Drug therapy forms an integral part of the management of many orthopaedic conditions. However, many medicines can produce serious adverse reactions if prescribed inappropriately, either alone or in combination with other drugs. Often these hazards are not appreciated. In response to this, the European Union recently issued legislation regarding safety measures which member states must adopt to minimise the risk of errors of medication.

In March 2014 the Medicines and Healthcare products Regulatory Agency and NHS England released a Patient Safety Alert initiative focussed on errors of medication. There have been similar initiatives in the United States under the auspices of The National Coordinating Council for Medication Error and The Joint Commission on the Accreditation of Healthcare Organizations. These initiatives have highlighted the importance of informing and educating clinicians.

Here, we discuss common drug interactions and contra-indications in orthopaedic practice. This is germane to safe and effective clinical care.

Cite this article: Bone Joint J 2015;97-B:434–41.

Recent recommendations by the National Institute for Health and Care Excellence (NICE) suggest that all patients undergoing elective orthopaedic surgery should be assessed for the risk of venous thromboembolism (VTE).

Little is known about the incidence of symptomatic VTE after elective external fixation. We studied a consecutive series of adult patients who had undergone elective Ilizarov surgery without routine pharmacological prophylaxis to establish the incidence of symptomatic VTE.

A review of a prospectively maintained database of consecutive patients who were treated between October 1998 and February 2011 identified 457 frames in 442 adults whose mean age was 42.6 years (16.0 to 84.6). There were 425 lower limb and 32 upper limb frames. The mean duration of treatment was 25.7 weeks (1.6 to 85.3).

According to NICE guidelines all the patients had at least one risk factor for VTE, 246 had two, 172 had three and 31 had four or more.

One patient (0.23%) developed a pulmonary embolus after surgery and was later found to have an inherited thrombophilia. There were 27 deaths, all unrelated to VTE.

The cost of providing VTE prophylaxis according to NICE guidelines in this group of patients would be £89 493.40 (£195.80 per patient) even if the cheapest recommended medication was used.

The rate of symptomatic VTE after Ilizarov surgery was low despite using no pharmacological prophylaxis. This study leads us to question whether NICE guidelines are applicable to these patients.

Cite this article: Bone Joint J 2014;96-B:426–30.

We performed a systematic review and meta-analysis to compare the efficacy of intermittent mechanical compression combined with pharmacological thromboprophylaxis, against either mechanical compression or pharmacological prophylaxis in preventing deep-vein thrombosis (DVT) and pulmonary embolism in patients undergoing hip or knee replacement. A total of six randomised controlled trials, evaluating a total of 1399 patients, were identified. In knee arthroplasty, the rate of DVT was reduced from 18.7% with anticoagulation alone to 3.7% with combined modalities (risk ratio (RR) 0.27, p = 0.03; number needed to treat: seven). There was moderate, albeit non-significant, heterogeneity (I² = 42%). In hip replacement, there was a non-significant reduction in DVT from 8.7% with mechanical compression alone to 7.2% with additional pharmacological prophylaxis (RR 0.84) and a significant reduction in DVT from 9.7% with anticoagulation alone to 0.9% with additional mechanical compression (RR 0.17, p < 0.001; number needed to treat: 12), with no heterogeneity (I² = 0%). The included studies had insufficient power to demonstrate an effect on pulmonary embolism.

We conclude that the addition of intermittent mechanical leg compression augments the efficacy of anticoagulation in preventing DVT in patients undergoing both knee and hip replacement. Further research on the role of combined modalities in thromboprophylaxis in joint replacement and in other high-risk situations, such as fracture of the hip, is warranted.

This study was undertaken to evaluate the safety and efficacy of retrievable inferior vena cava filters in high-risk orthopaedic patients. A total of 58 patients had a retrievable inferior vena cava filter placed as an adjunct to chemical and mechanical prophylaxis, most commonly for a history of previous deep-vein thrombosis or pulmonary embolism, polytrauma, or expected prolonged immobilisation. In total 56 patients (96.6%) had an uncomplicated post-operative course. Two patients (3.4%) died in the peri-operative period for unrelated reasons.

Of the 56 surviving patients, 50 (89%) were available for follow-up. A total of 32 filters (64%) were removed without complication at a mean of 37.8 days (4 to 238) after placement. There were four filters (8%) which were retained because of thrombosis at the filter site, and four (8%) were retained because of incorporation of the filter into the wall of the inferior vena cava. In ten cases (20%) the retrievable filter was left in place to continue as primary prophylaxis. No patient had post-removal thromboembolic complications.

A retrievable inferior vena cava filter, as an adjunct to chemical and mechanical prophylaxis, was a safe and effective means of reducing the acute risk of pulmonary embolism in this high-risk group of patients. Although most filters were removed without complications, thereby avoiding the long-term complications that have plagued permanent indwelling filters, a relatively high percentage of filters had to be left in situ.

Over a 13-year period we studied all patients who underwent major hip and knee surgery and were diagnosed with objectively confirmed symptomatic venous thromboembolism, either deep venous thrombosis or non-fatal pulmonary embolism, within six months after surgery. Low-molecular-weight heparin had been given while the patients were in hospital.

There were 5607 patients. The cumulative incidence of symptomatic venous thromboembolism was 2.7% (150 of 5607), of which 1.1% had developed pulmonary embolism, 1.5% had deep venous thrombosis and 0.6% had both. Patients presented with deep venous thrombosis at a median of 24 days and pulmonary embolism at 17 days after surgery for hip fracture. After total hip replacement, deep venous thrombosis and pulmonary embolism occurred at a median of 21 and 34 days respectively. After total knee replacement, the median time to the presentation of deep venous thrombosis and pulmonary embolism was 20 and 12 days respectively. The cumulative risk of venous thromboembolism lasted for up to three months after hip surgery and for one month after total knee replacement. Venous thromboembolism was diagnosed after discharge from hospital in 70% of patients who developed this complication.

Despite hospital-based thromboprophylaxis, most cases of clinical venous thromboembolism occur after discharge and at different times according to the operation performed.

The risk of venous thromboembolism in patients following arthroplasty may be reduced by continuing chemical thromboprophylaxis for up to 35 days post-operatively. This prospective cohort study investigated the compliance of 40 consecutive consenting patients undergoing lower limb arthroplasty with self-administration of a recommended subcutaneous chemotherapeutic agent for six weeks after surgery. Compliance was assessed by examination of the patient for signs of injection, number of syringes used, and a self-report diary at the end of the six-week period. A total of 40 patients, 15 men and 25 women, were recruited. One woman was excluded because immediate post-operative complications prevented her participation. Self-administration was considered feasible in 87% of patients (95% confidence interval (CI) 76 to 98) at the time of discharge. Among this group of 34 patients, 29 (85%) were compliant (95% CI 73 to 97). Patients can learn to self-administer subcutaneous injections of thromboprophylaxis, and compliance with extended prophylaxis to six weeks is good.