The use of imageless navigation to quantify cutting error in total knee arthroplasty

( Ran Schwarzkopf ),( Morteza Meftah ),( Scott E. Marwin ),( Michelle A. Zabat ),( Jeffrey M. Muir ),( Iain R. Lamb ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-

Purpose: Navigated total knee arthroplasty (TKA) improves implant alignment by providing feedback on resection parameters based on femoral and tibial cutting guide positions. However, saw blade thickness, deflection, and cutting guide motion may lead to final bone cuts differing from planned resections, potentially contributing to suboptimal component alignment. We used an imageless navigation device to intraoperatively quantify the magnitude of error between planned and actual resections, hypothesizing final bone cuts will differ from planned alignment. Materials and methods: A retrospective study including 60 consecutive patients undergoing primary TKA using a novel imageless navigation device was conducted. Device measurements of resection parameters were obtained via attachment of optical trackers to femoral and tibial cutting guides prior to resection. Following resection, optical trackers were placed directly on the bone cut surface and measurements were recorded. Cutting guide and bone resection measurements of both femoral and tibial varus/valgus, femoral flexion, tibial slope angles, and both femoral and tibial medial and lateral resection depths were compared using a Student’s t-test. Results: Femoral cutting guide position differed from the actual cut by an average 0.6 ± 0.5° (p = 0.85) in the varus/ valgus angle and 1.0 ± 1.0° (p = 0.003) in the flexion/extension angle. The difference between planned and actual cut measurements for medial and lateral femoral resection depth was 1.1 ± 1.1 mm (p = 0.32) and 1.2 ± 1.0 mm (p = 0.067), respectively. Planned cut measurements based on tibial guide position differed from the actual cut by an average of 0.9 ± 0.8° (p = 0.63) in the varus/valgus angle and 1.1 ± 1.0° (p = 0.95) in slope angle. Measurement of medial and lateral tibial resection depth differed by an average of 0.1 ± 1.8 mm (p = 0.78) and 0.2 ± 2.1 mm (p = 0.85), respectively. Conclusions: Significant discrepancies between planned and actual femoral bone resection were demonstrated for flexion/extension angle, likely the result of cutting error. Our data highlights the importance of cut verification postresection to confirm planned resections are achieved, and suggests imageless navigation may be a source of feedback that would allow surgeons to intraoperatively adjust resections to achieve optimal implant alignment.

Are there avoidable causes of early revision total knee arthroplasty?

( Mackenzie A. Roof ),( Jason B. Kreinces ),( Ran Schwarzkopf ),( Joshua C. Rozell ),( Vinay K. Aggarwal ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Introduction: Surgeons can improve their practice by understanding potentially avoidable reasons for early revision total knee arthroplasty (rTKA). The purpose of this study is to describe potentially avoidable indications for rTKA within 5 years of the index procedure. Methods: This retrospective observational analysis utilized the rTKA database at a large, academic orthopedic specialty hospital to identify 167 consecutive rTKA from 2014 to 2019 performed within 5 years after primary TKA (pTKA). Two fellowship-trained arthroplasty surgeons reviewed the cases to classify them as potentially avoidable or unavoidable. Unavoidable indications for rTKA included infection/wound complication, arthrofibrosis, instability due to underlying collagen disease or significant weight loss, and any traumatic event leading to pTKA failure. Potentially avoidable indications included atraumatic instability, intraoperative fracture, metal allergy, and atraumatic patellar instability or maltracking. Aseptic loosening was considered avoidable if it occurred in the presence of component malpositioning or poor cementation technique. Results: There were 112 (67.1%) unavoidable cases and 55 avoidable cases (32.9%). Of the unavoidable cases, there were 68 rTKA for infection or wound complications (60.7%), 23 for arthrofibrosis (20.5%), 6 for instability (5.4%), 6 for postoperative fracture (5.4%), 6 for aseptic loosening (5.4%), and 3 for extensor mechanism pathology following trauma (2.6%). Of the potentially avoidable rTKA, 24 were for aseptic loosening (43.7%), 23 for atraumatic instability (41.8%), 6 for atraumatic extensor mechanism pathology (10.9%), 1 for nickel allergy (1.8%), and 1 for intraoperative fracture (1.8%). Conclusion: These findings indicate that over 30% of early rTKA are potentially avoidable. Interventions should focus on addressing potentially avoidable causes such as short-term aseptic loosening and instability to reduce the need for costly and resource-intensive rTKA. Level of evidence III, retrospective observational analysis

Characterizing patient factors, perioperative interventions, and outcomes associated with inpatients falls after total knee arthroplasty

( Kyle W. Lawrence ),( Lauren Link ),( Patricia Lavin ),( Ran Schwarzkopf ),( Joshua C. Rozell ) 대한슬관절학회 2024 대한슬관절학회지 Vol.36 No.-

Introduction Mechanical falls represent a potential adverse event after total knee arthroplasty (TKA) and may introduce further injury and delay postoperative recovery. This study aimed to identify patient characteristics associated with inpatient falls, to determine the impact of inpatient falls on surgical outcomes following TKA, and to describe the relationship between tourniquet and/or adductor canal block (ACB) use and fall rates. Methods Patients undergoing primary, elective TKA at a single institution between 2018 and 2022 were retrospectively analyzed. Patients were stratified into groups based on whether they sustained a postoperative inpatient fall or not. Perioperative characteristics, lengths of stay (LOS), rates of 90-day readmissions, and revisions were compared, and fall characteristics were described. Subanalysis was conducted comparing fall incidence based on tourniquet and/or ACB use. Results In total 6472 patients were included with 39 (0.6%) sustaining falls. Falls most commonly occurred on postoperative days one (43.6%) and two (30.8%), and were most commonly due to loss of balance (41.9%) or buckling (35.5%). Six (15.4%) fall patients sustained minor injuries, and one (2.6%) sustained major injury (malleolar fracture requiring non-operative orthopaedic management). The LOS (3.0 ± 1.5 vs 2.3 ± 1.5 days, p = 0.002) and all-cause revision rates at latest follow-up (10.3% vs. 2.0%, p = 0.008) were significantly higher in the fall group. Falls were comparable across subgroups based on tourniquet and/or ACB use (p = 0.429). Conclusion Patients who fell had a longer LOS and higher revision rate postoperatively. Rates of inpatient falls were comparable regardless of tourniquet and/or ACB use. Concern for inpatient falls should not influence surgeons when considering the use of tourniquets and/or ACBs, though well-designed, large-volume, prospective randomized studies are warranted to better understand this relationship.

Does body mass index influence improvement in patient reported outcomes following total knee arthroplasty? A retrospective analysis of 3918 cases

( Kyle W. Lawrence ),( Walter Sobba ),( Vinaya Rajahraman ),( Ran Schwarzkopf ),( Joshua C. Rozell ) 대한슬관절학회 2023 대한슬관절학회지 Vol.35 No.-

Purpose The study aimed to determine whether body mass index (BMI) classification for patients undergoing total knee arthroplasty (TKA) is associated with differences in mean patient reported outcome measure (PROM) score improvements across multiple domains―including pain, functional status, mental health, and global physical health. We hypothesized that patients with larger BMIs would have worse preoperative and postoperative PROM scores, though improvements in scores would be comparable between groups. Materials and methods Patients undergoing primary TKA from 2018 to 2021 were retrospectively reviewed and stratified into four groups: Normal Weight; 18.5-25 kg/m², Overweight; 25.01-30 kg/m², Obese; 30.01-40 kg/ m², and Morbidly Obese > 40 kg/m². Preoperative, postoperative, and pre/post-changes (Δ) in knee injury and osteoarthritis, joint replacement (KOOS, JR) and Patient-Reported Outcome Measurement Information System (PROMIS) measures of pain intensity, pain interference, physical function, mobility, mental health, and physical health were compared. Multivariate linear regression was used to assess for confounding comorbid conditions. Results In univariate analysis, patients with larger BMIs had worse scores for KOOS, JR and all PROMIS metrics preoperatively. Postoperatively, scores for KOOS, JR and PROMIS pain interference, mobility, and physical health were statistically worse in higher BMI groups, though differences were not clinically significant. Morbidly obese patients achieved greater pre/post-Δ improvements in KOOS, JR and global physical health scores. Multivariate regression analysis showed high BMI was independently associated with greater pre/post-Δ improvements in KOOS, JR and global health scores. Conclusion Obese patients report worse preoperative scores for function and health, but greater pre/post-Δ improvements in KOOS, JR and physical health scores following TKA. Quality of life benefits of TKA in obese patients should be a factor when assessing surgical candidacy.

Botulinum toxin injections as salvage therapy is beneficial for management of patellofemoral pain syndrome

( Yuval Kesary ),( Vivek Singh ),( Tal Frenkel ),( Rutenberg ),( Arie Greenberg ),( Shmuel Dekel ),( Ran Schwarzkopf ),( Nimrod Snir ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-

Purpose: Patellofemoral pain syndrome (PFPS) is a common pathology usually presenting with anterior or retropatellar pain. It is associated with a relative imbalance between the vastus medialis oblique (VMO) and the vastus lateralis (VL) muscles. This can lead to considerable morbidity and reduced quality of life (QOL). This study aims to assess the long-term functional outcome of PFPS treated with VL muscle botulinum toxin A (BoNT-A) injection. Materials and methods: A retrospective review was performed on 26 consecutive patients (31 knees) with a mean age of 50.1 years (± 19.7 years) who were treated with BoNT-A injections to the VL muscle followed by physiotherapy between 2008 and 2015. Pre- and post-treatment pain levels (numerical rating scale, NRS), QOL (SF-6D), and functional scores (Kujala and Lysholm questionnaires) were measured. Demographics, physical therapy compliance, previous surgeries, perioperative complications, and patient satisfaction levels were collected. Results: The mean follow-up time was 58.8 ± 36.4 months. There were significant improvements in all the examined domains. The average pain score (NRS) decreased from 7.6 to 3.2 (P < 0.01), and the Kujala, Lysholm, and SF-6D scores improved from 58.9 to 82.7 (P < 0.001), 56.2 to 83.2 (P < 0.001), and 0.6 to 0.8 (P < 0.001), respectively. Similar delta improvement was achieved irrespective of gender, age, compliance to post-treatment physical therapy, or coexisting osteoarthritis. Patients who presented with a worse pre-treatment clinical status achieved greater improvement. Prior to BoNT-A intervention, 16 patients (18 knees) were scheduled for surgery, of whom 12 (75%, 13 knees) did not require further surgical intervention at the last follow-up. Conclusions: A single intervention of BoNT-A injections to the VL muscle combined with physiotherapy is beneficial for the treatment of patients with persistent PFPS. Level III evidence: Retrospective cohort study.

Dual-mobility versus Fixed-bearing in Primary Total Hip Arthroplasty: Outcome Comparison

Vivek Singh,Jeremy Loloi,William Macaulay,Matthew S. Hepinstall,Ran Schwarzkopf,Vinay K. Aggarwal 대한고관절학회 2022 Hip and Pelvis Vol.34 No.2

Purpose: Use of dual mobility (DM) articulations can reduce the risk of instability in both primary and revision total hip arthroplasty (THA). Knowledge regarding the impact of this design on patient-reported outcome measures (PROMs) is limited. This study aims to compare clinical outcomes between DM and fixed bearing (FB) prostheses following primary THA. Materials and Methods: All patients who underwent primary THA between 2011-2021 were reviewed retrospectively. Patients were separated into three cohorts: FB vs monoblock-D vs modular-DM. An evaluation of PROMs including HOOS, JR, and FJS-12, as well as discharge-disposition, 90-day readmissions, and revisions rates was performed. Propensity-score matching was performed to limit significant demographic differences, while ANOVA and chi-squared test were used for comparison of outcomes. Results: Of the 15,184 patients identified, 14,652 patients (96.5%) had a FB, 185 patients (1.2%) had a monoblock-DM, and 347 patients (2.3%) had a modular-DM prosthesis. After propensity-score matching, a total of 447 patients were matched comparison. There was no statistical difference in the 90-day readmission (P=0.584), revision rate (P=0.265), and 90-day readmission (P=0.365) and revision rate due to dislocation (P=0.365) between the cohorts. Discharge disposition was also non-significant (P=0.124). There was no statistical difference in FJS-12 scores at 3-months (P=0.820), 1-year (P=0.982), and 2-years (P=0.608) between the groups. Conclusion: DM bearings yield PROMs similar to those of FB implants in patients undergoing primary THA. Although DM implants are utilized more often in patients at higher-risk for instability, we suggest that similar patient satisfaction may be attained while achieving similar dislocation rates.

Impact of time to revision total knee arthroplasty on outcomes following aseptic failure

( Mackenzie A. Roof ),( Shankar Narayanan ),( Nathan Lorentz ),( Vinay K. Aggarwal ),( Morteza Meftah ),( Ran Schwarzkopf ) 대한슬관절학회 2023 대한슬관절학회지 Vol.35 No.-

Introduction Prior studies have demonstrated an association between time to revision total knee arthroplasty (rTKA) and indication; however, the impact of early versus late revision on post-operative outcomes has not been reported. Materials and methods A retrospective, observational study examined patients who underwent unilateral, aseptic rTKA at an academic orthopedic hospital between 6/2011 and 4/2020 with > 1-year of follow-up. Patients were early revisions if they were revised within 2 years of primary TKA (pTKA) or late revisions if revised after greater than 2 years. Patient demographics, surgical factors, and post-operative outcomes were compared. Results 470 rTKA were included (199 early, 271 late). Early rTKA patients were younger by 2.5 years (p = 0.002). The predominant indications for early rTKA were instability (28.6%) and arthrofibrosis/stiffness (26.6%), and the predominant indications for late rTKA were aseptic loosening (45.8%) and instability (26.2%; p < 0.001). Late rTKA had longer operative times (119.20 ± 51.94 vs. 103.93 ± 44.66 min; p < 0.001). There were no differences in rTKA type, disposition, hospital length of stay, all-cause 90-day emergency department visits and readmissions, reoperations, and number of re-revisions. Conclusions Aseptic rTKA performed before 2 years had different indications but demonstrated similar outcomes to those performed later. Early revisions had shorter surgical times, which could be attributed to differences in rTKA indication. Level of evidence III, retrospective observational analysis.

A comparison of utilization and short-term complications of technology-assisted versus conventional total knee arthroplasty

( Trevor Simcox ),( Vivek Singh ),( Christian T. Oakley ),( Omid S. Barzideh ),( Ran Schwarzkopf ),( Joshua C. Rozell ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Background: While technology-assisted total knee arthroplasty (TA-TKA) improves implant positioning, whether it confers improved clinical outcomes remains inconclusive. We sought to examine national TA-TKA utilization trends and to compare outcomes between TA-TKA and unassisted TKA (U-TKA). Methods: Patients who underwent primary, elective TKA from 2010 to 2018 were identified using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Demographic, perioperative, and 30-day outcomes were collected. Patients were stratified on the basis of whether they underwent TA-TKA, which included computer navigation and robotics, or U-TKA. The proportion of patients undergoing TKA using TA-TKA was calculated. One-to-one propensity-score matching paired patients undergoing TA-TKA or U-TKA. Independent samples t-tests and Mann-Whitney U tests were used to compare continuous variables, and chi-squared tests were used to compare categorical variables. Results: Of the 402,284 TKA patients, 10,429 (2.6%) cases were performed using TA-TKA. Comparing the unmatched TA-TKA and U-TKA groups, race (p < 0.001), smoking status (p = 0.050), baseline functional status (p < 0.001), and body mass index (BMI) (p < 0.001) significantly differed. Propensity-score matching yielded 8633 TA-TKA and U-TKA pairs. The TA-TKA cohort had shorter hospital length of stay (LOS) (2.7 ± 2.5 versus 2.8 ± 1.9 days, p = 0.017) but similar operative times (92.4 ± 33.4 versus 92.6 ± 39.8 min, p = 0.670). Compared with the U-TKA group, the TA-TKA group had lower major complication (7.6% versus 9.4%, p < 0.001) and transfusion (3.9% versus 5.1%, p < 0.001) rates and higher rates of discharge to home (73.9% versus 70.4%, p < 0.001). Reoperation and readmission rates did not significantly differ between groups. Conclusions: TA-TKA utilization remains low among orthopedic surgeons. Compared with U-TKA, TA-TKA yielded improved perioperative and 30-day outcomes. Nonetheless, surgeons must consider the benefits and drawbacks of TA-TKA when determining the proper surgical technique and technology for each patient. Level III evidence: Retrospective cohort study.

Comparing Outcomes of Bicruciate-Stabilized and Cruciate-Retaining Total Knee Arthroplasty

Lorena Hernandez,Ittai Shichman,Thomas H. Christensen,Joshua C. Rozell,Morteza Meftah,Ran Schwarzkopf 대한정형외과학회 2024 Clinics in Orthopedic Surgery Vol.16 No.1

Background: Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Conventional cruciate-retaining (CR) design in TKA has shown previous clinical success with lower complication rates. This study compared the patient-reported outcomes between the BCS and CR TKA designs. Methods: This retrospective study examined patients who underwent primary TKA using a CR or a BCS implant. Patient demographics, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), and Forgotten Joint Score (FJS) were compared between two cohorts. Patient-reported outcome measures were analyzed using independent samples t -tests. Results: There were no significant preoperative demographic differences between groups. The CR cohort (n = 756) had significantly higher average KOOS, JR Scores compared to the BCS cohort (n = 652) at 3 months (59.7 ± 3.8 vs. 53.0 ± 3.9, p < 0.001) and 2 years (62.6 ± 8.0 vs. 53.8 ± 6.7, p = 0.001) after TKA. Within the cohort, KOOS, JR delta differences were not significant for CR when comparing patient scores 3 months to 1 year after surgery. Meanwhile, the BCS patients did show significant delta improvement (4.1 ± 1.9, p = 0.030) when compared 3 months to 1 year after surgery. One year postoperatively, the BCS cohort (n = 134) showed a significantly higher average FJS score (49.5 ± 31.4, vs. 36.8 ± 28.5, p = 0.028) than the CR cohort (n = 203). Both cohorts displayed a significant difference in delta improvements within their respective cohort when measuring FJS from 3 months to 1 year, 2 years, and 3 years after surgery. Conclusions: The CR cohort performed better on average, compared to the BCS cohort in measures of KOOS, JR scores at the 2-year follow-up. The BCS cohort performed marginally better regarding FJS only at 1-year follow-up.

Preoperative Patient Expectation of Discharge Planning is an Essential Component in Total Knee Arthroplasty

( James E. Feng ),( Afshin A. Anoushiravani ),( Jessica S. Morton ),( William Petersen ),( Vivek Singh ),( Ran Schwarzkopf ),( William Macaulay ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Purpose: A better understanding of total knee arthroplasty (TKA) candidate expectations within the perioperative setting will enable clinicians to promote patient-centered practices, optimize recovery times, and enhance quality metrics. In the current study, TKA candidates were surveyed pre- and postoperatively to elucidate the relationship between patient expectations and length of stay (LOS). Material and methods: This is a prospective study of patients undergoing TKA between December 2017 and August 2018. Patients were electronically administered surveys regarding their discharge plan 10 days pre-/postoperatively. All patients were categorized into three cohorts based on their LOS: 1, 2, and 3+ days. The effect of preoperative discharge education on patient postoperative satisfaction was evaluated. Results: In total, 221 TKAs were included, of which 83 were discharged on postoperative day (POD) 1, 96 on POD-2, and 42 POD-3+. Female gender, increasing body mass index (BMI), and surgical time correlated with increased LOS. Preoperative discussions regarding LOS occurred in 84.62% (187/221) of patients but did correlate with differences in LOS. However, patients discharged on POD-1 were more inclined to same-day surgery preoperatively. Patients discharged on POD-3+ were found to be more uncomfortable regarding their discharge during the preoperative phase. Multivariable regressions demonstrated that preoperative discharge discussion was positively correlated with home discharge. Conclusion: Physician-driven discussion regarding patient discharge did not alter patient satisfaction or length of stay but did correlate with improved odds of home discharge. These findings underscore the importance of patient education, shared decision-making, and managing patient expectations.