Tourniquets have potential adverse effects including postoperative thigh pain, likely caused by their ischaemic and possible compressive effects. The aims of this preliminary study were to determine if it is possible to directly measure intramuscular pH in human subjects over time, and to measure the intramuscular pH changes resulting from tourniquet ischaemia in patients undergoing knee arthroscopy. For patients undergoing short knee arthroscopic procedures, a sterile calibrated pH probe was inserted into the anterior fascial compartment of the leg after skin preparation, but before tourniquet inflation. The limb was elevated for three minutes prior to tourniquet inflation to 250 mmHg or 300 mmHg. Intramuscular pH was recorded at one-second intervals throughout the procedure and for 20 minutes following tourniquet deflation. Probe-related adverse events were recorded.Aims
Methods
The aim of this study was to compare the incidence of anterior knee pain after antegrade tibial nailing using suprapatellar and infrapatellar surgical approaches A total of 95 patients with a tibial fracture requiring an intramedullary nail were randomized to treatment using a supra- or infrapatellar approach. Anterior knee pain was assessed at four and six months, and one year postoperatively, using the Aberdeen Weightbearing Test – Knee (AWT-K) score and a visual analogue scale (VAS) score for pain. The AWT-K is an objective patient-reported outcome measure that uses weight transmitted through the knee when kneeling as a surrogate for anterior knee pain.Aims
Patients and Methods
Accurate characterisation of fractures is essential in fracture management trials. However, this is often hampered by poor inter-observer agreement. This article describes the practicalities of defining the fracture population, based on the Neer classification, within a pragmatic multicentre randomised controlled trial in which surgical treatment was compared with non-surgical treatment in adults with displaced fractures of the proximal humerus involving the surgical neck. The trial manual illustrated the Neer classification of proximal humeral fractures. However, in addition to surgical neck displacement, surgeons assessing patient eligibility reported on whether either or both of the tuberosities were involved. Anonymised electronic versions of baseline radiographs were sought for all 250 trial participants. A protocol, data collection tool and training presentation were developed and tested in a pilot study. These were then used in a formal assessment and classification of the trial fractures by two independent senior orthopaedic shoulder trauma surgeons.Objectives
Methods
This ongoing prospective RCT compares two surgical approaches with respect to accuracy of guidewire and tibial nail position. 29 patients with tibial fractures were randomised to semi-extended (SE) or standard (S) approaches of tibial nail insertion. Fluoroscopy obtained guidewire and final nail position. The SE approach is more proximal with the guidewire inserted posterior to the patella, theoretically allowing more accurate wire and nail placement. Measurements were taken in both planes of the nail and guidewire to determine deviation from optimum angle of insertion (relative to the long axes of the tibial shaft). 14 and 15 patients were treated with semi-extended and standard approaches respectively. The semi-extended approach results in better guidewire and nail placement in both planes with mean deviation from the optimal angle of insertion as below: Guidewire AP 4.5° (SE) versus 4.04° (S) Lateral 24.59° (SE) versus 33.36° (S) Nail AP 3.21° (SE) versus 3.68° (S) Lateral 17.73° (SE) versus 24.04° (S) Anterior knee pain may be due to excessive anterior placement of the nail. We assessed anterior placement of the guidewire and nail in the lateral plane. This was expressed as a percentage from the anterior cortex of the tibia. Mean results are below: Guidewire 9.7% (SE) versus 9.3% (S) Nail 19.5% (SE) versus 16.3% (S) Semi-extended nailing may allow for better guidewire position and as such nail placement. This may reduce anterior knee pain.
Failure to treat acute compartment syndrome (ACS) early leads to significant morbidity. Current practice depends on using clinical signs and intracompartmental pressure (ICP) monitoring to diagnose the syndrome but there is still debate regarding their accuracy and interpretation. Patients admitted with injuries at risk of ACS underwent intramuscular (IM) pH and ICP monitoring combined with regular clinical assessment. Fasciotomies were performed on those with clinical and/or pressure based evidence of ACS. All patients were subsequently assessed for evidence of a missed ACS at at 6 & 12 months. Of the 62 patients, 51 completed the protocol and were included in the analysis. They were divided into 2 groups: those who had ACS, either initially (fasciotomies; 13), or diagnosed at follow up (no fasciotomies; 7), and those with no evidence of ACS (31). The sensitivity and specificity for the worst values for each variable were calculated and receiver operator characteristic (ROC) curves generated. The area under the curve for pH was 0.92, 0.73 for absolute pressure and 0.59 for delta pressure. To achieve a sensitivity of 95%, an absolute pressure of >30mmHg was 30% specific, a delta pressure of <33mmHg was 27%, while IM pH of 6.38 was 80% specific. This study highlights the issues concerning current diagnostic methods for ACS. By comparison, IM pH radically out performed both the highest ICP and the lowest delta pressure, identifying patients early and accurately.
Magnetic resonance imaging (MRI) validation of a novel method of assessing Distal Radial Fracture (DRF) reduction using the hypothesised constant relationship between the dorsal radial cortex (DC) and the superior pole of the lunate (SL). MRI scans of 28 normal wrists were examined. Scans included the distal third of the radius to the proximal carpal row. Beginning 5cm proximal to the distal radius articular surface, a line was superimposed upon the DC extending distally through the metaphyseal flare. Lunate height (LH) and distance from the DC line to the SL (DC-SL) were measured at 5-degree rotational increments around the radial shaft central axis to a total of 30 degrees of supination and pronation (S+P). The DC-SL/LH ratio was compared to 0 degrees (anatomical lateral) using the two-tailed paired student t-test. There was no significant difference in DC-SL:LH between 0 degrees of rotation and any 5-degree increment up to 30 degrees of S+P (lowest p=0.075). The DC line lay consistently dorsal to the SL. A constant DC-SL relationship exists with up to 30 degrees of S+P. This reference can be quickly and accurately used to assess DRF reduction in poorly-taken films with malrotation up to 30 degrees from anatomical lateral. Research comparing DC-SL distance with volar tilt to assess DRF reduction is needed.
The purpose of the study was to evaluate if use of the ArthroCare Radiofrequency Ablation Wand caused excess heating and collateral damage to the surrounding tissues during Arthroscopic Subacromial Decompression. Cadaveric studies have shown worryingly high temperatures are reached when using Radiofrequency Ablation Wands in arthroscopic shoulder surgery. We are unaware of any published literature which assesses these temperature rises in the clinical setting. 10 patients were recruited to participate in the study. A standard Arthroscopic Subacromial Decompression was performed using continuous flow irrigation with intermittent use of the Radiofrequency Ablation Wand for soft tissue debridement. The temperature of the irrigation fluid in the subacromial bursa and the outflow fluid from the suction port of the wand were measured continuously during the procedure using fibre-optic thermometers. Temperatures above 45oC in the subacromial bursa were deemed to be unsafe. The mean peak temperature recorded in the subacromial bursa was 28.6oC (23.49 – 31.94oC) with a mean rise from baseline of 6.1oC. The mean peak temperature recorded from the outflow fluid from the wand was 73.1oC (69.09 – 76.1oC) with a mean rise from baseline of 47.66oC. Significantly high temperatures were noted in the outflow fluid from the wand but this was not evident in the subacromial bursa itself. Although high temperatures are generated at the tip of the wand this does not appear to be transmitted to the surrounding irrigation fluid in the subacromial bursa. We therefore conclude that safe temperatures are maintained within the bursa when using this device, thereby minimizing damage to the surrounding tissues, meaning collateral thermal damage is unlikely.
Suture anchors are widely used to secure tendons and ligaments to bone during both arthroscopic and open surgery. However, single stage insertion suture anchors, i.e. anchors that could be inserted without predrilling of the bone, are not currently available. We aimed to record the impact needed for insertion of the new design single stage suture anchors, and to compare their pull out strength with another range of commercially available suture anchors. The force required to insert the new design of suture anchors was investigated using an impact hammer capable of recording the number and force of each of the hits. The anchors were inserted in a consistent manner into animal (porcine) bone at sites analogous to common anchor sites used in clinical practice. Pull out strength was assessed using a digital force gauge after tying the suture to create a secure loop. Thereafter, force was applied steadily until either the anchor or the suture failed and compared with a popular range of commercially available suture anchors (Mitek). Our initial investigations using prototype designs for small, medium and large anchors compared favourably with the Mini-mitek, GII, and Superanchor range of Mitek anchors. Essentially the most common point of failure for each of the suture anchor families was the suture itself with both suture anchor systems performing similarly. In addition, similar pull out strengths were demonstrated for both the Mitek and new design of suture anchors when loaded parallel, or at 90°, to the line of anchor insertion. The new design single stage suture anchors have an equivalent pull out strength compared with a popular commercially available family of suture anchors, but in addition have the significant advantage of being suitable for single stage insertion in many clinical settings.
Distal locking screw fixation, in intramedullary nail (IMN) fixation, remains the most technically demanding and problematic portion of the procedure being responsible for as much as one-half of the exposure of the surgeon‘s hands to radiation. This biomechanical study was undertaken to compare the effectiveness of using one distal locking cross screw instead of two cross screws in femoral fractures fixed with IMN system. A composite model made from a stainless steel IMN (12mm×1mm), was axially loaded to 2kN (3 times body weight) to reproduce the forces experienced during weight bearing, or until a maximum displacement of 1 mm was reached. The distal locking end of the intramedullary nail was attached to the centre of the cylinder, representing different parts of the distal femur, with a dedicated single or two rods (5mm diameter), made from stainless steel and titanium, to represent the distal locking cross screw. In the 50mm×5mm cylinder (diaphyseal femur), the mean stability of fracture model using either single or two screws were similar. But in the 75mm×5mm and 100mm×3mm cylinders (metaphyseal and distal femur), the mean stability of the fracture model significantly decreased (50%) with single distal locking cross screw fixation when compared to two distal locking cross screws fixation. Similarly, stainless steel alloy provided more stability compared to titanium alloy cross screws in 75mm×5mm and 100mm×3mm cylinders. However there was no difference between the cross screws performance for 50mm×5mm when comparing both the alloys. As shown in this experiment, femoral shaft (diaphyseal) fractures fixed with shorter IMN had the same stability for one or two distal locking cross screws. However fractures fixed with longer IMNs, to fix diaphyseo-metaphyseal junction fractures and extreme distal femoral fractures, single distal locking cross screw fixation provide poorer fracture stability compared to two distal locking cross screws fixation.
It is well recognised that meniscal tears situated within the inner, avascular region do not heal. We investigated the potential effect of insulin-like growth factor-I (IGF-I) in promoting regeneration of meniscal tissue in the inner, middle and outer zones of the meniscus. Sheep menisci were harvested and monolayer cell cultures prepared. Various concentrations of IGF-I were used in the presence or absence of 10% fetal calf serum (FCS). We measured the uptake of radioactive thymidine, sulphur, and proline to assess cell proliferation and formation of extracellular matrix (ECM). IGF-I, in the presence or absence of FCS, increased the formation of DNA and ECM in all meniscal zones. However, the response of the cells from the avascular zone was greater than that from the vascular zone. Our findings indicate that fibrochondrocytes cultured from avascular meniscal tissue have the ability to regenerate when exposed to anabolic cytokines such as IGF-I.
