The MCL apprehension sign: A novel test for MCL instability.

Purpose: This study describes a new clinical sign to diagnose clinically relevant medial collateral ligament (MCL) injury and evaluates its use in diagnosis and planning treatment for MCL injuries. Methods: A total of 30 consecutive patients with suspected MCL injury, visiting the sports knee clinic were screened by the senior author and the knee fellow for any clinical laxity. Of these, 9 patients did not have any clinically demonstrable laxity but did have MRI evidence of MCL injury. The presence of apprehension sign was compared against the standard criteria for MCL laxity and was evaluated as a novel test to diagnose clinically significant MCL laxity. Results: Of the 21 patients who were diagnosed to have MCL laxity, 18 had a positive apprehension sign at the time of presentation. Eight out of the nine patients who were negative for MCL laxity, did not have a demonstrable apprehension sign. According to the gold standard index, the apprehension sign had a sensitivity of 85.7% and a specificity of 88.8%. The positive and negative predictive values were 94.7% and 72.7% respectively. The pre-test probability of MCL laxity based on the diagnostic criteria was 70% and increased to 94.7% with a positive apprehension sign. Conclusions: A positive apprehension sign is suggestive of MCL injury requiring active treatment. It also helps in deciding the length of bracing required and the need for further operative treatment. The authors recommend its use as a reliable & reproducible adjunct to standard clinic-radiological work-up for MCL injuries.

Genome-wide association and genomic prediction for a reproductive index summarizing fertility outcomes in U.S. Holsteins.

Subfertility represents one major challenge to enhancing dairy production and efficiency. Herein, we use a reproductive index (RI) expressing the predicted probability of pregnancy following artificial insemination (AI) with Illumina 778K genotypes to perform single and multi-locus genome-wide association analyses (GWAA) on 2,448 geographically diverse U.S. Holstein cows and produce genomic heritability estimates. Moreover, we use genomic best linear unbiased prediction (GBLUP) to investigate the potential utility of the RI by performing genomic predictions with cross validation. Notably, genomic heritability estimates for the U.S. Holstein RI were moderate (h2 = 0.1654 ± 0.0317-0.2550 ± 0.0348), while single and multi-locus GWAA revealed overlapping quantitative trait loci (QTL) on BTA6 and BTA29, including the known QTL for the daughter pregnancy rate (DPR) and cow conception rate (CCR). Multi-locus GWAA revealed seven additional QTL, including one on BTA7 (60 Mb) which is adjacent to a known heifer conception rate (HCR) QTL (59 Mb). Positional candidate genes for the detected QTL included male and female fertility loci (i.e. spermatogenesis and oogenesis), meiotic and mitotic regulators, and genes associated with immune response, milk yield, enhanced pregnancy rates, and the reproductive longevity pathway. Based on the proportion of the phenotypic variance explained (PVE), all detected QTL (n = 13; P ≤ 5e - 05) were estimated to have moderate (1.0% < PVE ≤ 2.0%) or small effects (PVE ≤ 1.0%) on the predicted probability of pregnancy. Genomic prediction using GBLUP with cross validation (k = 3) produced mean predictive abilities (0.1692-0.2301) and mean genomic prediction accuracies (0.4119-0.4557) that were similar to bovine health and production traits previously investigated.

The effect of sire predicted transmitting ability for production traits on fertility, survivability, and health of Holstein dairy cows.

The major objective of this study was to evaluate, using survival analysis and multivariable regression models, the relationship of sire predicted transmitting ability (PTA) for production traits with their daughters' milk production, fat, and protein percentage (PROPCT), reproductive performance, postpartum disease incidence, and survivability. Data were collected from six large commercial dairy farms, and data analysis included 22,205 cows. Information regarding each sire's genetic evaluation included the following: PTA for fat yield (FAT), fat percentage (FATPCT), milk yield (MILK), protein yield, and PROPCT. Sire PTA was categorized into quartiles to facilitate data analysis and interpretation. Retained placenta, metritis, displaced abomasum, and clinical mastitis were diagnosed and treated by farm personnel. The overall average daily milk production, milk fat and PROPCT during the first 10 months of lactation was higher for the cows in the highest quartile of sire PTA, and cows in the lowest quartile had lower averages. There was no significant association between sire PTA for production traits and first test day fat to protein ratio or the incidence of postpartum disease. Sire PTA for MILK, FATPCT, and PROPCT were significantly associated with the hazard of pregnancy. The median days from calving to conception were 159, 155, 170, and 181 days for cows in the sire PTA for MILK quartiles 1, 2, 3, and 4, respectively. Sire PTA for PROPCT and FATPCT were also significantly associated with the hazard of pregnancy. The median days from calving to conception were 175, 189, 152, and 145 for cows in the sire PTA for PROPCT groups 1, 2, 3, and 4, respectively. Additionally, cows in the highest quartile for sire PTA for FATPCT had the lowest median days from calving to conception (144 days) and cows in lowest quartile had the highest median interval (177 days). Sire PTA for FAT was the only sire PTA significantly associated with the hazard of death/culling. When compared with the cows in the highest sire PTA for FAT quartile cows in the first, second, and third quartiles were at 1.51, 1.30, and 1.13 times higher hazard of death/culling, respectively. In conclusion, this study shows that high sire PTA for MILK and low sire PTA for milk fat and PROPCT are associated with decreased daughters' reproductive performance. Sire PTA for production traits were not found to be associated with postpartum disease incidence.

The diagnostic value of the stump impingement reflex sign for determining anterior cruciate ligament stump impingement as a cause of knee locking.

BACKGROUND: The stump impingement reflex is a subtle bounce to the knee thought to be caused by hamstring contraction when the knee is brought into extension and the torn ACL stump impinges between the distal femur and the tibial plateau. We have studied the diagnostic value of this sign. FINDINGS: From Feb 2008-Feb 2009, we audited 30 patients who underwent urgent arthroscopy for acutely locked knees. The presence of the stump impingement reflex prior to surgery was compared with the intra-operative findings. The diagnostic values of the stump impingement sign were found to be: Sensitivity 58%, Specificity 81%, Positive predictive value 70%, Negative predictive value 72% and Accuracy 71%. CONCLUSIONS: We believe that the stump impingement reflex is a specific sign for ACL stump impingement as a cause of knee locking. We recommend close inspection for this sign when examining locked knees.

Functional results of isolated femoral revision of hip resurfacing arthroplasty.

BACKGROUND: Conversion of a failed femoral resurfacing component is reportedly a straightforward procedure; however, little has been published regarding the functional results following revision. Our primary aim was to compare the functional results for a group of patients who had had isolated femoral component revision after a failed hip resurfacing with those for a group of patients with a surviving hip resurfacing. Our secondary aim was to identify whether the mode of failure affects functional outcome. METHODS: Between 1997 and 2002, data were prospectively collected on 5000 Birmingham Hip Resurfacing procedures. One hundred and seventy-seven hips were revised, and, of those, seventy-six had an isolated femoral component revision. We reviewed the modes of failure and the post-revision clinical outcomes for this subgroup (the revised implant group) and compared the results with those for the patients who had a surviving hip resurfacing implant (the surviving implant group). RESULTS: The median Harris and Merle d'Aubigné hip scores were significantly better in the surviving implant group than in the revised implant group (median Harris score, 96 compared with 82 [p < 0.001]; median Merle d'Aubigné score, 17 compared with 14 [p < 0.001]). When we analyzed outcomes following revision, we found that the mode of failure affected outcome. Patient satisfaction and clinical outcomes were worse following revision because of femoral component loosening in comparison with revision because of femoral neck fracture or revision because of femoral head collapse or osteonecrosis. In these three subgroups, the median Harris hip scores were 66, 87, and 92, respectively, and the median Merle d'Aubigné scores were 10, 14, and 15, respectively. Six of fifteen patients in the femoral loosening group believed that they were worse or much worse after the revision than they had been before the primary procedure, compared with four of twenty-five patients in the femoral neck fracture group and two of twenty-two patients in the femoral head collapse or osteonecrosis group. Four patients (four hips) experienced complications as a consequence of revision surgery (three deep infections and one case of loosening of an uncemented femoral stem). CONCLUSIONS: The functional results for patients who had revision of the femoral component of a current-generation metal-on-metal resurfacing arthroplasty were worse than those for patients with a surviving hip resurfacing. Patients who had revision because of femoral component loosening had worse outcomes than those who had revision because of femoral neck fracture or femoral head collapse or osteonecrosis.

The Mayo Conservative Hip: experience from a district general hospital.

The Mayo Conservative Hip femoral prosthesis has been designed to optimise proximal femoral loading as well as preserving proximal femoral bone stock. Between October 2003 and May 2006, 42 patients (49 hips) underwent total hip replacement (THR) using the Mayo Conservative Hip femoral component. The mean age at operation was 57.8 years (range 44 to 74) and the mean clinical follow up was 3.1 years (range 2.3 to 4.7 years). The aim of our study was to review the short term results of this unorthodox femoral component. We found that 18% degrees of stems were malaligned >or= 5 degrees and the prevalence of intra-operative femoral fracture was 4%. We feel this prosthesis is difficult to implant and has an unacceptable fracture rate.