Pain control using local anaesthetics to improve surgical results after shoulder, hip and knee replacement surgery

Review question

Doctors can use regional analgesia (injection of local anaesthetics near the nerves or the surgical site) rather than conventional pain control after surgery. Does this choice improve long-term function after elective major joint (knee, shoulder and hip) replacement? We conducted this systematic review to explore controversy about the use of regional analgesia amidst efforts to limit healthcare costs and demonstrate value for interventions.

Background

People undergo knee, shoulder and hip joint replacement to improve their mobility, pain and function. Local anaesthetics are injected near the nerves or the surgical site to decrease pain after surgery. Regional analgesia has been shown to lead to better surgical results (joint range of motion, strength, ability to walk, climb stairs, etc.) in the days immediately after surgery. It is unclear whether this effect lasts beyond three months.

Study characteristics

We searched electronic databases and abstracts for relevant studies. The search was last updated in June 2015. We found six studies, with 350 participants followed-up for at least three months. All of these studies enrolled participants undergoing knee replacement.

Key results

Because the studies did not report the same outcomes, it was difficult to pool the results. We could only pool three out of six randomized controlled trials studying regional anaesthesia for better function after total knee replacement. Pooling data from 140 participants, with range of motion assessed at three months after surgery, there was no statistically significant difference between the use of regional analgesia and conventional pain control with intravenous medications.

None of the included studies examined long-term adverse effects like persistent nerve damage.

Quality of the evidence

We deemed the quality of the evidence to be very low, as the included studies were not considered to be of high calibre and included few participants.

Conclusions

We do not have enough information to determine if regional anaesthesia improves function after major joint replacement or not. We need more and better clinical trials to decide whether there is an effect of regional analgesia on the surgical results after total shoulder, hip or knee replacement surgery. We need more research to understand if regional analgesia increases the risk of falls after joint replacement.

Authors' conclusions: 

More high-quality studies are needed to establish the effects of regional analgesia on function after major joint replacement, as well as on the risk of adverse events (falls).

Read the full abstract...
Background: 

Regional analgesia is more effective than conventional analgesia for controlling pain and may facilitate rehabilitation after large joint replacement in the short term. It remains unclear if regional anaesthesia improves functional outcomes after joint replacement beyond three months after surgery.

Objectives: 

To assess the effects of regional anaesthesia and analgesia on long-term functional outcomes 3, 6 and 12 months after elective major joint (knee, shoulder and hip) replacement surgery.

Search strategy: 

We performed an electronic search of several databases (CENTRAL, MEDLINE, EMBASE, CINAHL), and handsearched reference lists and conference abstracts. We updated our search in June 2015.

Selection criteria: 

We included randomized controlled trials (RCTs) comparing regional analgesia versus conventional analgesia in patients undergoing total shoulder, hip or knee replacement. We included studies that reported a functional outcome with a follow-up of at least three months after surgery.

Data collection and analysis: 

We used standard methodological procedures expected by Cochrane. We contacted study authors for additional information.

Main results: 

We included six studies with 350 participants followed for at least three months. All of these studies enrolled participants undergoing total knee replacement. Studies were at least partially blinded. Three studies had a high risk of performance bias and one a high risk of attrition bias, but the risk of bias was otherwise unclear or low.

Only one study assessed joint function using a global score. Due to heterogeneity in outcome and reporting, we could only pool three out of six RCTs, with range of motion assessed at three months after surgery used as a surrogate for joint function. All studies had a high risk of detection bias. Using the random-effects model, there was no statistically significant difference between the experimental and control groups (mean difference 3.99 degrees, 95% confidence interval (CI) − 2.23 to 10.21; P value = 0.21, 3 studies, 140 participants, very low quality evidence).

We did not perform further analyses because immediate adverse effects were not part of the explicit outcomes of any of these typically small studies, and long-term adverse events after regional anaesthesia are rare.

None of the included studies elicited or reported long-term adverse effects like persistent nerve damage.

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