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Objectives: Patellofemoral instability is a common injury seen in adolescents and young adults. More than 95% of patella dislocations result in an injury to the medial patellofemoral ligament (MPFL) and a large percentage of these patients also sustain cartilage injuries at the time of their dislocation. These chondral injuries range from cracks and fissures to full-thickness chondral shear injuries to osteochondral fractures. MPFL reconstruction is the standard of care treatment for patients with recurrent dislocations, but the impact of concomitant full-thickness chondral injuries on the patient-reported outcome measures (PROMs) in patients who undergo isolated MPFL reconstruction without bony realignment remains unclear. The purpose of this study is to compare PROMs between individuals who underwent isolated MPFL reconstruction with concomitant cartilage restoration to those patients whose cartilage injuries were not full-thickness and thus did not require a concomitant cartilage restoration procedure at the time of their MPFL reconstruction. We hypothesized that cartilage injury in patients with patellofemoral instability would result in worse preoperative PROMs compared to patients without chondral injury, and that these differences would be mitigated by concomitant surgical intervention to address chondral damage performed in addition to their MPFL reconstruction. Methods: Patients with recurrent patellar instability were collected in an institutional registry starting March 2014. Exclusion criteria included history of prior patella stabilization procedure, an off-loadable (inferior/lateral) Outerbridge grade 4 chondral defect, anterior knee pain >50% of their chief complaint and a "Jumping J" sign. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of their bony anatomy. PROMS, episodes of recurrent instability, and return to sports data were obtained at baseline and annually. Radiographic measurements were obtained at baseline. Cartilage lesion characteristics including location, Outerbridge grade, and lesion size were identified intraoperatively. Patients were retrospectively assigned to the cartilage intervention group if they underwent concomitant particulated juvenile cartilage allograft, osteochondral allograft, open reduction internal fixation, microfracture, or removal of loose body. Those without intervention or chondroplasty comprised the comparison group. Results: A total of 138 patients underwent isolated MPFL reconstruction between March 2014 and December 2019. Two patients were excluded from the study for concomitant anterior cruciate ligament reconstruction and meniscus repair, respectively. Twenty-two patients underwent concomitant cartilage restoration, while 114 patients underwent chondroplasty or no concomitant cartilage intervention. Average tourniquet time was significantly greater in the intervention group at 61.32 ± 20.18 minutes compared to 43.65 ± 9.71 minutes (p = 0.0002). 50 patients reached ≥ 5-years, of which 40 (80%) completed follow-up PROMs. A total of 119 patients reached ≥2-years, of which 89 (75%) completed follow-up PROMs. All PROMs improved over time except for Pediatric Functional Activity Brief Scale scores which had no change (P = 0.095). Baseline PROMs were significantly different between the intervention and no-intervention groups for Knee injury and Osteoarthritis Outcome Score – Quality of Life (KOOS-QoL), KOOS – Physical Function Shortform (KOOS-PS), and Kujala scores (p < 0.05) (Table 1). The baseline KOOS-QoL, KOOS-PS, and Kujala scores for the intervention group were 17.08 ± 15.93, 33.24 ± 15.81, and 49.80 ± 20.51, respectively, compared to 32.98 ± 20.53. 42.42 ± 12.58, and 60.05 ± 18.19 for the no-intervention group (Table 1). On average, those who received a concomitant cartilage restoration procedure scored lower on all three measures at baseline compared to those who did not receive intervention. There was no statistically significant difference in PROMs between the intervention and no-intervention groups at 2- or 5-year time points, nor in the change in outcomes scores between timepoints for the 2 groups (Table 2, Table 3). Conclusions: The treatment of cartilage lesions in addition to MPFL reconstruction for recurrent patellar instability resulted in similar improvement in PROMs when compared to isolated MPFL reconstruction without cartilage intervention at 2 and 5 years after surgery. This was true despite patients with cartilage injuries initially displaying significantly worse PROMs prior to surgery. We concluded that intervening with cartilage restoration in full-thickness cartilage lesions at the time of isolated MPFL reconstruction can result in equivalent outcomes and thus can mitigate the preoperative difference in PROMs seen between patients with significant chondral injuries at the time of presentation and those with isolated instability in the absence of a significant chondral injury. Future work will seek to confirm the durability of these results with longer term follow-up. [ABSTRACT FROM AUTHOR]

Miller et al. (2005) assert that the estimate of White et al. (2005) of 1.94% of eastern Colorado being occupied by black-tailed prairie dogs (Cynomys ludovicianus) was biased high. The subsequent surveys conducted by Miller et al. (2005) do not provide a valid bias correction for the estimate of White et al. (2005) because 1) their survey protocol could only result in estimating a negative bias, with no possibility of estimating a positive bias; 2) their nonrandom selection of intercepts did not provide valid inferences to the sampling frame used in White et al. (2005); 3) evidence suggests that they did not survey the same aerial tracks as surveyed by White et al. (2005); and 4) their surveys were conducted 2 years after the original surveys, thus not comparable given the temporal dynamics in prairie dog colonies. [ABSTRACT FROM AUTHOR]

In 2001 the Colorado Division of Wildlife (CDOW) began writing a conservation plan for shortgrass prairie species including the black-tailed prairie dog (Cynomys ludovicianus), partly in response to a petition filed to list the black-tailed prairie dog as a Threatened Species and a finding made by the United States Fish and Wildlife Service (USFWS) that a listing was warranted but precluded. To determine the status of the species in Colorado, acreage of active black-tailed prairie dog colonies was estimated in eastern Colorado during June-August 2002, using aerial line intercept methods. We stratified the survey by county boundaries based on imperfect prior knowledge of colony areas by county and computed the proportion of each line intersecting active prairie dog colonies. Active colonies were defined as colonies with prairie dogs observed from the air or fresh digging at burrow entrances. For 131,615 km2 surveyed, estimated area of active colonies was 255,398 ha, with a 95% confidence interval of ±9.5%, indicating that 1.94% of the surveyed range was occupied. This estimate may be biased low because some active colonies might have been misclassified as inactive or because some active colonies might not have been spotted when flown over. In contrast, this estimate may be biased high because some active colonies included in the survey may be active in only a portion of the colony considered as intersecting the survey line. However, our estimate for Colorado was consistent with the estimated area of active black-tailed prairie dog colonies in Wyoming from Sidle et al. (2001), where 2.02% of 66,085 km2 was estimated to be occupied. [ABSTRACT FROM AUTHOR]