MID-AMERICA ORTHOPAEDIC ASSOCIATION 33rd Annual Meeting April 22-26, 2015 The Westin Hilton Head Island Resort Hilton Head Island, SC Podium and Poster Abstracts NOTE: Disclosure information is listed at the end of this document. *Denotes presenter MAOA FIRST PLENARY SESSION April 23, 2015 Irrigation and Debridement Prior to a Two-Stage Revision TKA Does Not Increase Risk of Failure Abstract ID: Paper 001 Olubusola Brimmo, M.D. Nicholas Schlitz, Ph.D. Aiswarya Pillai Chandran, M.S. Siran Koroukian, Ph.D. *Alison K. Klika, M.S. Carlos A. Higuera, M.D. Wael K. Barsoum, M.D. Cleveland, OH INTRODUCTION: Studies have shown an increased rate of failure of two-stage revision total knee arthroplasty (rTKA) after a failed irrigation and debridement (I&D) for prosthetic joint infections (PJI) of the knee. The objective of this study was to compare failure rates of patients following two-stage rTKA with and without a previous I&D. METHODS: The 2005-2011 State Inpatient Database (SID) from 2 states (CA and NY) was used to identify patients who underwent two-stage rTKA for PJI between 2007-2009 (using ICD- 9-CM procedure and diagnosis codes). The main exposure was I&D. A two-year look back period was used to detect those patients who had an I&D prior to two-stage rTKA, and the outcomes of the two groups (with and without prior I&D) were compared. The primary outcome was failure of the two-stage rTKA (i.e., defined as the need for subsequent surgery due to infection, including ICD-9 diagnosis code 996.66). Follow-up time ranged from 2 - 4 years. Bootstrapping analysis and Kaplan-Meier curves were used to compare failure for groups treated with and without I&D prior to two-stage rTKA. RESULTS: A total of 628 two-stage rTKA patients were included, with n=45 (7.2%) who had an I&D prior to revision, and n=583 who did not. Overall rTKA failure rate was 74/628 (11.8%). Estimated failures by year two, was 9.0% (95% CI: 2.0% - 18.3%) for patients with a prior I&D, and 12.1% (9.3% - 14.8%) for patients with no I&D, which rose to 15.2% by four years postoperative. The mean time to failure was 119 days (standard deviation[SD]: 38) and 398 (SD: 46) days for patients with and without prior I&D, respectively (p=<.001). CONCLUSION: Patients who had an I&D prior to two-stage rTKA for infection did not have an increased need for surgery following the revision for infection-related reasons, although the time to failure was significantly shorter. Periarticular Injection Following TKA Using Liposomal Bupivacaine vs. a Modified Ranawat Suspension. A Prospective, Randomized Study Abstract ID: Paper 002 *Philip N. Collis, M.D. Allison Hunter, B.S. Derek Vaughn, M.D. Langan Smith, B.S. Leah Carreon, M.D. Jiapeng Huang, M.D. Jeffrey Stimac, M.D. Arthur L. Malkani, M.D. Louisville, KY INTRODUCTION: Many advancements have been made in an effort to decrease narcotic consumption while improve pain relief, including multimodal drug therapies, regional nerve blocks, and local periarticular injections following TKA. Liposomal bupivacaine has recently been introduced as a long acting local anesthetic. The purpose of this study is to compare liposomal bupivacaine to a modified (Ranawat’s) local injection for TKA. METHODS: This is a prospective, randomized study of 85 consecutive patients undergoing primary TKA. Group A patients received a periarticular injection with liposomal bupivacaine ($285) and Group B with a mixture of ropivacaine, epinephrine, ketorolac, and clonidine ($40). Both groups received the same preoperative teaching, implant type, and postoperative management. Outcome measures included knee pain at rest and with activity, amount of narcotics, knee range of motion, and walking distance. Measures were recorded at intervals of 24 hours, 48 hours, 72 hours, two weeks and four to eight weeks postoperatively. RESULTS: There were 44 patients in the Group A (liposomal bupivacaine) and 41 in group B. There were no differences in the groups with respect to age, sex, and preoperative knee scores. Pain levels at rest and activity showed no differences between groups at all time intervals. There were no differences with respect to narcotic usage and knee ROM. Liposomal bupivacaine group had a greater walking distance at 24, 48, and 72 hours, but only significant at 24 hours (p = 0.034). There was a trend towards increased discharge to home vs. rehabilitation in the liposomal bupivacaine group, but this was not significant. CONCLUSION: Liposomal bupivacaine as a periarticular injection following TKA demonstrated similar pain levels, narcotic usage, and ROM compared to a modified Ranawat suspension, but improved walking distance and a trend towards home discharge. What Safe Zone? The Majority of 224 Dislocated THA were within the Lewinnek Zone Abstract ID: Paper 003 *Matthew P. Abdel, M.D. Philipp von Roth, M.D. Matthew T. Jennings, B.S. Arlen D. Hanssen, M.D. Mark W. Pagnano, M.D Rochester, MN INTRODUCTION: One long held tenet is that cup inclination and anteversion should be 40±10° and 15±10°, respectively, to minimize dislocations after primary total hip arthroplasty (THA). Recent interest in navigation, robotics, and advanced 3-D imaging has focused on those classic targets defined by Lewinnek in 1978. In contemporary THA practice (characterized by multiple femoral heads size options, multiple liner options, and the predominance of uncemented femoral fixation), we questioned whether those target values accurately predict dislocation remains poorly understood. METHODS: From a consecutive cohort of 11,246 primary THAs done at our institution between 2003 and 2012, we retrospectively identified 224 THAs (1.9%) which subsequently dislocated. Clinical demographics including age, gender, and BMI, as well as radiographic parameters including inclination, anteversion, center of rotation, and limb length discrepancy were analyzed. The mean age was 64 years, mean was BMI 29 kg/m2, and mean time to first dislocation was 18 months. Minimum follow-up was 2 years. RESULTS: The majority (58%) of these dislocated THAs had an acetabular socket position that was within the Lewinnek safe-zone. Mean cup inclination was 44 ± 8° (95% CI = 42-45°), with 84% within the safe zone. The mean anteversion was 15 ± 9° (95% CI = 13-16°), with 69% within the safe zone. The mean lateralization of the center of rotation was 6 ± 4 mm from the native center of rotation, and the mean limb length difference was 4 ± 7 mm longer. CONCLUSION: The historical target values for cup inclination and anteversion defined by Lewinnek may be useful, but should not be considered a safe-zone given that the majority of these contemporary THAs which dislocated were in fact within those target values. It is likely that the ideal cup position for some patients lies outside the Lewinnek zone and that more advanced analysis is required to identify the right target in that subgroup. Does Prior Cartilage Restoration Negatively Impact Outcomes of Knee Arthroplasty? Abstract ID: Paper 004 Rachel M. Frank, M.D. / Chicago, IL *Darren Plummer, M.S. / Chicago, IL Peter N. Chalmers, M.D. / Chicago, IL Scott M. Sporer, M.D. / Winfield, IL Brett R. Levine, M.D. / Chicago, IL Brian J. Cole, M.D. / Chicago, IL Craig J. Della Valle, M.D. / Chicago, IL INTRODUCTION: Cartilage restoration procedures are being performed with increasing frequency and if these procedures fail, patients may require unicompartmental (UKA) or total knee arthroplasty (TKA) to alleviate their symptoms. The purpose of this study was to compare patients who failed a cartilage restoration procedure to matched-controls undergoing primary knee arthroplasty. METHODS: A retrospective review of prospectively collected data on patients who underwent cartilage restoration by a single surgeon and subsequently progressed to arthroplasty was performed. Patients were matched to primary UKA/TKA controls based on gender, age ± 5 years, body mass index (BMI) ± 5, smoking status, and arthroplasty type and were followed for a minimum of 2 years (mean, 3.7; range, 2.0-7.2). The primary outcome was the Knee Society Score (KSS). Secondary outcomes were range of motion (ROM) and revision rate. Appropriate statistical analysis was performed for continuous data with between and within group comparisons. RESULTS: A total of 26 patients (13 per group: 8 TKAs and 5 UKAs) were included. There were no significant differences in age, gender, BMI, smoking status, worker's compensation status, preoperative ROM, postoperative ROM, or preoperative KSS scores between groups (P>0.05 in all cases), suggesting adequate matching. Patients in the cartilage group had a significantly lower pre-arthroplasty (post-cartilage) Kellgren and Lawrence grade (average 2.6±0.9) compared to matched controls (average 3.7 ± 0.5, P=0.004). There were no significant differences in pre-cartilage to post-cartilage (pre-arthroplasty) Tegner (2.4 ± 2.4 to 2.3 ± 0.8, P=0.729), Lysholm (30.8 ± 17.1 to 38.2 ± 20.0, P=0.474), IKDC (26.4 ± 10.3 to 33.0 ± 10.3, P=0.847), or KOOS-pain (41.7 ± 19.4 to 59.0 ± 19.9, P=0.672) scores. Patients in the cartilage group had significantly lower postoperative KSS scores (78 ± 13 vs. 91 ± 5, P=0.005) and experienced significantly less improvement in KSS scores (30 ± 10 vs. 46 ± 10, P<0.001). Two patients (15%) in the cartilage group required revision TKA at 1.9 years (for pain) and 4.7 years (for infection) following the index TKA. DISCUSSION AND CONCLUSION: While patients with a failed cartilage procedure do still derive benefit from knee arthroplasty, the magnitude of improvement and final scores are lower than matched controls.