Knee dislocations, vascular injuries and floating knee injuries can be initially managed by a external fixator. Fixator design constructs include the AO pattern and the Diamond pattern. However, these traditional constructs do not adhere to basic principles of external fixation. The Manchester pattern knee-spanning external fixator is a new construct pattern, which uses beam loading and multiplanar fixation. There is no data on any construct pattern. This study compares the stability of these designs. Hoffman III (Stryker, USA) external fixation constructs were applied to articulated models of the lower limb, spanning the knee with a diamond pattern and a Manchester pattern. The stiffness was loaded both statically and cyclically with a Bose 3510 Electroforce mechanical testing jig (TA Instruments). A ramp to load test was performed initially and cyclical loading for measurement of stiffness over the test period. The results were analysed with a paired t-test and ANOVA.Introduction
Materials & Methods
MIS (minimally invasive surgery) aims to improve cosmesis and facilitate early recovery by using a small skin incision with minimal soft tissue disruption. When using MIS in the forefoot, there is concern about neurovascular and tendon damage and cutaneous burns. The aim of this anatomical study was to identify the structures at risk with the proposed MIS techniques and to determine the frequency of iatrogenic injury. 10 paired normal cadaver feet were used. All procedures were performed using a mini C-arm in a cadaveric lab by 2 surgeons: 1 consultant who has attended a cadaveric MIS course but does not perform MIS in his regular practice (8 feet), and 1 registrar who was supervised by the same consultant (2 feet). In each foot, the surgeon performed a lateral release, a MICA (minimally invasive chevron and Akin) procedure for the correction of The dorsal medial cutaneous and the plantar interdigital nerves were intact in all specimens. There was no obvious damage to the arterial plexus supplying the first metatarsal head. No flexor or extensor tendon injuries were identified. There is a significant learning curve to performing the osteotomy cuts in the desired plane. In the DMO, the dissection also revealed some intact soft tissue at the osteotomy site indicating that the metatarsal heads were not truly floating.Materials and Methods
Results
Determination of ankle stability is straightforward when the injury involves both the medial and lateral For the study 10 fresh-frozen cadaveric lower limbs were used. Mortise radiographs were taken at neutral, 15 and 30 degrees of plantarflexion and neutral external rotation. These measurements were repeated after dividing the deltoid ligament. To ensure consistent ankle position, the ankle was placed in a specially constructed rig, which recreated the above positions. The medial clear space and talar tilt were measured. Differences in the means between the groups were determined with the paired ‘t’ test and ANOVA within the groups. Statistical significance was set a p-value of 0.05. Increasing the plantarflexion from neutral to 30 degrees in both groups resulted in increase in the medial clear space and talar tilt. The mean increase in medial clear space became statistically significant at 30 degrees when compared to neutral. Between the groups there was a significant difference in medial clear space at 30 degrees plantarflexion. Dividing the deltoid ligament also had a significant effect on talar tilt. Plantarflexion has an influence on the medial clear space in ankle mortise views therefore pre and post ankle fixation radiographs must be interpreted with caution.
Locking compression plate (LCP) fixation is an established method of treatment of distal third tibial fractures. No biomechanical data exists in the literature regarding their use. Additionally no data exists on the biomechanical advantage of locking screw fixation over non-locking screw fixation for these fractures. In this study the axial and torsional stiffness, axial load to failure and fatigue performance of a 3.5 mm LCP medial distal tibia Synthes plate was evaluated for the stabilisation of distal third tibial fractures. Additionally the performance of the plate in uni and bicortical locked mode as well as non-locked mode was evaluated. A standardized oblique fracture pattern was created in the tibial metaphysis of 3rd generation composite tibias, 40 mm from the distal end of the tibia (AO 43-A2.3). A 10mm fracture gap was used to model a comminuted metaphyseal fracture. A 3.5 mm medial distal tibia LCP was applied with bi or unicortical locking or bicortical non-locking screws to 5 tibias respectively. All the bio-mechanical tests were performed on a Bose 3510 Electroforce material testing machine. A ramp to load, loading profile was used to determine the static axial and torsional performance of the construct. Fatigue testing simulated a 6 week gradual weight bearing régime with the load increasing every two weeks by 400N until either 250,000 cycles were completed or the construct failed.Introduction
Methods
Thromboprophylaxis remains a controversial issue and many disagree about the optimum method or even if it is required at all. We present a new method of performing meta-analysis incorporating studies with both experimental and observational study designs. We have developed a model that compares study cohorts of several different methods of thromboprophylaxis with a simulated matched control group whose variance helps to adjust for bias. This allows meaningful comparisons between studies and treatments that have not been directly compared. We performed a systematic review of the literature from 1981 to October 2004. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of symptomatic, proximal DVT, fatal PE and major bleeding events. We identified 1242 studies of which 203 met the inclusion criteria for further analysis. This represented the results of over fifty thousand studied patients. We expressed the results for the different prophylactic methods as odds ratios compared to no prophylaxis. All methods showed a beneficial effect in reducing VTEs apart from stockings and aspirin which showed an increase in the number of PE events. These results are particularly interesting when viewed from the standpoint of an individual NHS hospital trust that performs around 500 hip and knee replacements per year. Over a 5 year period, the more effective methods of prophylaxis prevented between 15 and 40 symptomatic DVTs and up to 3 fatal PEs compared to no treatment. However, they cause between 8 and 40 more major bleeding events. We do not know the proportion of these major bleeding events that are fatal.
Subacromial corticosteroid injection has been shown to be effective in treating impingement syndrome. The exact mechanism of action is not clear but it may be due to its anti-inflammatory properties. However, there are potential side effects of steroid injection including tendon weakening, dermal atrophy and infection. NSAIDs may offer similar anti-inflammatory properties but without the side effects of corticosteroids. Tenoxicam is a long-acting water soluble NSAID and is available without irritant preservatives. Studies have shown that peri-articular Tenocixam injection was useful in treating painful shoulders and local tolerability was good. The aim of this study is to carry out a blinded ran-domised controlled study comparing subacromial Tenoxicam injection (NSAID) against methylprednisolone (steroid) injection in patients with clinical subacromial impingement syndrome. The study protocol was approved by local research ethics committee. Patients over 18 with a clinical diagnosis of subacromial impingement syndrome were considered eligible to this study. Patients with other known causes of shoulder pain, contraindication or sensitivity to NSAID and pregnant patients were excluded. Three functional outcome measures were used – Constant-Murley Shoulder Score, DASH and the Oxford Shoulder Score. The patients completed all three outcome measures before and 2, 4 and 6 weeks after the subacromial injection. Simple randomisation method was used and blinded to both researcher and the patient. 58 patients randomised into two groups were reviewed at the end of six weeks. Patients treated with subacromial steroid injection had a much better outcome compared to patients treated with subacromial tenoxicam injection and this difference was highly significant (p<
.003) In conclusion, patients with subacromial impingement syndrome have a better clinical outcome when treated with subacromial steroid injection than NSAID injection.
Hip and knee arthroplasty has been associated with relatively high rates of thromboembolic events and the majority of UK orthopaedic surgeons use at least one form of prophylaxis. Of the many different subgroups of thromboembolic rates that are commonly presented in the literature, symptomatic proximal deep vein thrombosis (spDVT) and fatal pulmonary embolism (fPE) are perhaps the most important clinical outcomes. To determine the effectiveness of common chemical and mechanical prophylactic methods in preventing spDVT and fPE in patients undergoing primary hip and knee arthroplasty. A systematic review of the literature from 1981 to December 2002 was performed. Predetermined inclusion and exclusion criteria were applied. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of spDVT, fPE and major bleeding events. Absolute risk reduction estimates for spDVT, fPE and major bleeding events were calculated by comparing the thromboembolic rates for each method of prophylaxis with using no prophylaxis of any kind. 992 studies were identified of which 162 met the inclusion criteria. No method of prophylaxis was statistically significantly more effective at preventing spDVT and fPE than using nothing. There were at least as many major bleeding complications as spDVTs. The number of fPEs prevented was very small. When complications such as major bleeding are considered, the evidence behind the use of any prophylaxis is unconvincing.
