Search

Background: Within the hip joint, the anatomy of the acetabulum and cotyloid fossa is well established. There is little literature describing the association between the size of the cotyloid fossa relative to the acetabulum and characteristics of patients with femoroacetabular impingement (FAI). Purpose/Hypothesis: The purpose was to calculate the cotyloid fossa coverage percentage in the acetabulum and determine its association with patient characteristics, radiographic parameters, intra-articular findings, and preoperative patient-reported outcomes in patients with FAI. We hypothesized there is an association between the cotyloid fossa coverage percentage of the acetabulum and characteristics of patients with FAI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients were included who underwent standard clinical 3-T magnetic resonance imaging of the hip and primary arthroscopic FAI correction surgery during 2015 and 2016. Exclusion criteria were age 40 years, osteoarthritis, labral reconstruction, previous ipsilateral hip surgery, and hip dysplasia. Measurements of the cotyloid fossa and surrounding lunate cartilage were performed to calculate cotyloid fossa width (CFW) and cotyloid fossa height (CFH) coverage percentages. The relationships between coverage percentages and patient characteristics and intraoperative findings were assessed using independent t tests or Pearson correlations. Results: An overall 146 patients were included. Alpha angle negatively correlated with CFH coverage percentage ( r = −0.19; P = .03) and positively correlated with labral tear size ( r = 0.28; P < .01). CFH coverage percentage was negatively correlated with labral tear size ( r = −0.24; P < .01). Among patients with degenerative tears, CFH was negatively correlated with labral tear size ( r = −0.31; P < .01). However, this association was no longer significant after adjusting for sex (partial r = −0.10; P = .39). Cotyloid fossa coverage was not associated with the condition of the cotyloid fossa synovium (synovitis vs no synovitis). CFW coverage percentage was negatively correlated with the 12-Item Short Form Health Survey (SF-12) physical component summary score ( r = −0.23; P < .01). Conclusion: The CFW and CFH coverage percentages may be associated with alpha angle, labral tear size, and SF-12 physical component summary score in patients with FAI. We may be able to predict the labral condition based on preoperative measurements of CFH and CFW coverage percentages.

Background: Evidence, mainly from animal models, suggests that exercise during periods of pubertal growth can produce a hypertrophied anterior cruciate ligament (ACL) and improve its mechanical properties. In humans, the only evidence of ACL hypertrophy comes from a small cross-sectional study of elite weight lifters and control participants; that study had methodological weaknesses and, thus, more evidence is needed. Purpose: To investigate bilateral differences in the ACL cross-sectional area (CSA) for evidence of unilateral hypertrophy in athletes who have habitually loaded 1 leg more than the other. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We recruited 52 figure skaters and springboard divers (46 female and 6 male; mean age, 20.2 ± 2.7 years) because the former always land/jump on the same leg while the latter always drive the same leg into the board during their hurdle approach. Sport training for all participants began before puberty and continued throughout as well as after. Using oblique axial– and oblique sagittal–plane magnetic resonance imaging, we measured the ACL CSA and the anteroposterior diameter of the patellar tendon, respectively. In addition, isometric and isokinetic knee extensor and flexor peak torques were acquired using a dynamometer. Bilateral differences in the ACL CSA, patellar tendon diameter, and knee muscle strength were evaluated via 2-sided paired-samples t tests. Correlations between the bilateral difference in the ACL CSA and age of training onset as well as between the bilateral difference in the ACL CSA and years of training were also examined. Results: A significantly larger ACL CSA (mean difference, 4.9% ± 14.0%; P = .041), as well as patellar tendon diameter (mean difference, 4.7% ± 9.4%; P = .002), was found in the landing/drive leg than in the contralateral leg. The bilateral difference in the ACL CSA, however, was not associated with the age of training onset or years of training. Last, the isometric knee flexor peak torque was significantly greater in the landing/drive leg than the contralateral leg (mean difference, 14.5% ± 33.8%; P = .019). Conclusion: Athletes who habitually loaded 1 leg more than the other before, during, and after puberty exhibited significant unilateral ACL hypertrophy. This study suggests that the ACL may be able to be “trained” in athletes. If done correctly, it could help lower the risk for ACL injuries.

Objective The purpose of this work was to compare measurements of talar cartilage thickness and cartilage and bone surface geometry from clinically feasible magnetic resonance imaging (MRI) against high-accuracy laser scan models. Measurement of talar bone and cartilage geometry from MRI would provide useful information for evaluating cartilage changes, selecting osteochondral graft sources or creating patient-specific joint models. Design Three-dimensional (3D) bone and cartilage models of 7 cadaver tali were created using (1) manual segmentation of high-resolution volumetric sequence 3T MR images and (2) laser scans. Talar cartilage thickness was compared between the laser scan– and MRI-based models for the dorsal, medial, and lateral surfaces. The laser scan– and MRI-based cartilage and bone surface models were compared using model-to-model distance. Results Average cartilage thickness within the dorsal, medial, and lateral surfaces were 0.89 to 1.05 mm measured with laser scanning, and 1.10 to 1.22 mm measured with MRI. MRI-based thickness was 0.16 to 0.32 mm higher on average in each region. The average absolute surface-to-surface differences between laser scan– and MRI-based bone and cartilage models ranged from 0.16 to 0.22 mm for bone (MRI bone models smaller than laser scan models) and 0.35 to 0.38 mm for cartilage (MRI bone models larger than laser scan models). Conclusions This study demonstrated that cartilage and bone 3D modeling and measurement of average cartilage thickness on the dorsal, medial, and lateral talar surfaces using MRI were feasible and provided similar model geometry and thickness values to ground-truth laser scan–based measurements.

Background: The therapeutic efficacy of orthobiologic therapies for rotator cuff repair is difficult to evaluate owing to reporting inconsistences. In response, the Minimum Information for Studies Evaluating Biologics in Orthopaedics (MIBO) guidelines were developed to ensure standard reporting on orthobiologic therapies. Purpose: To systematically review clinical studies evaluating platelet-rich plasma (PRP) for full-thickness rotator cuff repair and adherence to MIBO guidelines. Study Design: Scoping review; Level of evidence, 4. Methods: A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, EMBASE, and the Cochrane Library databases. Inclusion criteria were clinical studies reporting on rotator cuff tears (≥1 cm) surgically repaired with PRP. Patient demographics, biologic intervention, and adherence to the MIBO guidelines were systematically reviewed. Results: A total of 19 studies (1005 patients) were included in this review. Across all studies, 58.5% of the MIBO checklist items for PRP were reported. Out of 47 checklist items, 19 were reported in over 85% of studies, whereas 22 were reported in less than half of studies. Details of whole-blood processing and characteristics, as well as PRP processing and characteristics, were reported inconsistently, and no study provided adequate information to enable the precise replication of preparation protocols for PRP. Conclusion: This systematic review highlights the current reporting deficiencies within the scientific literature of important variables for evaluating PRP for full-thickness rotator cuff repair. There was widespread variability among published studies that evaluate PRP for this application and, more specifically, studies were limited by inconsistent universal reporting of whole-blood and PRP processing and postprocessing characteristics. To improve our understanding of biologic efficacy and to promote repeatability, stricter adherence to the MIBO guidelines is necessary. We propose that the checklist limitations be addressed and that modification of the MIBO guidelines be considered to improve the reporting of individual components within certain categories.

Objectives: Several morphological risk factors for anterior cruciate ligament (ACL) injury have been identified,1,6,12,13 including the size of the ACL.5,8,12,15 A smaller ACL volume and diameter are associated with a greater risk of injury when comparing ACL-injured subjects to matched controls.5,8,12,15 Although morphological risk factors as a group have been largely characterized as non-modifiable,9,10 ACL surface and cross-sectional areas (CSA) have the potential for modifiability, especially during growth and development.7,11 These ACL area measures have increased and the mechanical properties of the ACL have improved following exercise through periods of growth in animal models.2,7,11,14 In humans, we are only aware of one study of ACL hypertrophy—a small study of elite weightlifters.7The main purpose of this study, therefore, was to determine whether the ACL can hypertrophy in response to mechanical loading by comparing bilateral differences in ACL CSA in athletes who habitually load one leg more than the other in training for their sport. Based on the work of Grzelak et al. in weightlifters,7 as well as animal evidence that the ACL responds to exercise,2,11,14 we hypothesized that these athletes would present with significantly greater ACL CSAs in the landing/drive leg, the knee that is loaded the most in comparison with the contralateral control knee. Demonstrating the potential for the ACL to hypertrophy via mechanical loading would provide a scientific basis for exploring ACL injury prevention strategies aimed at increasing ACL CSA and robustness given that a small ACL volume and diameter are known risk factors for injury. This is particularly important for all children and especially females since they are at a much higher risk for ACL injury, and thereafter the development of knee osteoarthritis. Methods: We recruited 50 figure skaters and springboard divers because they consistently and repeatedly use one leg more than the other, thereby ensuring that one knee was habitually loaded more than the other (Table 1). More specifically, figure skaters always land their jumps on the same leg, while springboard divers always drive the same leg (‘drive’ leg) into the board during their hurdle approach. Sport training for all participants began prior to puberty and continued through and after. Bilateral knee magnetic resonance images (MRIs) were acquired with a Philips Ingenia 3.0-T scanner using a dedicated knee coil. Each knee, resting in slight flexion in the coil, was scanned using three sequences, all in the plane of the ACL: (1) oblique-sagittal (repetition time (TR): 5100 ms; echo time (TE): 30 ms; slice thickness: 2.5 mm; pixel spacing: 0.19 x 0.19 mm); (2) oblique-coronal (TR: 4000 ms; TE: 30 ms; slice thickness: 2.5 mm; pixel spacing: 0.20 x 0.20 mm); (3) oblique-axial (TR: 5100 ms; TE: 30 ms; slice thickness: 2.5 mm; pixel spacing: 0.20 x 0.20 mm). Using the oblique-axial-plane scans, the ACL CSA was measured on the three slices that were closest to 50% of the ligament’s length, and then averaged (Figure 1). Using the oblique-sagittal-plane scans, which were reconstructed to run parallel to the patellar tendon, the anteroposterior diameter of the patellar tendon was measured perpendicular to the tendon’s longitudinal axis at a distance of 2 cm distal to the patella3,4 on the slice displaying the thickest part of the tendon at that height (Figure 2). In addition, isometric and isokinetic knee extensor and knee flexor peak torques were acquired using a dynamometer. Bilateral differences in ACL CSA, PT diameter, and knee muscle strength were evaluated via one-sample t-tests that compared the mean percent difference between limbs to a null hypothesis of a zero mean percent difference. Correlations between bilateral ACL CSA differences, age of training onset and years of training were also examined. Results: Athletes with repeated unilateral lower limb loading had significantly greater ACL CSAs in the dominant knee than the non-dominant knee (Table 1; ACL CSAs: dominant = 42.0 ± 8.8 mm2; non-dominant = 40.8 ± 9.1 mm2; % difference = 4.4 ± 13.8%; t = 2.236; p = 0.030). Also, these athletes had significantly greater AP patellar tendon diameters in the dominant knee than the non-dominant knee (Table 1; patellar tendon diameters: dominant = 4.1 ± 0.6 mm; non-dominant = 3.9 ± 0.5 mm; % difference = 4.5 ± 9.4%, t = 3.322; p = 0.002). The percent bilateral difference in ACL CSA, however, was not associated with training onset (r = 0.087, p = 0.553) or years of training (r = -0.068, p = 0.641). Lastly, isometric knee flexor peak torques were significantly greater in the landing/drive leg than the contralateral knee (Table 2). Peak torques from other contraction types or muscle group did not differ between limbs (Table 2). Conclusions: Athletes who habitually loaded one leg more than the other prior to, during and after puberty exhibited significant unilateral ACL hypertrophy in their landing/drive leg. These results support existing evidence that exercise, including resistance and endurance regimens, during periods of pubertal growth has the potential to increase ACL CSA and, therefore, its strength.2,7,14 This suggests that perhaps the ACL could be ‘trained’ to become larger, more robust, and thus at lower risk of injury given that a smaller ligament is associated with a greater risk of injury. The bilateral difference in patellar tendon morphology supports our assumption that the athletes participating in this study consistently loaded one knee more than the other during their sport training, and that increased loading led to the hypertrophy of two important structures in that knee. Many gaps in knowledge—ACL development during growth and how exercise may alter its morphology and mechanical properties—need to be addressed as injury prevention strategies that involve ‘training’ the ACL are explored.