Errors in visual estimation of flexion contractures during total knee arthroplasty.

AIM: To quantify and reduce the errors in visual estimation of knee flexion contractures during total knee arthroplasty (TKA). METHODS: This study was divided into two parts: Quantification of error and reduction of error. To quantify error, 3 orthopedic surgeons visually estimated preoperative knee flexion contractures from lateral digital images of 23 patients prior to and after surgical draping. A repeated-measure analysis of variance was used to compare the estimated angles prior to and following the placement of the surgical drapes with the true knee angle measured with a long-arm goniometer. In an effort to reduce the error of visual estimation, a dual set of inclinometers was developed to improve intra-operative measurement of knee flexion contracture during TKA. A single surgeon performed 6 knee extension measurements with the device during 146 consecutive TKA cases. Three measurements were taken with the desired tibial liner trial thickness, and 3 were taken with a trial that was 2 mm thicker. An intraclass correlation coefficient (ICC) was calculated to assess the test-retest reliability for the 3 measurements taken with the desired liner thickness, and a paired t test was used to determine if the knee extension measurements differed when a thicker tibial trial liner was placed. RESULTS: The surgeons significantly overestimated flexion contractures in 23 TKAs prior to draping and significantly underestimated the contractures after draping (actual knee angle = 6.1° ± 6.4°, pre-drape estimate = 6.9° ± 6.8°, post-drape estimate = 4.3° ± 6.1°, P = 0.003). Following the development and application of the measurement devices, the measurements were highly reliable (ICC = 0.98), and the device indicated that 2.7° ± 2.2° of knee extension was lost with the insertion of a 2 mm thicker tibial liner. The device failed to detect a difference in knee extension angle with the insertion of the 2 mm thicker liner in 9/146 cases (6.2%). CONCLUSION: We determined the amount of error associated with visual estimation of knee flexion contractures, and developed a simple, reliable device and method to improve feedback related to sagittal alignment during TKA.

Clinical utility of traditional and new tests in the diagnosis of biceps tendon injuries and superior labrum anterior and posterior lesions in the shoulder.

BACKGROUND: Clinical tests are a key element in diagnosing shoulder lesions. PURPOSE: This study examined the clinical utility of traditional and new examination tests, the upper cut for biceps injuries, and the modified dynamic labral shear for superior glenoid labral lesions. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: A total of 325 consecutive patients who were seen for shoulder pain underwent a standardized clinical testing battery. Six clinical tests that have been previously reported in the literature (Yergason's, Speed's, bear hug, belly press, O'Brien's, and anterior slide) and 2 new examination tests (upper cut and modified dynamic labral shear) were performed. Clinical examination findings were correlated with findings in those who came to surgery (101 patients). Sensitivity, specificity, accuracy, positive/negative predictive value, and positive/negative likelihood ratio were calculated for each test. A binary logistic regression analysis was used to determine which tests produced the most significant findings. RESULTS: For biceps disease, the bear hug and upper cut were most sensitive (0.79 and 0.73, respectively), whereas the belly press and Speed's test were most specific (0.85 and 0.81, respectively). The upper cut was most accurate (0.77) and produced the highest positive likelihood ratio (3.38). For labral injury, the modified dynamic labral shear demonstrated sensitivity of 0.72, specificity of 0.98, accuracy of 0.84, and a positive likelihood ratio of 31.57. A binary logistic regression analysis revealed that the combination of the upper cut and Speed's tests were significantly better at detecting biceps lesions (P = .021, R(2) = .400) than other tests, whereas labral lesions were best identified by combination of the modified dynamic labral shear and O'Brien's maneuvers (P = .045, R(2) = .641). CONCLUSION: The new tests are helpful additions to the clinical examination for shoulder injury. The modified dynamic labral shear test demonstrates high scores for clinical utility and exhibits a high likelihood ratio, indicating a significant probability of affecting the clinical decision, which should moderately or significantly improve the diagnostic conclusion and allow the clinician to be more efficient in making an accurate diagnosis.

Biomechanical superiority of plate fixation for proximal tibial osteotomy.

Proximal tibial osteotomies require secure and durable fixation to allow early range of motion; however, biomechanical data comparing commonly used fixation methods are lacking. The current study was done to quantify the dynamic biomechanical performance of blade staple fixation and plate fixation of simulated proximal tibial osteotomies. A 15 degrees proximal tibial osteotomy was done on each of 18 synthetic adult composite tibias. Blade staples were used as the means of fixation in nine tibias; plate fixation was used in the remaining nine tibias. The specimens were stressed cyclically in sinusoidal loading whose peak compression and tension loads imitate those measured during normal gait. Device performance was quantified by measuring displacement at the osteotomy site and the number of cycles to failure. Plate fixation had a greater fatigue life than staples (eight plates surviving past 200,000 cycles versus one blade staple) and showed a trend toward less displacement (0.69 mm versus 0.97 mm). Plate fixation of proximal tibial osteotomies offers better fixation and dynamic mechanical performance than blade staples.

Double-bundle posterior cruciate ligament reconstruction with allograft tissue: 2-year postoperative outcomes.

In addition to minimizing graft site morbidity, providing stable fixation, and enabling early progressive rehabilitation, the ideal PCL reconstruction would closely simulate natural ligament function. This study retrospectively examined the 2-year postoperative outcomes of 19 athletically active patients referred with clinically symptomatic PCL-deficient knees. Preoperatively 18 patients had severely abnormal knee ligament examination scores, and one had an abnormal score (IKDC). All but one patient was confirmed negative for observable posterolateral corner injury via MRI. Eighteen patients had clinical evidence of posterolateral instability. All patients underwent double-bundle PCL reconstruction (using allograft tissue) without concomitant posterolateral corner reconstruction. Two years after surgery 100% of patients had normal ( n=18) or near normal ( n=1) passive knee joint motion. The results were: one-leg hop test, 58% normal, 37% nearly normal, 5% abnormal; knee ligament examination, 47% normal, 42% nearly normal, 5% abnormal, 5% severely abnormal; knee arthrometry, 2.4+/-2 mm posterior tibial displacement; IKDC subjective assessment section, 47% normal, 42% nearly normal, 5% abnormal, 5% severely abnormal; IKDC symptom-activity level section, 47% normal, 42% nearly normal, 5% abnormal, 5% severely abnormal; final knee ligament evaluation, 47% normal, 42% nearly normal, 5% abnormal, 5% severely abnormal; Lysholm knee scoring scale, 63% excellent, 27% good, 5% fair and 5% poor. Improved stability with clinical ligamentous laxity tests and good IKDC subjective and symptom-activity results 2 years after surgery suggest that for patients with PCL rupture and grade I or II posterolateral instability the double-bundle procedure alone sufficiently restores PCL function through a greater range of knee motion than traditional single-bundle techniques.