Routine use of antibiotic-laden bone cement in total knee arthroplasty is a cost-effective practice in the single-payer healthcare system.

PURPOSE: The purpose of this study was to determine the cost-effectiveness of antibiotic-laden bone cement (ALBC) in primary total knee arthroplasty (TKA) from the perspective of a single-payer healthcare system. METHODS: A cost-utility analysis (CUA) was performed over a 2-year time horizon comparing primary TKA with either ALBC or regular bone cement (RBC) from the perspective of the single-payer Canadian healthcare system. All costs were in 2020 Canadian dollars. Health utilities were in the form of quality-adjusted life years (QALYs). Model inputs for cost, utilities and probabilities were derived from the literature as well as regional and national databases. One-way deterministic sensitivity analysis was performed. RESULTS: Primary TKA with ALBC was found to be more cost-effective compared to primary TKA with RBC with an incremental cost-effectiveness ratio (ICER) of -3,637.79 CAD/QALY. The use of routine ALBC remained cost-effective even with cost increases of up to 50% per bag of ALBC. TKA with ALBC was no longer cost-effective if the rate of PJI following this practice increased 52%, or the rate of PJI following the use of RBC decreased 27%. CONCLUSIONS: The routine use of ALBC in TKA is a cost-effective practice in the single-payer Canadian healthcare system. This remains to be the case even with a 50% increase in the cost of ALBC. Policy makers and hospital administrators of single-payer healthcare systems can leverage this model to inform their local funding policies. Future prospective reviews and randomized controlled trials from the perspective of various healthcare models can further shed light on this issue. LEVEL OF EVIDENCE: III.

The quality of diagnostic studies used for the diagnostic criteria of periprosthetic joint infections.

BACKGROUND: Although periprosthetic joint infection (PJI) is a serious complication following a total joint arthroplasty procedure, there remains uncertainty regarding the diagnosis of PJI due to the lack of a globally accepted, standardized definition. The goal of this review is to critically analyze the quality of the evidence used for the novel 2018 MSIS PJI definition and identify gaps and limitations with using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. METHODS: References from the modified 2018 MSIS definition for PJI by Parvizi et al. were retrieved and manually reviewed. A total of 11 studies were assessed using a validated QUADAS-2 tool. RESULTS: Many included studies had an unclear or high risk of bias for the Index Test domain due to a lack of blinding and lack of prespecified thresholds. A majority of studies utilized Youden's J statistic to optimize the thresholds which may diminish external validity. Likewise, several studies were assessed to have an unclear and high risk of bias for the Flow and Timing domain primarily due to a lack of reporting and a large number of exclusions. Overall, there was a low risk of bias for the choice of reference standard, its conduct and interpretation, as well as for the Patient Selection domain. CONCLUSION: Although the literature used for the MSIS 2018 PJI definition is fraught with potential sources of bias, there may be a trend toward an improvement in the quality of evidence when compared to the earlier definition of PJI.

Are Functional Outcomes of a Total Hip Arthroplasty Predictive of a Contralateral Total Hip Arthroplasty: A Retrospective Cohort Study.

BACKGROUND: Current literature suggests that 8%-35% of patients undergoing total hip arthroplasty (THA) undergo a subsequent contralateral THA. This study aims to determine if functional outcomes after primary THA predict outcomes in the subsequent primary THA of the contralateral side. METHODS: A retrospective cohort of patients undergoing staged bilateral primary THA was reviewed. The Oxford Hip Score (OHS) was utilized as the functional outcome measurement tool and was assessed preoperatively and at one year postoperatively. The minimal clinically important difference (MCID) was assessed. Based on the first-side THA one-year outcomes, the odds of maintaining an MCID, or not, for the second-side THA were determined. RESULTS: The study cohort consisted of 551 patients and 1102 primary THAs. The average postoperative OHSs were similar after the first and second THA. Patients achieving the MCID with the first-side surgery were 2.6 times (95% confidence interval 1.0 to 6.64, P = .04) more likely to achieve the MCID for the second-side surgery than patients failing to reach the MCID for their first-side surgery. After the first THA, 29 (5.3%) patients failed to reach the predefined MCID for the OHS compared with 54 (9.8%) patients undergoing their second THA (odds ratio: 1.96 [95% confidence interval: 1.23 to 3.1], χ2 = 8.14, P = .005). CONCLUSIONS: Functional outcomes after the first THA are predictive of functional outcomes of the second THA. Patients are more likely to achieve a clinically significant improvement after their first THA related to higher preoperative OHSs before the second THA.

Is There a Role for Preclosure Dilute Betadine Irrigation in the Prevention of Postoperative Infection Following Total Joint Arthroplasty?

BACKGROUND: Conflicting evidence exists surrounding the use of preclosure irrigation solutions in primary total joint arthroplasty (TJA). We aimed to determine the role of dilute betadine lavage in preventing early infection after primary TJA. METHODS: We retrospectively reviewed primary TJAs between 2010 and 2018. Dilute betadine lavage was introduced to our practice in November 2014. We included 3513 total hip arthroplasties, 3932 total knee arthroplasties, and 1033 hip resurfacings (HRs). In group 1 (n = 5588), surgical wounds were irrigated with saline; group 2 used dilute betadine solution (n = 2890). Subanalyses using propensity matching based on known risk factors of infection-age, body mass index, American Society of Anesthesiologists grade, diabetes, and procedure-were completed. RESULTS: There were 48 acute infections in group 1 (0.9%) and 23 in group 2 (0.8%) (P = .762). HR without betadine had the highest acute infection prevalence (P = .028). When groups in the whole cohort were propensity score-matched, group 1 had more acute infections than group 2 (P = .033). The effect of betadine was isolated to HR patients. After excluding HR cases, betadine continued to reduce the acute infection rate when compared with the no betadine group, but this was not statistically significant (0.4% vs 0.8%; P = .101). Likewise, we did not find a significant difference in total hip arthroplasty and total knee arthroplasty patients (P = .796). CONCLUSION: There was a decreased infection rate in the betadine group overall when groups were propensity-matched. Because the reduction in the acute infection rate was clinically significant, we feel this practice is an effective means to prevent infections.

Backside Wear Is Not Dependent on the Acetabular Socket Design in Crosslinked Polyethylene Liners.

BACKGROUND: Although it is understood that backside damage occurs in polyethylene acetabular liners, the effect of highly crosslinked polyethylene, which has completely replaced conventional polyethylene, has yet to be examined. QUESTIONS/PURPOSES: The purpose of this study was to answer the following questions: (1) With conventional polyethylene (CPE), did the acetabular design make a difference in backside wear? (2) Is there a difference in backside damage between CPE and crosslinked polyethylene (XLPE) liners? (3) With XLPE, is the difference in backside wear between designs still present? (4) Is there any difference in backside damage in various zones on backside of individual liners? METHODS: This single-institution retrieval analysis involved visual damage scoring on the backside of 233 polyethylene liners implanted between 2002 and 2011. The liners were retrieved from either polished/dovetail cups (PD) or roughened/wire cups (RW) made by two different manufacturers. The inserts were divided into four groups: PD-CPE (n = 105), PD-XLPE (n = 16), RW-CPE (n = 99), and RW-XLPE (n = 13). Aseptic loosening and polyethylene wear were the predominant reasons for revision of CPE liners, whereas instability and infection were the common reasons for revision of XLPE liners. The time in situ (TIS) was shorter for the XLPE liners as compared with the CPE liners (PD-CPE: 8.5 years [SD 4.4]; RD-CPE: 9.5 [SD 4.8]; PD-CPE: 3.8 [SD 3.7]; RD-XLPE: 4.0 [SD 4.3]). The backside of each liner was divided into five zones and graded initially from a scale of 0 to 3 for seven different damage modes by one observer. There was substantial interobserver (kappa 0.769) and intraobserver (0.736) reliability on repeat scoring. To compare the effects of crosslinking, a subset of the conventional polyethylene liners was matched to the crosslinked liners based on TIS, resulting in 16 per group for the two PD types and 13 per group for the two RW types. RESULTS: Total damage scores in the RW-CPE (19 ± 7) group were greater (p < 0.001) than the PD-CPE group (8 ± 4). Damage was reduced with XLPE (p = 0.02) only for the RW-XLPE (9 ± 9) versus RW-CPE-type sockets (4 ± 4). There was no difference (p = 0.16) between the RW-XLPE group and the PD-XLPE group. Damage scores in the peripheral zone of the locking mechanisms were higher for RW-CPE (4 ± 3) compared with PD-CPE (1.4 ± 1.0, p < 0.001) and RW-XLPE (1.3 ± 1.3, p = 0.02). Damage was greater (p < 0.001) within the superior zones (7 ± 4) compared with the inferior zones (3.0 ± 2.8) of all liners. CONCLUSIONS: The current study shows greater backside damage for CPE in the roughened, wire lock cups. XLPE was shown to be more resistant to backside damage for both socket designs. CLINICAL RELEVANCE: Although the polished/dovetail cups seem to cause less backside damage in the CPE liners than roughened/wire cups, the use of XLPE liners has been shown to protect the liner from backside damage in either cup design. If an acetabular shell has a functional locking mechanism, surgeons should not worry about cup design when undertaking isolated liner revision using XLPE liners.

Comparison of Tibial Insert Polyethylene Damage in Rotating Hinge and Highly Constrained Total Knee Arthroplasty: A Retrieval Analysis.

This study compared the damage scores and damage patterns in 19 tibial inserts from rotating hinge (RH) implants with 19 inserts from highly constrained (HC) implants. Each insert was divided into 16 damage zones and each zone was subjectively graded from a scale of 0-3 for seven different damage modes. The overall damage scores were comparable for the two groups (RH: 64.1 ± 15.4; HC: 66.1 ± 29.0; P = 0.59). The HC group, however, had greater post damage (compared to the post-hole of RH) while the RH group had greater backside damage. The pattern of damage was also different, with burnishing and cold flow being more common in HC group while pitting, scratching and embedded debris were more common in the RH group.

The innervation of the human acetabular labrum and hip joint: an anatomic study.

BACKGROUND: The aim of the current study was to evaluate the innervation of the acetabular labrum in the various zones and to understand its potential role in nociception and proprioception in hips with labral pathology. METHODS: A total of twenty hip labrums were tagged and excised intraoperatively from patients undergoing a total hip replacement. After preparation, the specimens were cut to a thickness of 10 µm and divided into four quadrants (zones) using a clock face pattern. Neurosensory structure distribution was then evaluated using Hematoxylin and Eosin (H and E), and immunoreactivity to S-100. RESULTS: All specimens had abundant free nerve endings (FNEs). These were seen predominantly superficially and on the chondral side of the labrum. In addition, predominantly three different types of nerve end organs (NEOs) were identified in all twenty specimens. FNEs and NEOs were more frequently seen in the antero-superior and postero-superior zones. Four specimens had abundant vascularity and disorganised architecture of FNEs in the deeper zones of the antero-superior quadrant suggestive of a healed tear. Myofibroblasts were present in abundance in all the labral specimens and were distributed uniformly throughout all labral zones and depth. CONCLUSIONS: The current study shows that the human acetabular labrum has abundant FNEs and NEOs. These are more abundant in the antero-superior and postero-superior zones. The labrum, by virtue of its neural innervation, can potentially mediate pain as well as proprioception of the hip joint, and be involved in neurosecretion that can influence connective tissue repair.

Neutrophil to Lymphocyte Ratio as an Indicator of Periprosthetic Joint Infection: A Retrospective Cohort Study.

INTRODUCTION: Periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) is a serious complication posing notable clinical implications for patients and substantial economic burdens. Neutrophil to lymphocyte ratio (NLR) is an emerging biomarker of inflammation, which may better predict PJI. The objective of this review was to evaluate NLR changes in patients with confirmed PJI, to compare NLR between an aseptic revision and a revision for PJI, and to establish whether an NLR of 2.45 is an appropriate cutoff for predicting infection. METHODS: A retrospective review of patients who underwent revision TJA for PJI at a single center between January 1, 2005, and December 31, 2018, was performed and compared with an aseptic cohort who underwent aseptic revision TJA. NLR was calculated from complete blood counts performed at index surgery and at the time of revision surgery. Receiver operating characteristic curves were analyzed, along with sensitivity, specificity, and positive and negative likelihood ratios. RESULTS: There were 89 patients included in each cohort. Mean NLR in patients who underwent revision for PJI was 2.85 (± 1.27) at the time of index surgery and 6.89 (± 6.64) at the time of revision surgery ( P = 0.017). Mean NLR in patients undergoing revision for PJI (6.89) was significantly higher than aseptic revisions (3.17; P < 0.001). DISCUSSION: In patients who underwent revision surgery for PJI, NLR was markedly elevated at time of revision compared with the time of index surgery. Because it is a cost-effective and readily available test, these findings suggest that NLR may be a useful triage test in the diagnosis of PJI. LEVEL OF EVIDENCE: Level III Diagnostic Study.

Distal femoral osteochondroma masquerading as deep vein thrombosis in an adolescent male.

Deep venous thrombosis (DVT) is uncommonly seen in children and adolescents. A distal femoral osteochondroma causing isolated lower limb DVT is even rarer and to our knowledge only four such cases have been reported in the literature. We report a case of a solitary distal femoral osteochondroma in a 15-year-old adolescent presenting as isolated DVT. We highlight the potential of coexistence of DVT and osteochondroma in young patients. We also emphasize the importance of timely diagnosis and outline the plan of management when faced with such a rare condition.

Steroid-induced stress fracture of medial tibial condyle: a case report.

Corticosteroid-induced stress fractures have been described, but such a presentation is rare in tibial condyle where osteonecrosis secondary to steroid use is more common. In this report we describe a case of stress fracture of medial tibial condyle secondary to corticosteroid (glucocorticoid) intake in a 47-year-old man. We discuss in detail the pathogenesis of this condition, and highlight the importance of various diagnostic modalities to avoid misdiagnosis of the condition. We also reiterate the importance of early diagnosis and prompt immobilization to prevent long-term morbidity in such cases.

Cephalomedullary fixation for femoral neck/intertrochanteric and ipsilateral shaft fractures: surgical tips and pitfalls.

OBJECTIVE: Surgical management options for femoral shaft fracture and ipsilateral proximal femur fracture vary from single-implant to double-implant fixation. Cephalomedullary fixation in such fractures has relative advantages over other techniques especially because of less soft tissue dissection and immediate postoperative weight bearing with accelerated rehabilitation. However, the surgery is technically demanding and there is a paucity of literature describing the surgical techniques for this fixation. The aim of the study was to describe the surgical technique of cephalomedullary fixation for femoral shaft fracture and ipsilateral proximal femur fracture. METHODS: Sixteen cases (10 males and 6 females with a mean age of 41.8 years) of ipsilateral proximal femur and shaft fractures were treated by single-stage cephalomedullary fixation at tertiary level trauma center in northern India. The fractures were classified according to AO classification. An intraoperative record of duration of surgery as well as technical challenges unique to each fracture pattern was kept for all the patients. RESULTS: The most common proximal femoral pattern was AO B2.1 observed in 9 of our patients. The AO B2.3 fractures were seen in 4 patients while the AO A1.2 fractures in 3 patients. Four of the AO B2.1 and 2 of the AO B2.3 fractures required open reduction with Watson-Jones approach. The mean operative time was around 78 minutes, which tended to decrease as the surgical experience increased. There was only one case of malreduction, which required revision surgery. CONCLUSION: Combination of ipsilateral femoral shaft fracture and neck/intertrochanteric fracture is a difficult fracture pattern for trauma surgeons. Cephalomedullary nail is an excellent implant for such fractures but it requires careful insertion to avoid complications. Surgery is technically demanding with a definite learning curve. Nevertheless, a majority of these fractures can be surgically managed by single-implant cephalomedullary fixation by following basic surgical principles that have been summarized in this article.

Causes and predictors of failed same-day home discharge following primary hip and knee total joint arthroplasty: a Canadian perspective.

PURPOSE: Same-day home (SDH) discharge in total joint arthroplasty (TJA) has increased in popularity in recent years. The objective of this study was to evaluate the causes and predictors of failed discharges in planned SDH patients. METHODS: A consecutive cohort of patients who underwent total knee (TKA) or total hip arthroplasty (THA) that were scheduled for SDH discharge between 01 April 2019 and 31 March 2021 were retrospectively reviewed. Patient demographics, causes of failed discharge, perioperative variables, 30-day readmissions and 6-month reoperation rates were collected. Multivariate regression analysis was undertaken to identify independent predictors of failed discharge. RESULTS: The cohort consisted of 527 consecutive patients. 101 (19%) patients failed SDH discharge. The leading causes were postoperative hypotension (20%) and patients who were ineligible for the SDH pathway (19%). 2 individual surgeons, later operative start time (OR 1.3; 95% CI, 1.15-1.55; p = 0.001), ASA class IV (OR 3.4; 95% CI, 1.4-8.2; p = 0.006) and undergoing a THA (OR 2.0; 95% CI, 1.2-3.1, p = 0.004) were independent predictors of failed SDH discharge. No differences in age, BMI, gender, surgical approach or type of anaesthetic were found (p > 0.05). The 30-day readmission or 6-month reoperation were similar between groups (p > 0.05). CONCLUSIONS: Hypotension and inappropriate patient selection were the leading causes of failed SDH discharge. Significant variability existed between individual surgeons failed discharge rates. Patients undergoing a THA, classified as ASA IV or had a later operative start time were all more likely to fail SDH discharge.

Open reduction and internal fixation of isolated PCL fossa avulsion fractures.

PURPOSE: The study was aimed to share the experience of managing posterior cruciate ligament (PCL) avulsion fractures of tibia with open reduction and internal fixation (ORIF). The study also evaluated the effect of delay in treatment and presence of occult PCL injury on the final outcome after surgery. METHODS: Forty-two patients (30 males and 12 females) with a median age of 26 years (range: 14-53 years) who underwent ORIF through a modified posterior approach for PCL fossa avulsion fractures were assessed after a median follow up of 18 months (range 10-42 months). In 30 patients surgery was performed within 3 weeks of injury. Fifteen patients had an occult intrasubstance PCL tear as seen on MRI. Assessment of results was made using Hughston criteria. RESULTS: There was a statistically significant difference in the outcomes between acutely treated patients and patients with chronic injury. Although patients with acute fixation were found to fare better, the results were fair or good in majority of the patients (9 out of 12) with delayed presentation. Patients with occult injury to PCL had poorer outcomes and these results were found to be statistically significant. CONCLUSION: ORIF for PCL avulsion fractures of tibia results in stable fixation, early mobilization and good functional outcomes. Although ORIF done acutely leads to best clinical outcomes, a delay in presentation (>3 weeks) does not necessarily contraindicate ORIF. An occult injury to PCL usually leads to inferior outcomes and primary PCL reconstruction should be considered as a viable option in these patients.

Evaluation of echogenic emboli during total knee arthroplasty using transthoracic echocardiography.

PURPOSE: Tranesophageal echocardiography or direct sampling of arterial and/or right atrial blood with histological evaluation are invasive techniques used to evaluate embolic material entering the heart during total knee arthroplasty (TKA). The aim of this study was to develop a non-invasive method of detecting and quantifying the embolic matter using transthoracic echocardiography and to apply this method to compare the incidence and severity of embolism between computer-navigated (N) and conventional (C) TKA done under tourniquet. METHODS: Twenty-eight patients (15 N-TKA and 13 C-TKA) were enrolled. Transthoracic echocardiography was performed in all standard views prior to surgery and continuously after the tourniquet release for monitoring the echodense particulates appearing in the right atrium. To estimate the severity of echogenic embolization, maximum absolute increase in luminosity after tourniquet release (peak embolic load) and area under the curve (AUC; total embolic load) were both calculated. RESULTS: Twenty-four (85%) had significant particulate matter in right atrium (median time from release of thigh tourniquet to peak embolization in right atrium: 18.0 s). Peak embolic load was lower in N-TKA than C-TKA [17.0 versus 35.0 arbitrary luminosity units, p = 0.03]. Total embolic load, by area under the curve, was lower in the N-TKA group. CONCLUSIONS: Perioperative particulate embolization during TKA can be quantified non-invasively with the use of transthoracic echocardiography and off-line image analysis. N-TKA, by virtue of avoiding intramedullary guides, causes lesser total embolic load and hence can lead to decreased the severity and incidence of this potentially fatal phenomenon. LEVEL OF EVIDENCE: II.

Efficacy of immunohistological methods in detecting functionally viable mechanoreceptors in the remnant stumps of injured anterior cruciate ligaments and its clinical importance.

PURPOSE: Various histological and immunological methods have been used to detect the mechanoreceptors and nerve fibers on the intact ACLs as well as on the remnant stumps. However, some of these methods lack standardization, and the variable thickness of slices used often leads to misinterpretation. The study was based on the hypothesis that immunohistological methods are easier and more reliable means to demonstrate mechanoreceptors in the remnant ACL stumps as compared with the conventional methods. We also attempted to validate the methodology of immunohistology as a means of characterizing functional mechanoreceptors in the residual stump of an injured ACL. METHODS: The remnants of the ruptured ACL in 95 patients were harvested during arthroscopic ACL reconstruction and evaluated immunohistologically using hematoxylin and eosin (H&E), and monoclonal antibodies to S-100 and NFP. Multiple sections from each specimen were serially examined by two histologists. RESULTS: The positivity of monoclonal antibody against NFP showed a statistically significant relationship with the presence of morphologically normal mechanoreceptors, whereas the positivity of monoclonal antibody against S-100 showed a statistically significant relationship with the presence of free nerve ending in the residual stump of an injured ACL. CONCLUSIONS: Immunological methods are more reliable and easier to use as compared with the conventional methods of histological staining for identifying remnant stumps likely to be of some proprioceptive benefit after an ACL injury. Such an identification might help us preserve certain remnant stumps during ACL reconstruction which might in turn improve the postoperative functional outcomes.

Custom-fit total knee arthroplasty: our initial experience in 32 knees.

We share our initial experience of total knee arthroplasty (TKA) using customized cutting block technology in 32 TKAs from May 2010 to March 2011. Ten of these patients had prior TKA done on the other side using conventional or navigation-assisted TKA. Customized cutting blocks were generated for each of the knee using preoperative magnetic resonance imaging of knee and long-leg weight-bearing radiographs. At 6 weeks, long-leg radiographs were obtained to evaluate the coronal alignment. There were no adverse intraoperative events. Twenty-nine of the 32 knees had a mechanical axis restored to within 3°° of neutral. Of 10 patients with prior TKA without custom-fit technology, the mean blood loss and the mean skin-to-skin time was found to be lower in knees that had undergone custom-fit TKA. We conclude that this technology can be safely used in most of the cases of osteoarthritis.

Primary malignant melanoma of proximal tibia.

Primary malignant melanoma (clear cell sarcoma) of bone is a very rare neoplasm. Although metastatic melanoma to bone is not uncommon, primary malignant melanoma of bone is extremely uncommon. To date, only nine cases have been reported in the English literature. In this report, we present a case of primary malignant melanoma arising from the medial aspect of the proximal tibia in a 26-year-old woman. We treated the patient with above-knee amputation without any chemotherapy or radiotherapy. At final follow-up of 18 months, the patient was free of disease.

Displaced femoral neck fractures in the young: significance of posterior comminution and raised intracapsular pressure.

BACKGROUND: Osteosynthesis in fracture neck of femur (NOF) in young is a universally acceptable procedure. Various factors affect the outcome; with AVN (avascular necrosis) and non-union primarily contributing to adverse results in such patients. To identify factors affecting outcome of displaced fracture NOF, a prospective cohort study was carried out in the setting of a tertiary care centre in developing country. METHODS: 27 consecutive patients with displaced fracture NOF suitable for osteosynthesis underwent closed reduction and fixation with three 6.5 mm cancellous cannulated screws. A record of posterior comminution and its extent (as seen on CT scan) and the intracapsular pressure difference between the fractured and the opposite side was kept in all the patients. The patients were followed-up for 1 year. The main outcomes measured at 1 year were non-union (as identified by CT scan) and AVN (as identified by bone scan). RESULTS: Cases with pressure difference >30 mm were found to have a higher rate of AVN and this result was found to be statistically significant (p value 0.034). The patients with significant posterior comminution were found to have higher non-union rates and this result was also found to be statistically significant (p value 0.04). CONCLUSIONS: Prognosis of displaced fracture NOF is significantly associated significant with posterior comminution and intracapsular pressure difference between fractured and normal side.

Diagnosing Periprosthetic Joint Infection: a Scoping Review.

PURPOSE OF REVIEW: The goal of this review is to provide an up to date understanding of the utility and limitations of the current tests utilized in the diagnosis of periprosthetic joint infection (PJI) in total knee and hip arthroplasty. RECENT FINDINGS: Despite the growth in literature surrounding PJI diagnosis, there remains challenges in establishing a diagnosis of PJI. A combination of clinical, serum, and synovial tests and microbiologic and histologic examinations can yield a diagnosis in the majority of cases. Novel molecular and imaging studies may be beneficial for indeterminant cases. A number of emerging diagnostic tests have been proposed and may be incorporated into diagnostic algorithms in the future. Recently proposed stepwise diagnostic algorithms have shown high sensitivity and specificity. The diagnosis of PJI remains challenging due to a lack of tests that can definitively rule out infection. Diagnosis and investigations should occur in a stepwise fashion. There has been a plethora of new diagnostic tests introduced in attempts to improve the accuracy of diagnostic algorithms. The definition and algorithms for the diagnoses of PJI will continue to evolve as new techniques and tests are introduced.