Delayed sciatic nerve compression following hamstring injury.

A 47-year-old man presented three months post-hamstring injury with posterior thigh and buttock pain, paraesthesia over the lateral part of the leg and dorsum of the foot and a foot drop. MRI identified a hamstring muscle injury with a lesion surrounding 20 cm of the proximal sciatic nerve consistent with an extensive haematoma. Surgical debridement and release was planned; however, his signs spontaneously resolved with rest, physiotherapy and splintage prior to surgery. There have been no other reports of a sciatic nerve lesion with neurological signs resolving without surgical exploration.

The treatment of segmental tibial fractures: does patient preference differ from surgeon choice?

INTRODUCTION: Segmental tibial fractures are complex injuries with a prolonged recovery time. Current definitive treatment options include intramedullary fixation or a circular external fixator. However, there is uncertainty as to which surgical option is preferable and there are no sufficiently rigorous multi-centre trials that have answered this question. The objective of this study was to determine whether patient and surgeon opinion was permissive for a randomised controlled trial (RCT) comparing intramedullary nailing to the application of a circular external fixator. MATERIALS AND METHODS: A convenience questionnaire survey of attending surgeons was conducted during the United Kingdom's Orthopaedic Trauma Society annual meeting 2017 to determine the treatment modalities used for a segmental tibial fracture (n=63). Patient opinion was obtained from clinical patients who had been treated for a segmental tibial fracture as part of a patient and public involvement focus group with questions covering the domains of surgical preference, treatment expectations, outcome, the consent process and follow-up regime (n=5). RESULTS: Based on the surgeon survey, 39% routinely use circular frame fixation following segmental tibial fracture compared to 61% who use nail fixation. Nail fixation was reported as the treatment of choice for a closed injury in a healthy patient in 81% of surgeons, and by 86% for a patient with a closed fracture who was obese. Twenty-one percent reported that they would use a nail for an open segmental tibia fracture in diabetics who smoked, whilst 57% would opt for a nail for a closed injury with compartment syndrome, and only 27% would use a nail for an open segmental injury in a young fit sports person. The patient and public preference exercise identified that sleep, early functional outcomes and psychosocial measures of outcomes are important. CONCLUSION: We concluded that a RCT comparing definitive fixation with an intramedullary nail and a circular external fixator is justified as there remains uncertainty on the optimal surgical management for segmental tibial fractures. Furthermore, psychosocial factors and early post-operative outcomes should be reported as core outcome measures as part of such a trial.

Femoral cement pressurisation for hip arthroplasty in previously fixated hips: an experimental study.

INTRODUCTION: It is common to use a cemented total hip replacement following failed hip screw fixation of a fractured femoral neck; this solution, however, is complicated by the presence of the holes that are left in the femur when the screws are removed. These holes can allow cement to leak out while being pressurised. The aim of this study was to look at the cement femoral pressures proximally and distally in a sawbone model with pre-drilled holes to assess if the commonest surgical technique of occluding the holes with fingers could maintain the cement pressure high enough. MATERIALS AND METHODS: We used eight synthetic proximal femurs, four with dynamic hip screw holes drilled in them on the lateral surface ("drilled femurs") and four with no holes ("undrilled femurs"). We used pressure sensors positioned in holes drilled in the proximal and distal parts of the medial surface to measure the pressure in the cement as it was being delivered and pressurised into the femur canal. The tests were conducted while the femur was clamped at its distal end and, in the case of the drilled femurs, while the screw holes were occluded manually. RESULTS: We found that on the proximal side, the peak cement pressure in undrilled femurs was significantly greater than in drilled femurs (p=0.006). On the distal side, the difference in peak cement pressure between the two study groups was not significant (p=0.22). At both the proximal and distal positions, the time over which the cement pressure exceeded both 5 and 100 kPa was significantly longer in undrilled femurs than in drilled femurs (p<0.05). CONCLUSION: Our results show that it is difficult to fully occlude the drill holes completely with finger tips, especially when using pressurised cement. There are significant differences in the peak cement pressures between drilled and undrilled femurs with possible consequences for patients undergoing total hip replacement.

Changes in R-R interval at the start of muscle contraction in the decerebrate cat.

1. The effect on R-R interval of a brief hindlimb contraction, elicited by electrical stimulation of L7 ventral roots, was investigated in decerebrate cats. The first series of experiments was performed at both low and high carotid sinus pressure to vary the level of vagal tone. When carotid sinus pressure was elevated to increase vagal tone, contraction commenced 1 s later. 2. The change in R-R interval at low carotid sinus pressure was expressed as the difference between the mean of the five R-R intervals immediately preceding contraction and the mean of the last five R-R intervals at the end of a 5 s contraction. At high carotid sinus pressure, the change was expressed as the difference between the mean of the last five R-R intervals at the end of a 5 s contraction and the mean of five R-R intervals at an equivalent time after raising pressure alone. 3. Hindlimb contraction at low carotid sinus pressure produced a significant reduction in R-R interval from 359 +/- 25 (mean +/- S.E.M. n = 8) to 336 +/- 24 ms (P less than 0.005). At high carotid sinus pressure the response was enhanced with contraction producing a reduction in R-R interval from 474 +/- 45 to 419 +/- 47 ms (P less than 0.001). 4. The shortening of R-R interval produced by hindlimb contraction at high carotid sinus pressure, 55 +/- 8 ms, was significantly greater than that observed at low sinus pressure, 23 +/- 5 ms (P less than 0.001, n = 8, paired t test). This pattern of response was also seen at stimulation frequencies as low as 10 Hz. 5. In a second series of experiments, designed to determine the latency of the cardiac acceleration, the minimum latency between the onset of L7 ventral root stimulation and the end of the first shortened R-R interval was 687 +/- 29 ms (n = 5). 6. Atropine (0.4 mg kg-1, I.V.) prevented a 5 s contraction from producing any change in R-R interval. 7. These results indicate that afferent information originating from receptors in contracting muscles is responsible for producing an immediate shortening of R-R interval, which is mediated by vagal withdrawal. The possibility that the shortening of R-R interval at the start of contraction is linked to a reduction in arterial baroreceptor reflex sensitivity, possibly via inhibitory effects on neurones forming the central pathway of the baroreceptor reflex, is discussed.