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Radiographic Imaging in the Postanesthesia Care Unit is Unnecessary After Partial Knee Arthroplasty
The Journal of Arthroplasty xxx (2016) 1e3
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Original Article
Radiographic Imaging in the Postanesthesia Care Unit is Unnecessary After Partial Knee Arthroplasty Andrew S. Longenecker, MD, Gregory S. Kazarian, BS, AB, Giovanni P. Boyer, BA, Jess H. Lonner, MD * Department of Orthopaedic Surgery, The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania
a r t i c l e i n f o
a b s t r a c t
Article history: Received 9 June 2016 Received in revised form 25 October 2016 Accepted 18 November 2016 Available online xxx
Background: Obtaining routine radiographs in the postanesthesia care unit (PACU) after primary uncomplicated partial knee arthroplasty (PKA) is a common practice with unclear utility. The objective of this study is to determine the rate at which immediate postoperative radiographs identify an actionable problem after primary uncomplicated PKA and to determine the potential cost savings associated with foregoing the routine acquisition of these radiographs. Methods: This was a retrospective review that assessed a consecutive series of 1366 primary uncomplicated PKAs (including 873 unicondylar knee arthroplasties, 313 patellofemoral arthroplasties, and 180 bicompartmental knee arthroplasties) performed between January 2008 and March 2016. Patients were separated into 2 cohorts: (1) those who had PACU radiographs (n ¼ 1184), and (2) those who did not (n ¼ 182). Operative reports and clinical follow-up records at the initial postoperative visit were reviewed to determine whether patients underwent early reoperation based on radiographic findings. The direct cost of PACU radiographs was estimated to be $33.63 based on average global Medicare payments from our institution. Results: The rate of reoperation because of radiographic findings in the PACU or at the first follow-up was 0% (95% confidence interval: 0.0%-0.027%). The estimated direct radiographic expenditure for our 1366 patient cohort was nearly $46,000. Conclusion: Routine immediate postoperative PACU radiographs after primary uncomplicated PKA have limited clinical utility. Therefore, delaying postoperative radiographs until the initial follow-up office visit would result in substantial cost-savings without compromising the quality of patient care. © 2016 Elsevier Inc. All rights reserved.
Keywords: unicondylar knee patellofemoral bicompartmental arthroplasty radiograph cost
In an era that emphasizes high value care and cost containment, efforts are being made to moderate medical interventions and diagnostic studies that provide unclear benefit to the patient or fail to impact clinical decisions [1,2]. A common practice with unclear clinical utility is the routine acquisition of immediate postoperative radiographs in the postanesthesia care unit (PACU) after total and partial knee arthroplasties (TKA and PKA). PACU radiographs are traditionally obtained after joint arthroplasty to assess gross limb alignment, implant position, fracture, limb length, or the presence of retained extruded cement or foreign bodies. Such radiographs are technically demanding to acquire [3], One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.11.033. * Reprint requests: Jess H. Lonner, MD, The Rothman Institute, 825 Old Lancaster Ave, 2nd Floor, Bryn Mawr, PA 19010. http://dx.doi.org/10.1016/j.arth.2016.11.033 0883-5403/© 2016 Elsevier Inc. All rights reserved.
and the resulting images are often imperfect, nonorthogonal, and poorly penetrated. This not only makes these images difficult to interpret, but it prevents them from serving as a valuable baseline for long-term follow-up [4,5]. Because of their unclear impact on subsequent clinical care, the utility of routine PACU radiographs has been called into question in total hip, knee, and shoulder arthroplasties [4-10]. To date, no study has analyzed the clinical utility of immediate PACU radiographs after PKA, including unicondylar knee arthroplasty (UKA), patellofemoral arthroplasty (PFA), or bicompartmental knee arthroplasty (BiKA). The primary purpose of this study is to determine the frequency at which immediate postoperative radiographs identify a problem that requires immediate or early reoperation after routine PKA, and whether delaying postoperative radiographs until the initial postoperative visit is detrimental to patient care. The secondary purpose is to calculate the potential cost savings associated with foregoing the routine acquisition of PACU radiographs after PKA.
2
A.S. Longenecker et al. / The Journal of Arthroplasty xxx (2016) 1e3
Materials and Methods This was a retrospective review of 1366 consecutive primary PKAs performed by a single surgeon (JHL) between January 2008 and March 2016. Of the 1366 PKAs, there were 873 UKAs (64%), 313 PFAs (23%), and 180 BiKAs (13%). After institutional review board's approval, the senior surgeon's surgical records and electronic medical records were queried to identify patients who had undergone primary PKA during the period under study. Patients were separated into 2 cohorts: (1) patients who had PACU anteroposterior (AP) and lateral radiographs (group 1), and (2) those who did not undergo radiographic evaluation until the initial postoperative office visit (group 2). Whether or not PACU radiographs were performed was a function of the location where surgery took place. All patients who had surgery at a hospital had PACU radiographs; those who had surgery at an ambulatory surgery center did not. Operative reports and clinical follow-up records were reviewed to determine the incidence of reoperation based on complications (gross implant malalignment, implant loosening, retained extruded cement, or fracture) identified either from immediate or 6-week postoperative radiographs. Instances of reoperation due to arthrofibrosis or infection were excluded, as they were not considered problems that would have been detected on early radiographic assessment. Mean patient body mass index in groups 1 and 2 was 28.6 kg/m2 (range, 17.2-42.2 kg/m2) and 29.4 kg/m2 (range, 18.5-39.1 kg/m2), respectively. Mean age in groups 1 and 2 was 59.4 years (range, 27.8-89.6 years) and 59.2 years (range, 33.2-85.6 years), respectively. The groups were statistically identical with respect to these measures. The breakdown of PFA, UKA, and BiKA between groups 1 and 2 are shown in Table 1. Costs The direct cost of postoperative radiographs was estimated from reimbursement data from our institution. The 2016 reimbursement for 1-2 radiographic images of the knee (CPT 73560) was $33.61 (technical component: $24.58; professional component: $9.03). Similar fees can be found by querying the Center for Medicare and Medicaid Services database. Results Of the 1184 knees that underwent radiographic imaging in the PACU and the 182 knees that did not undergo imaging until the first clinical follow-up, there were no instances of reoperation because of unanticipated abnormalities or derangements detected on radiographs from either time interval. There were no cases of gross malalignment, displacement, fracture, retained extruded cement, or loose body. The direct cost of immediate postoperative portable PACU supine AP and lateral radiographs is $33.67 per patient. Therefore, the cost of obtaining immediate postoperative PACU radiographs after PKA for the 1184 knees included in this study was nearly $46,000. Discussion The conventional protocol after joint arthroplasty has commonly included the acquisition of immediate postoperative portable PACU radiographs, ostensibly to confirm implant position and limb alignment, as well as to rule out fracture, retained extruded cement or foreign body. The utility of this routine for uncomplicated primary TKA has been called into question [4-6]. Unlike total hip arthroplasty, where early scrutiny of radiographs
Table 1 Distribution of PKAs by Group. Procedure Type
Group 1
Group 2
Totals
Reoperations Due to Radiographic Findings
UKA PFA BiKA Total
716 291 177 1184
157 22 3 182
873 313 180 1366
0 0 0 0
No reoperations were found in either group for any procedure type based on radiographic findings. BiKA, bicompartmental knee arthroplasty; PFA, patellofemoral arthroplasty; PKA, partial knee arthroplasty; UKA, unicondylar knee arthroplasty.
has value for assessing component position and ruling out femoral fracture, gross limb lengthening, or immediate dislocation [7,8], these problems are uncommon after TKA and PKA. The incidence of intraoperative periprosthetic fracture after primary TKA is between 0.1% and 0.39% [6,11]. In addition, roughly 96% of intraoperative periprosthetic fractures in primary TKA are identified during surgery before radiographic review [11]. Periprosthetic fractures may be less common after PKA. In an analysis of 20,488 UKA patients, the incidence of periprosthetic fractures occurring within 90 days after surgery was less than 0.2% [9]. It is unclear what percentage of those occurred intraoperatively. Nonetheless, it highlights the low incidence of fracture after PKA that would require early reintervention. In our study of nearly 1400 postoperative radiographs after PKA, we observed no fractures or other problems requiring adjustment in postoperative protocols or immediate reoperation, further questioning the need for routine postoperative PACU radiographs in this unique and previously unstudied cohort of patients. In an assessment of 192 uncomplicated primary TKAs, Glaser and Lotke found that of the 189 uncomplicated primary TKAs, there were no instances in which postoperative radiographs altered the postoperative management. Furthermore, in the 3 cases in which intraoperative complications necessitated alterations to surgical technique or postoperative management, postoperative radiographs merely confirmed operative findings, but did not further influence the postoperative plan. They also found that postoperative PACU radiographs were of sufficient quality to provide an accurate baseline for future studies in only 36% of patients. In an additional cohort of 550 patients on whom initial postoperative radiographs were not performed until the 6-week follow-up visit, there were no instances in which radiographs taken before discharge would have altered patient management [4]. Similarly, Namdari et al [10] found limited value and undue cost of immediate PACU radiographs after shoulder arthroplasty. In their retrospective analysis of 283 patients who had radiographs taken before discharge, none of the studies changed postoperative management. Furthermore, 71% were underpenetrated, and none were considered adequate to serve as baseline views, leading the authors to conclude that routine PACU radiographs after shoulder arthroplasty are an unnecessary expense. Our considerably larger series corroborates these findings for the particular cohort that we studied. Some have argued that postoperative PACU radiographs are an important means of providing the surgeon with immediate feedback regarding their surgical technique, and may be a valuable training tool for educating students, fellows, and residents [10]. Especially in the case of using these radiographs as a teaching aid, they may serve a valuable purpose as a source of immediate feedback. However, several studies have demonstrated that limb malalignment, bulky dressings, and/or poor radiographic technique degrade the quality of these radiographs and often preclude their
A.S. Longenecker et al. / The Journal of Arthroplasty xxx (2016) 1e3
use in evaluating implant position and alignment [4,5], diminishing their utility as a diagnostic or training tool. Another argument in favor of obtaining routine PACU radiographs is that they may aid in identifying problems requiring reoperation or adjustment in postoperative protocols without delay. Although this analysis has theoretical merit, it is a concern that seems unfounded based on findings from the present study. In a cohort of nearly 1400 knees, we found 0 reoperations because of radiographic findings. Based on these results, a binomial distribution indicates that the incidence of reoperation falls within a 95% confidence interval of 0.0%-0.27%. Even if 0.27% of the cases in our study had a mechanical complication, findings from Alden et al [11] indicate that 96% of these cases would be identified intraoperatively. Therefore, only 0.0108% of PKA patients (1 in 10,000) would benefit from, or have their postoperative care impacted by, immediate PACU radiographs. This finding is corroborated by the fact that, among the 182 PKAs in our cohort who did not receive PACU radiographs, there were no apparent adverse consequences because of delaying standard radiographic evaluation until the initial postoperative office visit. To be clear, however, if intraoperative problems are encountered, postoperative and even intraoperative radiographs are advisable to inform treatment, and at the very least confirm the suspected problem. The results of this study demonstrate that after PKA, postoperative PACU radiographs offer little information, and rarely prompt modification to postoperative protocols. Therefore, there is no evidence that would suggest that these radiographs provide a sufficient benefit to justify the cost and radiation dose (albeit minimal) associated with this imaging modality. In our series of 1366 PKAs, PACU radiographs were taken with no subsequent reoperation or protocol modification. Based on these findings, we estimate that forgoing PACU radiographs would have resulted in savings of nearly $46,000 in our cohort. Currently in the United States, an estimated 40-45,000 PKAs are performed annually. If immediate postoperative PACU radiographs were avoided in just two-thirds of these cases, potential cost savings would approach $1,000,000. There are several limitations to this study. Firstly, we were unable to evaluate all postoperative radiographs and were, therefore, unable to quantify the accuracy and quality of these AP and lateral radiographs after PKA. Based on publications regarding the inaccuracy of immediate postoperative PACU radiographs after TKA [4,5], however, it is likely that a large proportion of these PACU films would have lacked the quality to function as an accurate
3
measure of implant alignment. Secondly, this study appears to be under-powered, as we did not capture a single instance of immediate revision for mechanical failure after PKA. A study with a larger sample size is necessary to establish a true incidence of immediate reoperation after PKA. Such findings would facilitate a more robust cost-benefit analyses that would allow us to determine whether the cost-savings associated with foregoing PACU radiographs truly supersede any potential pitfalls associated with delaying the treatment of an unnoticed complication after PKA.
Conclusions Our study demonstrates that immediate postoperative portable PACU radiographs after primary uncomplicated PKA are an unnecessary expense and provide little clinical utility inasmuch as they do not appear to impact patient management after primary uncomplicated PKA.
References 1. Nwachukwu BU, Bozic KJ, Schairer WW, et al. Current status of cost utility analyses in total joint arthroplasty: a systematic review. Clin Orthop Relat Res 2015;473(5):1815. 2. Oberlander J. Unfinished journeyea century of health care reform in the United States. N Engl J Med 2012;367(7):585. 3. Berquist TH. Imaging of joint replacement procedures. Radiol Clin North Am 2006;44(3):419. 4. Glaser D, Lotke P. Cost-effectiveness of immediate postoperative radiographs after uncomplicated total knee arthroplasty: a retrospective and prospective study of 750 patients. J Arthroplasty 2000;15(4):475. 5. Moussa ME, Malchau H, Freiberg AA, et al. Effect of immediate postoperative portable radiographs on reoperation in primary total knee arthroplasty. Orthopedics 2014;37(9):e817. 6. Hassan S, Wall A, Ayyaswamy B, et al. Is there a need for early post-operative x-rays in primary total knee replacements? Experience of a centre in the UK. Ann R Coll Surg Engl 2012;94(3):199. 7. Mulhall KJ, Masterson E, Burke TE. Routine recovery room radiographs after total hip arthroplasty: ineffective for screening and unsuitable as baseline for longitudinal follow-up evaluation. J Arthroplasty 2004;19(3):313. 8. Ndu A, Jegede K, Bohl DD, et al. Recovery room radiographs after total hip arthroplasty: tradition vs utility? J Arthroplasty 2012;27(6):1051. 9. Ong K, Lau E, Kurtz SM, et al. Short-term complications and revision following unicondylar knee arthroplasty. In: Proceedings of the Orthopaedic Research Society; 2015. Las Vegas (NV). 10. Namdari S, Hsu JE, Baron M, et al. Immediate postoperative radiographs after shoulder arthroplasty are often poor quality and do not alter care. Clin Orthop Relat Res 2013;471(4):1257. 11. Alden KJ, Duncan WH, Trousdale RT, et al. Intraoperative fracture during primary total knee arthroplasty. Clin Orthop Relat Res 2010;468(1):90.
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Original Article
Radiographic Imaging in the Postanesthesia Care Unit is Unnecessary After Partial Knee Arthroplasty Andrew S. Longenecker, MD, Gregory S. Kazarian, BS, AB, Giovanni P. Boyer, BA, Jess H. Lonner, MD * Department of Orthopaedic Surgery, The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania
a r t i c l e i n f o
a b s t r a c t
Article history: Received 9 June 2016 Received in revised form 25 October 2016 Accepted 18 November 2016 Available online xxx
Background: Obtaining routine radiographs in the postanesthesia care unit (PACU) after primary uncomplicated partial knee arthroplasty (PKA) is a common practice with unclear utility. The objective of this study is to determine the rate at which immediate postoperative radiographs identify an actionable problem after primary uncomplicated PKA and to determine the potential cost savings associated with foregoing the routine acquisition of these radiographs. Methods: This was a retrospective review that assessed a consecutive series of 1366 primary uncomplicated PKAs (including 873 unicondylar knee arthroplasties, 313 patellofemoral arthroplasties, and 180 bicompartmental knee arthroplasties) performed between January 2008 and March 2016. Patients were separated into 2 cohorts: (1) those who had PACU radiographs (n ¼ 1184), and (2) those who did not (n ¼ 182). Operative reports and clinical follow-up records at the initial postoperative visit were reviewed to determine whether patients underwent early reoperation based on radiographic findings. The direct cost of PACU radiographs was estimated to be $33.63 based on average global Medicare payments from our institution. Results: The rate of reoperation because of radiographic findings in the PACU or at the first follow-up was 0% (95% confidence interval: 0.0%-0.027%). The estimated direct radiographic expenditure for our 1366 patient cohort was nearly $46,000. Conclusion: Routine immediate postoperative PACU radiographs after primary uncomplicated PKA have limited clinical utility. Therefore, delaying postoperative radiographs until the initial follow-up office visit would result in substantial cost-savings without compromising the quality of patient care. © 2016 Elsevier Inc. All rights reserved.
Keywords: unicondylar knee patellofemoral bicompartmental arthroplasty radiograph cost
In an era that emphasizes high value care and cost containment, efforts are being made to moderate medical interventions and diagnostic studies that provide unclear benefit to the patient or fail to impact clinical decisions [1,2]. A common practice with unclear clinical utility is the routine acquisition of immediate postoperative radiographs in the postanesthesia care unit (PACU) after total and partial knee arthroplasties (TKA and PKA). PACU radiographs are traditionally obtained after joint arthroplasty to assess gross limb alignment, implant position, fracture, limb length, or the presence of retained extruded cement or foreign bodies. Such radiographs are technically demanding to acquire [3], One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.11.033. * Reprint requests: Jess H. Lonner, MD, The Rothman Institute, 825 Old Lancaster Ave, 2nd Floor, Bryn Mawr, PA 19010. http://dx.doi.org/10.1016/j.arth.2016.11.033 0883-5403/© 2016 Elsevier Inc. All rights reserved.
and the resulting images are often imperfect, nonorthogonal, and poorly penetrated. This not only makes these images difficult to interpret, but it prevents them from serving as a valuable baseline for long-term follow-up [4,5]. Because of their unclear impact on subsequent clinical care, the utility of routine PACU radiographs has been called into question in total hip, knee, and shoulder arthroplasties [4-10]. To date, no study has analyzed the clinical utility of immediate PACU radiographs after PKA, including unicondylar knee arthroplasty (UKA), patellofemoral arthroplasty (PFA), or bicompartmental knee arthroplasty (BiKA). The primary purpose of this study is to determine the frequency at which immediate postoperative radiographs identify a problem that requires immediate or early reoperation after routine PKA, and whether delaying postoperative radiographs until the initial postoperative visit is detrimental to patient care. The secondary purpose is to calculate the potential cost savings associated with foregoing the routine acquisition of PACU radiographs after PKA.
2
A.S. Longenecker et al. / The Journal of Arthroplasty xxx (2016) 1e3
Materials and Methods This was a retrospective review of 1366 consecutive primary PKAs performed by a single surgeon (JHL) between January 2008 and March 2016. Of the 1366 PKAs, there were 873 UKAs (64%), 313 PFAs (23%), and 180 BiKAs (13%). After institutional review board's approval, the senior surgeon's surgical records and electronic medical records were queried to identify patients who had undergone primary PKA during the period under study. Patients were separated into 2 cohorts: (1) patients who had PACU anteroposterior (AP) and lateral radiographs (group 1), and (2) those who did not undergo radiographic evaluation until the initial postoperative office visit (group 2). Whether or not PACU radiographs were performed was a function of the location where surgery took place. All patients who had surgery at a hospital had PACU radiographs; those who had surgery at an ambulatory surgery center did not. Operative reports and clinical follow-up records were reviewed to determine the incidence of reoperation based on complications (gross implant malalignment, implant loosening, retained extruded cement, or fracture) identified either from immediate or 6-week postoperative radiographs. Instances of reoperation due to arthrofibrosis or infection were excluded, as they were not considered problems that would have been detected on early radiographic assessment. Mean patient body mass index in groups 1 and 2 was 28.6 kg/m2 (range, 17.2-42.2 kg/m2) and 29.4 kg/m2 (range, 18.5-39.1 kg/m2), respectively. Mean age in groups 1 and 2 was 59.4 years (range, 27.8-89.6 years) and 59.2 years (range, 33.2-85.6 years), respectively. The groups were statistically identical with respect to these measures. The breakdown of PFA, UKA, and BiKA between groups 1 and 2 are shown in Table 1. Costs The direct cost of postoperative radiographs was estimated from reimbursement data from our institution. The 2016 reimbursement for 1-2 radiographic images of the knee (CPT 73560) was $33.61 (technical component: $24.58; professional component: $9.03). Similar fees can be found by querying the Center for Medicare and Medicaid Services database. Results Of the 1184 knees that underwent radiographic imaging in the PACU and the 182 knees that did not undergo imaging until the first clinical follow-up, there were no instances of reoperation because of unanticipated abnormalities or derangements detected on radiographs from either time interval. There were no cases of gross malalignment, displacement, fracture, retained extruded cement, or loose body. The direct cost of immediate postoperative portable PACU supine AP and lateral radiographs is $33.67 per patient. Therefore, the cost of obtaining immediate postoperative PACU radiographs after PKA for the 1184 knees included in this study was nearly $46,000. Discussion The conventional protocol after joint arthroplasty has commonly included the acquisition of immediate postoperative portable PACU radiographs, ostensibly to confirm implant position and limb alignment, as well as to rule out fracture, retained extruded cement or foreign body. The utility of this routine for uncomplicated primary TKA has been called into question [4-6]. Unlike total hip arthroplasty, where early scrutiny of radiographs
Table 1 Distribution of PKAs by Group. Procedure Type
Group 1
Group 2
Totals
Reoperations Due to Radiographic Findings
UKA PFA BiKA Total
716 291 177 1184
157 22 3 182
873 313 180 1366
0 0 0 0
No reoperations were found in either group for any procedure type based on radiographic findings. BiKA, bicompartmental knee arthroplasty; PFA, patellofemoral arthroplasty; PKA, partial knee arthroplasty; UKA, unicondylar knee arthroplasty.
has value for assessing component position and ruling out femoral fracture, gross limb lengthening, or immediate dislocation [7,8], these problems are uncommon after TKA and PKA. The incidence of intraoperative periprosthetic fracture after primary TKA is between 0.1% and 0.39% [6,11]. In addition, roughly 96% of intraoperative periprosthetic fractures in primary TKA are identified during surgery before radiographic review [11]. Periprosthetic fractures may be less common after PKA. In an analysis of 20,488 UKA patients, the incidence of periprosthetic fractures occurring within 90 days after surgery was less than 0.2% [9]. It is unclear what percentage of those occurred intraoperatively. Nonetheless, it highlights the low incidence of fracture after PKA that would require early reintervention. In our study of nearly 1400 postoperative radiographs after PKA, we observed no fractures or other problems requiring adjustment in postoperative protocols or immediate reoperation, further questioning the need for routine postoperative PACU radiographs in this unique and previously unstudied cohort of patients. In an assessment of 192 uncomplicated primary TKAs, Glaser and Lotke found that of the 189 uncomplicated primary TKAs, there were no instances in which postoperative radiographs altered the postoperative management. Furthermore, in the 3 cases in which intraoperative complications necessitated alterations to surgical technique or postoperative management, postoperative radiographs merely confirmed operative findings, but did not further influence the postoperative plan. They also found that postoperative PACU radiographs were of sufficient quality to provide an accurate baseline for future studies in only 36% of patients. In an additional cohort of 550 patients on whom initial postoperative radiographs were not performed until the 6-week follow-up visit, there were no instances in which radiographs taken before discharge would have altered patient management [4]. Similarly, Namdari et al [10] found limited value and undue cost of immediate PACU radiographs after shoulder arthroplasty. In their retrospective analysis of 283 patients who had radiographs taken before discharge, none of the studies changed postoperative management. Furthermore, 71% were underpenetrated, and none were considered adequate to serve as baseline views, leading the authors to conclude that routine PACU radiographs after shoulder arthroplasty are an unnecessary expense. Our considerably larger series corroborates these findings for the particular cohort that we studied. Some have argued that postoperative PACU radiographs are an important means of providing the surgeon with immediate feedback regarding their surgical technique, and may be a valuable training tool for educating students, fellows, and residents [10]. Especially in the case of using these radiographs as a teaching aid, they may serve a valuable purpose as a source of immediate feedback. However, several studies have demonstrated that limb malalignment, bulky dressings, and/or poor radiographic technique degrade the quality of these radiographs and often preclude their
A.S. Longenecker et al. / The Journal of Arthroplasty xxx (2016) 1e3
use in evaluating implant position and alignment [4,5], diminishing their utility as a diagnostic or training tool. Another argument in favor of obtaining routine PACU radiographs is that they may aid in identifying problems requiring reoperation or adjustment in postoperative protocols without delay. Although this analysis has theoretical merit, it is a concern that seems unfounded based on findings from the present study. In a cohort of nearly 1400 knees, we found 0 reoperations because of radiographic findings. Based on these results, a binomial distribution indicates that the incidence of reoperation falls within a 95% confidence interval of 0.0%-0.27%. Even if 0.27% of the cases in our study had a mechanical complication, findings from Alden et al [11] indicate that 96% of these cases would be identified intraoperatively. Therefore, only 0.0108% of PKA patients (1 in 10,000) would benefit from, or have their postoperative care impacted by, immediate PACU radiographs. This finding is corroborated by the fact that, among the 182 PKAs in our cohort who did not receive PACU radiographs, there were no apparent adverse consequences because of delaying standard radiographic evaluation until the initial postoperative office visit. To be clear, however, if intraoperative problems are encountered, postoperative and even intraoperative radiographs are advisable to inform treatment, and at the very least confirm the suspected problem. The results of this study demonstrate that after PKA, postoperative PACU radiographs offer little information, and rarely prompt modification to postoperative protocols. Therefore, there is no evidence that would suggest that these radiographs provide a sufficient benefit to justify the cost and radiation dose (albeit minimal) associated with this imaging modality. In our series of 1366 PKAs, PACU radiographs were taken with no subsequent reoperation or protocol modification. Based on these findings, we estimate that forgoing PACU radiographs would have resulted in savings of nearly $46,000 in our cohort. Currently in the United States, an estimated 40-45,000 PKAs are performed annually. If immediate postoperative PACU radiographs were avoided in just two-thirds of these cases, potential cost savings would approach $1,000,000. There are several limitations to this study. Firstly, we were unable to evaluate all postoperative radiographs and were, therefore, unable to quantify the accuracy and quality of these AP and lateral radiographs after PKA. Based on publications regarding the inaccuracy of immediate postoperative PACU radiographs after TKA [4,5], however, it is likely that a large proportion of these PACU films would have lacked the quality to function as an accurate
3
measure of implant alignment. Secondly, this study appears to be under-powered, as we did not capture a single instance of immediate revision for mechanical failure after PKA. A study with a larger sample size is necessary to establish a true incidence of immediate reoperation after PKA. Such findings would facilitate a more robust cost-benefit analyses that would allow us to determine whether the cost-savings associated with foregoing PACU radiographs truly supersede any potential pitfalls associated with delaying the treatment of an unnoticed complication after PKA.
Conclusions Our study demonstrates that immediate postoperative portable PACU radiographs after primary uncomplicated PKA are an unnecessary expense and provide little clinical utility inasmuch as they do not appear to impact patient management after primary uncomplicated PKA.
References 1. Nwachukwu BU, Bozic KJ, Schairer WW, et al. Current status of cost utility analyses in total joint arthroplasty: a systematic review. Clin Orthop Relat Res 2015;473(5):1815. 2. Oberlander J. Unfinished journeyea century of health care reform in the United States. N Engl J Med 2012;367(7):585. 3. Berquist TH. Imaging of joint replacement procedures. Radiol Clin North Am 2006;44(3):419. 4. Glaser D, Lotke P. Cost-effectiveness of immediate postoperative radiographs after uncomplicated total knee arthroplasty: a retrospective and prospective study of 750 patients. J Arthroplasty 2000;15(4):475. 5. Moussa ME, Malchau H, Freiberg AA, et al. Effect of immediate postoperative portable radiographs on reoperation in primary total knee arthroplasty. Orthopedics 2014;37(9):e817. 6. Hassan S, Wall A, Ayyaswamy B, et al. Is there a need for early post-operative x-rays in primary total knee replacements? Experience of a centre in the UK. Ann R Coll Surg Engl 2012;94(3):199. 7. Mulhall KJ, Masterson E, Burke TE. Routine recovery room radiographs after total hip arthroplasty: ineffective for screening and unsuitable as baseline for longitudinal follow-up evaluation. J Arthroplasty 2004;19(3):313. 8. Ndu A, Jegede K, Bohl DD, et al. Recovery room radiographs after total hip arthroplasty: tradition vs utility? J Arthroplasty 2012;27(6):1051. 9. Ong K, Lau E, Kurtz SM, et al. Short-term complications and revision following unicondylar knee arthroplasty. In: Proceedings of the Orthopaedic Research Society; 2015. Las Vegas (NV). 10. Namdari S, Hsu JE, Baron M, et al. Immediate postoperative radiographs after shoulder arthroplasty are often poor quality and do not alter care. Clin Orthop Relat Res 2013;471(4):1257. 11. Alden KJ, Duncan WH, Trousdale RT, et al. Intraoperative fracture during primary total knee arthroplasty. Clin Orthop Relat Res 2010;468(1):90.