Optimal posterior screw placement configuration in Sanders 2B calcaneal fractures: A biomechanical study

BACKGROUND

Calcaneal fractures can be high energy intra-articular injuries associated with joint depression. Challenges to fracture reduction include lateral wall blow out, medial wall overlap, comminution and central bone loss. Secondary deformity such as hindfoot varus alters foot biomechanics. Minimally invasive approaches with indirect reduction of the calcaneal tuberosity to maintain the reduction using posterior screws is routinely being used in the treatment of joint depression fractures. Biomechanically, optimum screw numbers and configuration is not known. Biomechanical studies have evaluated and proposed different screw configurations, however, it is not clear which configuration best controls varus deformity. This study aims to determine the optimum screw configuration to control varus deformity in Sanders 2B calcaneal fractures.

METHODS

Sawbone models were prepared to replicate Sanders type 2-B fracture, with central bone loss and comminution. 0.5 cm medial wedge of the calcaneal tuberosity was removed to create varus instability. After stabilising posterior facet with a single 4 mm partial threaded screw, and applied an 8 hole contoured plate to stabilise the angle of Gissane, inserted one or two 7 mm cannulated partially threaded Charlotte^TM (Wright Medical Technology, Memphis, USA) Headless Multi-use Compression (under image guidance) extra screws to control varus and subsidence deformity of the fracture. Coronal plane displacement of the dissociated calcaneal tuberosity fragment relative to the body when applying 5 N, 10 N and 20 N force was measured in millimetres (mm).

RESULTS

2 screws inserted (one medial screw into the sustentaculum talus from inferior to superior and, one lateral screw into the long axis anterior process) provides the least displacement (0.88 ± 0.390 at 5 N and 1.7 ± 1.251 at 20 N) and the most stable construct (p < 0.05) when compared to other configurations. A single medial screw into the sustentaculum tali (conf. 3) resulted in the least stable construct and most displacement (4.04 ± 0.971 at 5 N and 11.24 ± 7.590 at 20 N) (p < 0.05).

CONCLUSION

This study demonstrates the optimal screw configuration to resist varus in calcaneal fractures using minimally invasive techniques. Optimal stability is achieved using 2 screws; one located along the long axis of the calcaneus (varus control) and the other placed in the short axis directed towards the posterior facet of the calcaneus (control varus and subsidence). Further cadaver research would help evaluate optimal screw placement in simulated fractures to further assess reproducibility.

Optimal posterior screw placement configuration in Sanders 2B calcaneal fractures: A biomechanical study

BACKGROUND

Calcaneal fractures can be high energy intra-articular injuries associated with joint depression. Challenges to fracture reduction include lateral wall blow out, medial wall overlap, comminution and central bone loss. Secondary deformity such as hindfoot varus alters foot biomechanics. Minimally invasive approaches with indirect reduction of the calcaneal tuberosity to maintain the reduction using posterior screws is routinely being used in the treatment of joint depression fractures. Biomechanically, optimum screw numbers and configuration is not known. Biomechanical studies have evaluated and proposed different screw configurations, however, it is not clear which configuration best controls varus deformity. This study aims to determine the optimum screw configuration to control varus deformity in Sanders 2B calcaneal fractures.

METHODS

Sawbone models were prepared to replicate Sanders type 2-B fracture, with central bone loss and comminution. 0.5cm medial wedge of the calcaneal tuberosity was removed to create varus instability. After stabilising posterior facet with a single 4mm partial threaded screw, and applied an 8 hole contoured plate to stabilise the angle of Gissane, inserted one or two 7mm cannulated partially threaded Charlotte™ (Wright Medical Technology, Inc. 5677 Airline Road Arlington, TN) Headless Multi-use Compression (under image guidance) extra screws to control varus and subsidence deformity of the fracture. Coronal plane displacement of the dissociated calcaneal tuberosity fragment relative to the body when applying 5N, 10N and 20N force was measured in millimetres (mm).

RESULTS

2 screws inserted (one medial screw into the sustentaculum talus from inferior to superior and, one lateral screw into the long axis anterior process) provides the least displacement (0.88±0.390 at 5N and 1.7±1.251 at 20N) and the most stable construct (p<0.05) when compared to other configurations. A single medial screw into the sustentaculum tali (conf. 3) resulted in the least stable construct and most displacement (4.04±0.971 at 5N and 11.24±7.590 at 20N) (p<0.05).

CONCLUSION

This study demonstrates the optimal screw configuration to resist varus in calcaneal fractures using minimally invasive techniques. Optimal stability is achieved using 2 screws; one located along the long axis of the calcaneus (varus control) and the other placed in the short axis directed towards the posterior facet of the calcaneus (control varus and subsidence). Further cadaver research would help evaluate optimal screw placement in simulated fractures to further assess reproducibility.

Tennis elbow: A clinical review article

Lateral epicondylitis, or tennis elbow is a common condition that presents with pain and tenderness around the common extensor origin of the elbow. Tennis elbow is estimated to affect 1-3% of the adult population each year and is more common in the dominant arm. It is generally regarded as an overuse injury involving repeated wrist extension against resistance, although it can occur as an acute injury (trauma to the lateral elbow). Up to 50% of all tennis players develop symptoms due to various factors including poor swing technique the use of heavy racquet. It's also seen in labourers who utilise heavy tools or engage in repetitive gripping or lifting task. In this article, we discuss the existing literature in the field and the current thinking on optimum treatment modalities. We have reviewed the literature available on med line and have discussed the condition with our specialist colleagues in the field.

Adult respiratory distress syndrome

Adult respiratory distress syndrome (ARDS) has now been described as a sequela to such diverse conditions as burns, amniotic fluid embolism, acute pancreatitis, trauma, sepsis and damage as a result of elective surgery in general. Patients with ARDS require immediate intubation, with the average patient now being ventilated for between 8 and 11 days. While the acute management of ARDS is conducted by the critical care team, almost any surgical patient can be affected by the condition and we believe that it is important that a broader spectrum of hospital doctors gain an understanding of the nature of the pathology and its current treatment.

Adult respiratory distress syndrome

Adult respiratory distress syndrome (ARDS) has now been described as a sequela to such diverse conditions as burns, amniotic fluid embolism, acute pancreatitis, trauma, sepsis and damage as a result of elective surgery in general. Patients with ARDS require immediate intubation, with the average patient now being ventilated for between 8 and 11 days. While the acute management of ARDS is conducted by the critical care team, almost any surgical patient can be affected by the condition and we believe that it is important that a broader spectrum of hospital doctors gain an understanding of the nature of the pathology and its current treatment.

Plantar fasciitis

INTRODUCTION

In this article we look at the aetiology of plantar fasciitis, the other common differentials for heel pain and the evidence available to support each of the major management options. We also review the literature and discuss the condition.

METHODS

A literature search was performed using PubMed and MEDLINE®. The following keywords were used, singly or in combination: ‘plantar fasciitis’, ‘plantar heel pain’, ‘heel spur’. To maximise the search, backward chaining of reference lists from retrieved papers was also undertaken.

FINDINGS

Plantar fasciitis is a common and often disabling condition. Because the natural history of plantar fasciitis is not understood, it is difficult to distinguish between those patients who recover spontaneously and those who respond to formal treatment. Surgical release of the plantar fascia is effective in the small proportion of patients who do not respond to conservative measures. New techniques such as endoscopic plantar release and extracorporeal shockwave therapy may have a role but the limited availability of equipment and skills means that most patients will continue to be treated by more traditional techniques.

Fascia iliaca compartment block reduces morphine requirement pre-operatively for patients with fractured neck of femur

INTRODUCTION

Fascia iliaca compartment block, performed in the emergency department (A&E) in patients presenting with femoral neck fracture, has gained increasing recognition as an adjunctive analgesic. The purpose of this study was to investigate whether fascia iliaca block (FIB) significantly reduced the requirement for systemic opiates in the pre-operative setting.

MATERIALS AND METHODS

Analgesia requirements for all patients admitted with fractured neck of femur to one unit over a 9-month period were gathered prospectively. Fifty percent of patients had received FIB at diagnosis in the A&E, dependant on the expertise of the attending physician. Morphine administration between groups was analysed.

RESULTS

Over a 9-month period, 286 patients with complete documentation were admitted with fractured neck of femur. At the start of the study, an informal education programme in A&E was introduced, increasing the incidence of FIB provision at diagnosis (p = <0.0001, Fisher's exact test) and reducing the average amount of morphine administered (p = 0.027, linear regression analysis). The administration of FIB reduced the average morphine requirement for a patient in A&E by 41 % when compared with those who received systemic analgesia alone (p = 0.018, Mann-Whitney test). No adverse effects were reported with FIB.

CONCLUSION

Fascia iliaca compartment block is a safe and effective method of providing analgesia to patients with fractured neck of femur and reduces morphine requirement.

Early failure modalities in hip resurfacing?

Between 1996 and 2002, we treated 60 patients (65 hips) by hip resurfacing. The notes and radiographs of these cases were studied retrospectively and the modalities of failure identified. At a mean follow-up of 51 months, 14 of these cases (22%) required revision surgery. One patient had died from unrelated causes and one was lost to follow-up. At the time of primary surgery, the mean age of the patients in our series was 55 years. The commonest mechanism of failure in our series was fractured neck of femur (six cases). Four of these occurred in females over the age of 60. None of the fractured necks of femur were associated with trauma. There were four cases of loose acetabular components and one case of progressive AVN (avascular necrosis). Two patients required revision surgery for ongoing hip pain and one required a twostage revision for early deep infection. (Hip International 2005; 15: 155-8).

Dopamine agonist activity of 8-OH-DPAT

We have investigated the effects of 8-OH-DPAT in the mouse isolated vas deferens preparation and found it to possess a biphasic (initial inhibition followed by potentiation) dose-response curve. The initial inhibitory phase of the dose-response curve was not antagonized by naltrexone (300 nM), idazoxan (300 nM) or propranolol (300 nM), indicating that neither opioid, alpha 2- nor beta-receptors were involved in the inhibition. (+/-)-Cyanopindolol (300 nM) was also devoid of any antagonist activity versus 8-OH-DPAT, showing that the effect of the compound is not due to 5-HT1A or 5-HT1B agonist activity. Domperidone (10 nM), fluphenthixol (30 nM) and sulpiride, three chemically dissimilar DA2 antagonists, all antagonized the effects of DPAT, indicating that the compound is acting as a dopamine agonist in this preparation. A comparison, in the same preparations, of the agonist effects of DPAT and apomorphine, showed that DPAT possesses ca 0.01 the potency of apomorphine. The dose-response curve produced by DPAT was much shallower than that produced by apomorphine, indicating that DPAT is only a partial agonist in this preparation. This was confirmed by subsequent experiments which showed that DPAT, at a concentration of 3 microM, which had no effect on dose-response curves to the opioid agonist normorphine, produced a ca 10-fold shift in the dose-response curve to dopamine.

Validation of the 30-item General Health Questionnaire in postpartum women

Two hundred consecutive women from five Southampton general practices who were between 8 and 14 weeks postpartum were visited at home. Each subject was given the 30-item General Health Questionnaire (GHQ-30) and a standardized psychiatric interview. Thirty-seven (18%) were identified as 'cases' by the psychiatric interview. Eighty-nine (44.5%) scored highly on the GHQ. Analysis of the results indicates that slight modification of the content and a raised cut-off point of the GHQ-30 make it a useful screening instrument for postpartum psychiatric disorder.