Can C-Reactive Protein Be Used To Predict Acute Native Joint Septic Arthritis in the Adult Population?

Background:

The hot swollen joint is a common presentation to the emergency department. A wide range of potential differential diagnoses exist. There is evidence to support CRP as a predictor of septic arthritis(SA) in children.  Limited evidence exists in adults.  The primary aim of this study was to establish whether C-reactive protein (CRP) can predict native joint SA in the adult population.

 

Method:

Retrospective cohort study. All patients who underwent native joint aspiration by the orthopaedic team over a 4 year period were identified from the lab microbiology records. Exclusion criteria applied.  Patients were divided into three groups for analysis: patients with SA, crystal arthropathy and those with normal/arthritic joints.

 

Results:

190 patients were identified. 15 (8%) were deemed to have SA giving a local incidence of 1 per 100,000.18 had a crystal arthopathy (10%) and 157 (82%) had normal or osteo/inflammatory arthritis.  We identified a significant difference in mean CRP between the SA group and the other two groups (p<0.001).  Receiver operative curves produced a CRP of 90mg/L as the cut off to differentiate between non-infective causes and SA (Sensitivity 100%, Specificity 96%).  We showed a significant difference in the aspirate WCC in SA compared with normal joints. There was no significant difference when comparing infected and crystal arthropathy.  However we identified 20,000 as the cut off to effectively exclude SA (Sensitivity 27%, Specificity 100%).   We identified a low sensitivity of aspiration gram stain (27%).

 

Conclusion:

Gram stain has a low sensitivity.  It is therefore useful to identify markers predictive of SA.  CRP is a reliable independent marker to differentiate cause of a hot swollen joint.  A threshold of 90mg/L is a very sensitive tool to diagnose septic arthritis.  This, combined with a WCC of <20,000 is very sensitive and specific way to exclude SA.

Association of Regular Preoperative Antiplatelet and Anticoagulant Medication With Surgical Site Infection Following Total Knee Arthroplasty: A Retrospective Case Control Study

Background

Periprosthetic joint infection (PJI) is a disastrous complication following total knee arthroplasty (TKA), which can develop from a surgical site infection (SSI). The use of antiplatelet and anticoagulant medication are becoming ever more prevalent in todays ageing population and such agents but have been linked to an increased incidence of SSI during following surgical procedures. In this paper, we seek to compare the rates of SSI in those patients undergoing TKA taking preoperative anti platelet or anticoagulant

medication compared with those who were not on such medication.

Study Design & Methods

A retrospective case-control study was undertaken looking at patients who had undergone a primary TKA between July 2013 and March 2018. We then identified those who developed an SSI, and matched them to a group who did not develop a SSI by age, gender and year of operation. The rates of those on antiplatelet/antocoagulant

medication was then compared between the two.

Results

A total of 1516 TKA procedures were undertaken with 20 SSIs recorded (1.3%). Incidence of SSI was significantly higher in males (OR = 2.6; 95% CI: 1.0 to 6.5; P = 0.045). The rate of preoperative antiplatelet or anticoagulant medication use was higher in the SSI group (40.0%) than non-SSI group (30.0%), but failed to show significance (OR = 1.6; 95% CI: 0.4 to 5.8; P = 0.508). Within the SSI group, the relative risk of patients requiring a one-or-two-stage replacement, who took regular preoperative antiplatelet or anticoagulant medication, was 1.9 (95% CI: 0.7-4.9; P = 0.201).

Conclusions

The study failed to identify a significant association between the regular use of preoperative antiplatelet or anticoagulant medication with SSI following primary TKA.

BMI Change Associated with Waiting Times for Primary Lower Limb Arthroplasty

Background:

Raised BMI (Body Mass Index) gives worse outcomes, higher revision risks and increased complications in lower limb arthroplasty. Lengthy NHS (National Health Service) waiting lists allow patients an opportunity to increase BMI by time of surgery, thus affecting outcomes. This study assesses association of BMI change with waiting time for lower limb arthroplasty.

Methods:

This is a retrospective analysis of prospective primary THAs (Total Hip Arthroplasty) and TKAs (Total Knee Arthroplasty) performed between August 2018 to May 2019, collecting patient demographics, ASA (American Society of Anaesthetists) grade, BMI at pre- operative assessment and day of surgery and time interval between these. Descriptive analysis of demographics and ASA grade was performed, unpaired T-test used to examine significance of weight change and Pearson’s coefficient used to assess the association between BMI change and time.

Results:

There were 213 patients; 107 THA and 106 TKA, average age 70.3 (30-95), median ASA 2. 40% of patients had a BMI increase (average 2.5), 44% remained unchanged and 16% had a BMI decrease (average 1.5). 28% of patients put on >5kg whereas 14% lost >5kg (p>0.0001). As a whole, there was no correlation between weight change and waiting time (Pearson coefficient -0.2, P=0.0007) (Graph 1). However, patients who did increase weight showed significant positive correlation with waiting time: 22% (46) patients put on >5kg (average waiting time 59.3 days, median BMI increase 3.5; Pearson coefficient 0.98, p>0.0001), 15% (32) patients put on >1 stone/6.3kg (average waiting time 67.5 days, median BMI increase 3.7; Pearson coefficient 0.98, p>0.0001) and 6.1% (13) patients put on >10kg (average waiting time 43.8 days, median BMI increase 4.4; Pearson coefficient 0.99, p>0.0001).

Conclusion:

We recommend repeat pre-op assessment no more than 6 weeks before surgery to ensure BMI has not unduly changed to give patients the best potential post-op outcomes.

Is the use of antibiotic loaded cement compared to top plain cement associated with lower rate of revision?

Background

Antibiotic loaded bone cement (ALBC) is commonly used in cemented total hip arthroplasty (THA) in an attempt to reduce the risk of prosthetic joint infection (PJI). However, its role versus plain cement remains controversial due to the potential risk of developing resistant organisms and potential excess costs incurred from its usage. We investigated the relationship of ALBC and plain cement in affecting outcome of revision surgery after primary THA.

Methods

We conducted a retrospective study of data collected from National Joint Registry for England and Wales, Northern Ireland and the Isle of Man between 1st September 2005 until 31st August 2017. A logistic regression analysis model was used to investigate the association between ALBC versus plain cement and the odds ratio(OR) for revision, adjusting for age, ASA grade, bearing surfaces, head size and cup and stem fixation. Indications for revision recorded in NJR were considered in separate models.

Results

We identified 418,925 THAs where bone cements were used (22,037 plain cement; 396,888 ALBC). After adjusting for confounding factors, the risk of revision for infection was lower with ALBC (OR 0.77, 95% CI 0.62-0.95). There were also lower risk of revision for aseptic loosening of stem (OR 0.53, 95% CI 0.39-0.72), aseptic loosening of socket (OR 0.46, 95% CI 0.37- 0.58). When breaking down hips into fully cemented or hybrid fixation, the protective effect of ALBC against infection was only apparent in fully cemented (OR 0.65, 95% CI 0.48-0.87) when compared against hybrid fixation (OR 0.90, 95% CI 0.66-1.23).

Conclusion

Within the limits of registry analysis, this study has demonstrated an association between the use of ALBC and lower rates of revision for infection and aseptic loosening. This finding supports the current use of ABLC in cemented THAs.

Do Patient Predicted Oxford Scores Correlate with Actual Outcomes

Background

Patient reported outcome measures (PROMs) are utilised as a means of assessing the subjective experience of the patient. The Oxford Hip (OHS) and Knee Scores (OKS) are joint specific instruments designed to quantify the patient’s experience before and after their surgery. Uniquely, we asked patients attending pre-operatively to estimate a predicted Oxford Score (pOS). To our knowledge this is the first study to utilise a pOS and the relationship to actual outcome 12 months post joint replacement.

Objectives

To assess the relationship between the predicted OHS and OKS collected pre- operatively and compare the patient’s score reported 12 months post-operatively.

Study Design & Methods

This is a prospective cohort study of a database of 3853 patients over 6 years undergoing hip and knee arthroplasty (November 2012 – March 2018). Pre and post- operative variables were available for comparison for 389 patients (10%). A Pearson Correlation Co-Efficient was calculated to assess the relationship between the absolute values of these scores.

Results

Comparing the predictive Oxford Scores to the 12 month scores yielded an r value of 0.14 (Pearson Correlation Co-Efficient). There was no relationship between the patient pOS and the combined OHS and OKS at 12 months. The mean pOS for total hip replacement was 47 compared to an actual mean score of 39 at 12 months. The mean pOS for total knee replacement was 42 compared to an actual mean score of 37 at 12 months.

Conclusions

Our study demonstrates there is no relationship between the patients’ perception of their future outcome following arthroplasty surgery using a predicted Oxford score and further self-evaluation at 12 months. The majority of patients over estimate long term clinical outcomes. These predicted scores may be a means of flagging patients who over estimate outcomes so that expectation may be moderated pre-operatively.

HTO is a good option in the older patient: a single surgeon case series

Background:

The number of high tibial osteotomies (HTOs) are increasing year on year as documented in the United Kingdom Knee Osteotomy Registry (UKKOR). There is a paucity of evidence for their use in the older patient. Traditionally they are reserved for select, younger patients wishing to defer the need for total knee arthroplasty for a few more years. Approximately 70% of HTOs are performed on patients between 40 and 55 years of age.

Methods:

50 adult patients underwent consecutive HTOs for medial compartment osteoarthritis under the same Consultant Orthopaedic Surgeon at the Warrington & Halton NHS Hospital Trust from 2014 onwards. Validated Patient Reported Outcome Measure (PROM) scores were collected prospectively. Oxford and Knee Injury and Osteoarthritis Outcome Score (KOOS) scores were collected at 1 year, 2 year and up to 5 years. The cohort was divided into two groups based on age: group 1 were 53 years old or above. Those who were 52 or below were in group 2.

Results:

Both patient groups had comparable demographics and baseline PROMs scores. Group 1 had 27 patients with an age range between 53 and 71 years. Group 2 had 23 patients ranging from 26 to 52 years of age. There was no significant difference between the scores at either 1 year or 2 years (p<0.12, p<0.13).

Conclusion:

With good clinical acumen and appropriate patient selection HTO is a good option in the older patient with patients reporting just as good results in terms of pain, function, sport and quality of life as their younger counter parts.

Use of In-Space Balloons in Irreparable Cuff Tears

Background

Irreparable cuff repairs present a difficult conundrum for shoulder surgeons, with no consensus on the best form of treatment. In-Space balloons (ISB) are a novel arthroscopic solution, seeking to reduce pain and improve function in patients suffering with this issue. Our aim was to evaluate the ISBs that had been inserted by one surgeon at our two local hospitals.

Methods

Oxford Shoulder Scores (OSS) were obtained for all patients as part of their preoperative assessment. The details of the patients with ISBs were prospectively collected and notes retrospectively analysed. Patients were contacted by phone and consented to take part in the study. Those who agreed were sent questionnaires based on the OSS and compared to their preoperative scores. Patients who went on to have reverse shoulder replacements were deemed to have failed treatment.

Results

A total of fourteen ISBs were inserted arthroscopically in the last two years. Three patients progressed to having reverse shoulder replacements.

Conclusion

Over 75% of patients were satisfied with their treatment at an average of 12 months of followup, as shown by a reduction in their OSS. We have shown ISBs to be a commendable approach to treating irreparable cuff tears, delaying or removing the need for reverse shoulder replacements.

Functional Outcomes of Elbow Injuries Managed According to the Wrightington Classification of Elbow Fracture Dislocations

Objectives

The aim of this study is to review the functional outcomes of patients managed by application of the Wrightington elbow fracture-dislocation classification system and its corresponding management algorithm.

Methods

This is a retrospective case-series of all adult patients who were managed according the Wrightington classification. Images were retrospectively reviewed and classified by all investigators. Any disagreement was resolved by discussion. The content validity of the classification was assessed by comparing each subgroup classification with the intraoperative findings. Primary outcome measures were the range of movement (ROM) and Mayo Elbow Performance Score (MEPS). Complications were collected as a secondary outcome.

Results

Sixty patients were managed using the Wrightington classification (32F/28M) with a mean age of 48(19-84). In order of observed frequency 20 cases (33%) were classified as type B+,18(30%) Type C,11(28%) Type B and 7(12%) Type A. There were 3 Type D+ and 1 Type D.
Fifty eight(96.7%) patients completed a minimum of 3 months follow up. Average follow up was 5.7 months (2-18).The average MEPS at final follow up was 93(55-100) and mean ROM of 15 to 131 degrees. Sub-group analysis showed average MEPS of 91(65- 100) in group A, 93(70-100) in group B, 92(55-100) in group B+,94 (65-100) in group C,100 in group D and 90(70-100) in group D+. The average ROM is 10-136 degrees in group A, 22-128 in group B, 17-127 in group B+, 12-134 in group C, 0-130 in group D and 18-131 degrees in group D+. Four patients underwent secondary surgery. All 4 patients had improved outcomes with average MEPS score improvement from 65 to 94.

Conclusions

The Wrightington Classification system facilitates pattern recognition and provides an algorithm for management for these complex injuries. Our results suggest that predictably good outcomes can be achieved by application of surgical algorithms related to this classification.

Does a skin incision following Langers Lines reduce complications following fixation of displaced middle third clavicle fractures

Background

Internal fixation of displaced mid-third clavicle fractures reduces the rate of non-union and offers a faster return of functioncomparedtonon-operative management. Several studies have reported a significant rate of complications with this procedure however. The aim of this study is to investigate whether or not using a skin incision following Langer’s lines, as opposed to a traditional transverse incision, reduces the rate of complications.

Methods

In this retrospective cohort study, data on 108 patients who underwent open reduction and internal fixation of mid-shaft clavicle fractures between 2014 and 2018 was reviewed. Either a standard transverse incision or an oblique incision along skin Langer’s lines was used according to surgeon’s preference. A pre-contoured diaphyseal locking plate was used in all cases. We collected data on fracture classification, minor complications (irritation from prominent plate, chest wall numbness, superficial wound infection) and major complications (irritation from plate necessitating metalwork removal, periprosthetic fracture, deep infection, neurovascular injury and non-union). Statistical analysis was performed using Chi squared tests.

Results

57 patients underwent fixation using the oblique incision and 51 via the transverse incision. Age, gender and fracture pattern in the two groups were comparable. There were 15 minor and 6 major complications in the oblique group. In the transverse group there were 18 minor and 5 major complications. The major complication rate was 10.5% in the oblique group and 9.8% in the transverse group. The overall major complication rate was 10.2%. No statistically significant difference in the rate of complications between the two groups was identified.

Conclusions

Based on our data, neither incision is superior to the other meaning that selection of incision should follow surgeon’s usual practice. Of note the overall rate of major complications was lower than reported elsewhere in the literature.

Analysing the Benefit of Histology Alongside Microbiology Samples in the Diagnosis of Prosthetic Joint Infection

Introduction:

Both the diagnosis and treatment of Prosthetic Joint Infection (PJI) can be challenging. The International Consensus meeting on PJI primarily defined joint infection as having two culture samples with phenotypically identical organisms or the presence of a sinus tract. Positive histology is only considered as one of the minor criteria of which 3 are required for diagnosis.

Methods:

We developed a retrospective, multicentre database of prosthetic joint revision procedures where tissue samples were halved and sent for both microbiology and histology. 9% had only one histology sample sent. The correlation between microbiology and histology was observed with the aim of identifying what role histology has to play in the diagnosis.

Results:

208 revision procedures for all causes were analysed between 2012 and 2018. 152 (73%) were single stage revisions. In 132 (63.5%) cases, the histology matched the microbiology result. Of the 76 cases in which histology contradicted the microbiology, 48 (63%) helped support a conclusion of a 'contaminant' with a single false positive culture. Histology correlated well with both CRP and ESR on 66% of occasions and at least one on 83% of occasions in which the microbiology results differed.

Conclusion:

Histology is beneficial in the confirmation of infection when intraoperative samples fail to culture. Histology indicating 'no infection' is also very useful in the presence of possible contamination in which only one sample developed positive culture or there were differing cultured organisms. Histology gives no additional information in the obviously infected joint such as those with sinuses. All the results however should be interpreted alongside other investigations such as inflammatory markers and pre- operative aspirates.

Implications:

The authors agree that histology is one of the minor criteria for PJI, but would encourage samples be sent to help with decision making in the presence of negative or inconclusive cultures.