The additive use of an external modular device may improve dorsal compression forces in pelvic external fixation. This would improve the efficiency of indirect reduction and stabilization with an anterior pelvic external fixator. The purpose of this study was to determine the forces of the posterior pelvis achieved by a new device improving the application of a supraacetabular anterior external fixator compared with other constructs. Synthetic pelvic models were used. Complete pelvic ring instability was created by symphyseal and unilateral sacroiliac joint disruption. Four different constructs of fixation were tested. A pressure-sensitive film was placed in the sacroiliac joint. The constructs were applied in a standardized way. The maximum sacroiliacal compression loads (N) of each trial was recorded. Statistics was performed with the student t-test.Objectives
Material and Method
Overlooked compartment syndrome represents a devastating complication for the patient. Invasive compartment pressure measurement continues to be the gold standard. However, repeated measurements in uncertain cases may be difficult to achieve. We developed a new, noninvasive method to assess tissue firmness by pressure related ultrasound. Decreased tissue elasticity by means of rising compartment pressures was mimicked by infusion of saline directly into the anterior tibial compartment of 6 human specimens post mortem. A pressure transducer (Codman) monitored the pressure of the anterior tibial compartment. A second transducer was located in a saline filled ultrasound probe head to allow a simultaneous recording of the probe pressure provoked by the user. The ultrasound images were generated at 5 and 100mmHg probe pressures to detect the tissue deformity by B-mode ultrasound. The fascial displacement was measured before and after compression (d). Subsequently, increments of 5mmHg pressure increases were used to generate a standard curve (0–80mmHg), thus mimicking rising compartment pressures. The intra-observer reliability was tested using 10 subsequent measurements. A correlation was determined between d and the simulated intacompartmental pressure (ICP) in the compartment. The Pearson correlation coefficient (r) was calculated. The reliability determined by the kappa value and a regression analysis was performed.Background
Methods
A recognised treatment for severe sub-talar arthritis is joint fusion. This can be performed using a well established open technique or achieved through an arthroscopic approach. The aim of this retrospective study was to investigate the results of arthroscopic sub-talar arthrodesis performed by a single surgeon in our institution. 13 arthroscopic sub-talar joint fusions were performed over a 2 year period in patients presenting with isolated arthritis of the joint in question. All arthrodeses were carried out using two posterolateral portals and one posteromedial portal and fixed with two single 7 mm partially threaded cancellous screws. Outcome measures included the American Foot and Ankle (AFOS) score, time to union and post-operative complications. No patients were lost to follow-up. 12 out of 13 arthrodeses went onto clinical and radiological fusion. The AFOS score improved from36 (range 32–50) pre-operatively to 75 (range 65–80) at final follow up. Complications included 1 non-union, 1 DVT and 1 superficial wound infection. 3 patients have had metalwork removed secondary to screw irritation. The results of subtalar arthrodesis performed using an arthroscopic technique is comparable with an open approach and provides high patient satisfaction.
MRI was used to diagnose occult hip pathology in patients with a clinically suspected femoral neck fracture where no abnormality was detected on plain x-ray. All patients admitted into our unit with post traumatic hip pain, an inability to weight bear, and no abnormality found on a series of plain radiographs, underwent an MRI scan of the pelvis and affected hip to look for an occult femoral neck fracture. The study included 102 consecutive patients who were prospectively studied over a 10 year period between 1997 and 2007. Four patients were excluded due to contraindications or an inability to tolerate having an MRI scan. Of the remaining 98 patients 81 had abnormalities detected (83%). 42 of these patients had evidence of a proximal femoral fracture. 23 patients underwent an operative procedure. Eight incomplete intertrochanteric fractures were treated non-operatively with good results. One patient had a primary diagnosis of malignancy made on the basis of the MRI scan. One patient had a known primary malignancy but this was the first diagnosis of bony metastatic disease. Seventy five patients were scanned within 48 hours of admission (average 2.4 days). The use of MRI in our unit was felt to be appropriate in patients with a high suspicion of proximal femoral fracture. Our results show that there is a significant incidence of fractures that are not apparent on plain x-rays. MRI led to early diagnosis and initiation of definitive management, potentially reducing cost and complications of immobility. It was most useful in showing the extent of the fracture, and picked up on other occult pathologies of the hip and pelvis. We recommend stabilisation of femoral neck fractures and non operative management of all incomplete intertrochanteric fractures if able to non weight bear. There must be a high index of suspicion of undiagnosed malignancy
An MR scan was performed on all patients who presented to our hospital with a clinical diagnosis of a fracture of the proximal femur, but who had no abnormality on plain radiographs. This was a prospective study of 102 consecutive patients over a ten-year period. There were 98 patients who fulfilled our inclusion criteria, of whom 75 were scanned within 48 hours of admission, with an overall mean time between admission and scanning of 2.4 days (0 to 10). A total of 81 patients (83%) had abnormalities detected on MRI; 23 (23%) required operative management. The use of MRI led to the early diagnosis and treatment of occult hip pathology. We recommend that incomplete intertrochanteric fractures are managed non-operatively with protected weight-bearing. The study illustrates the high incidence of fractures which are not apparent on plain radiographs, and shows that MRI is useful when diagnosing other pathology such as malignancy, which may not be apparent on plain films.
