Trends in the use of ankle arthrodesis and total ankle replacements in Australia over the past 20 years.

BACKGROUND: End stage ankle osteoarthritis (OA) is debilitating. Surgical management consists of either ankle arthrodesis (AA) or a total ankle replacement (TAR). The purpose of this study is to assess the trends in operative intervention for end stage ankle OA in an Australian population. METHODS: This is a retrospective epidemiological study of 15,046 surgeries. Data were collected from publicly available national registries including the Australian Medicare Database and Australian Orthopaedic Association National Joint Replacement Registrar from 2001 to 2020. RESULTS: There was a significant increase in all ankle surgeries performed across the period of interest. AA remained the more commonly performed procedure throughout the course of the study (11,946 cases, 79.4%) and was never surpassed by TAR (3100, 20.6%). The overall proportions demonstrated no significant changes from 2001 to 2020. CONCLUSION: The incidence of ankle surgeries continues to increase with the ageing and increasingly comorbid population of Australia. Despite demonstrating no significant overall change in the ratio of TAR and AA in our study population and period, there are noticeable trends within the timeframe, with a recent surge favouring TAR in the last 5 years.

Dual Construct Fixation of the Scaphoid.

Dual construct fixation has been increasingly used in complex peri-articular or peri-prosthetic long bone fractures, those with poor bone quality and in revision situations. We describe the utilisation of a screw-plate construct in the setting of a juxta-articular distal pole scaphoid fracture, review the literature and provide recommendations for future use. Level of Evidence: Level V (Therapeutic).

Open versus Single- or Dual-Portal Endoscopic Carpal Tunnel Release: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Compared to the traditional open carpal tunnel release (OCTR), the additional safety and efficacy benefits of endoscopic carpal tunnel release (ECTR) remains unclear. The aim of this study is to evaluate the outcomes of ECTR versus conventional OCTR as well as determine if a difference exists between the 2 most common endoscopic techniques: the single-portal and the dual-portal endoscopic technique. METHODS: We conducted a systematic literature search of Medline, Embase, PubMed, and the CENTRAL. Additional articles were identified by handsearching reference lists. We included all randomized controlled trials that compared outcomes of ECTR with OCTR technique. Outcomes assessed included length of surgery, patient reported symptom and functional measures, time to return to work, and complications. A sub-group analysis was performed to indirectly compare single- versus dual-portal endoscopic approaches. Statistical analysis was performed via a random-effects model using Review Manager 5 Software. RESULTS: A meta-analysis of 23 studies revealed a significantly higher incidence of transient postoperative nerve injury with ECTR, regardless of the number of portals, as compared with OCTR, although overall complication and re-operation rates were equivalent. Scar tenderness was significantly diminished with dual-portal endoscopic release when compared to single-portal and open methods. The rates of pillar pain, symptom relief, and patient reported satisfaction did not differ significantly between treatment groups. CONCLUSIONS: Although endoscopic surgery may be appealing in terms of reduced postoperative morbidity and a faster return to work for patients, surgeons should be mindful of the associated learning curve and higher incidence of transient nerve injury. Further study is required to identify if an advantage exists between different endoscopic techniques.

Overlapping surgery in arthroplasty - a systematic review and meta-analysis.

BACKGROUND: Planned overlapping surgery can improve efficiency, reduce costs and help manage long waiting lists; yet, this practice has been questioned due to patient safety concerns. A systematic review and meta-analysis were performed to answer the question: (1) are there any differences in the risk of postoperative adverse outcomes; and (2) are there any differences in length of stay or length of surgery, in elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) performed either as non-overlapping surgery (NOS) or overlapping surgery (OS). PATIENTS AND METHODS: A systematic search of literature in the databases of MEDLINE, PubMed, Embase and Cochrane from dates of inception was performed. All studies published in English were included. Risk of Bias in Non-randomised Studies-of Interventions (ROBINS-I) and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework were utilised. Relative risk (RR) was used for dichotomous outcomes, while mean difference (MD) was used for continuous variables, with 95% confidence intervals. Alpha was set at 0.05. RESULTS: A total of nine studies with 120,625 patients were included for analyses. There were no statistically significant differences for overall rates of postoperative complications, dislocations, fractures, infections, readmissions or revision surgery nor with length of stay or length of surgery (p>0.05). Patient characteristics between groups were similar (p>0.05). DISCUSSION: There were no differences in postoperative adverse outcomes for elective orthopaedic THA and TKA performed as NOS when compared to OS. Operating schedules for OS in elective lower limb arthroplasty appear to be safe, given appropriate patient selection processes and may be a useful method to improve hospital efficiency. Informed consent and preoperative patient education should remain paramount. LEVEL OF EVIDENCE: IV.

Temporal trends in the management of metacarpal and phalangeal fractures in the 21st century: an analysis of Australian population-based data.

BACKGROUND: Fractures of the hand, specifically the metacarpals and phalanges, are a common injury. Whilst many of these fractures can be treated non-operatively, a number of advances have led to the increase in popularity of surgical intervention. The aim of this study was to assess and describe trends in management of phalangeal and metacarpal fractures in Australia over the last two decades. METHODS: A review was conducted of the Medicare Benefits Scheme (MBS), specifically querying the item numbers pertaining to the management of metacarpal and phalanx fractures. Data was recorded as the incidence per 100 000 patients. RESULTS: Overall, there was a statistically significant decrease in the incidence of closed reduction of metacarpal and phalanx fractures, with a converse statistically significant increase in open reduction internal fixation. CONCLUSION: This study demonstrates that over the last 20 years, there has been a decrease in closed reduction of intra- and extra-articular phalangeal and metacarpal fractures, with a converse but smaller increase in open reduction and fixation. These trends are likely multi-factorial in aetiology, and should be monitored to guide resource allocation and health provision in the future.

Basic Statistics for Surgeons.

Interpreting research is an important skill to ensure one can maintain their practise with current evidence. The technicalities of statistics can be daunting and thus, this article aims to provide a clear overview of key statistical tests that a surgeon will encounter. It highlights the various study designs, summary statistics and comparative tests that are used in clinical research. Furthermore, it provides a guide to determine which statistical method is most appropriate for various study designs. Overall, it aims to act as an introductory text to supplement further reading into the more advanced statistical methodologies. Level of Evidence: Level V.

Fibular fixation in mid and distal extra-articular tibia fractures - A systematic review and meta-analysis.

BACKGROUND: The surgical management of extra-articular mid and distal tibia fractures has primarily focused on reducing rates of non-union and malunion, preserving hip-knee-ankle alignment and improving functional outcomes. Fibular fractures commonly accompany these injuries and the contributory role of fixation of these fractures has been increasingly studied. A systematic review and meta-analysis were performed to determine whether concurrent fibular fixation (FF) during extra-articular mid and distal tibia fracture fixation (AO/OTA 42 and 43-A) altered the risk of malunion, non-union and post-operative complications when compared to no fibular fixation (NF). METHODS: A systematic search of literature in the databases of MEDLINE (via OvidSP), PubMed, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) from the dates of inception was performed for randomised and non-randomised controlled trials. All studies published in English were included. Risk of Bias in Non-randomised Studies (ROBINS-I) and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework were utilised. Relative risk (RR) was used for dichotomous outcomes, while mean difference (MD) was used for continuous variables, with 95% confidence intervals. Alpha was set at 0.05. RESULTS: A total of ten studies with 1174 patients were included for analysis. There was a statistically significant reduced risk of overall malunion in the FF group compared to the NF group (11.8% vs 21.9%, RR 0.63, 95% CI: 0.41-0.98, p = 0.04) and this was supported through a sensitivity analysis of only randomised controlled trials (21.8% vs 40.3%, RR 0.37, 95% CI: 0.18-0.76, p = 0.006). There was no statistically significant difference in rates of non-union between groups (p > 0.05). Overall, there were similar incidences of diabetes, open fractures and smoking history between groups (p > 0.05). Detailed information regarding methods of tibial fixation were not available for subgroup analysis. CONCLUSION: In conclusion, in extra-articular mid and distal tibia (AO/OTA 42 and 43-A) fracture fixation, additional fibular fixation (FF) appears to significantly reduce the risk of overall malunion (RR, 0.37, 95% CI: 0.18-0.76, p = 0.006) without increasing the risk of non-union. These results should be interpreted with caution given the lack of subgroup analysis for methods of tibial fixation. Future high-quality randomised controlled trials should therefore delineate between types of tibial fixation.

Rehabilitation protocols following rotator cuff repair: a meta-analysis of current evidence.

BACKGROUND: Rotator cuff tears are a common shoulder pathology with an increasing incidence. The optimum post-operative rehab protocol remains unclear and can consist of either conservative rehabilitation or more aggressive early range-of-motion. Multiple studies have assessed these treatment protocols. This meta-analysis aims to compare post-operative clinical outcomes following either conservative or aggressive rehabilitation post rotator cuff repair. METHODS: A systematic electronic literature search was undertaken using a number of databases. Eligible studies included randomized control trials published between January 2013 and April 2019 in English with patients having had received rotator cuff repair. Post-operative clinical outcomes considered included shoulder range-of-motion, overall function status (Costant-Murley score) and rates of rotator-cuff re-tear. Studies were evaluated for methodological quality in accordance with the Physiotherapy Evidence Database (PEDro) scale. Summarized pooled statistics were calculated using Review Manager (v5.3) software. RESULTS: A total of six randomized controlled trials were included. Standardized mean difference (SMD) in shoulder flexion, abduction and external rotation was not statistically significant at either 6 or 12 months post rotator cuff repair. Functional assessment suggests a slight benefit in Constant-Murley Score (SMD = 1.77; 95% CI -3.93, 7.47) in aggressive treatment groups with no significant risk increase for cuff re-tear (RR = 1.22; 95% CI 0.60, 2.47). CONCLUSION: This meta-analysis suggests there is no clear benefit of either rehabilitation protocol when considering range-of-motion, with a possible benefit in functional outcome at the cost of increased re-tear risk post aggressive rehabilitation. Both protocols have been shown to offer safe reproducible short- and long-term outcomes.

Dedicated hip fracture services: a systematic review.

BACKGROUND: Hip fractures (HFs) are common and pose a significant burden to both the individual and the community. Prompt operative management and aggressive rehabilitation have been shown to improve outcomes. However, there is often a delay in treatment due to lack of theatre availability and appropriate perioperative multi-disciplinary care. This study reviews the literature and reports on outcomes of HFs treated in dedicated units with allocated theatre time and pre-determined multi-disciplinary perioperative pathways. It also provides comparison against outcomes data from HF registries, both domestically and internationally. METHODS: An electronic literature search was performed to identify original, English language studies reporting on patient outcomes from dedicated HF units (HFUs). Studies were graded using the Journal of Bone and Joint Surgery criteria. Data were extracted from the text, table and figures of the selected studies. RESULTS: Five appropriate studies, with a total cohort of 6633 patients (4032 of whom were treated in a dedicated HFU), were identified. Patients treated in these units sustained a lower mortality rate (Risk Ratio  = 0.62, p = 0.01). CONCLUSIONS: This review demonstrates that centres with dedicated HFUs result in improved 30-day mortality. Further research may demonstrate more sustained improvements in outcomes. The implementation of dedicated HFUs within health systems should be considered.

Hip fracture surgery performed out-of-hours-A systematic review and meta-analysis.

INTRODUCTION: . Early hip fracture surgery (<48 hours) has shown to improve mortality for geriatric patients and is recommended in national hip fracture guidelines. However, this may be at the expense of surgery being performed out-of-hours where concerns about mortality risk exist. A systematic review and meta-analysis were performed to determine the mortality risk for hip fracture surgery performed in-hours (IH) compared to out-of-hours (OH), and on weekdays (WD) compared to weekends (WE). MATERIALS AND METHODS: . A systematic search of literature in the databases of MEDLINE, PubMed, Embase and Cochrane from the dates of inception was performed. All studies published in English were included. Risk of Bias in Non-randomised Studies (ROBINS-I) and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) framework were utilised. Relative risk (RR) was used for dichotomous outcomes, while mean difference (MD) was used for continuous variables, with 95% confidence intervals. Alpha was set at 0.05. RESULTS: . A total of 13 studies with 177,090 patients were included for analysis. Overall, there was no statistically significant difference for 30-day or inpatient mortality in IH vs OH groups (RR 0.93, p=0.46 and RR 1.16, p=0.63) and for WD vs WE groups (RR 0.98, p=0.73 and RR 0.76, p=0.67). There was no difference in length of stay between groups (p>0.05). The number of patients with American Society of Anaesthesiology (ASA) physical status classification ≥3 and male gender between the groups were similar (p>0.05). CONCLUSION: . Performing hip fracture surgery OH or on the WE does not appear to increase the risk of 30-day or inpatient mortality or post-operative complications. Consideration should be given to performing hip fracture surgery out-of-hours to meet national guidelines (<48 hours).

Aspirin versus enoxaparin for the initial prevention of venous thromboembolism following elective arthroplasty of the hip or knee: A systematic review and meta-analysis.

BACKGROUND: Aspirin is perceived to be non-inferior to enoxaparin, a low-molecular-weight heparin, for the prevention of venous thromboembolism (VTE) following elective arthroplasty of the hip or knee and is recommended in clinical guidelines internationally. Previous systematic reviews of aspirin as VTE prophylaxis have been limited by the inclusion of heterogenous studies where aspirin is commenced after the initial high-risk postoperative period. The purpose of this systematic review and meta-analysis was to compare the efficacy and associated harms of aspirin and enoxaparin when used as VTE prophylaxis in the initial postoperative period following elective arthroplasty of the hip or knee. We sought to: (1) to compare the use of aspirin versus enoxaparin following elective joint replacement of the hip or knee on the primary outcomes of incidence of VTE and mortality up to 3 months postoperatively and (2) assess the efficacy of aspirin with respect to secondary outcomes such as major or minor bleeding events. We hypothesised that aspirin would have equivalent efficacy for the prevention of VTE when used as initial prophylactic agent, without increasing harm from bleeding events. PATIENTS AND METHODS: We searched Pubmed, Embase, Medline and Cochrane Central for randomized controlled trials reporting the primary outcomes of VTE incidence and mortality. Secondary outcomes included major (compromise of organ, limb or muscle function requiring unplanned re-operation) and minor bleeding events (wound ooze, minor bleed, infection). Included trials underwent a risk of bias and quality of evidence assessment using the GRADE criteria. RESULTS: Four trials involving 1507 participants who underwent elective lower limb arthroplasty were included. We did not detect a significant difference in overall VTE rates when comparing aspirin versus enoxaparin (RR, 0.84; 95% CI: 0.41 to 1.75; p=0.65). Mortality was reported by one study and no events were recorded. There were no significant differences in the rates of all major (RR, 0.84; 95% CI: 0.08 to 9.16) or minor (RR, 0.77; 95% CI: 0.34 to 1.72) bleeding events between the aspirin and enoxaparin groups. Included trials demonstrated a significant risk of bias, and Low to Very Low quality of evidence for primary outcomes, and Moderate to Very Low for secondary outcomes. CONCLUSION: There is currently a lack of high quality randomised controlled trials supporting the use of aspirin as VTE chemoprophylaxis in the initial postoperative period for both total hip and total knee arthroplasty. The results of this meta-analysis provide cautious endorsement for the position that aspirin is likely a safe alternative to enoxaparin for TKA patients as part of a multimodal enhanced recovery protocol, but care is advised for THA patients owing to a lack of data from trials. Current evidence from randomized controlled trials is generally of low quality, and does not estimate critical event data for VTE incidence or mortality, as well as major and minor bleeding events with sufficient certainty. PROSPERO Registration CRD42018110784. LEVEL OF EVIDENCE: II, systematic review.

Subacromial analgesia via continuous infusion catheter vs. placebo following arthroscopic shoulder surgery: a systematic review and meta-analysis of randomized trials.

BACKGROUND: Subacromial analgesia (SAA) is hypothesized to reduce pain after arthroscopic shoulder surgery by delivering a continuous infusion of local anesthetic directly to the surgical site. The purpose of this systematic review and meta-analysis was to evaluate the efficacy of SAA vs. placebo for pain relief after arthroscopic subacromial shoulder procedures. METHODS: MEDLINE, Embase, PubMed, and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials comparing SAA with placebo after arthroscopic shoulder surgery. Outcomes collected included pain scores (converted to equivalent ordinal visual analog scores; minimal clinically important difference 1.4 cm), oral morphine equivalents used postoperatively, and catheter-related complications. Meta-analysis was performed via a random-effects model. Included trials underwent a risk of bias and quality of evidence assessment. RESULTS: Nine studies involving 459 participants were included. There were no clinically significant changes for pain scores in SAA at 6-, 12-, 24-, and 48-hour postoperative timepoints. Patients receiving SAA used less morphine equivalents of pain medication at 12 hours only (-0.37 mg, 95% confidence interval: -0.63 to -0.11), but there was no significant difference at 24 and 48 hours. There were no major complications (infection or reoperation). Included trials demonstrated a moderate risk-of-bias, and low to very low quality of evidence for primary outcomes. CONCLUSION: Subacromial continuous infusion of local anesthetic does not provide a clinically significant benefit compared with placebo as part of a multimodal analgesia regime after arthroscopic subacromial surgical procedures. Future, high-quality trials are required to further assess the efficacy of SAA against placebo.

Non-union in lateral locked plating for distal femoral fractures: A systematic review.

INTRODUCTION: This study aims to identify patient and intra-operative factors that contribute to non-union in locked lateral plating for distal femoral fractures. METHODS: Systematic searches of English-language articles in Ovid Medline, PubMed, Embase, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews were undertaken in February 2018 according to the PRISMA guidelines. The search terms were (fracture or fracture*) AND (distal femur or distal femoral) AND (malunion or non-union). Eligible studies published at any time reported non-union rates and compared patient and intraoperative factors in patients who underwent locked lateral plating for traumatic distal femoral fractures. The quality of included papers was assessed using The Journal of Bone and Joint Surgery levels of evidence (Wright et al., 2003), and further appraised using the Downs and Black score (Downs and Black, 1998). RESULTS: Eight studies investigating 1380 distal femoral fractures were found to satisfy the inclusion and exclusion criteria. These studies analysed a variety of patient and intra-operative factors that may contribute to non-union. These include high BMI, open fracture, comminution, fracture infection, stainless steel plate material, shorter working length, open reduction and internal fixation when compared with minimally invasive plate osteosynthesis, high construct rigidity scores and purely locking screw constructs. CONCLUSION: This review has identified multiple factors which potentially contribute to non-union including stainless steel plate material, high construct rigidity scores and purely locking screw constructs. These findings may reflect that overly rigid plating constructs can contribute to non-union. However, they should be taken in the context of heterogeneity amongst included studies, with further research necessary to support these findings.

Extensile lateral versus sinus tarsi approach for displaced, intra-articular calcaneal fractures: a meta-analysis.

BACKGROUND: Operative management of displaced, intra-articular calcaneal fractures is associated with improved functional outcomes but associated with frequent complications due to poor soft tissue healing. The use of a minimally invasive sinus tarsi approach to the fixation of these fractures may be associated with a lower rate of complications and therefore provide superior outcomes without the associated morbidity of operative intervention. METHODS: We reviewed four prospective and seven retrospective trials that compared the outcomes from the operative fixation of displaced intra-articular calcaneal fractures via either an extensile lateral approach or minimally invasive fixation via a sinus tarsi approach. RESULTS: Patients managed with a sinus tarsi approach were less likely to suffer complications (OR = 2.98, 95% CI = 1.62-5.49, p = 0.0005) and had a shorter duration of surgery (OR = 44.29, 95% CI = 2.94-85.64, p = 0.04). CONCLUSION: In displaced intra-articular calcaneal fractures, a minimally invasive sinus tarsi approach is associated with a lower complication rate and quicker operation duration compared to open reduction and internal fixation via an extensile lateral approach.

Arthroscopic simulation using a knee model can be used to train speed and gaze strategies in knee arthroscopy.

PURPOSE: This study aimed to determine the effect of a simulation course on gaze fixation strategies of participants performing arthroscopy. METHODS: Participants (n = 16) were recruited from two one-day simulation-based knee arthroscopy courses, and were asked to undergo a task before and after the course, which involved identifying a series of arthroscopic landmarks. The gaze fixation of the participants was recorded with a wearable eye-tracking system. The time taken to complete the task and proportion of time participants spent with their gaze fixated on the arthroscopic stack, the knee model, and away from the stack or knee model were recorded. RESULTS: Participants demonstrated a statistically decreased completion time in their second attempt compared to the first attempt (P = 0.001). In their second attempt, they also demonstrated improved gaze fixation strategies, with a significantly increased amount (P = 0.008) and proportion of time (P = 0.003) spent fixated on the screen vs. knee model. CONCLUSION: Simulation improved arthroscopic skills in orthopaedic surgeons, specifically by improving their gaze control strategies and decreasing the amount of time taken to identify and mark landmarks in an arthroscopic task.

Prior Lumbar Spinal Fusion is Associated With an Increased Risk of Dislocation and Revision in Total Hip Arthroplasty: A Meta-Analysis.

BACKGROUND: The biomechanical relationship between the lumbar spine and the hip is well-documented. It follows that fusing the lumbar spine would have implications on the outcomes of total hip arthroplasty (THA). This study aimed to determine the effect of preexisting lumbar spinal fusion surgery on the outcomes of THA by synthesizing the available evidence via systematic review and meta-analysis. METHODS: A systematic review with meta-analysis was performed in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic searches were performed in 6 different databases for studies comparing outcomes in patients after THA with or without a history of lumbar fusion. Studies were required to report at least one outcome out of dislocation, revision due to hip instability or patient-reported outcomes. RESULTS: Patients with a history of lumbar spinal fusion are at a significantly increased risk of dislocation (relative risk 2.03, P < .00001) and revision (relative risk 3.36, P = .006) after THA. Patient-reported outcomes were also poorer in patients with prior lumbar fusion compared with those without, although meta-analysis could not be performed due to heterogeneity in the outcome measure used between studies. CONCLUSION: Previous lumbar spinal fusion increases risk of dislocation and revision, and may negatively impacts patient-reported outcomes after THA. Orthopaedic surgeons should pay particular attention to these patients and could use patient-specific planning, instrumentation, and targeted counselling to optimize clinical and subjective outcomes. Future studies could clarify the impact of prior fusion on patient-reported outcomes after THA.

Accuracy of MRI-based vs. CT-based patient-specific instrumentation in total knee arthroplasty: A meta-analysis.

INTRODUCTION: The technical objective of total knee arthroplasty (TKA) is to restore normal mechanical parameters to the knee. Patient-specific instrumentation (PSI) was developed to streamline the operative process and improve accuracy. PSI produces individualized cutting guides based on three-dimensional models of the patient's anatomy acquired from computed-tomography (CT) or magnetic-resonance imaging (MRI). However, the superiority of one modality over the other remains unclear. Therefore, we aimed to compare the accuracy of patient-specific cutting guides produced from MRI or CT imaging methods in TKA. METHODS: Electronic databases were systematically searched using relevant keywords and MeSH terms for original-data English-language publications comparing the accuracy of CT and MRI-based PSI cutting guides in TKA. Data was extracted from the text, tables and figures of studies and meta-analysed. RESULTS: MRI-based PSI cutting guides produced a lower proportion of coronal plane outliers (>3°) with regard to overall limb mechanical axis (OR 2.75, p = 0.01). There were no significant differences between the two in terms of sagittal femoral and tibial component placement, or coronal femoral and tibial placement, or femoral component axial rotation. Tibial rotation was not analysed in the literature. CONCLUSIONS: MRI-based patient-specific cutting guides produced a lower proportion of outliers in the overall coronal alignment of the limb compared to CT, with no significant difference between the two in terms of femoral or tibial component placement. Future studies should investigate the differences in resource usage and operative time between the two to inform surgeons' decision making when choosing an ideal imaging modality for PSI TKA. STUDY DESIGN: Meta-analysis. LEVEL OF EVIDENCE: III, systematic review of cohort and comparative studies.

The accuracy of bony resection from patient-specific guides during total knee arthroplasty.

PURPOSE: In patient-specifically instrumented (PSI) total knee arthroplasty, the correlation between the pre-operative surgical plan, accuracy of the cutting block, and intra-operative resection size is unclear. The aim of this study was to evaluate the ability to accurately execute the PSI surgical plan and to add to the merging information with respect to this technology with the hypothesis that the PSI blocks would demonstrate good accuracy with regard to the bony thickness of the resections. METHODS: One hundred and thirty TKAs using PSI (MRI/long-leg radiographs) were retrospectively analysed. All surgeries were conducted via similar surgical approach and technique, with resection performed after guide placement and alignment assessment. The bony cut thicknesses of the medial (MTP) and lateral tibial plateau (LTP), distal medial (DM), distal lateral (DL), posterior medial (PM) and posterior lateral (PL) femur were measured with a vernier calliper. The measured resection thickness was subtracted from the planned resection. Errors were defined as ≤1.5 mm (acceptable), 1.5-2.5 mm (borderline), and >2.5 mm (outliers). RESULTS: Overall, 81 (62.3 %) of the knees were free of outliers. The distal femur cut had the highest proportion of acceptable cut error with 209 of 260 total cuts acceptable (80.4 %). The tibial cuts had the lowest proportion of "acceptable" cuts (68.9 %). Tibial cuts had more outliers (33 of 260 cuts, 12.7 %) than the femur (39 of 520 cuts, 7.5 %) (p = 0.01). Pre-operative varus (n = 97) and valgus (n = 33) deformities demonstrated 7.7 % (45/482) and 13.6 % (27/198) of cuts which were outliers, respectively (p = 0.01). CONCLUSION: PSI showed only fair to moderate accuracy with 62.3 % of the knees presenting no outliers. The tibia cutting guide was less accurate than the femur. Specific attention is needed when cutting the tibia and in correction of valgus deformity. Moreover, intra-operative verifying measurements can provide feedback to the accuracy of the surgical plan. LEVEL OF EVIDENCE: IV, case series with no comparison group.