Kara G. Fields

MRI Predicts ALVAL and Tissue Damage in Metal-on-Metal Hip Arthroplasty

BackgroundAdverse local tissue reactions (ALTR) around metal-on-metal (MOM) hip arthroplasties are increasingly being recognized as a cause of failure. These reactions may be associated with intraoperative tissue damage and complication rates as high as 50% after revision. Although MRI can identify ALTR in MOM hips, it is unclear whether the MRI findings predict those at revision surgery.Questions/purposesWe therefore (1) identified which MRI characteristics correlated with histologically confirmed ALTR (using the aseptic lymphocytic vasculitis-associated lesions [ALVAL] score) and intraoperative tissue damage and (2) developed a predictive model using modified MRI to detect ALVAL and quantify intraoperative tissue damage.MethodsWe retrospectively reviewed 68 patients with failed MOM hip arthroplasties who underwent preoperative MRI and subsequent revision surgery. Images were analyzed to determine synovial volume, osteolysis, and synovial thickness. The ALVAL score was used to grade tissue samples, thus identifying a subset of patients with ALTR. Intraoperative tissue damage was graded using a four-point scale. Random forest analysis determined the sensitivity and specificity of MRI characteristics in detecting ALVAL (score ≥ 5) and intraoperative tissue damage.ResultsMaximal synovial thicknesses and synovial volumes as determined on MRI correlated with the ALVAL score and were higher in cases of severe intraoperative tissue damage. Our MRI predictive model showed sensitivity and specificity of 94% and 87%, respectively, for detecting ALVAL and 90% and 86%, respectively, for quantifying intraoperative tissue damage.ConclusionsMRI is sensitive and specific in detecting ALVAL and tissue damage in patients with MOM hip implants. MRI can be used as a screening tool to guide surgeons toward timely revision surgery.Level of EvidenceLevel III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

The effect of femoral and acetabular version on clinical outcomes after arthroscopic femoroacetabular impingement surgery

BACKGROUND The impact of proximal femoral and combined femoral and acetabular version on patient-reported outcomes after arthroscopic surgery for femoroacetabular impingement (FAI) remains undefined. The purpose of this study was to identify associations of proximal femoral version as well as combined version (McKibbin index) with disease-specific, validated, patient-reported outcomes following arthroscopic correction of symptomatic FAI. METHODS A prospective hip arthroscopy registry was utilized to evaluate 243 patients who underwent arthroscopic surgery to correct FAI. Femoral version and the McKibbin index were measured prospectively on preoperative computed tomography scans. Disease-specific, patient-reported outcomes included the modified Harris hip score (mHHS) and the Hip Outcome Score (HOS) ADL (Activities of Daily Living) and Sports subscales. Disease impact on quality of life was determined with use of the International Hip Outcome Tool (iHOT-33). Comparative analyses were used to evaluate the impact of femoral version on changes in patient-reported outcome scores; multiple regression was used to adjust for potential confounders. RESULTS The patient cohort contained 243 patients (123 female and 120 male) with a mean age of 29.2 years and a mean postoperative follow-up of twenty-one months (range, twelve to forty-two months). The cohort experienced significant improvements (p < 0.001) in all patient-reported outcome measures, with most patients improving by at least the minimal clinically important difference for all of these measures. The mean improvement was 20 points for the mHHS, 15 for the HOS ADL, 23 for the HOS Sports, and 23 for the iHOT-33. When stratified by femoral version, the postoperative improvements in patients with relative femoral retroversion (<5° anteversion) were clinically important but of significantly smaller magnitude than those in the other version groups. We did not find any associations between the McKibbin index and any patient-reported outcomes. CONCLUSIONS Although clinically important improvements can be expected after arthroscopic FAI surgery in all femoral version groups, patients with relative femoral retroversion (<5° femoral anteversion) may experience less improvement than those with normal or increased version.

Causes and Risk Factors for Revision Hip Preservation Surgery

Background: Identifying causes and risk factors for failure of hip preservation surgery is critical to properly address residual pathological abnormalities in the revision setting and improve outcomes in this subset of patients. Purpose: To identify the structural causes of failure in both open and arthroscopic hip preservation procedures and to identify demographic and radiographic risk factors that correlate with the need for revision surgery. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A single-center hip preservation registry was reviewed (N = 1898 procedures in 1600 patients) to identify 147 patients (n = 152 procedures) who had undergone previous pelvic surgery. Exclusion criteria included residual deformity from pediatric hip disease (n = 5 patients). Preoperative demographics, intraoperative findings, radiographic data, and clinical outcome scores were compared between cohorts with and without revision surgery in the registry. Postoperative, short-term patient-reported outcome scores for the revision cohort were described. Results: The most common reason for revision was residual intra-articular femoroacetabular impingement (74.8%), followed by extra-articular impingement (9.5%). The majority of revision cases (78.9%) could be addressed with arthroscopic surgery, with the exception of extra-articular impingement or residual acetabular dysplasia, which necessitated open approaches. Patients who underwent revision were more likely to be female, were younger in age, and had worse preoperative outcome scores than did those in the primary cohort. Abnormal femoral version and the presence of acetabular dysplasia were not significantly different between the revision and primary cohorts. Short-term improvements in patient-reported outcome scores were found in the revision cohort at a mean of 15.0 months from the last revision surgery. Conclusion: Residual intra- and extra-articular impingement were the most common reasons for revision in this cohort. Patients who underwent revision tended to be younger in age, were female, and had worse preoperative hip functional outcomes than did those in the primary cohort. Abnormal femoral version or acetabular coverage was not increased in our revision cohort.

Outcomes After Arthroscopic Treatment of Femoroacetabular Impingement for Patients With Borderline Hip Dysplasia

Background: The outcomes of hip arthroscopy in the treatment of dysplasia are variable. Historically, arthroscopic treatment of severe dysplasia (lateral center-edge angle [LCEA] <18°) resulted in poor outcomes and iatrogenic instability. However, in milder forms of dysplasia, favorable outcomes have been reported. Purpose: To compare outcomes after hip arthroscopy for femoroacetabular impingement (FAI) in borderline dysplastic (BD) patients compared with a control group of nondysplastic patients. Study Design: Cohort study; Level of evidence, 3 Methods: Between March 2009 and July 2012, a BD group (LCEA, 18°-25°) of 46 patients (55 hips) was identified. An age- and sex-matched control group of 131 patients (152 hips) was also identified (LCEA, 25°-40°). Patient-reported outcome scores, including the modified Harris Hip Score (mHHS), the Hip Outcome Score–Activities of Daily Living (HOS-ADL) and Sport-Specific Subscale (HOS-SSS), and the International Hip Outcome Tool (iHOT-33), were collected preoperatively and at 1 and 2 years postoperatively. Results: The mean LCEA was 22.4° ± 2.0° (range, 18.4°-24.9°) in the BD group and 31.0° ± 3.1° (range, 25.4°-38.7°) in the control group (P < .001). The mean preoperative alpha angle was 66.3° ± 9.9° in the BD group and 61.7° ± 13.0° in the control group (P = .151). Cam decompression was performed in 98.2% and 99.3% of cases in the BD and control groups, respectively; labral repair was performed in 69.1% and 75.3% of the BD and control groups, respectively, with 100% of patients having a complete capsular closure performed in both groups. At a mean follow-up of 31.3 ± 7.6 months (range, 23.1-67.3 months) in unrevised patients and 21.6 ± 13.3 months (range, 4.7-40.6 months) in revised patients, there was significant improvement (P < .001) in all patient-reported outcome scores in both groups. Multiple regression analysis did not identify any significant differences between groups. Importantly, female sex did not appear to be a predictor for inferior outcomes. Two patients (4.3%) in the BD group and 6 patients (4.6%) in the control group required revision arthroscopy during the study period. Conclusion: Favorable outcomes can be expected after the treatment of impingement in patients with borderline dysplasia when labral refixation and capsular closure are performed, with comparable outcomes to nondysplastic patients. Further follow-up in larger cohorts is necessary to prove the durability and safety of hip arthroscopy in this challenging group and to further explore potential sex-related differences in outcome.

Unused Opioid Pills After Outpatient Shoulder Surgeries Given Current Perioperative Prescribing Habits

Background: In the past 16 years, the number of prescription opioids sold in the United States, as well as deaths from prescription opioids, has nearly quadrupled. However, the overall amount of pain reported by patients has not changed significantly. Specific information about opioid prescriptions in the perioperative period is lacking. Of the studies that have been published, investigators have shown that the majority of patients have unused postoperative opioid pills. Moreover, patients appear to lack information about disposal of unused opioid pills. Purpose: To compare the number of pills prescribed versus the numbers left unused after outpatient shoulder surgeries at an orthopaedic surgery institution. Study Design: Case series; Level of evidence, 4. Methods: In this prospective, observational study, 100 patients (age >18 years) undergoing outpatient shoulder surgery (rotator cuff repair, labral repair, stabilization/Bankart repair, debridement) were enrolled. Follow-ups were conducted via surveys on postoperative days (PODs) 7, 14, 28, and 90. The primary outcome was the number of unused pills from the originally prescribed medication. Results: For all procedure types, the median (Q1, Q3) number of prescribed pills was 60 (40, 80). On POD 90, patients reported a median (Q1, Q3) of 13 (0, 32) unused pills; patients who underwent rotator cuff repairs had the lowest number of pills remaining (median [Q1, Q3], 0 [0, 16]), whereas patients who had stabilization/Bankart repairs had the highest number of unused pills (median [Q1, Q3], 37 [29, 50]). Patient satisfaction with pain management ranged from an average of 70% to 90%. Only 25 patients received instructions or education about opioid disposal. Conclusion: Most outpatient shoulder surgery patients who underwent certain operations were prescribed more opioid analgesics than they consumed. Patient education regarding the disposal of opioids was lacking.

Pregabalin and pain after total knee arthroplasty: a double-blind, randomized, placebo-controlled, multidose trial

BACKGROUND Pregabalin may reduce postoperative pain and opioid use. Higher doses may be more effective, but may cause sedation and confusion. This prospective, randomized, blinded, placebo-controlled study tested the hypothesis that pregabalin reduces pain at 2 weeks after total knee arthroplasty, but increases drowsiness and confusion. METHODS Patients (30 per group) received capsules containing pregabalin (0, 50, 100, or 150 mg); two capsules before surgery, one capsule twice a day until postoperative day (POD) 14, one on POD15, and one on POD16. Multimodal analgesia included femoral nerve block, epidural analgesia, oxycodone-paracetamol, and meloxicam. The primary outcome was pain with flexion (POD14). RESULTS Pregabalin did not reduce pain at rest, with ambulation, or with flexion at 2 weeks (P=0.69, 0.23, and 0.90, respectively). Pregabalin increased POD1 drowsiness (34.5, 37.9, 55.2, and 58.6% in the 0, 50, 100, and 150 mg arms, respectively; P=0.030), but did not increase confusion (0, 3.5, 0, and 3.5%, respectively; P=0.75). Pregabalin had no effect on acute or chronic pain, opioid consumption, or analgesic side-effects. Pregabalin reduced POD14 patient satisfaction [1-10 scale, median (first quartile, third quartile): 9 (8, 10), 8 (7, 10), 8 (5, 9), and 8 (6, 9.3), respectively; P=0.023). Protocol compliance was 63% by POD14 (50.0, 70.0, 76.7, and 56.7% compliance, respectively), with no effect of dose on compliance. Per-protocol analysis of compliant patients showed no effect of pregabalin on pain scores. CONCLUSIONS Pregabalin had no beneficial effects, but increased sedation and decreased patient satisfaction. This study does not support routine perioperative pregabalin for total knee arthroplasty patients. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov: http://www.clinicaltrials.gov/ct2/show/study/NCT01333956.

Return-to-play rates following arthroscopic treatment of femoroacetabular impingement in competitive baseball players.

ABSTRACT Objective: Femoroacetabular impingement (FAI) has been increasingly recognized in cutting sports including soccer, hockey and football. More recently, the prevalence among overhead athletes has also been recognized. The purpose of this study was to review impingement patterns, return-to-play rates and clinical outcome following arthroscopic treatment of FAI among high-level baseball players. Methods: Between 2010 and 2014, 70 competitive baseball players (86 hips; age 22.4 ± 4.5 years) were identified. Demographics and return-to-play rates were recorded. Patient-reported outcome scores, including the Modified Harris Hip Score (mHHS), the Hip Outcome Score-Activity of Daily Living (HOS-ADL), the Sport-specific Subscale (HOS-SSS), and the International Hip Outcome Tool (iHOT-33), were collected pre-operatively at 6 months and 1year (n = 34, 49% of cohort). Results: The cohort included professional (27.1%), college (57.1%), high-school (8.6%) and club-team athletes (7.1%). Infielder (37.5%), pitcher (22.9%) and catcher (16.7%) were the most common positions. Average follow-up was 16.8 months (range 12.1–34.2). There was no relationship between playing position and impingement pattern (p ≥ 0.459), or between symptom laterality and handedness, batting position or playing position (p ≥ 0.179). One patient required revision surgery (infection). Return to sport rate was 88%, at a mean of 8.6 ± 4.2 months, with 97.7% returning at/above their pre-injury level of play. There was significant improvement in all outcome measures: mHHS (60.1 ± 11.9 to 93 ± 9.5), HOS-ADL (71.3 ± 16.7 to 96.3 ± 3.6), HOS-SSS (51.3 ± 24.8 to 92.3 ± 8.2) and iHOT-33 (40.7 ± 19.9 to 85.9 ± 14) (p < 0.001). Conclusion: Arthroscopic treatment of FAI in competitive baseball players resulted in high return-to-play rates at short-term follow-up, with significant improvements in clinical outcome scores.

Preoperative Outcome Scores Are Predictive of Achieving the Minimal Clinically Important Difference After Arthroscopic Treatment of Femoroacetabular Impingement

Background: There is increasing interest in defining meaningful improvement in patient-reported outcomes. Knowledge of the thresholds and determinants for successful femoroacetabular impingement (FAI) outcomes is evolving. Purpose: To define preoperative outcome score thresholds and determine clinical/demographic patient factors predictive for achieving the minimal clinically important difference (MCID) after arthroscopic FAI surgery. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A prospective institutional hip preservation registry was reviewed to identify patients undergoing arthroscopic FAI surgery. The modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the international Hip Outcome Tool (iHOT-33) were administered at baseline and 1 year postoperatively. The MCID was calculated using a distribution-based method. Receiver operating characteristic (ROC) analysis was used to calculate cohort-based threshold values predictive of achieving the MCID. The area under the curve (AUC) was used to define predictive ability, with AUC >0.7 considered acceptably predictive. Multivariable analysis identified patient factors associated with achieving the MCID. Sensitivity analysis was performed to derive the MCID by an alternative anchor-based method. Results: There were 364 patients (mean [±SD] age, 32.5 ± 10.3 years), and 57.1% were female. The MCID for the mHHS, HOS–Activities of Daily Living (HOS-ADL), HOS-Sports, and iHOT-33 was 8.2, 8.3, 14.5, and 12.1, respectively. ROC analysis findings (threshold, percentage achieving the MCID, and strength of association) for these tools were as follows: mHHS (60.5, 77.2%, and 0.68, respectively), HOS-ADL (83.3, 68.1%, and 0.85, respectively), HOS-Sports (58.3, 65.9%, and 0.76, respectively), and iHOT-33 (53.9, 81.9%, and 0.65, respectively). The likelihood for achieving the MCID significantly declined above these thresholds. In multivariable analysis, a higher sagittal center-edge angle (CEA) (odds ratio [OR], 1.04; 95% CI, 1.01-1.08) was a positive predictor of achieving the MCID on the iHOT-33, while a higher Outerbridge grade for the acetabulum was a negative predictor (OR, 0.56; 95% CI, 0.32-0.99) on the mHHS. Sensitivity analysis confirmed these variables and identified relative femoral retroversion as another negative predictor (OR, 0.40; 95% CI, 0.17-0.94). Conclusion: The HOS had excellent predictive ability for identifying patient thresholds of achieving the MCID; patients with preoperative scores below identified thresholds were most likely to achieve the MCID. Additionally, anterior acetabular undercoverage, chondral injuries, and relative femoral retroversion were clinically significant negative modifiers of outcomes. These findings have implications for managing preoperative expectations of FAI surgery.

MR Imaging of Adverse Local Tissue Reactions around Rejuvenate Modular Dual-Taper Stems

PURPOSE To describe the magnetic resonance (MR) imaging characteristics associated with adverse local tissue reactions and tissue damage around hip arthroplasties in which the recalled Rejuvenate modular dual-taper stem was used. MATERIALS AND METHODS The institutional review board of the Hospital for Special Surgery approved the study. All study patients provided informed consent. MR imaging studies were retrospectively reviewed in a cohort of 58 patients with 66 hip arthroplasties with Rejuvenate stems who had presented for imaging evaluation because of recall of the implant. Multiple regression analysis was used to examine MR imaging features, biomechanical factors, and metal ion levels as predictors of aseptic lymphocytic vasculitis-associated lesion (ALVAL) score at histologic assessment while adjusting for age and sex for 54 revised hips. RESULTS Revision surgery was performed in 54 hips on the basis of clinical or imaging findings (24% of hips were completely asymptomatic). The median ALVAL score among the revised hips was 9 (range, 1-10). Imaging characteristics observed with high frequency in patients with ALVAL included synovitis, mixed- or solid-type synovitis, synovial thickening, and capsular dehiscence. CONCLUSION MR imaging provides an effective noninvasive method for assessing the presence and severity of adverse local tissue reaction, as well as the degree of pre-existing tissue damage, thereby facilitating early and accurate identification of candidates for revision surgery.

Cardiac Arrest and Seizures Caused by Local Anesthetic Systemic Toxicity After Peripheral Nerve Blocks: Should We Still Fear the Reaper?

Regional anesthesia (RA) and analgesia have enjoyed resurgence in recent years. Benefits in outcomes, increased emphasis on regional anesthesia/analgesia in training requirements, enhanced availability of guidelines for training in ultrasound guidance, and proliferation of RA fellowships have likely all improved access. Although the application of and skill levels in regional techniques have increased, potential serious risks remain poorly defined and may hamper full acceptance of RA. Major local anesthetic systemic toxicity (LAST), defined as cardiac arrest or seizures, is a potentially life-threatening risk of RA. Peripheral nerve blocks (PNBs) in particular may require large doses of local anesthetic, with a concomitant risk of LAST, and previous surveys report a perhaps 4to 5-fold greater risk of LAST after PNBs compared with epidural blocks. The severity of injury after LAST may be high because an analysis of the American Society of Anesthesiologists (ASA) closed claims database (cases from 1980 to 2000) reported that LAST after PNBs was associated with 7 of 19 claims resulting in death or brain damage. However, since these reported cases, multiple clinical safety steps have been recommended and implemented. Several recent prospective and retrospective surveys have attempted to define the incidence and risk factors for LASTafter PNBs, but precise definitions are hampered by the rarity of major LAST and the relatively modest sizes of the surveys (7000–25,000 PNBs). Estimated incidence of seizures was approximately 0.6 to 0.9/1000 PNBs, with a large 95% confidence interval (95% CI) of 0.3 to 1.3/1000. No incidence for the more severe complication of cardiac arrest was determinable because of a lack of index cases. Correspondingly, the American Society of Regional Anesthesia and Pain Medicine (ASRA) practice advisory on LAST noted that epidemiologic studies on LAST report statistics that vary widely depending on how toxicity is defined. Regardless of the exact risk of LASTafter PNBs, the ASRA practice advisory emphasized the primacy of prevention in reducing the frequency and severity of LAST. The first recommendation for risk reduction is the use of the least dose of local anesthetic necessary. This is certainly a prudent suggestion, yet large doses of local