Correlation of Obesity With Patient-Reported Outcomes and Complications After Hip Arthroscopy Jason A. Collins, M.D., Bryan G. Beutel, M.D., Garret Garofolo, B.S., and Thomas Youm, M.D.
Purpose: This study aimed to evaluate patient-reported outcomes and complications after hip arthroscopy in an obese population compared with a matched nonobese control group with a minimum 2-year follow-up, using the Modified Harris Hip Score (MHHS) and Nonarthritic Hip Score (NAHS). Methods: Data were analyzed from 21 consecutive obese patients (body mass index [BMI] 30) and 18 nonobese patients (BMI < 25) who underwent hip arthroscopy between 2009 and 2012 with a minimum follow-up of 2 years. Data collected included MHHS, NAHS, traction and intraoperative times, and postoperative complications. Results: Traction times were similar between obese and nonobese patients at 48 and 45 minutes (P ¼ .51), respectively. Operative times were also similar at 54 and 51 minutes (P ¼ .79), respectively. Each group had a statistically significant improvement in MHHS from baseline to final follow-up: 45 to 79 (P < .001) in the obese group and 49 to 81 (P < .001) in the nonobese cohort. Similarly, the NAHS showed significant improvement in each group from baseline to final follow-up: 43 to 75 (P < .001) in the obese cohort and 45 to 83 (P < .001) in the nonobese group. There was no difference between groups in MHHS or NAHS data. There were 8 complications in the obese group, most commonly deep vein thrombosis (DVT) and worsened pain, whereas the nonobese cohort had one complication (an instance of heterotopic ossification [HO]). Overall, obese patients had 11.1 times the risk of a complication developing than did nonobese patients (95% confidence interval, 1.2 to 99.7). Conclusions: Hip arthroscopy in the obese patient population leads to improved short- to mid-term patient-reported outcomes similar to those seen in nonobese patients. Obese patients, however, are at a significantly increased risk of postoperative complications such as DVTs and worsened hip pain. Level of Evidence: Level IV, therapeutic case series.
A
lthough hip arthroscopy was initially described in 1931, recent advances in imaging, technology, and surgical technique have expanded the indications of this procedure for the treatment of hip pain.1-3 Hip arthroscopy has traditionally been recommended after failure of nonoperative treatment and has even been proposed as a means to prevent the progression of intra-articular pathologic conditions such as femoroacetabular impingement (FAI).4-6 FAI, sex, and even sporting activities have been associated with a possible increase in degenerative joint disease of the hip.7-10 However, there is a paucity of literature focused on evaluating clinical outcomes within a patient From the Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received January 6, 2014; accepted July 11, 2014. Address correspondence to Thomas Youm, M.D., 1056 5th Ave, New York, NY 10028, U.S.A. E-mail: [email protected] Ó 2015 by the Arthroscopy Association of North America 0749-8063/1415/$36.00 http://dx.doi.org/10.1016/j.arthro.2014.07.013
population with respect to body mass index (BMI). The role of BMI in the development of hip osteoarthritis (OA) remains controversial, despite a strong correlation with knee OA.11 Several studies have observed an association between obesity and the development of hip OA, whereas others dispute this claim.12,13 Similarly, it is well documented that there is a significant difference in the clinical outcomes of an obese (BMI 30) patient who undergoes arthroscopic knee surgery compared with a nonobese patient undergoing the same surgical procedure.14 These trends have been reproduced in additional studies regarding arthroscopic rotator cuff repair, in which obesity was associated with poorer functional outcomes.15 Other reviews, however, have described a lack of consensus in the literature with respect to BMI and outcomes after ambulatory shoulder operations.16 In addition to potentially affecting outcomes, obesity has been implicated as a driver of increased operative times. This has been noted in cases of arthroscopic shoulder surgery.15 Similarly, longer operative times have been reported for obese patients undergoing primary total hip arthroplasty, particularly among the
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 31, No 1 (January), 2015: pp 57-62
57
58
J. A. COLLINS ET AL.
morbidly obese.17 Concomitant with protracted operative times, obesity has also been linked to increased rates of complications. Specifically, BMI has been associated with thromboembolic events, wound infections, increased operative blood loss, and surgical technical errors in both total hip arthroplasty and spine procedures.18-20 Moreover, BMI has been shown to be a significant determinant of overall complication rates after reverse total shoulder arthroplasty.21 To our knowledge, however, there is no study that compares the clinical outcomes and complications of an obese population after undergoing arthroscopic hip surgery to a nonobese control group. The purpose of our study was to evaluate patient-reported outcomes and complications after hip arthroscopy in an obese population compared with a matched nonobese control group with a minimum 2-year follow-up, using the Modified Harris Hip Score (MHHS) and Nonarthritic Hip Score (NAHS). We hypothesized that a BMI of 30 or more would be predictive of a worse clinical outcome, an increased number of complications, and increased operative time.
Methods To investigate the clinical outcomes and complications after hip arthroscopy in obese and nonobese patients, we retrieved prospectively collected data from our database of patients who underwent hip arthroscopy by a single surgeon (T.Y.) between 2009 and 2012. The patients initially presented to the outpatient orthopaedic office and were recommended for surgery if they were experiencing disabling hip or groin pain, were identified as having probable intra-articular hip pathologic conditions as the source of their pain, and did not have a satisfactory response to a 3-month trial of nonoperative treatment. Nonoperative management included a 6-week course of physical therapy, activity modification, and oral nonsteroidal anti-inflammatory drugs when medically appropriate. All patients were grouped into either obese or nonobese cohorts. Inclusion criteria for the obese group were patient BMI greater than or equal to 30 and hip arthroscopy. BMI was measured preoperatively and postoperatively, and BMI did not change in any patient over the study period. Patients were excluded if they had undergone previous hip surgery (arthroscopic or open). A control group of nonobese patients who underwent hip arthroscopy during the same period was used as a comparison cohort, matching the obese and nonobese patients for factors such as age, sex, types of procedures performed, and Kellgren-Lawrence hip OA grade.22 The same inclusion and exclusion criteria were applied to the nonobese group, with the exception of the BMI threshold (enrollment into the nonobese cohort required a BMI < 25).
All examinations and operations were performed by a single surgeon (T.Y.). Patients underwent hip arthroscopy after the induction of general anesthesia and pharmacologic muscle relaxation. The hip was prepared and draped in the usual sterile fashion, and traction was applied by a hip distractor. C-arm fluoroscopy was used to confirm adequate distraction. Diagnostic arthroscopy was then performed using one midanterior and one anterolateral portal created under spinal needle localization. Two cannulas were then inserted, and an interportal capsulotomy was performed. Intra-articular structuresdincluding the chondral surfaces of the femoral head and acetabulum, ligamentum teres, labrum, capsule, as well as the acetabular rim and femoral neckdwere examined. Pathologic processes at these sites were addressed surgically as needed. Postoperatively, all patients received acetylsalicylic acid 325 mg daily for 2 weeks for deep vein thrombosis (DVT) prophylaxis. Additionally, 2 weeks of celecoxib 200 mg daily was given for heterotopic ossification (HO) prophylaxis and 1 week of cephalexin 500 mg 4 times daily was prescribed for wound infection prophylaxis. A variety of principal data variables was gathered for each patient. From the hip arthroscopy, data were collected on the total operative and traction times for each case as well as the specific procedures and treatments performed during arthroscopy. This information was obtained from the surgeon’s operative report. Complications after arthroscopy were also carefully monitored and recorded postoperatively. Specifically, patients were seen for follow-up 2 weeks, 1 month, 3 months, 6 months, and 1 year postoperatively and then approximately every year thereafter. Patients were informed of possible complications as part of the consent process before arthroscopy. Immediately after the operation, as well as at each outpatient follow-up visit, the patients were specifically asked about and examined for possible complications, in addition to any other general issues or concerns they may have. Additionally, to evaluate functional outcomes, patients were also assessed preoperatively and postoperatively with the MHHS and the NAHS scores. All data were recorded and archived digitally and were available for review. Data were initially analyzed with the KolmogorovSmirnoff test to assess for normality of distribution. The independent t test was used for the comparison of 2 continuous variables, such as comparing scores between the nonobese and obese patient populations, and the paired t test was implemented to compare baseline (preoperative) and final follow-up (postoperative) scores when the data were normally distributed. The Mann-Whitney U test and the Wilcoxon signed rank test were used in lieu of the independent and paired t tests, respectively, when the data were not normally distributed. Additionally, the Pearson correlation
59
OBESITY AND HIP ARTHROSCOPY OUTCOMES Table 1. Characteristics of Nonobese and Obese Patient Cohorts Nonobese Characteristic Age, yr BMI, kg/m2 Kellgren-Lawrence grade
Sex Male Female Laterality Left Right
Mean 38 22.4 0.8
SD 11.7 2.2 0.8
Obese Range 21-64 18.1-24.9 0-3
Mean 41 33.4 0.9
SD 10.8 4.2 0.8
No.
%
No.
%
6 12
33 67
10 11
48 52
8 10
44 56
8 13
38 62
Range 22-61 30-46.2 0-3
P Value .43
Purpose: This study aimed to evaluate patient-reported outcomes and complications after hip arthroscopy in an obese population compared with a matched nonobese control group with a minimum 2-year follow-up, using the Modified Harris Hip Score (MHHS) and Nonarthritic Hip Score (NAHS). Methods: Data were analyzed from 21 consecutive obese patients (body mass index [BMI] 30) and 18 nonobese patients (BMI < 25) who underwent hip arthroscopy between 2009 and 2012 with a minimum follow-up of 2 years. Data collected included MHHS, NAHS, traction and intraoperative times, and postoperative complications. Results: Traction times were similar between obese and nonobese patients at 48 and 45 minutes (P ¼ .51), respectively. Operative times were also similar at 54 and 51 minutes (P ¼ .79), respectively. Each group had a statistically significant improvement in MHHS from baseline to final follow-up: 45 to 79 (P < .001) in the obese group and 49 to 81 (P < .001) in the nonobese cohort. Similarly, the NAHS showed significant improvement in each group from baseline to final follow-up: 43 to 75 (P < .001) in the obese cohort and 45 to 83 (P < .001) in the nonobese group. There was no difference between groups in MHHS or NAHS data. There were 8 complications in the obese group, most commonly deep vein thrombosis (DVT) and worsened pain, whereas the nonobese cohort had one complication (an instance of heterotopic ossification [HO]). Overall, obese patients had 11.1 times the risk of a complication developing than did nonobese patients (95% confidence interval, 1.2 to 99.7). Conclusions: Hip arthroscopy in the obese patient population leads to improved short- to mid-term patient-reported outcomes similar to those seen in nonobese patients. Obese patients, however, are at a significantly increased risk of postoperative complications such as DVTs and worsened hip pain. Level of Evidence: Level IV, therapeutic case series.
A
lthough hip arthroscopy was initially described in 1931, recent advances in imaging, technology, and surgical technique have expanded the indications of this procedure for the treatment of hip pain.1-3 Hip arthroscopy has traditionally been recommended after failure of nonoperative treatment and has even been proposed as a means to prevent the progression of intra-articular pathologic conditions such as femoroacetabular impingement (FAI).4-6 FAI, sex, and even sporting activities have been associated with a possible increase in degenerative joint disease of the hip.7-10 However, there is a paucity of literature focused on evaluating clinical outcomes within a patient From the Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received January 6, 2014; accepted July 11, 2014. Address correspondence to Thomas Youm, M.D., 1056 5th Ave, New York, NY 10028, U.S.A. E-mail: [email protected] Ó 2015 by the Arthroscopy Association of North America 0749-8063/1415/$36.00 http://dx.doi.org/10.1016/j.arthro.2014.07.013
population with respect to body mass index (BMI). The role of BMI in the development of hip osteoarthritis (OA) remains controversial, despite a strong correlation with knee OA.11 Several studies have observed an association between obesity and the development of hip OA, whereas others dispute this claim.12,13 Similarly, it is well documented that there is a significant difference in the clinical outcomes of an obese (BMI 30) patient who undergoes arthroscopic knee surgery compared with a nonobese patient undergoing the same surgical procedure.14 These trends have been reproduced in additional studies regarding arthroscopic rotator cuff repair, in which obesity was associated with poorer functional outcomes.15 Other reviews, however, have described a lack of consensus in the literature with respect to BMI and outcomes after ambulatory shoulder operations.16 In addition to potentially affecting outcomes, obesity has been implicated as a driver of increased operative times. This has been noted in cases of arthroscopic shoulder surgery.15 Similarly, longer operative times have been reported for obese patients undergoing primary total hip arthroplasty, particularly among the
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 31, No 1 (January), 2015: pp 57-62
57
58
J. A. COLLINS ET AL.
morbidly obese.17 Concomitant with protracted operative times, obesity has also been linked to increased rates of complications. Specifically, BMI has been associated with thromboembolic events, wound infections, increased operative blood loss, and surgical technical errors in both total hip arthroplasty and spine procedures.18-20 Moreover, BMI has been shown to be a significant determinant of overall complication rates after reverse total shoulder arthroplasty.21 To our knowledge, however, there is no study that compares the clinical outcomes and complications of an obese population after undergoing arthroscopic hip surgery to a nonobese control group. The purpose of our study was to evaluate patient-reported outcomes and complications after hip arthroscopy in an obese population compared with a matched nonobese control group with a minimum 2-year follow-up, using the Modified Harris Hip Score (MHHS) and Nonarthritic Hip Score (NAHS). We hypothesized that a BMI of 30 or more would be predictive of a worse clinical outcome, an increased number of complications, and increased operative time.
Methods To investigate the clinical outcomes and complications after hip arthroscopy in obese and nonobese patients, we retrieved prospectively collected data from our database of patients who underwent hip arthroscopy by a single surgeon (T.Y.) between 2009 and 2012. The patients initially presented to the outpatient orthopaedic office and were recommended for surgery if they were experiencing disabling hip or groin pain, were identified as having probable intra-articular hip pathologic conditions as the source of their pain, and did not have a satisfactory response to a 3-month trial of nonoperative treatment. Nonoperative management included a 6-week course of physical therapy, activity modification, and oral nonsteroidal anti-inflammatory drugs when medically appropriate. All patients were grouped into either obese or nonobese cohorts. Inclusion criteria for the obese group were patient BMI greater than or equal to 30 and hip arthroscopy. BMI was measured preoperatively and postoperatively, and BMI did not change in any patient over the study period. Patients were excluded if they had undergone previous hip surgery (arthroscopic or open). A control group of nonobese patients who underwent hip arthroscopy during the same period was used as a comparison cohort, matching the obese and nonobese patients for factors such as age, sex, types of procedures performed, and Kellgren-Lawrence hip OA grade.22 The same inclusion and exclusion criteria were applied to the nonobese group, with the exception of the BMI threshold (enrollment into the nonobese cohort required a BMI < 25).
All examinations and operations were performed by a single surgeon (T.Y.). Patients underwent hip arthroscopy after the induction of general anesthesia and pharmacologic muscle relaxation. The hip was prepared and draped in the usual sterile fashion, and traction was applied by a hip distractor. C-arm fluoroscopy was used to confirm adequate distraction. Diagnostic arthroscopy was then performed using one midanterior and one anterolateral portal created under spinal needle localization. Two cannulas were then inserted, and an interportal capsulotomy was performed. Intra-articular structuresdincluding the chondral surfaces of the femoral head and acetabulum, ligamentum teres, labrum, capsule, as well as the acetabular rim and femoral neckdwere examined. Pathologic processes at these sites were addressed surgically as needed. Postoperatively, all patients received acetylsalicylic acid 325 mg daily for 2 weeks for deep vein thrombosis (DVT) prophylaxis. Additionally, 2 weeks of celecoxib 200 mg daily was given for heterotopic ossification (HO) prophylaxis and 1 week of cephalexin 500 mg 4 times daily was prescribed for wound infection prophylaxis. A variety of principal data variables was gathered for each patient. From the hip arthroscopy, data were collected on the total operative and traction times for each case as well as the specific procedures and treatments performed during arthroscopy. This information was obtained from the surgeon’s operative report. Complications after arthroscopy were also carefully monitored and recorded postoperatively. Specifically, patients were seen for follow-up 2 weeks, 1 month, 3 months, 6 months, and 1 year postoperatively and then approximately every year thereafter. Patients were informed of possible complications as part of the consent process before arthroscopy. Immediately after the operation, as well as at each outpatient follow-up visit, the patients were specifically asked about and examined for possible complications, in addition to any other general issues or concerns they may have. Additionally, to evaluate functional outcomes, patients were also assessed preoperatively and postoperatively with the MHHS and the NAHS scores. All data were recorded and archived digitally and were available for review. Data were initially analyzed with the KolmogorovSmirnoff test to assess for normality of distribution. The independent t test was used for the comparison of 2 continuous variables, such as comparing scores between the nonobese and obese patient populations, and the paired t test was implemented to compare baseline (preoperative) and final follow-up (postoperative) scores when the data were normally distributed. The Mann-Whitney U test and the Wilcoxon signed rank test were used in lieu of the independent and paired t tests, respectively, when the data were not normally distributed. Additionally, the Pearson correlation
59
OBESITY AND HIP ARTHROSCOPY OUTCOMES Table 1. Characteristics of Nonobese and Obese Patient Cohorts Nonobese Characteristic Age, yr BMI, kg/m2 Kellgren-Lawrence grade
Sex Male Female Laterality Left Right
Mean 38 22.4 0.8
SD 11.7 2.2 0.8
Obese Range 21-64 18.1-24.9 0-3
Mean 41 33.4 0.9
SD 10.8 4.2 0.8
No.
%
No.
%
6 12
33 67
10 11
48 52
8 10
44 56
8 13
38 62
Range 22-61 30-46.2 0-3
P Value .43
