging (MRI), and blood cultures were positive for Gram-variable bacilli. The organism was identified initially as Pasteurella pneumotropica by the local routine diagnostic laboratory and as a Pasteurella species by the UK National Reference Laboratory (Colindale, London, UK), using standard operating procedures at the time. It was finally identified as an A. hominis using 16S rRNA gene sequence analysis. Difficulties in the accurate identification of this organism remain current, as other biochemical identification systems have also resulted in misidentifications. The patient refused admission and intravenous antibiotics. He was successfully treated using an 8-week course of oral ciprofloxacin and amoxicillin based on antibiotic disc susceptibility testing resulting in clinical, serological and radiological resolution. Conclusion: Laboratories should maintain a high index of suspicion for A. hominis as several commonly used bacterial identification systems may not accurately identify the organism. Colonial morphology and absence of animal contact should prompt consideration of this organism in appropriate clinical situations. Oral ciprofloxacin and amoxicillin treatment was successful in this case.

A Novel Technique for Femoral Canal Occlusion During Cement Pressurization in Proximal Femoral Arthroplasty

We describe a novel technique for occluding the femoral canal distal to the isthmus during proximal femoral arthroplasty. Synthetic bone models were reamed and sectioned to simulate loss of the proximal femur. Two experimental conditions were used. The first used no restrictor to act as a control. The second used calcium sulphate pellets impacted in distal femoral canal. A 100 × 12 mm Limb Preservation System stem (DePuy, Leeds, UK) was used in all experiments. We recorded cement pressure, leakage of cement, and penetration of cement into the femoral condyles. The calcium sulphate pellets prevented cement leakage, enabled higher cementing pressures, and prevented penetration of the cement into the femoral condyles. We would recommend this technique in cases where loss of proximal femoral bone loss requires the use of a cemented proximal femoral replacement.

Uncemented application of cemented LCS knee prosthesis leading to knee pain.

(DePuy Orthopaedics Inc, Warsaw, Ind) prosthesis is a total condylar, low contact stress, mobile bearing prosthesis, which allows retention or excision of the posterior cruciate ligament. The cemented version has a sandblasted finish on cobalt-chromemolybdenum metallic surface for cement fixation, whereas the cementless version uses Porocoat sintered beads (DePuy) for bone ingrowth (Figure 1). This article highlights a previously unreported cause of knee pain after arthroplasty, and emphasizes the importance of a surgeon’s familiarity with implant components. This is particularly relevant to the low-volume arthroplasty surgeon who is more susceptible to complications.1