The outcomes of acute periprosthetic joint infection following unicompartmental knee replacement managed with early debridement, Antibiotics, and implant retention

BACKGROUND

Periprosthetic joint infection (PJI) following unicompartmental knee replacement (UKR) is an uncommon, yet serious, complication. There is a paucity of evidence regarding the effectiveness of Debridement-Antibiotics-and-Implant-Retention (DAIR) in this setting. The aim of this study is to investigate the effectiveness of DAIR for acute UKR PJI.

METHOD

Between 2006 and 2019, 5195 UKR were performed at our institution. Over this period, sixteen patients underwent DAIR for early, acute PJI. All patients met MSIS PJI diagnostic criteria. The median age at DAIR was 67 years (range 40-73) and 12 patients were male (75.0%). The median time to DAIR was 24 days (range 6-60). Patients were followed up for a median of 6.5 years (range1.4-10.5) following DAIR.

RESULTS

0.3% (16/5195) of UKR in our institution had a DAIR within 3 months. 15 of 16 patients (93.8%) were culture positive, with the most common organism MSSA (n = 8, 50.0%). Patients were treated with an organism-specific intravenous antibiotic regime for a median of 6 weeks, followed by oral antibiotics for a median duration of 6 months. The Kaplan-Meier survivor estimate for revision for PJI was 57% (95%CI: 28-78%) at five years, and survivor estimate for all cause revision 52% (95%CI: 25-74%).The median Oxford Knee Score for patients with a viable implant at final follow-up was 45 points (range 39-46).

CONCLUSION

Early, acute PJI after UKR is rare. DAIR had a moderate success rate, with infection-free survivorship of 57% at 5 years. Those successfully treated with DAIR had excellent functional outcome and implant survival.

Indications and techniques for non-articulating spacers in massive bone loss following prosthetic knee joint infection: a scoping review

INTRODUCTION

Prosthetic joint infection (PJI) is a destructive complication of knee replacement surgery (KR). In two-stage revision a spacer is required to maintain limb length and alignment and provide a stable limb on which to mobilise. Spacers may be articulating or static with the gold standard spacer yet to be defined. The aims of this scoping review were to summarise the types of static spacer used to treat PJI after KR, their indications for use and early complication rates.

METHODS

We conducted a scoping review based on the Joanna Briggs Institute's "JBI Manual for Evidence Synthesis" Scoping review reported following Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. MEDLINE, EMBASE and CINAHL were searched from 2005 to 2022 for studies on the use of static spacers for PJI after KR.

RESULTS

41 studies (1230 patients/knees) were identified describing 42 static spacer constructs. Twenty-three (23/42 [54.2%]) incorporated cement augmented with metalwork, while nineteen (19/42, [45.9%]) were made of cement alone. Spacers were most frequently anchored in the diaphysis (22/42, [53.3%]), particularly in the setting of extensive bone loss (mean AORI Type = F3/T3; 11/15 studies 78.3% diaphyseal anchoring). 7.1% (79 of 1117 knees) of static spacers had a complication requiring further surgery prior to planned second stage with the most common complication being infection (86.1%).

CONCLUSIONS

This study has summarised the large variety in static spacer constructs used for staged revision KR for PJI. Static spacers were associated with a high risk of complications and further work in this area is required to improve the quality of care in this vulnerable group.

Patient-relevant outcomes following elective, aseptic revision knee arthroplasty: a systematic review

BACKGROUND

The aim of this systematic review was to summarise the evidence for the clinical effectiveness of revision knee arthroplasty (rKA) compared to non-operative treatment for the management of patients with elective, aseptic causes for a failed knee arthroplasty.

METHODS

MEDLINE, Embase, AMED and PsychINFO were searched from inception to 1st December 2020 for studies on patients considering elective, aseptic rKA. Patient-relevant outcomes (PROs) were defined as implant survivorship, joint function, quality of life (QoL), complications and hospital admission impact.

RESULTS

No studies compared elective, aseptic rKA to non-operative management. Forty uncontrolled studies reported on PROs following elective, aseptic rKA (434434 rKA). Pooled estimates for implant survivorship were: 95.5% (95% CI 93.2-97.7%) at 1 year [seven studies (5524 rKA)], 90.8% (95% CI 87.6-94.0%) at 5 years [13 studies (5754 rKA)], 87.4% (95% CI 81.7-93.1%) at 10 years [nine studies (2188 rKA)], and 83.2% (95% CI 76.7-89.7%) at 15 years [two studies (452 rKA)]. Twelve studies (2382 rKA) reported joint function and/or QoL: all found large improvements from baseline to follow-up. Mortality rates were low (0.16% to 2% within 1 year) [four studies (353064 rKA)]. Post-operative complications were common (9.1 to 37.2% at 90 days).

CONCLUSION

Higher-quality evidence is needed to support patients with decision-making in elective, aseptic rKA. This should include studies comparing operative and non-operative management. Implant survivorship following elective, aseptic rKA was ~ 96% at 1 year, ~ 91% at 5 years and ~ 87% at 10 years. Early complications were common after elective, aseptic rKA and the rates summarised here can be shared with patients during informed consent.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020196922.

Preoperative Severe Acute Respiratory Syndrome Coronavirus 2 Polymerase Chain Reaction Test at Between 48 and 72 Hours Preoperatively is Safe for Patients Undergoing Primary and Revision Hip and Knee Arthroplasty: A Multicentre International Study

BACKGROUND

Patients undergoing lower limb arthroplasty who are severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive at the time of surgery have a high risk of mortality. The National Institute for Health and Clinical Care Excellence and the British Orthopaedic Association advise self-isolation for 14 days preoperatively in patients at a high risk of adverse outcomes due to COVID-19. The aim of the study is to assess whether preoperative polymerase chain reaction (PCR) for SARS-CoV-2 could be performed at between 48 and 72 hours preoperatively with specific advice about minimizing the risk of SARS-CoV-2 restricted to between PCR and admission.

METHODS

A multicentre, international, observational cohort study of 1,000 lower limb arthroplasty cases was performed. The dual primary outcomes were 30-day conversion to SARS-CoV-2 positive and 30-day SARS-CoV-2 mortality. Secondary outcomes included 30-day SARS-CoV-2 morbidity.

RESULTS

Of the 1,000 cases, 935 (94%) had a PCR between 48 and 72 hours preoperatively. All cases were admitted to and had surgery through a COVID-free pathway. Primary knee arthroplasty was performed in 41% of cases, primary hip arthroplasty in 40%, revision knee arthroplasty in 11%, and revision hip arthroplasty in 9%. Six percent of operations were emergency operations. No cases of SARS-CoV-2 were identified within the first 30 days.

CONCLUSION

Preoperative SARS-CoV-2 PCR test between 48 and 72 hours preoperatively with advice about minimizing the risk of SARS-CoV-2 restricted to between PCR and admission in conjunction with a COVID-free pathway is safe for patients undergoing primary and revision hip and knee arthroplasty. Preoperative SARS-CoV-2 PCR test alone may be safe but further adequately powered studies are required. This information is important for shared decision making with patients during the current pandemic.

Efficacy of Liposomal Bupivacaine and Bupivacaine Hydrochloride vs Bupivacaine Hydrochloride Alone as a Periarticular Anesthetic for Patients Undergoing Knee Replacement: A Randomized Clinical Trial

Question

Among patients undergoing knee replacement surgery, does liposomal bupivacaine and bupivacaine hydrochloride administered at the surgical site improve postoperative recovery at 72 hours and postoperative pain from 6 to 72 hours compared with bupivacaine hydrochloride alone?

Findings

In this randomized clinical trial of 533 patients undergoing knee replacement surgery, no difference in the coprimary outcomes of Quality of Recovery 40 score at 72 hours or pain visual analog scale score area under the curve from 6 to 72 hours was detected between patients receiving liposomal bupivacaine and bupivacaine hydrochloride and those receiving bupivacaine hydrochloride alone. In addition, liposomal bupivacaine was not found to be cost-effective.

Meaning

This study found that liposomal bupivacaine did not improve postoperative recovery or pain compared with bupivacaine hydrochloride alone among patients undergoing knee replacement surgery.

Importance

More than half of patients who undergo knee replacement surgery report substantial acute postoperative pain.

Objective

To evaluate the efficacy and cost-effectiveness of periarticular liposomal bupivacaine for recovery and pain management after knee replacement.

Design, Setting, and Participants

This multicenter, patient-blinded, pragmatic, randomized clinical superiority trial involved 533 participants at 11 institutions within the National Health Service in England. Adults undergoing primary unilateral knee replacement for symptomatic end-stage osteoarthritis were enrolled between March 29, 2018, and February 29, 2020, and followed up for 1 year after surgery. Follow-up was completed March 1, 2021. A per-protocol analysis for each coprimary outcome was performed in addition to the main intention-to-treat analysis.

Interventions

Two hundred sixty-six milligrams of liposomal bupivacaine admixed with 100 mg of bupivacaine hydrochloride compared with 100 mg of bupivacaine hydrochloride alone (control) administered by periarticular injection at the time of surgery.

Main Outcome and Measures

The coprimary outcomes were Quality of Recovery 40 (QoR-40) score at 72 hours and pain visual analog scale (VAS) score area under the curve (AUC) from 6 to 72 hours. Secondary outcomes included QoR-40 and mean pain VAS at days 0 (evening of surgery), 1, 2, and 3; cumulative opioid consumption for 72 hours; functional outcomes and quality of life at 6 weeks, 6 months, and 1 year; and cost-effectiveness for 1 year. Adverse events and serious adverse events up to 12 months after randomization were also assessed.

Results

Among the 533 participants included in the analysis, the mean (SD) age was 69.0 (9.7) years; 287 patients were women (53.8%) and 246 were men (46.2%). Baseline characteristics were balanced between study groups. There was no difference between the liposomal bupivacaine and control groups in QoR-40 score at 72 hours (adjusted mean difference, 0.54 [97.5% CI, −2.05 to 3.13]; P = .64) or the pain VAS score AUC at 6 to 72 hours (−21.5 [97.5% CI, −46.8 to 3.8]; P = .06). Analyses of pain VAS and QoR-40 scores demonstrated only 1 statistically significant difference, with the liposomal bupivacaine arm having lower pain scores the evening of surgery (adjusted difference −0.54 [97.5% CI, −1.07 to −0.02]; P = .02). No difference in cumulative opioid consumption and functional outcomes was detected. Liposomal bupivacaine was not cost-effective compared with the control treatment. No difference in adverse or serious adverse events was found between the liposomal bupivacaine and control groups.

Conclusions and Relevance

This study found no difference in postoperative recovery or pain associated with the use of periarticular liposomal bupivacaine compared with bupivacaine hydrochloride alone in patients who underwent knee replacement surgery.

Trial Registration

isrctn.com Identifier: ISRCTN54191675

Systematic review and meta-analysis of bearing dislocation in lateral meniscal bearing unicompartmental knee replacement: Domed versus flat tibial surface

BACKGROUND

Bearing dislocation is a problem following mobile bearing Oxford lateral Unicompartmental Knee Replacement (UKR). Therefore, the design of the tibial component was changed from a flat tibial surface to a domed tibial surface with a biconcave bearing to increase bearing entrapment. This systematic review compared the dislocation and revision rates of the two designs.

METHODS

Two authors independently searched MEDLINE, EMBASE and ISI Web of Science, reference lists of retrieved articles, and the internet. Randomised, cohort, case-control and case studies of adult patients with lateral knee osteoarthritis treated with flat or domed Oxford lateral UKR and their outcomes were included. The overall dislocation rate and the annual revision rate (per 100 component years) were determined.

RESULTS

Nine studies (937 knees) met the inclusion criteria (3 flat, 6 domed). Four studies (all domed) had a low risk of bias and five had a high risk (3 flat, 2 domed), so data should be interpreted with caution. The bearing dislocation rate decreased from 17% (flat) to 3.7% (domed). Dislocations occurred on average at 16 months and medial dislocations were most common. The revision rate excluding dislocation decreased from 1.1%pa to 0.7%pa. PROSPERO registration: CRD42019139250.

CONCLUSION

Modifying the tibial component from a flat to a domed shape decreased the bearing dislocation rate to 3.7% and increased the 10 year survival rate excluding dislocation to 93%. The dislocation rate is still relatively high so bearing stability should be assessed intra-operatively and if unacceptable, a fixed bearing version of the Oxford lateral tibial component can be inserted.

30-day outcome after orthopaedic surgery in patients assessed as negative for COVID-19 at the time of surgery during the peak of the pandemic

INTRODUCTION

The aim of this study is to report the 30 day COVID-19 related morbidity and mortality of patients assessed as SARS-CoV-2 negative who underwent emergency or urgent orthopaedic surgery in the NHS during the peak of the COVID-19 pandemic.

METHOD

A retrospective, single centre, observational cohort study of all patients undergoing surgery between 17 March 2020 and 3May 2020 was performed. Outcomes were stratified by British Orthopaedic Association COVID-19 Patient Risk Assessment Tool. Patients who were SARS-CoV-2 positive at the time of surgery were excluded.

RESULTS

Overall, 96 patients assessed as negative for SARS-CoV-2 at the time of surgery underwent 100 emergency or urgent orthopaedic procedures during the study period. Within 30 days of surgery 9.4% of patients (n = 9) were found to be SARS-CoV-2 positive by nasopharyngeal swab. The overall 30 day mortality rate across the whole cohort of patients during this period was 3% (n = 3). Of those testing positive for SARS-CoV-2 66% (n = 6) developed significant COVID-19 related complications and there was a 33% 30-day mortality rate (n = 3). Overall, the 30-day mortality in patients classified as BOA low or medium risk (n = 69) was 0%, whereas in those classified as high or very high risk (n = 27) it was 11.1%.

CONCLUSION

Orthopaedic surgery in SARS-CoV-2 negative patients who transition to positive within 30 days of surgery carries a significant risk of morbidity and mortality. In lower risk groups, the overall risk of becoming SARS-CoV-2 positive, and subsequently developing a significant postoperative related complication, was low even during the peak of the pandemic. In addition to ensuring patients are SARS-CoV-2 negative at the time of surgery it is important that the risk of acquiring SARS-CoV-2 is minimized through their recovery.Cite this article: Bone Joint Open 2020;1-8:474-480.

Threshold for Computer- and Robot-Assisted Knee and Hip Replacements in the English National Health Service

OBJECTIVES

To estimate threshold prices for computer- and robot-assisted knee and hip replacement.

METHODS

A lifetime cohort Markov model provided the framework for analysis. Linked primary care and inpatient hospital records informed estimates of outcomes under current practice. Outcomes were estimated under a range of hypothetical relative improvements in quality of life if unrevised and in revision risk after computer or robot-assisted surgery. Threshold prices, a price at which the net health benefit from funding the intervention would be zero, for these improvements were estimated for a cost-effectiveness threshold of £20 000 per additional quality-adjusted life-year (QALY) gained.

RESULTS

For average patient profiles under current knee and hip replacement practice, lifetime QALYs were 10.3 (9.9 to 10.7) and 11.0 (10.6 to 11.4), with costs of £6060 (£5947 to £6203) and £6506 (£6335 to £6710) for knee and hip replacement, respectively. A combined 50% relative reduction in risk of revision and 5% improvement in postoperative quality of life if unrevised would, for example, result in QALYs increasing to 10.9 (10.4 to 11.3) and 11.6 (11.2 to 12.0), and costs falling to £5880 (£5816 to £5956) and £6258 (£6149 to £6376) after knee and hip replacement, respectively. These particular improvements would have an associated threshold price of £11 182 (£10 691 to £11 721) for knee replacement and £12 134 (£11 616 to £12 701) for hip replacement. The 50% reduction in revision rate alone would have associated threshold prices of £1094 (£788 to £1488) and £1347 (£961 to £1842), and the 5% improvement in quality of life alone would have associated threshold prices of £9911 (£9476 to £10 296) and £10 578 (£10 171 to £10 982).

CONCLUSIONS

At current prices, computer- and robot-assisted knee and hip replacement will likely need to lead to improvements in patient-reported outcomes in addition to any reduction in the risk revision.

Candidacy for medial unicompartmental knee replacement declines with age

BACKGROUND

The effect of age on the percentage of primary knee replacements appropriate for unicompartmental replacement (UKR), defined as candidacy, is unknown. The aim was to determine the candidacy and outcome of UKR in different age groups.

HYPOTHESIS

Age is associated with candidacy for medial UKR.

PATIENTS AND METHODS

This cross-sectional study determined UKR candidacy from preoperative radiographs, including stress views, from 457 consecutive knee replacements (TKR or UKR) in a specialist joint replacement centre. Candidacy, estimated from radiographs and from usage, was determined for all knees and then stratified by age group<50, 50-60, 60-70, 70-80, and 80+. The outcome of UKR implanted in these groups was also assessed. To avoid overestimating, candidacy estimated by usage was used for the primary analysis.

RESULTS

Candidacy decreased with age (OR 0.98, p=0.008) and was 61% (CI 42-78), 52% (CI 43-61), 43% (CI 35-51), 41% (CI 31-52), and 36% (CI 22-52) respectively. Candidacy estimated by radiographs was slightly higher overall (49% compared to 46%) and in all age groups than candidacy estimated from usage. Neither functional outcome (p=0.47) nor implant survival (p=0.54) was affected by age. Overall 80% achieved good/excellent Knee Society objective scores, and the five-year implant survival was 99%.

DISCUSSION

There is a strong association of candidacy for UKR with age in that younger patients are more likely to be candidates (61% in those<50 and 36% in those 80+). Good outcomes can be expected in patients of all ages who are appropriate for UKR.

LEVEL OF EVIDENCE

IV, Prognostic cross-sectional study.

Is Knee Joint Distraction a Viable Treatment Option for Knee OA?-A Literature Review and Meta-Analysis

Knee joint distraction (KJD) is a new application of an established technique to regenerate native cartilage using an external fixator. The purpose of this study is to perform a systematic review and meta-analysis of the literature to determine whether KJD is beneficial for knee osteoarthritis and how results compare with established treatments. Studies assessing the outcomes of KJD were retrieved, with three studies (one cohort and two randomized controlled trials), 62 knees, meeting the inclusion criteria. The primary outcome was functional outcome, assessed using a validated outcome score, at 1 year. Secondary outcomes included pain scores, structural assessment of the joint, and adverse events. KJD is associated with improvements in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) from baseline to 1 year as well as reductions in pain scores and improvements in structural parameters assessed radiographically and by magnetic resonance imaging. KJD is not associated with decreased knee flexion, but is associated with a high risk of pin site infection. In patients aged 65 years or under at 1 year, no differences in WOMAC or pain scores was detected between patients managed with KJD compared with high tibial osteotomy or total knee arthroplasty. KJD may represent a potential treatment for knee arthritis, though further trials with longer term follow-up are required to establish its efficacy compared with contemporary treatments. This is a Level I (systematic review and meta-analysis) study.

Upper tibial MRI vascular marks lost in early knee osteoarthritis

Background

We describe upper tibial radiating vascular marks on MRI scans. They are lost in early osteoarthritis (OA).

Methods

A literature search revealed no previous description of upper tibial MRI radial vascular marks. Fifty-six consecutive patients with anteroposterior knee X-rays and an axial PD_SPAIR MRI scan of the same knee within 1 year were studied. Their mean age was 53.1 years (range 22–85) with 27 males and 29 females. The medial and lateral compartments of each knee were scored for osteoarthritis using the Kellgren-Lawrence (K-L) classification. Marks on the MRI scans were counted by layer and quadrant position.

Results

Radial vascular marks were present in the first axial upper tibial subchondral slice, peaked between 6 and 10 mm depth and were absent by 16 mm depth. There was no association with age, left or right knee, BMI, or weight. There was more K-L graded OA medially and more vascular marks laterally. There was an inverse correlation between the number of marks and early grades of osteoarthritis medially (p < 0.001) and laterally (p < 0.002).

Conclusion

We demonstrate previously undescribed subchondral vascular marks on axial MRI scans of the tibia and their inverse correlation with the presence and severity of early knee osteoarthritis. Our work offers a new insight into the possible vascular aetiology of osteoarthritis and potentially a means of earlier diagnosis and a therapeutic target.

Age and Outcomes of Medial Meniscal-Bearing Unicompartmental Knee Arthroplasty

BACKGROUND

National joint registries report increasing revision rates with decreasing patient age for all types of joint arthroplasty. This study aimed to explore the effect of age on function and revision risk in patients undergoing medial meniscal-bearing UKA.

METHODS

A prospectively followed cohort of 1000 consecutive medial meniscal-bearing UKAs at a designer center was analyzed. All knees were implanted for recommended indications and had mean 10-year follow-up. Patients were grouped by age at surgery (<55, 55 to <65, 65 to <75, 75+). Oxford Knee Scores (OKS) were assessed at 5 and 10 years. Component-time revision incidence rates and Kaplan-Meier implant survival were calculated.

RESULTS

Mean patient age at surgery was 66.6 years (range, 33-88). All age-groups had significant (P < .001) improvement in OKS over time, and at 5 years achieved a median OKS of 44. At 10 years, median OKS, from youngest group to eldest, were 44, 45, 42, and 39, with the eldest group having a significantly lower OKS (P < .01). Ten-year implant survival rates were 97%, 94%, 94%, and 93%, respectively, and was not significantly associated with age at UKA.

CONCLUSION

Medial meniscal-bearing UKA provides good functional outcomes in all age-groups; however, in older patients (75+), the functional outcome deteriorated at 10 years presumably due to deteriorating health. Contrary to registry observations, the revision rate was not higher in younger patients. These results suggest that, with correct indications, patient age should not be considered a contraindication to medial meniscal-bearing UKA.

Cost-effectiveness of unicompartmental compared with total knee replacement: a population-based study using data from the National Joint Registry for England and Wales

OBJECTIVES

To assess the value for money of unicompartmental knee replacement (UKR) compared with total knee replacement (TKR).

DESIGN

A lifetime Markov model provided the framework for the analysis.

SETTING

Data from the National Joint Registry (NJR) for England and Wales primarily informed the analysis.

PARTICIPANTS

Propensity score matched patients in the NJR who received either a UKR or TKR.

INTERVENTIONS

UKR is a less invasive alternative to TKR, where only the compartment affected by osteoarthritis is replaced.

PRIMARY OUTCOME MEASURES

Incremental quality-adjusted life years (QALYs) and healthcare system costs.

RESULTS

The provision of UKR is expected to lead to a gain in QALYs compared with TKR for all age and gender subgroups (male: <60 years: 0.12, 60-75 years: 0.20, 75+ years: 0.19; female: <60 years: 0.10, 60-75 years: 0.28, 75+ years: 0.44) and a reduction in costs (male: <60: £-1223, 60-75 years: £-1355, 75+ years: £-2005; female: <60 years: £-601, 60-75 years: £-935, 75+ years: £-1102 per patient over the lifetime). UKR is expected to lead to a reduction in QALYs compared with TKR when performed by surgeons with low UKR utilisation but an increase among those with high utilisation (<10%, median 6%: -0.04, ≥10%, median 27%: 0.26). Regardless of surgeon usage, costs associated with UKR are expected to be lower than those of TKR (<10%: £-127, ≥10%: £-758).

CONCLUSIONS

UKR can be expected to generate better health outcomes and lower lifetime costs than TKR. Surgeon usage of UKR does, however, have a significant impact on the cost-effectiveness of the procedure. To achieve the best results, surgeons need to perform a sufficient proportion of knee replacements as UKR. Low usage surgeons may therefore need to broaden their indications for UKR.

Perioperative adjuvant corticosteroids for postoperative analgesia in knee arthroplasty

Background and purpose - Immediate postoperative pain management offered in knee arthroplasty is suboptimal in up to one-third of patients resulting in high opiate consumption and delayed discharge. In this meta-analysis we investigate the analgesic effect and safety of perioperative adjuvant corticosteroids in knee arthroplasty. Methods - Databases Medline, Embase, and Central were searched for randomized studies comparing the analgesic effect of adjuvant perioperative corticosteroids in knee arthroplasty. Our primary outcome was pain score at 24 hours postoperatively. Secondary outcomes included pain at 12, 48, and 72 hours, opiate consumption, postoperative nausea and vomiting, infection, and discharge time. Systemic (intravenous) and local (intra-articular) corticosteroids were analyzed separately. Results - 14 randomized controlled trials (1,396 knees) were included. Mean corticosteroid dosages were predominantly 50-75mg oral prednisolone equivalents for both systemic and local routes. Systemic corticosteroids demonstrated statistically significant and clinically modest reductions in pain at 12 hours by -1.1 points (95%CI -2.2 to 0.02), 24 hours by -1.3 points (CI -2.3 to -0.26) and 48 hours by -0.4 points (CI -0.67 to -0.04). Local corticosteroids did not reduce pain. Opiate consumption, postoperative nausea and vomiting, infection, or time till discharge were similar between groups. Interpretation - Corticosteroids modestly reduce pain postoperatively at 12 and 24 hours when used systemically without any increase in associated risks for dosages between 50 and 75 mg oral prednisolone equivalents.

Long-term outcomes of over 8,000 medial Oxford Phase 3 Unicompartmental Knees-a systematic review

Background and purpose - There is debate as to the relative merits of unicompartmental and total knee arthroplasty (UKA, TKA). Although the designer surgeons have achieved good results with the Oxford UKA there is concern over the reproducibility of these outcomes. Therefore, we evaluated published long-term outcomes of the Oxford Phase 3 UKA. Patients and methods - We searched databases to identify studies reporting ≥10 year outcomes of the medial Oxford Phase 3 UKA. Revision, non-revision, and re-operation rates were calculated per 100 component years (% pa). Results - 15 studies with 8,658 knees were included. The annual revision rate was 0.74% pa (95% CI 0.67-0.81, n = 8,406) corresponding to a 10-year survival of 93% and 15-year survival of 89%. The non-revision re-operation rate was 0.19% pa (95% CI 0.13-0.25, n = 3,482). The re-operation rate was 0.89% pa (95% CI 0.77-1.02, n = 3,482). The most common causes of revision were lateral disease progression (1.42%), aseptic loosening (1.25%), bearing dislocation (0.58%), and pain (0.57%) (n = 8,658). Average OKS scores were 40 at 10 years (n = 3,417). The incidence of medical complications was 0.83% (n = 1,443). Interpretation - Very good outcomes were achieved by both designer and non-designer surgeons. The PROMs, medical complication rate, and non-revision re-operation rate were better than those found in meta-analyses and publications for TKA but the revision rate was higher. However, if failure is considered to be all re-operations and not just revisions, then the failure rate of UKA was less than that of TKA.

Ten-year patient-reported outcomes following total and minimally invasive unicompartmental knee arthroplasty: a propensity score-matched cohort analysis

PURPOSE

For patients with medial compartment arthritis who have failed non-operative treatment, either a total knee arthroplasty (TKA) or a unicompartmental knee arthroplasty (UKA) can be undertaken. This analysis considers how the choice between UKA and TKA affects long-term patient-reported outcome measures (PROMs).

METHODS

The Knee Arthroplasty Trial (KAT) and a cohort of patients who received a minimally invasive UKA provided data. Propensity score matching was used to identify comparable patients. Oxford Knee Score (OKS), its pain and function components, and the EuroQol 5 Domain (EQ-5D) index, estimated on the basis of OKS responses, were then compared over 10 years following surgery. Mixed-effects regressions for repeated measures were used to estimate the effect of patient characteristics and type of surgery on PROMs.

RESULTS

Five-hundred and ninety UKAs were matched to the same number of TKAs. Receiving UKA rather than TKA was found to be associated with better scores for OKS, including both its pain and function components, and EQ-5D, with the differences expected to grow over time. UKA was also associated with an increased likelihood of patients achieving a successful outcome, with an increased chance of attaining minimally clinically important improvements in both OKS and EQ-5D, and an 'excellent' OKS. In addition, for both procedures, patients aged between 60 and 70 and better pre-operative scores were associated with better post-operative outcomes.

CONCLUSION

Minimally invasive UKAs performed on patients with the appropriate indications led to better patient-reported pain and function scores than TKAs performed on comparable patients. UKA can lead to better long-term quality of life than TKA and this should be considered alongside risk of revision when choosing between the procedures.

LEVEL OF EVIDENCE

II.

Early recovery following lower limb arthroplasty: Qualitative interviews with patients undergoing elective hip and knee replacement surgery. Initial phase in the development of a patient-reported outcome measure

AIMS AND OBJECTIVES

To explore the patients' perspective of surgery and early recovery when undergoing lower limb (hip or knee) arthroplasty.

BACKGROUND

Lower limb arthroplasty is a commonly performed procedure for symptomatic arthritis, which has not responded to conservative medical treatment. Each patient's perspective of the surgical process and early recovery period impacts on their quality of life.

DESIGN

Open, semistructured qualitative interviews were used to allow for a deeper understanding of the patient perspective when undergoing a hip or knee arthroplasty.

METHODS

Following ethical approval, 30 patients were interviewed between August and November 2016 during the perioperative period while undergoing an elective hip or knee arthroplasty (n = 30). The interviews were performed between the day of surgery and a nine-week postoperative clinic appointment. Data were analysed using an in-depth narrative thematic analysis method. NVivo qualitative data analysis software was used.

RESULTS

Seven main themes evolved from the interviews: "improving function and mobility", "pain", "experiences of health care", "support from others", "involvement and understanding of care decisions", "behaviour and coping" and "fatigue and sleeping".

CONCLUSIONS

The early postoperative recovery period is of vital importance to all surgical patients. This is no different for the orthopaedic patient. However, identifying key self-reported areas of importance from patients can guide clinical focus for healthcare professionals.

RELEVANCE TO CLINICAL PRACTICE

To have specific patient-reported information regarding key areas of importance during the perioperative phase is invaluable when caring for the orthopaedic surgical patient. It gives insight and understanding in to this increasing population group. This study has also served as a starting point in the development of a questionnaire which could be used to assess interventions in the lower limb arthroplasty population. These results will influence both items and content of the questionnaire.

Choosing Between Unicompartmental and Total Knee Replacement: What Can Economic Evaluations Tell Us? A Systematic Review

BACKGROUND AND OBJECTIVE

Patients with anteromedial arthritis who require a knee replacement could receive either a unicompartmental knee replacement (UKR) or a total knee replacement (TKR). This review has been undertaken to identify economic evaluations comparing UKR and TKR, evaluate the approaches that were taken in the studies, assess the quality of reporting of these evaluations, and consider what they can tell us about the relative value for money of the procedures.

METHODS

A search of MEDLINE, EMBASE and the Centre for Reviews and Dissemination National Health Service Economic Evaluation Database was undertaken in January 2016 to identify relevant studies. Study characteristics were described, the quality of reporting and methods assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist, and study findings summarised.

RESULTS

Twelve studies satisfied the inclusion criteria. Five were within-study analyses, while another was based on a literature review. The remaining six studies were model-based analyses. All studies were informed by observational data. While methodological approaches varied, studies generally had either limited follow-up, did not fully account for baseline differences in patient characteristics or relied on previous research that did not. The quality of reporting was generally adequate across studies, except for considerations of the settings to which evaluations applied and the generalisability of the results to other decision-making contexts. In the short-term, UKR was generally associated with better health outcomes and lower costs than TKR. Initial cost savings associated with UKR seem to persist over patients' lifetimes even after accounting for higher rates of revision. For older patients, initial health improvements also appear to be maintained, making UKR the dominant treatment choice. However, for younger patients findings for health outcomes and overall cost effectiveness are mixed, with the difference in health outcomes depending on the lifetime risk of revision and patient outcomes following revision.

CONCLUSIONS

UKR appears to be less costly than TKR. For older patients, UKR is also expected to lead to better health outcomes, making it the dominant choice; however, for younger patients health outcomes are more uncertain. Future research should better account for baseline differences in patient characteristics and consider how the relative value of UKR and TKR varies depending on patient and surgical factors.

The Interaction of Caseload and Usage in Determining Outcomes of Unicompartmental Knee Arthroplasty: A Meta-Analysis

BACKGROUND

Outcomes after unicompartmental knee arthroplasty (UKA) are variable and influenced by caseload (UKA/y) and usage (percentage of knee arthroplasty that are UKA), which relates to indications. This meta-analysis assesses the relative importance of these factors.

METHODS

MEDLINE (Ovid), Embase (Ovid), and Web of Science (ISI) were searched for consecutive series of cemented Phase 3 Oxford medial UKA. The primary outcome was revision rate/100 observed component years (% pa) with subgroup analysis based on caseload and usage.

RESULTS

Forty-six studies (12,520 knees) with an annual revision-rate ranging from 0% to 4.35% pa, mean 1.21% pa (95% confidence interval [CI], 0.97-1.47), were identified. In series with mean follow-up of 10-years, the revision-rate was 0.63% pa (95% CI, 0.46-0.83), equating to a 94% (95% CI, 92%-95%) 10-year survival. Aseptic loosening, lateral arthritis, bearing dislocation, and unexplained pain were the predominant failure mechanisms with revision for patellofemoral problems and polyethylene wear exceedingly rare. The lowest revision-rates were achieved with caseload >24 UKA/y (0.88% pa; 95% CI, 0.63-1.61) and usage >30% (0.69% pa; 95% CI, 0.50-0.90). Usage was more important than caseload; with high usage (≥20%), the revision-rate was low, whether the caseload was high (>12 UKA/y) or low (≤12 UKA/y; (0.94% pa; 95% CI, 0.69-1.23 and 0.85% pa; 95% CI, 0.65-1.08), respectively); with low usage (<20%), the revision-rate was high, whether the caseload was high or low (1.58% pa; 95% CI, 0.57-3.05 and 1.76% pa; 95% CI, 1.21-2.41, respectively).

CONCLUSION

To achieve optimum results, surgeons, whether high or low caseload, should adhere to the recommended indications such that ≥20%, or ideally >30% of their knee arthroplasties are UKA. If they do this, then they can expect to achieve results similar to those of the long-term series, which all had high usage (>20%) and an average 10-year survival of 94%.

Enhanced recovery programmes for lower limb arthroplasty in the UK

INTRODUCTION

Enhanced recovery programmes (ERPs) reduce patient morbidity and mortality, and provide significant cost savings by reducing length of stay. Currently, no uniform ERP guidelines exist for lower limb arthroplasty in the UK. The aim of this study was to identify variations in ERPs and determine adherence to local policy.

METHODS

Hospitals offering elective total knee arthroplasty (TKA) and total hip arthroplasty (THA) (23 and 22 centres respectively) contributed details of their ERPs, and performed an audit (15 patients per centre) to assess compliance.

RESULTS

Contrasting content and detail of ERPs was noted across centres. Adherence to ERPs varied significantly (40-100% for TKA, 17-94% for THA). Analysis identified perioperative use of dexamethasone, tranexamic acid and early mobilisation for TKA, and procedures performed in teaching hospitals for THA as being associated with a reduced length of stay.

CONCLUSIONS

This study highlights variation in practice and poor compliance with local ERPs. Given the proven benefits of ERPs, evidence-based guidelines in the context of local skillsets should be established to optimise the patient care pathway.

Evidence-Based Indications for Mobile-Bearing Unicompartmental Knee Arthroplasty in a Consecutive Cohort of Thousand Knees

BACKGROUND

The indications for unicompartmental knee arthroplasty remain controversial. Previously recommended contraindications include the following: age under 60 years, weight 180 lb (82 kg) or over, patients undertaking heavy labor, chondrocalcinosis, and exposed bone in the patellofemoral joint. This study explores whether these contraindications are valid in mobile-bearing unicompartmental knee arthroplasty.

METHODS

Using a prospective series of 1000 consecutive medial unicompartmental knee arthroplasties in which the reported contraindications were not applied, the functional outcome and survival in patients with or without contraindications were compared.

RESULTS

Of the 1000 consecutive unicompartmental knee arthroplasties (818 patients), 68% (678 knees) would be considered contraindicated based on published contraindications. At a mean follow-up of 10 years (5-17), there was no difference in American Knee Society (AKS) Objective Scores (P = .05) or Oxford Knee Score (P = .08) between groups. However, knees with contraindications had significantly (P = .02) fewer poor outcomes and significantly better AKS Functional Scores (P < .001) and Tegner Activity Scores (P < .001). At 15 years, no difference in implant survival (P = .33) was observed. The 3% of unicompartmental knee arthroplasties performed in young men (age <60) weighing 180 lb or over with high activity levels, who have been reported to have poor outcomes after fixed-bearing unicompartmental knee arthroplasty, had significantly better AKS Functional Scores (P < .001), Oxford Knee Score (P = .01), and Tegner Activity Score (P < .001) at 10 years. No difference in AKS Objective Scores (P = .54) at 10 years or implant survival at 15 years (P = .75) was seen.

CONCLUSION

This large case series provides evidence that patients with the previously reported contraindications do as well as, or even better than, those without contraindications. Therefore these contraindications should not apply to mobile-bearing unicompartmental knee arthroplasty.

Perioperative adjuvant corticosteroids for post-operative analgesia in elective knee surgery - A systematic review

BACKGROUND

Elective knee surgery is performed to reduce chronic pain and improve function in degenerate knees. Treatment of acute post-operative pain is suboptimal in 75% of patients despite multimodal analgesic approaches resulting in higher post-operative opiate consumption. The effect of corticosteroids as an adjunct for post-operative pain control remains undefined.

METHODS

The databases MEDLINE, EMBASE and CENTRAL (Cochrane library) will be searched from their inception to present using broad search criteria for eligible randomised/quasi-randomised controlled trials investigating perioperative corticosteroid adjunctive use in elective knee surgery. Meta-analyses will be conducted according to the recommendations from the Cochrane Handbook for Systematic Reviews of Interventions.

DISCUSSION

This systematic review of the perioperative adjunctive use of corticosteroids will assess the analgesic effects, post-operative nausea and vomiting, opiate consumption, infection rates and time till discharge and assess whether adjunctive corticosteroids should be encouraged in elective knee surgery.

SYSTEMATIC REVIEW REGISTRATION

PROPSERO CRD42016049336.

Five-year experience of cementless Oxford unicompartmental knee replacement

PURPOSE

Cementless unicompartmental knee replacement (UKR) was introduced to address some of the problems that can occur following cemented UKR. The aim of this study was to report the 5-year experience of the first 512 medial cementless Oxford UKR implanted by two surgeons for the recommended indications.

METHODS

The first consecutive 512 cementless Phase 3 Oxford UKRs implanted by two surgeons for the recommended indications between June 2004 and October 2013 were prospectively identified and followed up independently. All the procedures were carried out through a minimally invasive approach without eversion or dislocation of the patella. Patients were assessed clinically pre-operatively and at 1, 2, 5, 7 and 10 years after surgery with functional outcome scores and radiographs.

RESULTS

There were eight reoperations of which six were revisions giving a 5-year survival of 98 % (95 % CI 94-100 %). At a mean follow-up of 3.4 years (1.0-10.2), the mean OKS was 43 (SD 7), AKSS (objective) was 81 (SD 13), and AKSS (functional) was 86 (SD 17). The first 120 cases had a minimum follow-up of 5 years (mean 5.9; range 5-10.2). In these patients, the mean OKS was 41 (SD 8), AKSS (objective) was 81 (SD 14), and AKSS (functional) was 82 (SD 18). There were no femoral radiolucencies and no complete tibial radiolucencies. 11 % of tibial components had partial radiolucent lines; the remaining 89 % had no radiolucencies.

CONCLUSION

The clinical results are as good as or better than those previously reported for cemented fixation. The radiographic results are better with secure bony attachment to the implants in every case.

LEVEL OF EVIDENCE

IV.

Liposomal bupivacaine infiltration at the surgical site for the management of postoperative pain

BACKGROUND

Despite multi-modal analgesic techniques, acute postoperative pain remains an unmet health need, with up to three quarters of people undergoing surgery reporting significant pain. Liposomal bupivacaine is an analgesic consisting of bupivacaine hydrochloride encapsulated within multiple, non-concentric lipid bi-layers offering a novel method of sustained-release analgesia.

OBJECTIVES

To assess the analgesic efficacy and adverse effects of liposomal bupivacaine infiltration at the surgical site for the management of postoperative pain.

SEARCH METHODS

On 13 January 2016 we searched CENTRAL, MEDLINE, MEDLINE In-Process, Embase, ISI Web of Science and reference lists of retrieved articles. We obtained clinical trial reports and synopses of published and unpublished studies from Internet sources, and searched clinical trials databases for ongoing trials.

SELECTION CRITERIA

Randomised, double-blind, placebo- or active-controlled clinical trials in people aged 18 years or over undergoing elective surgery, at any surgical site, were included if they compared liposomal bupivacaine infiltration at the surgical site with placebo or other type of analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently considered trials for inclusion, assessed risk of bias, and extracted data. We performed data analysis using standard statistical techniques as described in the Cochrane Handbook for Systematic Reviews of Interventions, using Review Manager 5.3. We planned to perform a meta-analysis and produce a 'Summary of findings' table for each comparison however there were insufficient data to ensure a clinically meaningful answer. As such we have produced two 'Summary of findings' tables in a narrative format. Where possible we assessed the quality of evidence using GRADE.

MAIN RESULTS

We identified nine studies (10 reports, 1377 participants) that met inclusion criteria. Four Phase II dose-escalating/de-escalating trials, designed to evaluate and demonstrate efficacy and safety, presented pooled data that we could not use. Of the remaining five parallel-arm studies (965 participants), two were placebo controlled and three used bupivacaine hydrochloride local anaesthetic infiltration as a control. Using the Cochrane tool, we judged most studies to be at unclear risk of bias overall; however, two studies were at high risk of selective reporting bias and four studies were at high risk of bias due to size (fewer than 50 participants per treatment arm).Three studies (551 participants) reported the primary outcome cumulative pain intensity over 72 hours following surgery. Compared to placebo, liposomal bupivacaine was associated with a lower cumulative pain score between the end of the operation (0 hours) and 72 hours (one study, very low quality). Compared to bupivacaine hydrochloride, two studies showed no difference for this outcome (very low quality evidence), however due to differences in the surgical population and surgical procedure (breast augmentation versus knee arthroplasty) we did not perform a meta-analysis.No serious adverse events were reported to be associated with the use of liposomal bupivacaine and none of the five studies reported withdrawals due to drug-related adverse events (moderate quality evidence).One study reported a lower mean pain score at 12 hours associated with liposomal bupivacaine compared to bupivacaine hydrochloride, but not at 24, 48 or 72 hours postoperatively (very low quality evidence).Two studies (382 participants) reported a longer time to first postoperative opioid dose compared to placebo (low quality evidence).Two studies (325 participants) reported the total postoperative opioid consumption over the first 72 hours: one study reported a lower cumulative opioid consumption for liposomal bupivacaine compared to placebo (very low quality evidence); one study reported no difference compared to bupivacaine hydrochloride (very low quality evidence).Three studies (492 participants) reported the percentage of participants not requiring postoperative opioids over initial 72 hours following surgery. One of the two studies comparing liposomal bupivacaine to placebo demonstrated a higher number of participants receiving liposomal bupivacaine did not require postoperative opioids (very low quality evidence). The other two studies, one versus placebo and one versus bupivacaine hydrochloride, found no difference in opioid requirement (very low quality evidence). Due to significant heterogeneity between the studies (I2 = 92%) we did not pool the results.All the included studies reported adverse events within 30 days of surgery, with nausea, constipation and vomiting being the most common. Of the five parallel-arm studies, none performed or reported health economic assessments or patient-reported outcomes other than pain.Using GRADE, the quality of evidence ranged from moderate to very low. The major limitation was the sparseness of data for outcomes of interest. In addition, a number of studies had a high risk of bias resulting in further downgrading.

AUTHORS' CONCLUSIONS

Liposomal bupivacaine at the surgical site does appear to reduce postoperative pain compared to placebo, however, at present the limited evidence does not demonstrate superiority to bupivacaine hydrochloride. There were no reported drug-related serious adverse events and no study withdrawals due to drug-related adverse events. Overall due to the low quality and volume of evidence our confidence in the effect estimate is limited and the true effect may be substantially different from our estimate.

Radiological Decision Aid to determine suitability for medial unicompartmental knee arthroplasty: development and preliminary validation

Aims

An evidence-based radiographic Decision Aid for meniscal-bearing unicompartmental knee arthroplasty (UKA) has been developed and this study investigates its performance at an independent centre.

Patients and Methods

Pre-operative radiographs, including stress views, from a consecutive cohort of 550 knees undergoing arthroplasty (UKA or total knee arthroplasty; TKA) by a single-surgeon were assessed. Suitability for UKA was determined using the Decision Aid, with the assessor blinded to treatment received, and compared with actual treatment received, which was determined by an experienced UKA surgeon based on history, examination, radiographic assessment including stress radiographs, and intra-operative assessment in line with the recommended indications as described in the literature.

Results

The sensitivity and specificity of the Decision Aid was 92% and 88%, respectively. Excluding knees where a clear pre-operative plan was made to perform TKA, i.e. patient request, the sensitivity was 93% and specificity 96%. The false-positive rate was low (2.4%) with all affected patients readily identifiable during joint inspection at surgery.

In patients meeting Decision Aid criteria and receiving UKA, the five-year survival was 99% (95% confidence intervals (CI) 97 to 100). The false negatives (3.5%), who received UKA but did not meet the criteria, had significantly worse functional outcomes (flexion p < 0.001, American Knee Society Score - Functional p < 0.001, University of California Los Angeles score p = 0.04), and lower implant survival of 93.1% (95% CI 77.6 to 100).

Conclusion

The radiographic Decision Aid safely and reliably identifies appropriate patients for meniscal-bearing UKA and achieves good results in this population. The widespread use of the Decision Aid should improve the results of UKA.

Cite this article: Bone Joint J 2016;98-B(10 Suppl B):3–10.

Comparison of outcomes after UKA in patients with and without chondrocalcinosis: a matched cohort study

PURPOSE

Chondrocalcinosis can be associated with an inflammatory arthritis and aggressive joint destruction. There is uncertainty as to whether chondrocalcinosis represents a contraindication to unicompartmental knee arthroplasty (UKA). This study reports the outcome of a consecutive series of patients with chondrocalcinosis and medial compartment osteoarthritis treated with UKA matched to controls.

METHODS

Between 1998 and 2008, 88 patients with radiological chondrocalcinosis (R-CCK) and 67 patients with histological chondrocalcinosis (H-CCK) were treated for end-stage medial compartment arthritis with Oxford UKA. One-to-two matching was performed to controls, treated with UKA, but without evidence of chondrocalcinosis. Functional outcome and implant survival were assessed in each group.

RESULTS

The mean follow-up was 10 years. The mean Oxford Knee Score (OKS) at final follow-up was 43, 41 and 41 in H-CCK, R-CCK and control groups (change from baseline OKS was 21, 18 and 15, respectively). The change was significantly higher in H-CCK than in control but was not significantly different in R-CCK. Ten-year survival was 96 % in R-CCK, 86 % in H-CCK and 98 % in controls. Although the survival in H-CCK was significantly worse than in control, only one failure was due to disease progression.

CONCLUSION

The presence of R-CCK does not influence functional outcome or survival following UKA. Pre-operative radiological evidence of CCK should not be considered to be a contraindication to UKA. H-CCK is associated with significantly improved clinical outcomes but also a higher revision rate compared with controls.

LEVEL OF EVIDENCE

Case control study, Level III.

Patient-Reported Outcome Measure for Early Postoperative Recovery Following Lower Limb Arthroplasty: A Systematic Review

BACKGROUND

Lower limb arthroplasty is an effective surgical treatment option for patients with moderate to severe arthritis who have not responded to medical management. However, surgical interventions can lead to postoperative consequences such as limited mobility, pain, and infection. Consequently, improving postoperative recovery holds significant benefits for patients, health care professionals, and health care payers. The purpose of this review is to determine if any recovery tools exist that can effectively measure early postoperative recovery after hip or knee arthroplasty.

METHODS

The following databases were searched; PubMed (Ovid), EMBASE (Ovid), Medline (Ovid), Web of Science (ISI Web of Knowledge), PsycINFO, Applied Social Sciences Index and Abstracts, Cochrane library, and SCOPUS. We restricted our search to English language articles and adult respondents. Data were extracted by 2 independent reviewers using a proforma spreadsheet, and existing quality criteria were applied.

RESULTS

Our literature search identified 23 articles relating to development, assessment, and validation of 15 tools. Not all instruments demonstrated the same levels of quality. None of the tools found were specific to both the orthopedic arthroplasty population and early recovery periods.

CONCLUSION

At the present time, there are no fully validated tools to assess early postoperative recovery during the first week following lower limb arthroplasty. A brief, easy-to-complete, reliable patient-reported tool could be of great use. It could not only aid in assessment of recovery but could also evaluate the efficacy of perioperative interventions such as drugs or surgical technique and provide a foundation for evidence-based care.

One-stage versus two-stage exchange arthroplasty for infected total knee arthroplasty: a systematic review

PURPOSE

Infection complicating total knee arthroplasty (TKA) has serious implications. Traditionally the debate on whether one- or two-stage exchange arthroplasty is the optimum management of infected TKA has favoured two-stage procedures; however, a paradigm shift in opinion is emerging. This study aimed to establish whether current evidence supports one-stage revision for managing infected TKA based on reinfection rates and functional outcomes post-surgery.

METHODS

MEDLINE/PubMed and CENTRAL databases were reviewed for studies that compared one- and two-stage exchange arthroplasty TKA in more than ten patients with a minimum 2-year follow-up.

RESULTS

From an initial sample of 796, five cohort studies with a total of 231 patients (46 single-stage/185 two-stage; median patient age 66 years, range 61-71 years) met inclusion criteria. Overall, there were no significant differences in risk of reinfection following one- or two-stage exchange arthroplasty (OR -0.06, 95 % confidence interval -0.13, 0.01). Subgroup analysis revealed that in studies published since 2000, one-stage procedures have a significantly lower reinfection rate. One study investigated functional outcomes and reported that one-stage surgery was associated with superior functional outcomes. Scarcity of data, inconsistent study designs, surgical technique and antibiotic regime disparities limit recommendations that can be made.

CONCLUSION

Recent studies suggest one-stage exchange arthroplasty may provide superior outcomes, including lower reinfection rates and superior function, in select patients. Clinically, for some patients, one-stage exchange arthroplasty may represent optimum treatment; however, patient selection criteria and key components of surgical and post-operative anti-microbial management remain to be defined.

LEVEL OF EVIDENCE

III.

Liposomal bupivacaine peripheral nerve block for the management of postoperative pain

BACKGROUND

Postoperative pain remains a significant issue with poor perioperative pain management associated with an increased risk of morbidity and mortality. Liposomal bupivacaine is an analgesic consisting of bupivacaine hydrochloride encapsulated within multiple, non-concentric lipid bi-layers offering a novel method of sustained release.

OBJECTIVES

To assess the analgesic efficacy and adverse effects of liposomal bupivacaine infiltration peripheral nerve block for the management of postoperative pain.

SEARCH METHODS

We identified randomised trials of liposomal bupivacaine peripheral nerve block for the management of postoperative pain. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 1), Ovid MEDLINE (1946 to January Week 1 2016), Ovid MEDLINE In-Process (14 January 2016), EMBASE (1974 to 13 January 2016), ISI Web of Science (1945 to 14 January 2016), and reference lists of retrieved articles. We sought unpublished studies from Internet sources, and searched clinical trials databases for ongoing trials. The date of the most recent search was 15 January 2016.

SELECTION CRITERIA

Randomised, double-blind, placebo- or active-controlled clinical trials of a single dose of liposomal bupivacaine administered as a peripheral nerve block in adults aged 18 years or over undergoing elective surgery at any surgical site. We included trials if they had at least two comparison groups for liposomal bupivacaine peripheral nerve block compared with placebo or other types of analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently considered trials for inclusion in the review, assessed risk of bias, and extracted data. We performed analyses using standard statistical techniques as described in the Cochrane Handbook for Systematic Reviews of Interventions, using Review Manager 5. We planned to perform a meta-analysis, however there were insufficient data to ensure a clinically meaningful answer; as such we have produced a 'Summary of findings' table in a narrative format, and where possible we assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

MAIN RESULTS

We identified seven studies that met inclusion criteria for this review. Three were recorded as completed (or terminated) but no results were published. Of the remaining four studies (299 participants): two investigated liposomal bupivacaine transversus abdominis plane (TAP) block, one liposomal bupivacaine dorsal penile nerve block, and one ankle block. The study investigating liposomal bupivacaine ankle block was a Phase II dose-escalating/de-escalating trial presenting pooled data that we could not use in our analysis.The studies did not report our primary outcome, cumulative pain score between 0 and 72 hours, and secondary outcomes, mean pain score at 12, 24, 48, 72, or 96 hours. One study reported no difference in mean pain score during the first, second, and third postoperative 24-hour periods in participants receiving liposomal bupivacaine TAP block compared to no TAP block. Two studies, both in people undergoing laparoscopic surgery under TAP block, investigated cumulative postoperative opioid dose, reported opposing findings. One found a lower cumulative opioid consumption between 0 and 72 hours compared to bupivacaine hydrochloride TAP block and one found no difference during the first, second, and third postoperative 24-hour periods compared to no TAP block. No studies reported time to first postoperative opioid or percentage not requiring opioids over the initial 72 hours. No studies reported a health economic analysis or patient-reported outcome measures (outside of pain). The review authors sought data regarding adverse events but none were available, however there were no withdrawals reported to be due to adverse events.Using GRADE, we considered the quality of evidence to be very low with any estimate of effect very uncertain and further research very likely to have an important impact on our confidence in the estimate of effect. All studies were at high risk of bias due to their small sample size (fewer than 50 participants per arm) leading to uncertainty around effect estimates. Additionally, inconsistency of results and sparseness of data resulted in further downgrading of the quality of the data.

AUTHORS' CONCLUSIONS

A lack of evidence has prevented an assessment of the efficacy of liposomal bupivacaine administered as a peripheral nerve block. At present there is a lack of data to support or refute the use of liposomal bupivacaine administered as a peripheral nerve block for the management of postoperative pain. Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

A Meta-Analysis on the Use of Gabapentinoids for the Treatment of Acute Postoperative Pain Following Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty is a painful procedure, with approximately half of patients reporting severe pain during the early postoperative period. Gabapentinoids are used as an adjunct for the management of acute pain in approximately half of enhanced recovery programs. We performed a meta-analysis to assess the effectiveness and safety of gabapentinoids for the treatment of acute postoperative pain following total knee arthroplasty.

METHODS

Randomized controlled trials of patients undergoing elective primary total knee arthroplasty that compared the use of the gabapentinoid class of drugs (gabapentin [Neurontin; Pfizer]) or pregabalin [Lyrica; Pfizer]) with that of placebo were retrieved, with 12 studies meeting inclusion criteria. The primary outcome was pain intensity with activity at 48 hours following the surgical procedure. The secondary outcomes included pain intensity at other time points, opioid consumption, knee function, incidence of chronic pain, and adverse events.

RESULTS

No difference in pain score at 12, 24, 48, or 72 hours following the surgical procedure was seen between gabapentin and placebo. Although pregabalin was associated with reduced pain scores at 24 and 48 hours, this corresponded to a reduction of 0.5 point (95% confidence interval, 0 to 1.0 point) at 24 hours and 0.3 point (95% confidence interval, 0 to 0.6 point) at 48 hours on an 11-point numeric rating scale, which was assessed as not clinically important. Overall, no clinically relevant reduction in pain scores was associated with the use of gabapentinoids. Likewise, gabapentinoids were associated with a small, but not clinically important, reduction in cumulative opioid consumption at 48 hours (mean difference, -23.2 mg [95% confidence interval, -40.9 to -5.4 mg]). There was no difference in knee flexion at 48 hours (p = 0.63) or in the incidence of chronic pain at 3 months (p = 0.31) or 6 months (p = 0.54) associated with the use of gabapentinoids. Although gabapentinoids were associated with a significant reduction in the incidence of nausea (risk ratio, 0.7 [95% confidence interval, 0.6 to 0.9]; p < 0.001), pregabalin was also associated with a significant, clinically relevant increase in the risk of sedation (risk ratio, 1.4 [95% confidence interval, 1.1 to 1.9]; p = 0.02).

CONCLUSIONS

On the basis of this meta-analysis, we found no evidence to support the routine use of gabapentinoids in the management of acute pain following total knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Unicompartmental knee replacement: Does the macroscopic status of the anterior cruciate ligament affect outcome?

PURPOSE

ACL damage is associated with progression of arthritis and whilst in the population undergoing joint replacement in the majority of cases the ACL is intact there is a wide spectrum of ACL disease. This study investigated whether the macroscopic status of the ACL affected functional outcome or survival following UKR.

METHODS

The macroscopic status of the ACL was recorded in 820 cemented Oxford UKRs implanted by two surgeons for the recommended indications. The ACL was considered functionally normal in the setting of anteromedial tibial wear and macroscopically the ACL visually appeared normal or had synovial damage or longitudinal splits. The patients were followed up independently with a mean follow-up of 10.3years (range 5.3 to 16.6).

RESULTS

More marked ACL macroscopic damage was significantly associated with increasing age, male gender and a more extensive anteromedial tibial defect. Patients with more ACL damage had a significantly lower pre-operative AKSS Objective Score, however no difference in AKSS-Functional or OKS was detected between groups. At 10years no difference in functional outcome or activity level was found between groups. Compared to those with a macroscopically normal ACL at 10years a significantly greater improvement from baseline OKS score was seen in patients with macroscopic ACL abnormalities. At 15years no difference in implant survival, or failure mechanism, was detected between groups.

CONCLUSION

The macroscopic status of the ACL does not affect long term functional outcomes or implant survival and in the setting of an intact ACL macroscopic status is not a contraindication to mobile bearing UKR.

LEVEL OF EVIDENCE

Level IV.

The clinical outcome of minimally invasive Phase 3 Oxford unicompartmental knee arthroplasty: a 15-year follow-up of 1000 UKAs

There have been concerns about the long-term survival of unicompartmental knee arthroplasty (UKA). This prospective study reports the 15-year survival and ten-year functional outcome of a consecutive series of 1000 minimally invasive Phase 3 Oxford medial UKAs (818 patients, 393 men, 48%, 425 women, 52%, mean age 66 years; 32 to 88). These were implanted by two surgeons involved with the design of the prosthesis to treat anteromedial osteoarthritis and spontaneous osteonecrosis of the knee, which are recommended indications. Patients were prospectively identified and followed up independently for a mean of 10.3 years (5.3 to 16.6). At ten years, the mean Oxford Knee Score was 40 (standard deviation (sd) 9; 2 to 48): 79% of knees (349) had an excellent or good outcome. There were 52 implant-related re-operations at a mean of 5.5 years (0.2 to 14.7). The most common reasons for re-operation were arthritis in the lateral compartment (2.5%, 25 knees), bearing dislocation (0.7%, seven knees) and unexplained pain (0.7%, seven knees). When all implant-related re-operations were considered as failures, the ten-year rate of survival was 94% (95% confidence interval (CI) 92 to 96) and the 15-year survival rate 91% (CI 83 to 98). When failure of the implant was the endpoint the 15-year survival was 99% (CI 96 to 100). This is the only large series of minimally invasive UKAs with 15-year survival data. The results support the continued use of minimally invasive UKA for the recommended indications.

Clinical outcome after UKA and HTO in ACL deficiency: a systematic review

PURPOSE

In the treatment of medial osteoarthritis secondary to anterior cruciate ligament (ACL) injury there is no consensus about optimum treatment, with both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) being viable options. The aim of this review was to compare the outcomes of these treatments, both with or without ACL reconstruction.

METHODS

EMBASE, MEDLINE and the Clinical Trials Registers were searched to identify relevant studies. Studies meeting pre-defined inclusion criteria were assessed independently by two researchers for methodological quality and data extracted.

RESULTS

Twenty-six studies involving 771 patients were identified for inclusion. No randomized controlled trials were identified. Seventeen studies reported outcomes following HTO and nine studies reported outcomes following UKA. HTO patients were significantly younger than those receiving UKA, and ACL reconstruction patients were younger than non-reconstructed patients. Treatment with HTO ACL reconstruction had the lowest revision rate (0.62/100 observed component years) but the highest rate of complications (4.61/100 observed component years). Too little data were available to test for differences in outcome between different surgical techniques or prosthesis designs.

CONCLUSIONS

Limited conclusions about the optimum treatment can be made due to the absence of controlled trials. In patients treated with HTO ACL reconstruction, the high complication rate likely outweighs its minimally superior survival. Outcomes following UKA ACL reconstruction are similar to outcomes for UKA in the ACL intact knee without any increase in complications. As such in patients meeting indications for UKA, UKA ACL reconstruction should be performed with further work required to identify the optimum treatment in other patient groups.

LEVEL OF EVIDENCE

IV.

Trans-patella tendon approach for domed lateral unicompartmental knee arthroplasty does not increase the risk of patella tendon shortening

PURPOSE

Shortening of the patella tendon has been noted after total knee arthroplasty and has been associated with diminished functional outcomes. Traumatic and/or ischaemic injury peri-operatively are suggested causes. The Oxford domed lateral unicompartmental knee arthroplasty (UKA) requires a vertical incision through the patella tendon to facilitate orientation of the proximal tibial saw cut; this may induce scarring or impair vascularity of the tendon and can cause shortening. This study investigated the hypothesis that the trans-patella tendon incision increases the incidence of patella tendon shortening after domed lateral UKA when compared to flat lateral UKA performed without the trans-patella tendon incision.

METHODS

The radiographs of 50 patients who underwent domed lateral UKA, using the trans-patella tendon approach, and a cohort of 30 patients who underwent flat lateral UKA, in which an incision through the patella tendon was not employed, were reviewed retrospectively. The patella tendon length (PTL) and the Insall-Salvati ratio were measured. In addition, pre-operative and post-operative clinical scores were recorded using both the OKS and AKSS. A change in PTL of greater than or equal to 10 % was considered to be significant.

RESULTS

In the domed lateral UKA group, 13 patients demonstrated a >10 % change in the PTL at 1-year post-surgery (2 shortened and 11 lengthened). In the flat lateral UKA group, nine patients demonstrated a significant change in the PTL at 1-year post-surgery (2 shortened and 7 lengthened).

CONCLUSION

This study demonstrated that using a trans-patella approach during lateral domed UKA surgery did not significantly increase patella tendon shortening and did not result in reduced clinical outcomes.

The cost and consequences of proximal femoral fractures which require further surgery following initial fixation

We evaluated the cost and consequences of proximal femoral fractures requiring further surgery because of complications. The data were collected prospectively in a standard manner from all patients with a proximal femoral fracture presenting to the trauma unit at the John Radcliffe Hospital over a five-year period. The total cost of treatment for each patient was calculated by separating it into its various components. The risk factors for the complications that arose, the location of their discharge and the mortality rates for these patients were compared to those of a matched control group. There were 2360 proximal femoral fractures in 2257 patients, of which 144 (6.1%) required further surgery. The mean cost of treatment in patients with complications was £18,709 (£2606.30 to £60,827.10), compared with £8610 (£918.54 to £45,601.30) for uncomplicated cases (p < 0.01), with a mean length of stay of 62.8 (44.5 to 79.3) and 32.7 (23.8 to 35.0) days, respectively. The probability of mortality after one month in these cases was significantly higher than in the control group, with a mean survival of 209 days, compared with 496 days for the controls. Patients with complications were statistically less likely to return to their own home (p < 0.01). Greater awareness and understanding are required to minimise the complications of proximal femoral fractures and consequently their cost.

SAS weekly rounds: avascular necrosis

Osteonecrosis of the femoral head is a condition that affects upwards of 10,000 individuals in the USA each year. The peak incidence is in the fourth decade of life, and overall, there is a male preponderance. The condition accounts for up to 12% of total hip arthroplasties performed in developed countries. The etiology can be traumatic or non-traumatic, with 90% of atraumatic cases attributed to corticosteroid therapy or excess alcohol consumption. Osteonecrosis of the femoral head reflects the final common pathway of a range of insults to the blood supply and ultimately results in femoral head collapse, acetabular involvement, and secondary osteoarthritis. Currently, conservative treatment options, which aim to correct pathophysiologic features allowing revascularization and new bone formation, appear to be able to delay but not halt the progression of this condition. As a consequence of femoral head osteonecrosis, many individuals undergo surgical treatments including: core decompression, osteotomy, non-vascularized bone matrix grafting, free vascularized fibular grafts, limited femoral resurfacing, total hip resurfacing, and total hip arthroplasty.

Trappin-2 promotes early clearance of Pseudomonas aeruginosa through CD14-dependent macrophage activation and neutrophil recruitment

Microaspiration of Pseudomonas aeruginosa contributes to the pathogenesis of nosocomial pneumonia. Trappin-2 is a host defense peptide that assists with the clearance of P. aeruginosa through undefined mechanisms. A model of macrophage interactions with replicating P. aeruginosa (strain PA01) in serum-free conditions was developed, and the influence of subantimicrobial concentrations of trappin-2 was subsequently studied. PA01 that was pre-incubated with trappin-2 (at concentrations that have no direct antimicrobial effects), but not control PA01, was cleared by alveolar and bone marrow-derived macrophages. However, trappin-2-enhanced clearance of PA01 was completely abrogated by CD14- null macrophages. Fluorescence microscopy demonstrated the presence of trappin-2 on the bacterial cell surface of trappin-2-treated PA01. In a murine model of early lung infection, trappin-2-treated PA01 was cleared more efficiently than control PA01 2 hours of intratracheal instillation. Furthermore, trappin-2-treated PA01 up-regulated the murine chemokine CXCL1/KC after 2 hours with a corresponding increase in neutrophil recruitment 1 hour later. These in vivo trappin-2-treated PA01 effects were absent in CD14-deficient mice. Trappin-2 appears to opsonize P. aeruginosa for more efficient, CD14-dependent clearance by macrophages and contributes to the induction of chemokines that promote neutrophil recruitment. Trappin-2 may therefore play an important role in innate recognition and clearance of pathogens during the very earliest stages of pulmonary infection.