Abstract

Thirty-five patients were followed prospectively from their referral to the Problem Fracture Service with chronic osteomyelitis of diaphyseal bone between November 1994 and June 1999.

The patients were treated using a closed double-lumen suction irrigation system following reaming and arthroscopic debridement of the intramedullary canal; this is a modified system based on the work of Charles Lautenbach. Results of these procedures were regularly followed up in clinic, and between June and July 2007 the whole cohort was reviewed via postal questionnaire, telephone and case note review.

At a mean follow up of 101 months, 26 were living with no evidence of recurrence, 4 had died of unrelated causes with no evidence of recurrent infection. Four patients had persisting problems with sinus discharge requiring intermittent antibiotic therapy and 1 patient had his limb amputated for recurrent metaplastic change.

These results gave this cohort an 86% clearance of infection, with recurrence in 12%, which is comparable to the Papineau and Belfast techniques with significantly less surgical insult to the patient.

The Quebec Task Force defined whiplash as “an acceleration–deceleration mechanism of energy transfer to the neck”. It is logical that the lower the velocity change following impact, the lower the risk of injury. The accepted velocity change (delta-v) for whiplash injuries following rear impact has been quoted as 5 mph. There is some debate as whether this is valid in the clinical setting. We aimed to investigate this further.

A series of low speed controlled crash simulations were undertaken. There were a total of 27 runs on 23 individuals. Accelerometers were placed on the head and chest of the volunteers. Video recordings were analysed to assess relative displacement of the head and chest. The presence of symptoms was documented over a period of 7 days. The volunteers consisted of 23 males and 1 female with an average age of 38 (range 20–56). The average delta-v achieved was 2.3 mph (range 1.8–3.1 mph). The average maximum accelerations recorded were 3.46g at the chest and 2.93g at the head. The average difference was 0.53g. There was no significant displacement between the head and body. No symptoms were reported beyond 1 hour.

Whiplash is triggered if the disparity between movements of the head and neck is of sufficient magnitude. It seems logical that there is a threshold below which whiplash will not occur. Our results have shown that below a delta-v of 3 mph there is little difference in the magnitude and timing of the movements of the head and chest.

Therefore the whiplash mechanism of injury does not occur at these changes of velocity.

Introduction: The search continues for ideal markers and methods of monitoring cartilage degeneration. Various cartilage components, whole or fragmented, have been measured in synovial fluids. A common problem in quantitating these markers is often the unknown dilution of synovial fluid which can occur in obtaining the samples. In this study we have used urea (ratio in synovial fluid:serum) as a method to correct for the dilution of synovial fluid, and hence to quantify enzyme levels in patients with a spectrum of cartilage degradation, in addition to identifying aggrecan degradation products, many of them for the first time in such samples.

Methods: Forty synovial fluid samples were obtained from 4 groups of individuals (10 in each):

normal,

Levels of matrix metalloproteinases (MMPs) 2 and 3 and the inhibitor, TIMP 1, were measured in the fluids via ELISA assays. Urea levels were measured in blood and synovial fluids and enzymes and their inhibitors were normalized according to the ratio of serum:SF urea, to account for the dilution factor of the SF (Kraus et al 2001). Western blotting was used to identify the presence of aggrecan components (chondroitin-4-sulphate: 2B6 antibody; C-6-S: 3B3 and C-0-S: 1B5; keratan sulphate: BKS-1; the G1 domain: 7D1; interglobular domain: 6B4) and also enzyme degradation products of MMPs (BC14) and aggrecanases (BC3; BC-13).

Results: MMPs 2 and 3 and TIMP 1 were all significantly increased in the synovial fluids from OA patients compared to normals (P< 0.01, 0.001 and 0.01 respectively) and MMP3 was greater in the grade IV chondral and osteochondral defect groups than the normals (P< 0.01). Western blotting demonstrated fragmented aggrecan components with a range of molecular weights. Aggrecanase activity was seen in the OA and grade IV chondral damage groups but not in the osteochondral or normal groups, whereas MMP activity was seen in all 3 groups showing cartilage damage but not in the normals.

Conclusion: Dilution of the synovial fluid, either due to inflammation or joint lavage, is often a problem in quantitating metabolites and markers in joint cavities. This pilot study of a limited number of samples from well characterized patient groups indicates that using urea concentrations in synovial fluid relative to serum provides a mechanism to overcome this. It confirms elevated enzyme activity, both aggrecanase and MMPs, in the joints of patients with degenerate cartilage, compared to normals.

Fracture bending stiffness of 15 Nm/° measured in the sagittal plane provides an objective end-point for healing in tibial fractures treated with external fixation (1). Fracture stiffness in other planes has been shown to be significantly different (2). A method for measuring three-dimensional fracture stiffness has been developed (3) and refined. This study describes the results of omni-planar stiffness measurements.

A series of omniplanar fracture stiffness measurements were undertaken on patients with tibial fractures treated by external fixation. The first measurements were performed when the fracture was deemed sufficiently stiff to allow the fixator to be removed safely. These were continued at regular intervals until union, defined as a uniplanar stiffness of greater than 15Nm/° in at least two planes.

Polar stiffness plots were obtained and analysed. The stiffness envelope varied significantly in all planes but the general shape of the polar plot remained the same with successive tests, with an overall increase in stiffness. The polar stiffness measurements were significantly different than concurrent uniplanar measurements; this reflects the difficulty in defining the plane of bending accurately in uniplanar measurements. The fracture configuration and healing fibula had unpredictable effects on the polar stiffness.

The measurement of polar fracture stiffness polar gives new insight into how the mechanical environment of a fracture changes during healing. Fracture stiffness is not uniform and this may have implications on when it is safe to remove the fixator.

Fractures of the tibia should be reduced as accurately as possible. Fractures opened for internal fixation can be reduced accurately under direct vision, but unstable closed fractures treated by external fixation must be reduced by indirect means. Most surgeons reduce the fracture by manipulation, insert the bone-screws, apply the fixator and then manipulate the fracture again to improve the reduction before locking the fixator. Using this technique it is difficult to obtain a perfect reduction. A poor reduction can prolong healing time and may lead to malunion causing long-term impairment of function. A good reduction lessens the loading imposed on the bone-screws and fixator. We describe a device with which closed tibial fractures can be reduced with a predictable high degree of precision prior to external fixation.

A reduction device, the Staffordshire Orthopaedic Reduction Machine (STORM), was developed. Externally fixed unstable closed tibial fractures reduced by conventional methods (n=37) were compared with those reduced using the STORM (n=41). In the STORM group, the holes for the fixator pins were only drilled once the fracture had been perfectly reduced and no further manipulation was undertaken after the fixator had been applied. Reductions were assessed by measurements of radiographs taken at, and 4 weeks after, fixator removal. All cases were treated with monolateral external fixation.

The STORM significantly improves the precision of reduction of unstable tibial fractures without increasing operating time. Its use obviates the need for reduction joints on external fixators for the tibia.