Preoperative Predictors of Postoperative Opioid Usage,Pain Scores,and Referral to a Pain Management Service in Total Knee Arthroplasty

Background

Little is known about preoperative predictors of postoperative pain and referral to a recuperative pain management service after total knee arthroplasty (TKA).

Questions/Purposes

We sought to identify the preoperative predictors of postoperative pain scores, referral to a pain management service, and narcotic usage in patients undergoing primary total knee arthroplasty.

Methods

We performed a prospective cohort study of 97 TKAs from a single surgeon. Pre and 6-week postoperative WOMAC, visual analog pain scale (VAS) scores, narcotic usage, and catastrophizing pain scores were collected.

Results

After adjusting for all other variables, higher age and catastrophizing pain scores were associated with lower odds of postoperative opioid usage. Increasing age and BMI were associated with lower odds of being referred to pain management. There was no relationship between self-reported preoperative pain tolerance and postoperative change in WOMAC or VAS pain scores.

Conclusions

This information may help surgeons advise their patients preoperatively and set expectations during the recovery period.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-014-9418-4) contains supplementary material, which is available to authorized users.     

Muscle thixotropy as a tool in the study of proprioception

When a muscle relaxes after a contraction, cross-bridges between actin and myosin in sarcomeres detach, but about 1 % spontaneously form new, non-force-generating attachments. These bridges give muscle its thixotropic property. They remain in place for long periods if the muscle is left undisturbed and give the muscle a passive stiffness in response to a stretch. They are detached by stretch, but reform at the new length. If the muscle is then shortened, the presence of these bridges prevents muscle fibres from shortening and they fall slack. So, resting muscle can be in one of two states, where it presents in response to a stretch with a high stiffness, if no slack is present, or with a compliant response in the presence of slack. Intrafusal fibres of muscle spindles show thixotropic behaviour. For spindles, after a conditioning contraction, they are left stretch sensitive, with a high level of background discharge. Alternatively, if after the contraction the muscle is shortened, intrafusal fibres fall slack, leaving spindles with a low level of background activity and insensitivity to stretch. Muscle spindles are receptors involved in the senses of human limb position and movement. The technique of muscle conditioning can be used to help understand the contribution of muscle spindles to these senses and how the brain interprets signals arising in spindles. When, in a two-arm position-matching task, elbow muscles of the two arms are deliberately conditioned in opposite ways, the blindfolded subject makes large position errors of which they are unaware. The evidence suggests that the brain is concerned with the difference signal coming from the antagonists acting at the elbow and with the overall difference in signal from the two arms. Another way of measuring position sense is to use a single arm and indicate its perceived position with a pointer. Here, there is no access to a signal from the other limb, and position sense relies on referral to a central map of the body, the postural schema.     

Fluoroquinolones and Tendinopathy: A Guide for Athletes and Sports Clinicians and a Systematic Review of the Literature

Context:

Fluoroquinolone antibiotics have been used for several decades and are effective antimicrobials. Despite their usefulness as antibiotics, a growing body of evidence has accumulated in the peer-reviewed literature that shows fluoroquinolones can cause pathologic lesions in tendon tissue (tendinopathy). These adverse effects can occur within hours of commencing treatment and months after discontinuing the use of these drugs. In some cases, fluoroquinolone usage can lead to complete rupture of the tendon and substantial subsequent disability.

Objective:

To discuss the cause, pharmacology, symptoms, and epidemiology of fluoroquinolone-associated tendinopathy and to discuss the clinical implications with respect to athletes and their subsequent physiotherapy.

Data Sources:

We searched MEDLINE, Cumulative Index to Nursing and Allied Health (CINAHL), Allied and Complementary Medicine Database (AMED), and SPORTDiscus databases for available reports of fluoroquinolone-related tendinopathy (tendinitis, tendon pain, or rupture) published from 1966 to 2012. Search terms were fluoroquinolones or quinolones and tendinopathy, adverse effects, and tendon rupture. Included studies were written in or translated into English. Non—English–language and non-English translations of abstracts from reports were not included (n = 1).

Study Selection:

Eligible studies were any available reports of fluoroquinolone-related tendinopathy (tendinitis, tendon pain, or rupture). Both animal and human histologic studies were included. Any papers not focusing on the tendon-related side effects of fluoroquinolones were excluded (n = 71).

Data Extraction:

Data collected included any cases of fluoroquinolone-related tendinopathy, the particular tendon affected, type of fluoroquinolone, dosage, and concomitant risk factors. Any data outlining the adverse histologic effects of fluoroquinolones also were collected.

Data Synthesis:

A total of 175 papers, including 89 case reports and 8 literature reviews, were identified.

Conclusions:

Fluoroquinolone tendinopathy may not respond well to the current popular eccentric training regimes and may require an alternative, staged treatment approach. Clinicians, athletes, athletic trainers, and their medical support teams should be aware of the need to discuss and possibly discontinue these antibiotics if adverse effects arise.Key Words: adverse effects, tendinitis, tendon rupture

Key Points:

• Tendinopathy can be a complication of treatment with fluoroquinolone antibiotics and usually is linked with 1 or more synergistic factors.
• Symptoms of fluoroquinolone-related tendinopathy can present within hours of starting treatment or up to 6 months after ceasing treatment, and recovery can be slower and require a less aggressive approach early in rehabilitation than for other types of tendinopathy.
• Treatment with fluoroquinolones should be discontinued and treatment with a nonquinolone antibiotic should be considered in patients who present with tendinopathy.
• Clinicians, athletes, athletic trainers, and medical support teams should be aware of and alert to the potential adverse effects of fluoroquinolones.

The ability of fluoroquinolone antibiotics to adversely affect tendons has been the subject of many articles and case reports in the medical literature for nearly 3 decades. Clinicians, patients, athletes, and athletic trainers should be aware of the potential risks that fluoroquinolones pose with respect to both cause and potentiation of tendinopathy, which is described as the clinical presentation of pain associated with tendon loading.¹ These drugs also can cause tendon rupture. Therefore, the purpose of this systematic review is to discuss the cause, pharmacology, symptoms, and epidemiology of fluoroquinolone-related tendinopathy. We also discuss the clinical implications of fluoroquinolone-related tendinopathy with respect to athletes and their subsequent physiotherapy, because this type of tendinopathy requires a different rehabilitation approach to tendinopathy that is not associated with fluoroquinolones.