Citations

Objectives: The most common reason for reoperation following arthroscopic hip surgery is conversion to total hip arthroplasty (THA). The purpose of this study was to identify clinical and radiographic risk factors for early conversion to THA. Methods: Data were prospectively collected on all hip arthroscopy patients from January 2009 through December 2011. Inclusion criteria for the study group were patients undergoing hip arthroscopy for a labral tear who eventually converted to THA. Patients were then compared to a control group of patients who underwent hip arthroscopy for a labral tear and did not convert to THA during the same period. Exclusion criteria were patients with previous hip conditions such as Legg-Calves-Perthes, slipped capital femoral epiphysis, pigmented villonodular synovitis, and avascular necrosis. A bivariate analysis of 41 preoperative and intraoperative variables was performed. Results: A total of 792 patients met inclusion and exclusion criteria. A total of 72 (9%) converted to THA. The control group consisted of 720 patients who did not convert to THA. Bivariate analysis demonstrated that the study group had significantly higher means or frequencies than the control group for the following variables: male gender, age at time of surgery, BMI, back pain, previous back surgery, Tönnis grade above 0, acetabular inclination angle, alpha angle, Seldes combined-type labral tear, labral tear size, chondral injury, traction time, labral debridement (versus repair), number of anchors used repair or reconstruction, and capsular release (versus repair). The study group had significantly lower means or frequencies than the control group for the following variables: preoperative patient reported outcome scores, crossover sign, lateral center edge angle, and psoas release. A statistically significant difference in average joint space was not observed. Conclusion: Multiple risk factors are possible preoperative and intraoperative risk factors for conversion to THA following hip arthroscopy. The clinician and patient should be aware of these variables.

Objectives: Patients with patellar instability and tibial tubercle to trochlear groove (TT-TG) distances ≥ 20 mm are often considered to have pathologic lateralization of the tibial tubercle (TT) relative to the femoral trochlea and may be candidates for TT realignment surgery. Although this variable has proven valuable in predicting risk of recurrent dislocations, the measure is limited in that it is not individualized to the patient and does not consider patient size, bony morphology, or patellofemoral mechanics. The purpose of this study was to develop a Patellar Instability Ratio (PIR) that predicts the risk of recurrent instability based on the TT-TG distance relative to patient specific anatomy. Methods: Fifty-nine patients with a clinical diagnosis of patellar instability were included in the study. A number of measures were calculated on MRI by two observers (one staff orthopedic surgeon and one senior resident) in a blinded and randomized fashion. Variables analyzed included: TT-TG, tibial tubercle to posterior cruciate ligament distance (TT-PCL), sagittal patellar length (PL), sagittal trochlear length (TL), axial patellar width (PW), axial trochlear width (TW), sagittal patellofemoral engagement (SPE; SPE=TL/PL) and axial patellofemoral engagement (APE; APE=PW/TW). Patients were divided into two groups: those with ≤ 1 dislocation and those with ≥ 2 dislocations. Using these groups, the ability of TT-TG, TT-PCL, and 12 different ratios with cut-off values to predict recurrent instability was assessed by calculating odds ratios (OR), C-statistics, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each of the ratios. P values < 0.05 were considered significant. Results: Mean follow up was 6.6 years. Twelve patients (20%) did not experience recurrent instability while 47 (80%) sustained two or more dislocations during the study period. Pathologic TT-TG (≥ 20 mm) was predictive of recurrent instability with an OR of 5.38 (p=0.29). The highest OR's for recurrent instability were noted for TT-TG/PW ≥ 0.40 (OR > 7.37, p=0.02) and TT-TG/TW ≥ 0.5 (OR 8.88, p=0.04)(Table 1). PW was defined as the largest medial to lateral width of the articular surface of the patella. TW is defined as the largest articular width of the trochlea that is articulating with the patella and can be conceptualized as the “jump distance” that must be overcome for the patella to dislocate. The sensitivity and specificity of TT-TG/PW ratio ≥ 0.40 was 61% and 83% and that of TT-TG/TW ≥ 0.50 was 59% and 92%, respectively. PPV for TT-TG/PW ≥ 0.40 was 94% while that of TT-TG/TW ≥ 0.49 was 97%. Conclusion: Two distinct PIR (TT-TG/PW and TT-TG/TW) have been identified that predict recurrent patellar instability more accurately than TT-TG ≥ 20 mm with PPV's ≥ 94% and OR's > 7 for both measures. These ratios take into consideration the TT-TG relative to patient specific size and anatomy. Further research is needed to determine if patients with increased PIR benefit from TT osteotomy.

Objectives: Female athletes are an at-risk population for anterior cruciate ligament (ACL) injury, with rates of injury significantly higher than the general population. Few studies have reported on a second ACL injury for female athletes. The purpose of this study was to (1) report the rate of subsequent ACL injury (ACL graft rupture or contralateral ACL tear) in competitive female soccer players, (2) compare these rates to those of other female athletes of similar competitive level, and (3) determine risk factors for second ACL injury in this athletic population. Methods: The medical record at our institution was reviewed for patients treated with primary ACL reconstruction between 1998 and 2013. Female patients injured during a competitive athletic event were included for further review, and followed for an average of 7.1 years postoperatively (range 1.0 - 17.7 years). Chi-square analysis was used to compare rate of graft rupture and contralateral ACL injury based on pre-operative Tegner score, graft type, and injury side for soccer players vs. other female athletes. Wilcoxon rank-sum test was used to compare rate of subsequent ACL injury to patient age. Results: 337 patients met our inclusion/exclusion criteria (90 soccer players; 247 non-soccer playing athletes) with a mean age of 24.0 years. Of the 337 athletes, 6 were injured during professional competition, 43 were injured during collegiate athletics, 184 during high school play, and 136 during recreational athletics. No patient demographical differences were found at baseline between the soccer group and non-soccer group, including Tegner scores. Overall, 21 soccer players (23.3%) sustained a second ACL injury compared to 21 (8.5%) non-soccer athletes (P < 0.001). Soccer players had significantly more graft ruptures (10.0% vs. 2.0%, P = 0.003) and more contralateral ACL tears (13.3% vs. 6.5%, P = 0.04). Risk factors for ACL graft tear included young age (mean 16.0 vs 24.3 years; P < 0.0001) and higher Tegner Activity Level scores (mean 8.1 vs. 7.4, P = 0.049), but were not risk factors for contralateral ACL injury. Graft selection and injury side showed no statistical significance on graft rupture or contralateral injury. Conclusion: Female soccer players treated with ACL reconstruction had an increased rate of second ACL injury, including graft tear and contralateral ACL injury, compared to a similar group of non-soccer female athletes (23.3% vs. 8.5%, P < 0.001). In addition, young age and higher activity level were risk factors for graft rupture in this population.

Objectives: Arthroscopic treatment for femoroacetabular impingement (FAI) generally has good results, but the outcome can worsen with increasing arthritis, largely defined as joint space narrowing. There remains a subset of hips with maintained joint space but with subchondral edema and cystic change of the acetabulum on MRI, with unknown outcome. Therefore, the purpose of this study was (1) to determine if postoperative outcome was worse for patients with subchondral edema on preoperative MRI compared to a matched control group and (2) to identify risk factors on MRI leading to inferior outcome. Methods: A review of patients who underwent arthroscopic hip surgery for FAI between 2007 and 2013 identified 530 patients. Of these, 39 patients had evidence of subchondral edema or subchondral cyst on the preoperative MRI with maintained joint space on preoperative radiographs. Lesions were characterized by grade, location and type using an established radiographic MRI classification system. A matched cohort of patients without evidence of subchondral edema or cyst was identified, and 2:1 matching was based on patient age, surgeon, surgery year within one year, surgical procedure, Tegner activity score, and Tonnis grade osteoarthritis changes on preoperative x-ray. Outcome was compared using the Hip Outcome Score and Modified Harris Hip Score between the two groups. Risk factors were then analyzed for type of lesion, grade and location of bone marrow lesion. Results: Thirty-nine patients (20 males, 19 females) showed preoperative MRI evidence of subchondral edema, and were followed for a mean of 23 months postoperatively (range, 12 - 60 months). Patients had an average age of 41 years (range, 19 - 67) and a preoperative Tegner score of 3.8 (range, 1 - 9). 87% of patients with subchondral cystic change had evidence of a grade IV full thickness cartilage lesion at the time of hip arthroscopy. Average Modified Harris Hip Scores were inferior for the subchondral group (79.9 ± 18.7) compared to the control group (86.6 ± 12.5; p = 0.027). In addition, Sport sub-scales of the Hip Outcome Score showed significantly lower scores for the subchondral group for both score (69.1 ± 27.0 vs. 79.5 ± 21.4, p = 0.018) and rating (66.7 ± 27.5 vs. 78.0 ± 20.8, p = 0.044). No radiographic risk factors, including type, location, or size of lesion were significant predictors of outcome. Two patients in the subchondral group were later converted to a total hip replacement. Conclusion: The presence of a subchondral acetabular cyst on MRI is indicative of a full thickness cartilage lesion at the time of arthroscopy. These patients have inferior outcomes for arthroscopic treatment of FAI compared to patients with similar age and activity level without MRI subchondral changes. Therefore, we recommend caution with consideration of hip arthroscopy in this patient subset.

Abstract BACKGROUND The Kidney Disease Improving Global Outcomes (KDIGO) guideline recommends use of a cystatin C–based estimated glomerular filtration rate (eGFR) to confirm creatinine-based eGFR between 45 and 59 mL · min−1 · (1.73 m2)−1. Prior studies have demonstrated that comorbidities such as solid-organ transplant strongly influence the relationship between measured GFR, creatinine, and cystatin C. Our objective was to evaluate the performance of cystatin C–based eGFR equations compared with creatinine-based eGFR and measured GFR across different clinical presentations. METHODS We compared the performance of the CKD-EPI 2009 creatinine-based estimated GFR equation (eGFRCr) and the newer CKD-EPI 2012 cystatin C–based equations (eGFRCys and eGFRCr-Cys) with measured GFR (iothalamate renal clearance) across defined patient populations. Patients (n = 1652) were categorized as transplant recipients (n = 568 kidney; n = 319 other organ), known chronic kidney disease (CKD) patients (n = 618), or potential kidney donors (n = 147). RESULTS eGFRCr-Cys showed the most consistent performance across different clinical populations. Among potential kidney donors without CKD [stage 2 or higher; eGFR &gt;60 mL · min−1 · (1.73 m2)−1], eGFRCys and eGFRCr-Cys demonstrated significantly less bias than eGFRCr; however, all 3 equations substantially underestimated GFR when eGFR was &lt;60 mL · min−1 · (1.73 m2)−1. Among transplant recipients with CKD stage 3B or greater [eGFR &lt;45 mL · min−1 · (1.73 m2)−1], eGFRCys was significantly more biased than eGFRCr. No clear differences in eGFR bias between equations were observed among known CKD patients regardless of eGFR range or in any patient group with a GFR between 45 and 59 mL · min−1 · (1.73 m2)−1. CONCLUSIONS The performance of eGFR equations depends on patient characteristics that are readily apparent on presentation. Among the 3 CKD-EPI equations, eGFRCr-Cys performed most consistently across the studied patient populations.

Thunderclap headache is a sudden and severe headache that can occur after an aneurysmal subarachnoid hemorrhage (SAH). Subarachnoid hemorrhage is a medical emergency that requires prompt attention and hospitalization. Patients with thunderclap headache often undergo a noncontrast head computed tomography (CT) scan to ascertain SAH bleeding and, if the scan is negative, then undergo a lumbar puncture to look for cerebrospinal fluid (CSF) red blood cells (RBCs), which would be consistent with an aneurysmal leak. If the initial CT is negative and CSF is positive for RBCs, patients are usually admitted to the hospital for evaluation of intracranial aneurysm. We encountered a patient with thunderclap headache whose initial head CT was negative for SAH and whose CSF tested positive for RBCs. The patient was referred to our center for evaluation and management of aneurysmal SAH. However, on careful review of the patient’s medical history, serum laboratory values, and spinal fluid values, the patient was diagnosed with Ehrlichia chaffeensis meningitis. While Ehrlichia meningitis is rare, it is important to recognize the clinical clues that could help avoid formal cerebral angiography, a costly and potentially unnecessary procedure. We present how this case represented a cognitive framing bias and anchoring heuristic as well as steps that medical providers can use to prevent such cognitive errors in diagnosis.