The Tibial Tubercle-Trochlear Groove Distance/Trochlear Dysplasia Index Quotient Is the Most Accurate Indicator for Determining Patellofemoral Instability Risk.

PURPOSE: The primary aim of our study was to evaluate diagnostic accuracy of the tibial tubercle-trochlear groove (TT-TG) distance relative to associated quotients produced from trochlear width (TT-TG distance/TW) and trochlear dysplasia index (TT-TG distance/TDI) for detecting patellofemoral instability. Secondary aims included identifying thresholds for risk and comparing differences between cases and controls. METHODS: Consecutive sampling of electronic medical records produced 48 (21 males, 27 females) patellofemoral instability cases (19 ± 7 years old) and 79 (61 males, 18 females) controls (23 ± 4 years old) who had a history of isolated meniscal lesion, as evaluated by magnetic resonance imaging. Standardized methods were employed with measurements executed in a blinded and randomized manner. A receiver operating characteristic curve assessed accuracy by area under the curve (AUC). The index of union (IU) was employed to identify a threshold for risk. Two-sample t-tests examined group differences. P < .05 denoted statistical significance. RESULTS: The AUC values were .69 (.60, .79) for TT-TG distance, .81 (.73, .88) for TT-TG distance/TW, and .85 (.78, .91) for TT-TG distance/TDI. Thresholds were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. Cases demonstrated statistically significant (P < .001) greater values for each measure compared with controls: TT-TG distance (15.8 ± 4.2 mm vs 12.9 ± 3.6 mm, [1.4, 4.3]); TT-TG distance/TW (.51 ± .24 vs .31 ± .09, [.13, .27]); TT-TG distance/TDI (3.07 ± 1.55 vs 1.7 ± .7, [.9, 1.84]). CONCLUSION: The TT-TG distance, TT-TG distance/TW, and TT-TG distance/TDI measures were 69%, 81%, and 85%, respectively, accurate for determining patellofemoral instability risk. Thresholds for risk were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. The thresholds reported in this study may help in advancing clinical decision-making. LEVEL OF EVIDENCE: Level III, diagnostic retrospective comparative observatory trial.

The shear modulus of lower-leg muscles correlates to intramuscular pressure.

Shear wave elastography (SWE) is emerging as an innovative tool to evaluate muscle properties and function. It has been shown to correlate with both passive and active muscle forces, and is sensitive to physiological processes and pathological conditions. Similarly, intramuscular pressure (IMP) is an important parameter that changes with passive and active muscle contraction, body position, exercise, blood pressure, and several pathologies. Therefore, the objective of this study was to quantify the dependency of shear modulus within the lower-leg muscles on IMP in healthy individuals. Nineteen healthy individuals (age: Mean age ±â€¯SD, 23.84 ±â€¯6.64 years) were recruited. Shear modulus was measured using ultrasound SWE on the tibialis anterior (TA) and peroneus longus (PL) muscles using pressure cuff inflation around the thigh at 40 mmHg, 80 mmHg, and 120 mmHg. Changes in IMP were verified using a catheter connected to a blood pressure monitor. It was found that IMP was correlated to TA and PL shear modulus (spearman's rank correlation = 0.99 and 0.99, respectively). Applying a gradual increase of cuff pressure from 0 to 120 mmHg increased the shear modulus of the TA and PL muscles from 15.83 (2.46) kPa to 21.88 (4.33) kPa and from 9.64 (1.97) kPa to 12.88 (5.99) kPa, respectively. These results demonstrate that changes of muscle mechanical properties are dependent on IMP. This observation is important to improve interpretation of ultrasound elastograms and to potentially use it as a biomarker for more accurate diagnosis of pathologies related to increased IMP.

Comparison of Growth Plate Violations for Transtibial and Anteromedial Surgical Techniques in Simulated Adolescent Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Increases in the rates and intensity of youth sports participation have led to an elevated incidence of anterior cruciate ligament (ACL) injuries and reconstruction in adolescents. Traditional reconstruction techniques in the skeletally immature patient may violate the growth plates and potentially lead to deformities. HYPOTHESIS/PURPOSE: The purpose of this study was to compare the volume and location of femoral growth plate violations resulting from anteromedial (AM) and transtibial (TT) techniques in ACL reconstruction. The hypothesis was that the more oblique angle used in femoral tunnels drilled with the AM portal technique would produce larger and more lateral violations compared with those resulting from TT tunnels. STUDY DESIGN: Controlled laboratory study. METHODS: Growth plate disturbances were quantified by performing simulated reconstructions in computer models created from magnetic resonance imaging scans of the knees of 17 adolescent participants. Locations of tunnels drilled with simulated AM and TT portal techniques were specified by an orthopaedic surgeon blinded to the locations of the femoral physes in the knee models. Tunnels with lengths of 20, 25, and 30 mm were placed in each model using simulated drill diameters of 7, 8, and 9 mm in addition to a 4.5-mm tunnel breaching the lateral cortex. Normalized measures of the volume and laterality of violations were computed. RESULTS: Tunnels drilled with the AM portal technique disrupted a significantly larger percentage of the physis (P = .007), but the difference was not substantial. Tunnels drilled with the AM portal technique produced violations that were more lateral in the physis than those drilled with the TT technique (P < .001). Tunnels drilled with the AM portal technique resulted in mean violations that were 5.1% ± 2.1% of the physis as compared with 4.7% ± 2.0% for TT tunnels. The mean value for a normalized measure of the laterality of the violation (L score) was 0.590 ± 0.115 for tunnels drilled with the AM portal technique and 0.290 ± 0.104 for TT tunnels. The AM approach produced 16 of 153 simulated reconstructions with growth plate violations greater than 8% compared with only 10 with the TT approach. CONCLUSION: Results suggest that the AM approach produces growth plate violations that are larger and more lateral than the violations generated using the TT technique. AM approaches were more likely to remove more than 8% of the physeal volume, a level previously identified as posing a greater risk of growth disturbances. While the difference in the mean physeal volume removed between the approaches was small, the violations for the AM approach were much more lateral, a finding of potentially greater clinical significance. CLINICAL RELEVANCE: As progressively younger patients are considered candidates for ACL reconstruction, knowledge of how variations in technique affect the developing knee is critical to preventing iatrogenic injuries.

Elbow tendinopathy.

Overuse injuries of the lateral and medial elbow are common in sport, recreational activities, and occupational endeavors. They are commonly diagnosed as lateral and medial epicondylitis; however, the pathophysiology of these disorders demonstrates a lack of inflammation. Instead, angiofibroblastic degeneration is present, referred to as tendinosis. As such, a more appropriate terminology for these conditions is epicondylosis. This is a clinical diagnosis, and further investigations are only performed to rule out other clinical entities after conventional therapy has failed. Yet, most patients respond to conservative measures with physical therapy and counterforce bracing. Corticosteroid injections are effective for short-term pain control but have not demonstrated long-term benefit.