Oliver N. Schipper

Comparison of perioperative complications and hospitalization outcomes after ankle arthrodesis versus total ankle arthroplasty from 2002 to 2011.

Background: The aim of this study was to analyze a validated, nationally representative admissions database in order to compare perioperative complications and hospitalization outcomes associated with ankle arthrodesis (AAD) versus ankle arthroplasty (TAA). Methods: Using the Nationwide Inpatient Sample (NIS) database from 2002 to 2011, 12 250 patients who underwent AAD and 3002 patients who underwent TAA were identified based on International Classification of Diseases, Ninth Revision (ICD-9) codes. The demographics, comorbidities, and perioperative outcomes during the index hospital stay were compared between patients who underwent AAD and TAA. Multivariate analysis was performed to adjust for differences in demographics and comorbidities between the 2 groups. Results: Multivariate analysis demonstrated that TAA was independently associated with a decreased risk of blood transfusion (relative risk [RR] = 0.53, P < .001), non–home discharge (RR = 0.70, P < .001), and overall complication (RR = 0.79, P = .03). There were similar rates of pneumonia, deep vein thrombosis, pulmonary embolus, cerebrovascular accident, myocardial infarction, and mortality. TAA was independently associated with a significantly higher hospital charge (difference =

Effect of Obesity on Total Ankle Arthroplasty Outcomes

24 431, P < .001). There was no significant difference in the adjusted length of stay between the 2 groups (P = .13). Conclusion: TAA was independently associated with a lower risk of blood transfusion, non–home discharge, and overall complication when compared to AAD during the index hospitalization period. TAA was also independently associated with a higher hospitalization charge, but length of stay was similar between the 2 groups. Until long-term comparative studies are performed, the optimal treatment for end-stage ankle arthritis remains controversial, this study provides greater clarity with regard to hospitalization outcomes after the 2 procedures and shows no significant difference in risk for the majority of medical perioperative complications. Level of Evidence: Level III, comparative series.

Effect of Diabetes Mellitus on Perioperative Complications and Hospital Outcomes After Ankle Arthrodesis and Total Ankle Arthroplasty

Background: The purpose of this study was to evaluate the effect of obesity on intermediate- to long-term implant failure rates and survivorship after total ankle arthroplasty. Methods: A chart review was performed for all patients who underwent primary total ankle arthroplasty between 2004 and 2009 with a minimum 5-year follow-up. Patients were separated into a reference group with a body mass index less than 30 kg/m2 and an obese group with an index greater than or equal to 30 kg/m2. Minimum 5-year follow-up outcomes were available for 49 patients in the obese group and 48 patients in the nonobese group. Mean follow-up was 8.2 ± 2.0 years (range, 5.1-11.5 years) in the reference group and 7.7 ± 2.0 years (range, 5.0-11.9 years) in the obese group (P = .26). Results: Based on multivariable logistic regression, obese patients had a significantly greater probability of implant failure by final follow-up (adjusted odds ratio, 2.8 [95% CI, 1.04-7.53]; P = .04). Cox regression analysis of 5-year implant survivorship showed no significant difference between the 2 groups (adjusted hazard ratio, 1.89 [95% CI, 0.77-4.65]; P = .17). When compared with obese patients with inflammatory or posttraumatic arthritis, obese patients with osteoarthritis demonstrated a significantly decreased 5-year survivorship (adjusted hazard ratio, 3.73 [95% CI, 1.05-10.43]; P = .04). Conclusion: This study demonstrated an increased long-term risk of implant failure among obese patients that was not seen in the intermediate term. Furthermore, obese patients with primary osteoarthritis were found to have a significantly decreased 5-year implant survivorship after ankle arthroplasty as compared with obese patients with inflammatory or posttraumatic arthritis and therefore should be counseled appropriately when deciding between arthroplasty and arthrodesis. Level of Evidence: Level III, retrospective comparative series.

Reduction in Wound Complications After Total Ankle Arthroplasty Using a Compression Wrap Protocol

Background: The aim of this investigation was to analyze a nationally representative admissions database to evaluate the effect of diabetes mellitus on the rate of perioperative complications and hospitalization outcomes after ankle arthrodesis (AAD) and total ankle arthroplasty (TAA). Methods: Using the Nationwide Inpatient Sample database, 12 122 patients who underwent AAD and 2973 patients who underwent TAA were identified from 2002 to 2011 based on ICD-9 procedure codes. The perioperative complications and hospitalization outcomes were compared between diabetic and nondiabetic patients for each surgery during the index hospital stay. Results: The overall complication rate in the AAD group was 16.4% in diabetic patients and 7.0% in nondiabetic patients (P < .001). Multivariate analysis demonstrated that diabetes mellitus was independently associated with an increased risk of myocardial infarction (relative risk [RR] = 3.2, P = .008), urinary tract infection (RR = 4.6, P < .001), blood transfusion (RR = 3.0, P < .001), irrigation and debridement (RR = 1.9, P = .001), and overall complication rate (RR = 2.7, P < .001). Diabetes was also independently associated with a statistically significant increase in length of hospital stay (difference = 0.35 days, P < .001), more frequent nonhome discharge (RR = 1.69, P < .001), and higher hospitalization charges (difference =

Histological Analysis of Early Osteolysis in Total Ankle Arthroplasty

1908, P = .04). The overall complication rate in the TAA group was 7.8% in diabetic patients and 4.7% in nondiabetic patients. Multivariate analysis demonstrated that diabetes was independently associated with increased risk of blood transfusion (RR = 9.8, P = .03) and overall complication rate (RR = 4.1, P = .02). Diabetes was also independently associated with a statistically significant increase in length of stay (difference = 0.41 days, P < .001) and more frequent nonhome discharge (RR = 1.88, P < .001), but there was no significant difference in hospitalization charges (P = .64). Conclusion: After both AAD and TAA, diabetes mellitus was independently associated with a significantly increased risk of perioperative complications, nonhome discharge, and length of hospital stay during the index hospitalization. Level of Evidence: Level III, comparative series.

Radiographic Results of Nitinol Compression Staples for Hindfoot and Midfoot Arthrodeses

Background: The purpose of this study was to evaluate the clinical differences in wound complications after total ankle arthroplasty (TAA) between a cohort of patients that received a compression wrap protocol and a historical control group treated with cast immobilization. Methods: Patient charts and postoperative wound pictures were reviewed for 42 patients who underwent a compression wrap protocol and 50 patients who underwent circumferential casting after primary TAA from 2008 to 2013. A blinded reviewer graded each wound using a novel postoperative wound classification system, and recorded whether the wound was completely healed by or after 3 months. A second blinded review was performed to determine intraobserver reliability. Mean patient age was 55 years (range, 24-80) and all patients had at least 6-month follow-up. Results: There were significantly more total wound complications (P = .02) and mild wound complications (P = .02) in the casted group compared to the compression wrap group. There were no significant differences in the number of moderate and severe complications between each group. A significantly higher proportion of TAA incisions took longer than 3 months to heal in the casted group (P = .02). Conclusions: Based on our clinical experience with postoperative wound care after TAA, use of a compression wrap protocol was safe and effective at reducing wound-related complications, and well tolerated by patients. Further prospective, randomized clinical trials are warranted to evaluate the utility and cost-effectiveness of a compression wrap protocol after TAA. Level of Evidence: Level III, retrospective cohort study.

Wear Characteristics of Conventional Ultrahigh-Molecular-Weight Polyethylene Versus Highly Cross-Linked Polyethylene in Total Ankle Arthroplasty:

Background: The purpose of this study was to perform a histological comparative analysis of tibiotalar joint samples taken from areas of osteolysis adjacent to total ankle arthroplasties vs control synovial specimens to determine the reaction to and presence of polyethylene (PE) particles. Methods: A total of 57 pathology samples were identified in the osteolysis group, while 11 were identified in the control group. For each sample, hematoxylin and eosin, Oil Red O (ORO), and macrophage marker CD163-stained slides were created. Polarized light and ORO stain were used to identify PE particles. The presence of metal particles and giant cell reaction to PE particles were also scored. Results: Macrophages, PE particles, metallosis, and foreign body giant cell reaction scores were significantly higher in the osteolysis group compared with the control group. In the osteolysis group, ORO staining was positive in 93% (53/57), birefringent material was present in 96.5% (55/57), and macrophage infiltrates were present in 96.5% (55/57). Foreign body giant cell reaction with giant cells surrounding PE particles was present in 49.1% (28/57) of osteolytic specimens. The presence of foreign body giant cell reaction was associated with significantly higher macrophage, ORO, and polarizable material scores. The average time to surgery for osteolysis from the index ankle replacement was 6.0 (range, 0-15) years for the 57 patients in the osteolysis group. Conclusion: This study is the largest ankle arthroplasty histological analysis to show that areas of osteolysis consist of abundant polyethylene wear particles, present both intracellularly and extracellularly. Furthermore, these areas were associated with a CD163+ macrophage infiltrate and frequently a foreign body reaction with giant cells engulfing PE particles. It is likely that implant wear particles play a significant role in osteolysis based on the histopathology. Level of Evidence: Level III, retrospective comparative series.

Ankle Block vs Single-Shot Popliteal Fossa Block as Primary Anesthesia for Forefoot Operative Procedures: Prospective, Randomized Comparison:

Background: The purpose of this study was to determine the radiographic union rate after midfoot and hindfoot arthrodeses using a new generation of nitinol staples, and to compare outcomes between a nitinol staple construct and a nitinol staple and threaded compression screw construct. Methods: A retrospective chart review was performed to identify patients who underwent hindfoot or midfoot arthrodesis using a new generation of nitinol compression staples with or without a partially threaded cannulated screw with minimum 3-month radiographic follow-up. The primary outcome variable was radiographic evidence of arthrodesis on radiographs and, when available, computed tomographic scan in patients who underwent midfoot or hindfoot arthrodesis using nitinol staples. Ninety-six patients and 149 joints were eligible for analysis. Median radiographic follow-up was 5.7 months. Results: Radiographic union was seen in 93.8% (60/64) of patients and 95.1% (98/103) of joints using the nitinol staple construct. Radiographic union was seen in 90.6% (29/32) of patients and 95.7% (44/46) of joints using the nitinol combined staple and screw construct. There was no significant difference in radiographic union rate or revision surgery between the 2 groups. Seven patients developed nonunion, 4 in the nitinol staple construct group and 3 in the staple and screw group. Conclusions: New-generation nitinol staples were safe and effective for hindfoot and midfoot arthrodeses, with a high radiographic union rate. The use of a partially threaded screw for additional fixation was not found to either significantly increase or decrease radiographic fusion with nitinol staple fixation. Level of Evidence: Level III, comparative cohort study.

Clinical and Radiographic Outcomes of Revision Total Ankle Arthroplasty Using an Intramedullary Referencing Implant

Background: The aim of this study was to compare the polyethylene wear rate, particle size, and particle shape of primary semiconstrained, fixed-bearing, bone-sparing total ankle arthroplasty using conventional ultrahigh-molecular-weight polyethylene (CPE) versus highly cross-linked polyethylene (HXLPE) by applying a level walking input using a joint simulator. Methods: Two fixed-bearing total ankle replacement systems with different types of polyethylene liners were tested: (1) CPE sterilized in ethylene oxide, and (2) HXLPE sterilized with gas plasma after electron beam irradiation. Three implants for each design underwent wear testing using gravimetric analysis over 5 million simulated walking cycles. A fourth implant was used as a load soak control. Equivalent circle diameter (ECD) and equivalent shape ratio (ESR) were computed to determine particle size and particle shape, respectively. Results: The mean wear rate from 1.5 to 5 million cycles (MC) was 2.0 ± 0.3 mg/MC for HXLPE and 16.7 ± 1.3 mg/MC for CPE (P < .001). The total number of particles per cycle generated for HXLPE and CPE were 0.17 × 106 particles/cycle and 0.53 × 106 particles/cycle, respectively (P < .001). The mean ECD of HXLPE particles (0.22 ± 0.11 μm) was significantly smaller than the mean ECD of CPE particles (0.32 ± 0.14 μm) (P < .001). HXLPE particles were significantly more round than CPE particles (P < .001). Conclusions: HXLPE liners had a significantly lower wear rate and produced significantly fewer and rounder particles than CPE liners. The results of this study suggest that HXLPE has more favorable wear characteristics for total ankle arthroplasty. Clinical Relevance: Polyethylene wear particles have been linked to osteolysis after total ankle arthroplasty. There is no consensus on the importance of highly cross-linked polyethylene in total ankle arthroplasty with regard to implant wear. This is the first nonindustry study to compare the polyethylene wear rate, particle size, and particle shape of fixed-bearing total ankle arthroplasty conventional polyethylene versus highly cross-linked polyethylene. The lower wear rate and different particle size/morphology of highly cross-linked polyethylene could be beneficial in vivo to decrease osteolysis.

Outcomes After Primary Repair of Insertional Ruptures of the Achilles Tendon

Background: Postoperative pain is often difficult to control with oral medications, requiring large doses of opioid analgesia. Regional anesthesia may be used for primary anesthesia, reducing the need for general anesthetic and postoperative pain medication requirements in the immediate postoperative period. The purpose of this study was to compare the analgesic effects of an ankle block (AB) to a single-shot popliteal fossa block (PFB) for patients undergoing orthopedic forefoot procedures. Methods: All patients having elective outpatient orthopedic forefoot procedures were invited to participate in the study. Patients were prospectively randomized to receive either an ultrasound-guided AB or PFB by a board-certified anesthesiologist prior to their procedure. Intraoperative conversion to general anesthesia and postanesthesia care unit (PACU) opioid requirements were recorded. Postoperative pain was assessed using the visual analog scale (VAS) at regular time intervals until 8 am on postoperative day (POD) 2. Patients rated the effectiveness of the block on a 1 to 5 scale, with 5 being very effective. A total of 167 patients participated in the study with 88 patients (53%) receiving an AB and 79 (47%) receiving a single-shot PFB. Results: There was no significant difference in the rate of conversion to general anesthesia between the 2 groups (13.6% [12/88] AB vs 12.7% [10/79] PFB). PACU morphine requirements and doses were significantly reduced in the PFB group (P = .004) when compared to the AB group. The VAS was also significantly lower for the PFB patients at 10 pm on POD 0 (4.6 vs 1.6, P < .001), 8 am on POD 1 (5.9 vs 4.2, P = .003), and 12 pm on POD 1 (5.4 vs 4.1, P = .01). Overall complication rates were similar between the groups (AB 9% vs PFB 10.1%, P = .51) and there were no significant differences in residual sensory paresthesias (AB 2.3% [2/88] vs PFB 5.1% [4/79], P = .29), motor loss (0% vs 0%), or block site pain and/or erythema (AB 6.9% [6/88] vs PFB 5.1% [4/79], P = .44). The analgesic effect of the PFB lasted significantly longer when compared to the ankle block (AB 14.5 hours vs PFB 20.9 hours, P < .001). There was no significant difference in patient-perceived effectiveness of the block between the 2 groups, with both blocks being highly effective (AB 4.79/5 vs PFB 4.82/5, P = .68). Conclusion: Regional anesthesia was a safe and reliable adjunct to perioperative pain management and highly effective in patients undergoing elective orthopedic forefoot procedures. However, patients who received a PFB had significantly better pain management and decreased opioid requirements in the immediate perioperative period than patients who received an ankle block. Level of Evidence: Level I, prospective randomized study.