The Fate and Relevance of the Patella in Two-Stage Revision Total Knee Arthroplasty for Periprosthetic Joint Infection

BackgroundIt remains unclear whether reimplantation of a patellar component during a two-stage revision for periprosthetic total knee arthroplasty infection (PJI) affects patient reported outcome measures (PROMs) or implant survivorship. The purpose of this study was to evaluate whether patellar resurfacing during reimplantation confers a functional benefit or increases implant survivorship after two-stage treatment for PJI.MethodsTwo-stage revisions for knee PJI performed by three surgeons at a single tertiary care center were reviewed retrospectively. All original patellar components and cement were removed during resection and the patella was resurfaced whenever feasible during reimplantation. PROMs, implant survivorship, and radiographic measurements (patellar tilt and displacement) were compared between knees reimplanted with a patellar component versus those without a patellar component.ResultsA total of 103 patients met the inclusion criteria. Forty-three patients (41.7%) underwent reimplantation with, and 60 patients (58.3%) without a patellar component. At a mean follow-up of 33.5 months, there were no significant differences in patient demographics or PROMs between groups (P ≥ .156). No significant differences were found in the estimated Kaplan-Meier all-cause, aseptic, or septic survivorship between groups (P ≥ .342) at a maximum of 75 months follow-up. There was no significant difference in the change (pre-resection to post-reimplant) of patellar tilt (P = .504) or displacement (P = .097) between the groups.ConclusionPatellar resurfacing during knee reimplantation does not appear to meaningfully impact postoperative PROMs or survivorship. Given the risk of potential extensor mechanism complications with patellar resurfacing, surgeons may choose to leave the patella without an implant during total knee reimplantation and expect similar clinical outcomes.Level of EvidenceLevel III.     

A comparison of lateral release rates in fixed- versus mobile-bearing total knee arthroplasty

BackgroundWith increasing functional demands of patients undergoing total knee arthroplasty, mobile-bearing (MB) implants were developed in an attempt to increase the functional outcome of such patients. In theory, with MB implants, the self-alignment should reduce the rate of lateral release of the patella, which is usually performed to optimise patellofemoral mechanics. This study reports on the lateral release rates for the P.F.C. Sigma® MB posterior-stabilised total knee replacement (TKR) implant compared with its fixed-bearing (FB) equivalent.ResultsThe lateral release rate was the same for FB (10 %) and MB implants (10 %) (p = 0.9). However, patellar resurfacing resulted in lower lateral release rates when compared to patellar retention (6 vs 14 %; p = 0.0179) especially in MB implants (3 %).ConclusionsIt has been previously reported that alterations to the design of the P.F.C. system with a more anatomical trochlea in the femoral component improved patellar tracking. The addition of a rotating platform tibial component to the P.F.C. Sigma system has, on its own, had no impact on the lateral release rate in this study. Optimising patellar geometry by patellar resurfacing appears more important than tibial-bearing design. Although MB implants appear to reduce the need for lateral release in the P.F.C. Sigma Rotating Platform, this only occurs when the patellar geometry has been optimised with patellar resurfacing.

Level of evidence

Level 2.     

Patellar Denervation Reduces Postoperative Anterior Knee Pain After Patellar Resurfacing Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundThe benefit of patellar denervation (PD) in patellar resurfacing total knee arthroplasty (TKA) is still debatable. This prospective, randomized controlled trial investigated whether circumferential PD should be performed in patellar resurfacing TKA.MethodsA total of 241 patients who underwent unilateral TKA were randomized into PD or non-PD groups. Incidence, intensity, and presentation time of anterior knee pain (AKP) and clinical outcomes were evaluated at 3, 6, 9, 12, 18, and 24 months postoperatively.ResultsThe incidence of AKP was significantly lower in the PD group (6.4% vs 16.2%, P = .032). The intensity of AKP and patient satisfaction scores were significantly better in the PD group at 3 months but not after 3 months. The presentation time of AKP mostly occurs at 3 months after surgery. The Knee Society score, range of motion, Oxford score, patellar score, activity of daily living score, and visual analog scale of overall knee pain were not significantly different between the two groups during the follow-up period.ConclusionGiven that PD can improve AKP and patient satisfaction at an early period postoperatively without jeopardizing clinical outcomes at no additional cost, this inexpensive procedure readily available in nearly every operation room is strongly recommended during primary TKA with patellar resurfacing.     

Automated Detection of Periprosthetic Joint Infections and Data Elements Using Natural Language Processing

BackgroundPeriprosthetic joint infection (PJI) data elements are contained in both structured and unstructured documents in electronic health records and require manual data collection. The goal of this study is to develop a natural language processing (NLP) algorithm to replicate manual chart review for PJI data elements.MethodsPJI was identified among all total joint arthroplasty (TJA) procedures performed at a single academic institution between 2000 and 2017. Data elements that comprise the Musculoskeletal Infection Society (MSIS) criteria were manually extracted and used as the gold standard for validation. A training sample of 1208 TJA surgeries (170 PJI cases) was randomly selected to develop the prototype NLP algorithms and an additional 1179 surgeries (150 PJI cases) were randomly selected as the test sample. The algorithms were applied to all consultation notes, operative notes, pathology reports, and microbiology reports to predict the correct status of PJI based on MSIS criteria.ResultsThe algorithm, which identified patients with PJI based on MSIS criteria, achieved an f1-score (harmonic mean of precision and recall) of 0.911. Algorithm performance in extracting the presence of sinus tract, purulence, pathologic documentation of inflammation, and growth of cultured organisms from the involved TJA achieved f1-scores that ranged from 0.771 to 0.982, sensitivity that ranged from 0.730 to 1.000, and specificity that ranged from 0.947 to 1.000.ConclusionNLP-enabled algorithms have the potential to automate data collection for PJI diagnostic elements, which could directly improve patient care and augment cohort surveillance and research efforts. Further validation is needed in other hospital settings.Level of EvidenceLevel III, Diagnostic.     

Systematic review of patellar resurfacing in total knee arthroplasty

Controversies existing over resurfacing the patella in total knee arthroplasty remain in the literature. The purpose of this review was to evaluate the effectiveness of resurfacing versus nonresurfacing the patella in total knee arthroplasty. We searched the Cochrane Library, MEDLINE and EMBASE for published randomised clinical trials relevant to patellar resurfacing. The relative risk of reoperation was significantly lower for the patellar resurfacing group than for the nonresurfacing group (relative risk 0.57, 95% confidence interval 0.38–0.84, P = 0.004). The overall incidence of postoperative anterior knee pain of the 1,421 knees included was 12.9% in the patellar resurfacing group and 24.1% in the nonresurfacing group. The existing evidence indicates that patellar resurfacing can reduce the risk of reoperation with no improvement in postoperative knee function or patient satisfaction over total knee arthroplasty without patellar resurfacing. Whether it can decrease the incidence of anterior knee pain remains uncertain.     

Development of machine learning and natural language processing algorithms for preoperative prediction and automated identification of intraoperative vascular injury in anterior lumbar spine surgery

BACKGROUNDIntraoperative vascular injury (VI) may be an unavoidable complication of anterior lumbar spine surgery; however, vascular injury has implications for quality and safety reporting as this intraoperative complication may result in serious bleeding, thrombosis, and postoperative stricture.PURPOSEThe purpose of this study was to (1) develop machine learning algorithms for preoperative prediction of VI and (2) develop natural language processing (NLP) algorithms for automated surveillance of intraoperative VI from free-text operative notes.PATIENT SAMPLEAdult patients, 18 years or age or older, undergoing anterior lumbar spine surgery at two academic and three community medical centers were included in this analysis.OUTCOME MEASURESThe primary outcome was unintended VI during anterior lumbar spine surgery.METHODSManual review of free-text operative notes was used to identify patients who had unintended VI. The available population was split into training and testing cohorts. Five machine learning algorithms were developed for preoperative prediction of VI. An NLP algorithm was trained for automated detection of intraoperative VI from free-text operative notes. Performance of the NLP algorithm was compared to current procedural terminology and international classification of diseases codes.RESULTSIn all, 1035 patients underwent anterior lumbar spine surgery and the rate of intraoperative VI was 7.2% (n=75). Variables used for preoperative prediction of VI were age, male sex, body mass index, diabetes, L4-L5 exposure, and surgery for infection (discitis, osteomyelitis). The best performing machine learning algorithm achieved c-statistic of 0.73 for preoperative prediction of VI (https://sorg-apps.shinyapps.io/lumbar_vascular_injury/). For automated detection of intraoperative VI from free-text notes, the NLP algorithm achieved c-statistic of 0.92. The NLP algorithm identified 18 of the 21 patients (sensitivity 0.86) who had a VI whereas current procedural terminologyand international classification of diseases codes identified 6 of the 21 (sensitivity 0.29) patients. At this threshold, the NLP algorithm had a specificity of 0.93, negative predictive value of 0.99, positive predictive value of 0.51, and F1-score of 0.64.CONCLUSIONRelying on administrative procedural and diagnosis codes may underestimate the rate of unintended intraoperative VI in anterior lumbar spine surgery. External and prospective validation of the algorithms presented here may improve quality and safety reporting.     

Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing: A randomized study of 74 patients with 6 years of follow-up

Background and purpose — Knee pain after total knee arthroplasty (TKA) is not uncommon. Patellar retention in TKA is one cause of postoperative knee pain, and may lead to secondary addition of a patellar component. Patellar resurfacing in TKA is controversial. Its use ranges from 2% to 90% worldwide. In this randomized study, we compared the outcome after patellar resurfacing and after no resurfacing. Patients and methods — We performed a prospective, randomized study of 74 patients with primary osteoarthritis who underwent a Triathlon CR TKA. The patients were randomized to either patellar resurfacing or no resurfacing. They filled out the VAS pain score and KOOS questionnaires preoperatively, and VAS pain, KOOS, and patient satisfaction 3, 12, and 72 months postoperatively. Physical performance tests were performed preoperatively and 3 months postoperatively. Results — We found similar scores for VAS pain, patient satisfaction, and KOOS 5 subscales at 3, 12, and 72 months postoperatively in the 2 groups. Physical performance tests 3 months postoperatively were also similar in the 2 groups. No secondary resurfacing was performed in the group with no resurfacing during the first 72 months Interpretation — Patellar resurfacing in primary Triathlon CR TKA is of no advantage regarding pain, physical performance, KOOS 5 subscales, or patient satisfaction compared to no resurfacing. None of the patients were reoperated with secondary addition of a patellar component within 6 years. According to these results, routine patellar resurfacing in primary Triathlon TKA appears to be unnecessary.     

Influence of Patellar Morphology Classified by Wiberg Classification on Knee Joint Function and Patellofemoral Tracking After Total Knee Arthroplasty Without Patellar Resurfacing

BackgroundTo evaluate the influence of patellar morphology on knee joint function and patellofemoral tracking in patients with primary osteoarthritis after total knee arthroplasty (TKA) without patellar resurfacing.MethodsWe performed a retrospective study of 156 patients with primary osteoarthritis who underwent TKA without patellar resurfacing from April 2018 to July 2019. As per Wiberg classification, patients were divided into Wiberg type I (group A, n = 38), II (group B, n = 88), and III (group C, n = 30) groups. The clinical data, postoperative follow-up data, and radiological data between three groups were compared.ResultsThere was no statistically significant difference in the HSS score and Feller score between the three groups before surgery and at each follow-up point after surgery (P > .05). At the last follow-up, there were no significant differences in the height and relative thickness of the patella between the three groups (P > .05). However, the incidence of anterior knee pain was significantly higher in group C than in the group B (P < .05). The patellar tilt angle was significantly larger in group C than in the groups A and B (both P < .05). The patellar facet angle was significantly larger in group A than in group B and C, which was also significantly larger in group B than in group C (both P < .05).ConclusionPatients with three different morphologic types of the patella both exhibited improved knee joint function after TKA, however, patients with Wiberg type Ⅲ patella were more prone to have poor patellofemoral tracking and anterior knee pain after surgery.     

Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

BackgroundThe management of the patella during total knee arthroplasty (TKA) remains controversial. The aim of this study is to evaluate the evidence regarding the use of patellar resurfacing in TKA.MethodsA meta-analysis of randomized controlled trials (RCTs) was performed to compare outcomes between knees receiving patellar resurfacing vs those not receiving resurfacing during primary TKA. Outcomes of interest were the Knee Society Scores, reoperation rates, anterior knee pain, patient satisfaction, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score subscores, and range of motion.ResultsTwenty RCTs met all eligibility criteria and were included in the analysis. There were statistically significant differences favoring the resurfaced group in the knee component and functional component of Knee Society Scores that were not clinically significant. There was an increased risk of reoperation among knees that did not receive resurfacing with number needed to treat to prevent one case of reoperation of 25 knees (for reoperation for any reason) and 33 knees (for reoperation for anterior knee pain). There were no statistically significant differences in any other outcomes.ConclusionThe only clear relationship is that knees that do not receive patellar resurfacing are more likely to receive reoperation, most often for secondary resurfacing. However, the disease burden of differing complication profiles associated with resurfacing and nonresurfacing groups remains unclear. Continuing to collect data from large, well-designed RCTs would be beneficial in guiding management of the patella during TKA.     

The Outcome of Total Knee Arthroplasty With and Without Patellar Resurfacing up to 17 Years: A Report From the Australian Orthopaedic Association National Joint Replacement Registry

BackgroundPatellar resurfacing in total knee arthroplasty (TKA) remains a controversial issue after more than 4 decades of TKA. Despite a growing body of evidence from registry data, resurfacing is still based largely on a surgeon’s preference and training. The purpose of this study is to provide long-term outcomes for patellar resurfaced compared to when the patella is not resurfaced.MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry (1999-2017) were used for this study. The analysis included 570,735 primary TKAs undertaken for osteoarthritis. Hazard ratios (HRs) and 17-year cumulative percent revision rates were used to compare revision rates between 4 subgroups: minimally stabilized (MS) patellar resurfacing, posterior stabilized (PS) patellar resurfacing, MS unresurfaced, and PS unresurfaced patella. Additional analyses of the patellar implant type and a comparison of inlay and onlay patellar resurfacing were also performed.ResultsFor all primary TKA, procedures where the patella was not resurfaced have a higher rate of revision compared to procedures where the patella was resurfaced (HR, 1.31; confidence interval, 1.28-1.35; P < .001). Unresurfaced PS knees have the highest cumulative percent revision at 17 years (11.1%), followed by MS unresurfaced (8.8%), PS resurfaced (7.9%), and MS resurfaced (7.1%). Inlay patellar resurfacing has a higher rate of revision compared to onlay patellar resurfacing (HR, 1.27; confidence interval, 1.17-1.37; P < .001).ConclusionResurfacing the patella reduces the rate of revision for both MS and PS knees. MS knees with patellar resurfacing have the lowest rate of revision. Onlay patella designs are associated with a lower revision rate compared to inlay patella designs.     

Selective Patella Resurfacing in Contemporary Cruciate Retaining and Substituting Total Knee Arthroplasty: A Matched Cohort Analysis

BackgroundLeaving the patella unresurfaced in total knee arthroplasty (TKA) is increasing due to modern patella-friendly implants, awareness that complications are not uncommon with resurfacing, and knowledge that historical studies were scientifically confounded. This study examined the effect of selective patellar resurfacing on patient-reported outcome measures (PROMs) using modern implants and techniques in cohorts rigorously matched for demographics and osteoarthritis severity.MethodsA total of 166 TKAs performed without patellar resurfacing were case-control matched to 166 TKAs with patella resurfacing. Case-control matching was based on demographics, American Society of Anesthesiology Physical Status, comorbidities, and osteoarthritis severity. No significant differences were observed between cohorts for demographics (P ≥ .347), comorbidities (P ≥ .443), or radiographic osteoarthritis severity (P ≥ .078). Radiographic alignment and prospectively collected PROMs were evaluated preoperatively and at latest clinical follow-up.ResultsPreoperatively, patellar tilt was less for the unresurfaced patella group (3 versus 4°, P = .003); however, postoperative patellar tilt was not different (3 versus 3°, P = .225). At a mean of 2.1 years follow-up (range, 1 to 7), University of California Los Angeles Activity Level was significantly higher for the unresurfaced patella group (6.3 versus 5.5, P = .002), but the mean group difference did not reach a minimal clinically important difference. There were no other significant differences in PROMs or reoperation rates between cohorts (P ≥ .135).ConclusionIn contemporary cruciate retaining and substituting TKA designs, not resurfacing the patella in select patients may achieve comparable PROMs and re-operation rates; and potentially greater activity level compared to patella resurfacing at early follow-up.Level of EvidenceIII.     

Onlay Patellar Resurfacing in a Posterior-Stabilized Total Knee Arthroplasty Increases Patellar Crepitus Complication: A Randomized,Controlled Trial

BackgroundPatellar crepitus (PC) is a potentially problematic complication after total knee arthroplasty (TKA) more commonly occurring with a posterior-stabilized (PS) prosthesis. Patellar resurfacing has been reported to reduce PC complications; however, no study has compared the PC complication rates between 2 different resurfacing techniques, namely inlay and onlay.MethodsA prospective, randomized controlled trial was conducted to compare the PC complication between inlay and onlay patellar resurfacing techniques. A total of 222 patients who underwent unilateral TKA using a Legion PS Total Knee System were randomized into 2 groups. PC incidence, time of PC presentation, radiographic parameters associated with PC development, and clinical outcomes were evaluated at 3, 6, 9, 12, 18, and 24 months postoperatively.ResultsPC occurred significantly more in the onlay group (17.9% vs 6.5%, P = .009). Time of PC presentation in both groups was not different. Anterior knee pain was found in 11.5% of PC patients, and none required any surgical procedure. Postoperative radiographic parameters, range of motion, Knee Society score, Oxford score, patellar score, incidence and intensity of anterior knee pain, and visual analog scale of overall knee pain were not significantly different between the 2 groups during the follow-up period.ConclusionTo reduce the chance of PC development, we suggest an inlay patellar resurfacing technique during PS-TKA with this knee system.     

Natural language processing for prediction of readmission in posterior lumbar fusion patients: which free-text notes have the most utility?

BACKGROUND CONTEXTThe increasing volume of free-text notes available in electronic health records has created an opportunity for natural language processing (NLP) algorithms to mine this unstructured data in order to detect and predict adverse outcomes. Given the volume and diversity of documentation available in spine surgery, it remains unclear which types of documentation offer the greatest value for prediction of adverse outcomes.STUDY DESIGN/SETTINGRetrospective review of medical records at two academic and three community hospitals.PURPOSEThe purpose of this study was to conduct an exploratory analysis in order to examine the utility of free-text notes generated during the index hospitalization for lumbar spine fusion for prediction of 90-day unplanned readmission.PATIENT SAMPLEAdult patients 18 years or older undergoing lumbar spine fusion for lumbar spondylolisthesis or lumbar spinal stenosis between January 1, 2016 and December 31, 2020.OUTCOME MEASURESThe primary outcome was inpatient admission within 90-days of discharge from the index hospitalization.METHODSThe predictive performance of NLP algorithms developed by using discharge summary notes, operative notes, nursing notes, physical therapy notes, case management notes, medical doctor (MD) (resident or attending), and allied practice professional (APP) (nurse practitioner or physician assistant) notes were assessed by discrimination, calibration, overall performance.RESULTSOverall, 708 patients were included in the study and 83 (11.7%) had 90-day inpatient readmission. In the independent testing set of patients (n=141) not used for model development, the area under the receiver operating curve of NLP algorithms for prediction of 90-day readmission using discharge summary notes, operative notes, nursing notes, physical therapy notes, case management notes, MD/APP notes was 0.70, 0.57, 0.57, 0.60, 0.60, and 0.49 respectively.CONCLUSIONIn this exploratory analysis, discharge summary, physical therapy, and case management notes had the most utility and daily MD/APP progress notes had the least utility for prediction of 90-day inpatient readmission in lumbar fusion patients among the free-text documentation generated during the index hospitalization.     

Patellar resurfacing in total knee arthroplasty leads to better isokinetic performance

BackgroundFor decades there have been concerns about patellar resurfacing (PR) in total knee arthroplasty (TKA) and the individual preference of the surgeon is still the main determinant of whether or not resurfacing is applied. According to preference, surgeons can be categorized in 3 main groups of those who usually, selectively, or rarely resurface. The aim of this prospective, randomized, controlled study was to compare the isokinetic performance and clinical outcome of TKAs with PR and without PR.MethodsA total of 50 patients scheduled to undergo TKA for primary osteoarthritis of the knee were randomly assigned to either the PR or non-PR groups. There were no significant differences between the groups in respect of age, BMI, gender and preoperative Knee Society Score (KSS) and isokinetic performance. Patients were evaluated at postoperative 3, 6, and 12 months with KSS and at 6 months and 1 year with isokinetic measurements.ResultsThe PR group had a higher mean score, especially in the functional component of KSS, but the difference was not statistically significant. Knee extension peak torque was significantly higher in the PR group at 6 months (p = 0.029) and 1 year (p = 0.004) postoperatively. There were no significant differences between the groups in respect of knee flexion peak torque values following TKA.ConclusionsThe results of this study demonstrated that PR during TKA is associated with better isokinetic performance and higher knee scores. These results support routine/usually resurfacing of the patella. For surgeons who selectively resurface the patella, the advantage of better isokinetic performance may be taking into consideration in favor of resurfacing the patella where they are undecided.Level of evidenceLevel I, therapeutic study.     

Natural language processing for automated detection of incidental durotomy

BACKGROUNDIncidental durotomy is a common intraoperative complication during spine surgery with potential implications for postoperative recovery, patient-reported outcomes, length of stay, and costs. To our knowledge, there are no processes available for automated surveillance of incidental durotomy.PURPOSEThe purpose of this study was to develop natural language processing (NLP) algorithms for automated detection of incidental durotomies in free-text operative notes of patients undergoing lumbar spine surgery.PATIENT SAMPLEAdult patients 18 years or older undergoing lumbar spine surgery between January 1, 2000 and June 31, 2018 at two academic and three community medical centers.OUTCOME MEASURESThe primary outcome was defined as intraoperative durotomy recorded in free-text operative notes.METHODSAn 80:20 stratified split was undertaken to create training and testing populations. An extreme gradient-boosting NLP algorithm was developed to detect incidental durotomy. Discrimination was assessed via area under receiver-operating curve (AUC-ROC), precision-recall curve, and Brier score. Performance of this algorithm was compared with current procedural terminology (CPT) and international classification of diseases (ICD) codes for durotomy.RESULTSOverall, 1,000 patients were included in the study and 93 (9.3%) had a recorded incidental durotomy in the free-text operative report. In the independent testing set (n=200) not used for model development, the NLP algorithm achieved AUC-ROC of 0.99 for detection of durotomy. In comparison, the CPT/ICD codes had AUC-ROC of 0.64. In the testing set, the NLP algorithm detected 16 of 18 patients with incidental durotomy (sensitivity 0.89) whereas the CPT and ICD codes detected 5 of 18 (sensitivity 0.28). At a threshold of 0.05, the NLP algorithm had specificity of 0.99, positive predictive value of 0.89, and negative predictive value of 0.99.CONCLUSIONSInternal validation of the NLP algorithm developed in this study indicates promising results for future NLP applications in spine surgery. Pending external validation, the NLP algorithm developed in this study may be used by entities including national spine registries or hospital quality and safety departments to automate tracking of incidental durotomies.     

Advantage of Minimal Anterior Knee Pain and Long-term Survivorship of Cemented Single Radius Posterior-Stabilized Total Knee Arthroplasty without Patella Resurfacing

BackgroundThe single radius total knee prosthesis was introduced with the advantage of reduced patellar symptoms; however, there is no long-term follow-up study of the same. The purpose of this study was to determine the survival rate of single radius posterior-stabilized total knee arthroplasty and patellofemoral complication rates in a consecutive series.MethodsSeventy-one patients (103 knees) who underwent arthroplasty without patellar resurfacing using a single radius posterior-stabilized total knee prosthesis were followed up for a minimum 10 years. Clinical evaluation using Knee Society knee and function scores and radiologic evaluation were performed at regular intervals. Anterior knee pain as well as patellofemoral complications were evaluated with a simple questionnaire. The Kaplan-Meier product-limit method was used to estimate survival.ResultsSeventeen patients (23 knees) were excluded due to death (12 knees) or lost to follow-up (11 knees). Of the 80 knees enrolled, all femoral components and 78 tibial components were well fixed without loosening at final follow-up. Two revisions were performed because of tibial component loosening and periprosthetic joint infection. One patient with tibial component loosening refused to have revision surgery. No obvious tibial insert polyethylene wear was observed. The survivorships at 132 months were 96.7% using revision or pending revision as end points. Anterior knee pain was present in 6 patients (6 knees, 7.5%) at the latest follow-up. No patellofemoral complication requiring revision was encountered.ConclusionsThe single radius posterior-stabilized total knee prosthesis demonstrated an excellent minimum 10-year survivorship. The low rates of implant loosening and 7.5% of anterior knee pain as a patellofemoral complication are comparable with those reported for other modern total knee prosthesis.     

Stress and Strain During Total Joint Arthroplasty Are Not Impacted by Hand Dominance or Operative Laterality in Orthopedic Surgeons

BackgroundOrthopedic surgeons experience significant musculoskeletal pain and work-related injuries while performing total joint arthroplasty (TJA). We sought to investigate the impact of operative extremity and surgeon limb dominance on surgeon physiologic stress and energy expenditure during TJA.MethodsThis was a prospective cohort study conducted at a tertiary academic practice. Cardiorespiratory data was recorded continuously in 3 high-volume arthroplasty surgeons using a smart garment that measured heart rate (HR), HR variability, respiratory rate, minute ventilation, and energy expenditure (calories) during conventional total knee (TKA) and total hip arthroplasty (THA).ResultsSurgeon 1 and 2 (right-handed) performed 21 right TKAs, 10 left TKAs, 13 right THAs, and 10 left THAs. Surgeon 3 (left-handed) performed 6 right TKAs, 9 left TKAs, 16 right THAs, and 10 left THAs. While performing TKA or THA, limb laterality had no significant impact on operative time and no significant differences existed in HR, HR variability, respiratory rate, minute ventilation, or energy expenditure for any right-handed or left-handed surgeons, regardless of the operative limb laterality. While performing TKA, consistently standing on the side of hand dominance was associated with decreased strain and stress, compared to always standing on the operative side.ConclusionThis study suggests that surgeon hand dominance and operative limb laterality do not impact energy expenditure or physiologic strain during TJA. However, consistently standing on the side of hand dominance in TKA may lead to decreased physiologic strain and stress during surgery. Further study utilizing wearable technology during TJA may provide orthopedic surgeons with information about modifiable factors that contribute to differences in physiological parameters during surgery.     

Resurfacing in a Posterior-Stabilized Total Knee Arthroplasty Reduces Patellar Crepitus Complication: A Randomized,Controlled Trial

BackgroundPatellar crepitus (PC) is a common complication after total knee arthroplasty (TKA) using a posterior-stabilized (PS) prosthesis. While numerous factors have been associated with PC development after PS-TKA, patellar resurfacing (PR) which directly impacts the patellofemoral joint kinematics has been underinvestigated. A prospective, randomized, controlled trial was conducted to (1) compare the PC incidence in PR and non-PR PS-TKA, (2) determine the time of PC presentation in PS-TKA, (3) identify radiographic parameters associated with PC, and (4) compare clinical outcomes of patients with and without PR.MethodsA total of 84 patients who underwent unilateral TKA using the Legion PS Total Knee System were randomized into PR group or non-PR group. PC incidence, time of PC presentation, radiographic parameters associated with PC development, and clinical outcomes were evaluated at 3 months, 6 months, 9 months, and 1 year postoperatively.ResultsPC occurred significantly more in the non-PR group (23.1% vs 7.3%, P = .048). Time of PC presentation in both groups was not different. Anterior knee pain was found in 16.7% of crepitus patients, and none required any surgical procedure. The non-PR knees had significant decreases in patellar shift index, patellar displacement, Insall-Salvati ratio, and patellar component height and increase in change in posterior femoral offset. Oxford and patellar scores were significantly better in the PR group at 9 months and 1 year.ConclusionGiven higher PC incidence and several worse clinical outcomes in the non-PR, we recommend resurfacing during PS-TKA with this knee system to avoid PC development.