Faculty Bibliography

BACKGROUND:A prospective, randomized controlled trial was used to compare the efficacy of the arteriovenous (AV) impulse system and aspirin in reducing venous thrombosis after fracture to the femoral neck. METHODS:A total of 143 patients underwent hemiarthroplasty, after which 70 patients were treated with the AV pump and a second group of 73 patients were commenced on 325 mg of aspirin. Duplex ultrasound was used to assess both proximal and distal venous thrombi on days 7 to 10. Calf and thigh circumferences were also measured. RESULTS:Thrombi developed in seven of the patients treated with aspirin and in four patients treated with the AV pump. No statistically significant difference could be established (p = 0.109). There was a significant reduction in both calf (p = 0.003) and thigh (p = 0.002) swelling in the group treated with the AV pump. Neither treatment group was a significant predictor of a poorer outcome by using logistical regression analysis (p = 0.258). CONCLUSIONS:Both aspirin and the AV pump are effective in reducing thromboembolic events after hemiarthroplasty of the hip.

Cauda equina syndrome is rare, but when it does occur it can lead to poor outcomes with significant legal implications. Controversy exists as to whether the timing of surgical intervention may affect these outcomes. Recent studies have reinforced that early surgical decompression may be beneficial to early return of function. Expeditious surgery is, however, only one factor that can affect outcome in this syndrome

We report an unusual case of a femoral neck stress fracture leading to the fatigue failure of an AO spiral blade. An unreamed femoral nail with a spiral blade was inserted to treat an unstable subtrochanteric femoral fracture. which lead to fracture union at 5 months. Eight months post-operatively the patient started to complain of left hip pain. Serial radiographs revealed progressive osteoporosis of the proximal femur possibly due to the stress sharing effect of a stiff intramedullary device, which continued to bear a significant amount of the transmitted load. The cause of pain was a stress fracture of the femoral neck and the AO spiral blade, which only became radiologically visible 4 months after the start of the symptoms (1 year after the initial operation). The implant was removed and replaced by a cemented hemiarthroplasty. This case reaffirms the difficulty in diagnosing a stress fracture through a metallic implant. The delay in diagnosis may be shortened if stress fracture were included as an expected complication following an intramedullary nailing.

We present a case of post-traumatic subchondral cyst formation in the talus. No evidence of an osteochondral defect was observed, however, the histological findings suggested a synovial origin. This implicates synovial herniation through traumatized articular cartilage into subchondral bone in a fashion analogous to osteoarthritic pathogenesis

Previously reported cases of fracture dislocation of the tarsal navicular bone have implicated dorsiflexion and longitudinal compression as the mechanism of injury. We report a case of navicular fracture dislocation which, by the description of the incident and the reduction manoeuvre employed, suggests that plantarflexion combined with inversion were the forces required to produce the deformity. Understanding of the mechanism of injury in these fractures may lead to easier closed reduction and improved outcome.

This retrospective review examined the cause, level of pathology, onset of symptoms, time taken to treatment, and outcome of 19 patients with cauda equina syndrome (CES). The minimum time to follow up was 22 months. Logistical regression analysis was used to determine how these factors influenced the eventual outcome. Out of 19 patients, 14 had satisfactory recovery at 2 years post-decompression; 5 patients were left with some residual dysfunction. The mean time to decompression in the group with a satisfactory outcome was 14 h (range 6-24 h) whilst that of the group with the poor outcome was 30 h (range 20-72 h). There was a clear correlation between delayed decompression and a poor outcome (P = 0.023). Saddle hypoaesthesia was evident in all patients. In addition complete perineal anaesthesia was evident in 7/19 patients, 5 of whom developed a poor outcome. Bladder dysfunction was observed in 19/19 patients, with 12/19 regarded as having significant impairment. Of the five patients identified as having a poor overall outcome, all five presented with a significant sphincter disturbance and 4/5 were left with residual sphincter dysfunction. There was a clear correlation between the presence of complete perineal anaesthesia and significant sphincter dysfunction as both univariate and multivariate predictors of a poor overall outcome. The association between a slower onset of CES and a more favourable outcome did not reach statistical significance (P = 0.052). No correlation could be found between initial motor function loss, bilateral sciatica, level or cause of injury as predictors of a poor outcome (P>0.05). CES can be diagnosed early by judicious physical examination, with particular attention to perineal sensation and a history of urinary dysfunction. The most important factors identified in this series as predictors of a favourable outcome in CES were early diagnosis and early decompression.