Sex, military occupation and rank are associated with risk of anterior cruciate ligament injury in tactical-athletes.

INTRODUCTION: Anterior cruciate ligament (ACL) injury is common within the US military and represents a significant loss to readiness. Since recent changes to operational tempo, there has not been an analysis of ACL injury risk. The aim of this retrospective cohort study was to evaluate military occupation, sex, rank and branch of service on ACL injury risk in the US military from 2006 to 2018. METHODS: The Defense Medical Epidemiology Database was queried for the number of US tactical athletes with International Classification of Diseases diagnosis codes 717.83 (old disruption of ACL), 844.2 (sprain of knee cruciate ligament), M23.61 (other spontaneous disruption of ACL) and S83.51 (sprain of ACL of knee) on their initial encounter. Relative risk and χ2 statistics were calculated to assess sex and military occupation effects on ACL injury. A multivariable negative binomial regression model evaluated changes in ACL injury incidence with respect to sex, branch of service and rank. RESULTS: The study period displayed a significant decrease in the ACL injury rate at 0.18 cases per 1000 person-years or relative decrease of 4.08% each year (p<0.001) after averaging over the main and interactive effects of sex, rank and branch of service. The interaction effect of time with sex indicated a steeper decline in the incidence in men as compared with women. The risk of ACL injury by sex was modified by rank. The incidence among military personnel varied by occupation. CONCLUSION: Despite the decline among tactical athletes over time, rates of ACL injury remain much higher than the general US population. Sex, rank, branch of service and military occupation were found to be risk factors for ACL injury. It is critical for policy makers to understand the salient risk factors for ACL injury to guide proactive measures to prevent injury.

Is the native ACL insertion site "completely restored" using an individualized approach to single-bundle ACL-R?

PURPOSE: The goal of individualized anatomic anterior cruciate ligament reconstruction (ACL-R) is to reproduce each patient's native insertion site as closely as possible. The amount of the native insertion site that is recreated by the tunnel aperture area is currently unknown, as are the implications of the degree of coverage. As such, the goals of this study are to determine whether individualized anatomic ACL-R techniques can maximally fill the native insertion site and to attempt to establish a crude measure to evaluate the percentage of reconstructed area as a first step towards elucidating the implications of complete footprint restoration. METHODS: This is a prospective pilot study of 45 patients who underwent primary single-bundle anatomic ACL-R from May 2011 to April 2012. Length and width of the native insertion site were measured intraoperatively. Using published guidelines, reconstruction technique and graft choice were determined to maximize the percentage of reconstructed area. Native femoral and tibial insertion site area and femoral tunnel aperture area were calculated using the formula for area of an ellipse. On the tibial side, tunnel aperture area was calculated with respect to drill diameter and drill guide angle. Percentage of reconstructed area was calculated by dividing total tunnel aperture area by the native insertion site area. RESULTS: The mean areas for the native femoral and tibial insertion sites were 83 ± 20 and 125 ± 20 mm(2), respectively. The mean tunnel aperture area for the femoral side was 65 ± 17, and 86 ± 17 mm(2) for the tibial tunnel aperture area. On average, percentage of reconstructed area was 79 ± 13 % for the femoral side, and 70 ± 12 % for the tibial side. CONCLUSION: Anatomic ACL-R does not restore the native insertion site in its entirety. Percentage of reconstructed area serves as a rudimentary tool for evaluating the degree of native insertion site coverage using current individualized anatomic techniques and provides a starting point from which to evaluate the clinical significance of complete footprint restoration. LEVEL OF EVIDENCE: IV.

Anatomic anterior cruciate ligament (ACL) reconstruction: a global perspective. Part 1.

PURPOSE: In August 2011, orthopaedic surgeons from more than 20 countries attended a summit on anatomic anterior cruciate ligament (ACL) reconstruction. The summit offered a unique opportunity to discuss current concepts, approaches, and techniques in the field of ACL reconstruction among leading surgeons in the field. METHODS: Five panels (with 36 panellists) were conducted on key issues in ACL surgery: anatomic ACL reconstruction, rehabilitation and return to activity following anatomic ACL reconstruction, failure after ACL reconstruction, revision anatomic ACL reconstruction, and partial ACL injuries and ACL augmentation. Panellists' responses were secondarily collected using an online survey. RESULTS: Thirty-six panellists (35 surgeons and 1 physical therapist) sat on at least one panel. Of the 35 surgeons surveyed, 22 reported performing "anatomic" ACL reconstructions. The preferred graft choice was hamstring tendon autograft (53.1 %) followed by bone-patellar tendon-bone autograft (22.8 %), allograft (13.5 %), and quadriceps tendon autograft (10.6 %). Patients generally returned to play after an average of 6 months, with return to full competition after an average of 8 months. ACL reconstruction "failure" was defined by 12 surgeons as instability and pathological laxity on examination, a need for revision, and/or evidence of tear on magnetic resonance imaging. The average percentage of patients meeting the criteria for "failure" was 8.2 %. CONCLUSIONS: These data summarize the results of five panels on anatomic ACL reconstruction. The most popular graft choice among surgeons for primary ACL reconstructions is hamstring tendon autograft, with allograft being used most frequently employed in revision cases. Nearly half of the surgeons surveyed performed both single- and double-bundle ACL reconstructions depending on certain criteria. Regardless of the technique regularly employed, there was unanimous support among surgeons for the use of "anatomic" reconstructions using bony and soft tissue remnant landmarks.

The effects of limb alignment on anterior cruciate ligament graft tunnel positions estimated from plain radiographs.

PURPOSE: The aims of this study were (1) to evaluate the femoral tunnel position after anatomic double-bundle and nonanatomic single-bundle reconstruction; (2) to evaluate the influence of rotation of the femur caused by limb malalignment on measurements of the position of the femoral ACL tunnel aperture relative to Blumensaat's line. METHODS: 3D CT scans were performed in 5 patients after anatomic double-bundle reconstruction and 5 patients after nonanatomic single-bundle reconstruction. Digitally reconstructed lateral radiographs were generated from the 3D CT scans to determine the tunnel position on the femur along and perpendicular to Blumensaat's line. The femur was then rotated to simulate internal/external and varus/valgus rotations from 0° to 15° in 5° increments. At each rotated bone position, tunnel position relative to Blumensaat's line was calculated and the difference from the lateral radiograph was calculated. RESULTS: After double-bundle reconstruction, the AM tunnel was located at 31.5 (±5.0) % along Blumensaat's line and 29.7 (±13.6) % perpendicular to Blumensaat's line, and the PL tunnel at 36.2 (±12.9) % along Blumensaat's line and 34.2 (±7.6) % perpendicular to Blumensaat's line. Valgus greater than 10° significantly affected the assessment of tunnel position (P = 0.043). After nonanatomic single-bundle reconstruction, the tunnel position was 35.4 (±15.0) % along Blumensaat's line and -2.7 (±19.4) % perpendicular to Blumensaat's line. Internal rotation of more than 10° significantly affected the assessment of tunnel position (P = 0.043). CONCLUSIONS: Tunnel position after anatomic double-bundle reconstruction and nonanatomic single-bundle reconstruction can be determined on lateral radiographs. However, valgus and internal rotation of more than 10° can introduce significant errors in tunnel position estimates. LEVEL OF EVIDENCE: Case series, Level IV.

Meniscal root injury and spontaneous osteonecrosis of the knee: an observation.

We describe injuries to the posterior root of the medial meniscus in patients with spontaneous osteonecrosis of the medial compartment of the knee. We identified 30 consecutive patients with spontaneous osteonecrosis of the medial femoral condyle. The radiographs and MR imaging were reviewed. We found tears of the posterior root of the medial meniscus in 24 patients (80%). Of these, 15 were complete and nine were partial. Complete tears were associated with > 3 mm of meniscal extrusion. Neither the presence of a root tear nor the volume of the osteonecrotic lesion were associated with age, body mass index (BMI), gender, side affected, or knee alignment. The grade of osteoarthritis was associated with BMI. Although tears of the posterior root of the medial meniscus were frequently present in patients with spontaneous osteonecrosis of the knee, this does not prove cause and effect. Further study is warranted.

Neuromuscular and biomechanical characteristic changes in high school athletes: a plyometric versus basic resistance program.

BACKGROUND: In order to improve neuromuscular and biomechanical characteristic deficits in female athletes, numerous injury prevention programs have been developed and have successfully reduced the number of knee ligament injuries. However, few have investigated the neuromuscular and biomechanical changes following these training programs. It is also largely unknown what type of program is better for improving the landing mechanics of female athletes. OBJECTIVES: To investigate the effects of an 8 week plyometric and basic resistance training program on neuromuscular and biomechanical characteristics in female athletes. METHODS: Twenty seven high school female athletes participated either in a plyometric or a basic resistance training program. Knee and hip strength, landing mechanics, and muscle activity were recorded before and after the intervention programs. In the jump-landing task, subjects jumped as high as they could and landed on both feet. Electromyography (EMG) peak activation time and integrated EMG of thigh and hip muscles were recorded prior to (preactive) and subsequent to (reactive) foot contact. RESULTS: Both groups improved knee extensor isokinetic strength and increased initial and peak knee and hip flexion, and time to peak knee flexion during the task. The peak preactive EMG of the gluteus medius and integrated EMG for the gluteus medius during the preactive and reactive time periods were significantly greater for both groups. CONCLUSIONS: Basic training alone induced favourable neuromuscular and biomechanical changes in high school female athletes. The plyometric program may further be utilised to improve muscular activation patterns.

A pilot study on the relationship between physical impairment and activity restriction in persons with anterior cruciate ligament reconstruction at long-term follow-up.

This study examined the relationship between impairment of the knee and activity restriction during activities of daily living and sports following anterior cruciate ligament reconstruction. Knee range of motion, swelling, pain, instability, ligamentous laxity, isometric and isokinetic muscle function and performance-based measures of activity restriction were measured in 44 subjects. Four measures of patient-reported activity restrictions, including the Activities of Daily Living, Sports Activities Scales of the Knee Outcome Survey, and global ratings of function during activities of daily life and sports, were statistically combined to create a composite variable representing the level of patient-reported activity restrictions for each subject. Hierarchical regression analysis revealed that 17% of the variability in patient-reported activity restrictions was accounted for by age, length of postoperative follow-up, and mechanism of injury. Addition of the one-legged hop, Lachman, anterior drawer, and varus stress tests accounted for an additional 40% of the variability of function. When pain and giving way were added to the model, 79% of the variability was explained.

Development and validation of the international knee documentation committee subjective knee form.

A committee of international knee experts created the International Knee Documentation Committee Subjective Knee Form, which is a knee-specific, rather than a disease-specific, measure of symptoms, function, and sports activity. The purpose of this study was to evaluate the reliability and validity of the new International Knee Documentation Committee Subjective Knee Form. To provide evidence for reliability and validity, we administered the final version of the form, along with the Short Form-36, to 533 patients with a variety of knee problems. Analyses were performed to determine reliability, validity, and differential item function related to age, sex, and diagnosis. Factor analysis revealed a single dominant component, making it reasonable to combine all questions into a single score. Internal consistency and test-retest reliability were 0.92 and 0.95, respectively. Based on test-retest reliability, the value for a true change in the score was 9.0 points. The International Knee Documentation Committee Subjective Knee Form score was related to concurrent measures of physical function (r = 0.47 to 0.66) but not to emotional function (r = 0.16 to 0.26). Analysis of differential item function indicated that the questions functioned similarly for men versus women, young versus old, and for those with different diagnoses. In conclusion, the International Knee Documentation Committee Subjective Knee Form is a reliable and valid knee-specific measure of symptoms, function, and sports activity that is appropriate for patients with a wide variety of knee problems. Use of this instrument will permit comparisons of outcome across groups with different knee problems.

A comparison of a modified Oswestry Low Back Pain Disability Questionnaire and the Quebec Back Pain Disability Scale.

BACKGROUND AND PURPOSE: The quality of a disability scale should dictate when it is used. The purposes of this study were to examine the validity of a global rating of change as a reflection of meaningful change in patient status and to compare the measurement properties of a modified Oswestry Low Back Pain Disability Questionnaire (OSW) and the Quebec Back Pain Disability Scale (QUE). SUBJECTS: Sixty-seven patients with acute, work-related low back pain referred for physical therapy participated in the study. METHODS: The 2 scales were administered initially and after 4 weeks of physical therapy. The Physical Impairment Index, a measure of physical impairment due to low back pain, was measured initially and after 2 and 4 weeks. A global rating of change survey instrument was completed by each subject after 4 weeks. RESULTS: An interaction existed between patients defined as improved or stable based on the global rating using a 2-way analysis of variance for repeated measures on the impairment index. The modified OSW showed higher levels of test-retest reliability and responsiveness compared with the QUE. The minimum clinically important difference, defined as the amount of change that best distinguishes between patients who have improved and those remaining stable, was approximately 6 points for the modified OSW and approximately 15 points for the QUE. CONCLUSION AND DISCUSSION: The construct validity of the global rating of change was supported by the stability of the Physical Impairment Index across the study period in patients defined as stable by the global rating and by the decrease in physical impairment across the study period in patients defined as improved by the global rating. The modified OSW demonstrated superior measurement properties compared with the QUE.

Rehabilitation of the multiple-ligament-injured knee.

Rehabilitation for a patient with a multiple-ligament knee injury should be designed to reduce pain and swelling, restore range of motion, strength, and endurance, and to enhance proprioception, and dynamic stability of the knee, with the goals of restoring function and minimizing disability. The biomechanics of the knee must be considered when designing a rehabilitation program. General guidelines for rehabilitation of the multiple-ligament-injured knee include considerations for promoting tissue healing, decreasing pain and swelling, restoring full motion, increasing muscular strength and endurance, improving proprioception, enhancing dynamic stability of the knee, and reducing functional limitations and disability. A patient's progression through this sequence must be individualized and depends on the pattern of ligament injury or surgical procedure that was performed, and the principles of tissue healing. Specific guidelines for rehabilitation following ACL reconstruction combined with MCL repair, PCL reconstruction, combined ACL-PCL reconstruction, and reconstruction of the LCL and posterolateral corner have been provided.

Biomechanical considerations for rehabilitation of the knee.

Knowledge of the anatomy and biomechanics of the knee is critical for successful rehabilitation following knee injury and/or surgery. Biomechanics of both the tibiofemoral and patellofemoral joints must be considered. The purpose of this paper is to provide a framework for rehabilitation of the knee by reviewing the biomechanics of the tibiofemoral and patellofemoral joints. This will include discussion of the relevant arthrokinematics as well as the effects of open and closed chain exercises. The implications for rehabilitation of the knee will be highlighted.

Comparison of performance-based and patient-reported measures of function in anterior-cruciate-ligament-deficient individuals.

There is a dearth of reliable and valid instrumentation that measures disability following injury and/or surgery of the knee joint that is responsive to clinically significant changes over time. The purpose of this investigation was to determine whether performance-based or patient-reported measures of function are more effective in estimating disability in individuals with an anterior-cruciate-ligament (ACL)-deficient knee. Subjective rating of knee function was used as the criterion measure for disability, and selected performance-based and patient-reported measures were used as estimation variables. Twenty-nine individuals with an ACL-deficient knee participated in this investigation. Step-wise regression analysis revealed that the Cincinnati Knee Scale, Lysholm Knee Scale, and hop index were the most effective estimates of disability. The results demonstrate that patient-reported measures are more related to the patient's level of disability in individuals with an ACL-deficient knee. More research is necessary to substantiate these findings.

Rehabilitation following surgical procedures to address articular cartilage lesions in the knee.

Knowledge of the structure and function of articular cartilage is important when considering rehabilitation following surgical procedures for articular cartilage lesions of the knee. Articular cartilage is avascular and derives its nutrition primarily from synovial fluid, resulting in a limited potential for regeneration. Basic science evidence has demonstrated that compressive loading may have a positive impact on articular cartilage healing; however, excessive shear loading may be detrimental. Rehabilitation following surgical procedures for articular cartilage lesions should include controlled range of motion exercises. Exercises to enhance muscle function must be done in a manner which minimizes shear loading of the joint surfaces in the area of the lesion. A period of protected weight bearing is often necessary and should be followed by progressive loading of the joint. This article will: 1) provide a brief review of the structure and function of articular cartilage lesions as it relates to rehabilitation; 2) describe common surgical procedures to address articular cartilage lesions; and 3) provide guidelines for rehabilitation following surgical management of articular cartilage lesions.

Development of a patient-reported measure of function of the knee.

The purpose of the present study was to demonstrate the reliability, validity, and responsiveness of the Activities of Daily Living Scale of the Knee Outcome Survey, a patient-reported measure of functional limitations imposed by pathological disorders and impairments of the knee during activities of daily living. The study comprised 397 patients; 213 were male, 156 were female, and the gender was not recorded for the remaining twenty-eight. The mean age of the patients was 33.3 years (range, twelve to seventy-six years). The patients were referred to physical therapy because of a wide variety of disorders of the knee, including ligamentous and meniscal injuries, patellofemoral pain, and osteoarthrosis. The Activities of Daily Living Scale was administered four times during an eight-week period: at the time of the initial evaluation and after one, four, and eight weeks of therapy. Concurrent measures of function included the Lysholm Knee Scale and several global measures of function. The subjects also provided an assessment of the change in function, with responses ranging from greatly worse to greatly better, at one, four, and eight weeks. The Activities of Daily Living Scale was administered to an additional sample of fifty-two patients (thirty-two male and twenty female patients with a mean age of 31.6 years [range, fourteen to sixty-six years]) before and after treatment within a single day to establish test-retest reliability. Factor analysis revealed two dominant factors: one that reflected a combination of symptoms and functional limitations and the other, only symptoms. The internal consistency of the Activities of Daily Living Scale was substantially higher than that of the Lysholm Knee Scale (coefficient alpha, 0.92 to 0.93 compared with 0.60 to 0.73), resulting in a smaller standard error of measurement for the former scale. Validity was demonstrated by moderately strong correlations with concurrent measures of function, including the Lysholm Knee Scale (r = 0.78 to 0.86) and the global assessment of function as measured on a scale ranging from 0 to 100 points (r = 0.66 to 0.75). Analysis of variance with repeated measures revealed significant improvements in the score on the Activities of Daily Living Scale during the eight weeks of physical therapy (F2,236 = 108.13; p < 0.0001); post hoc testing indicated that the change in the score at eight weeks was significantly greater than the change at four weeks and that the change at four weeks was significantly greater than that at one week (p < 0.0001 for both). As had been hypothesized, the patients in whom the knee had somewhat improved had a significantly smaller change in the score, both at four weeks (F1,189 = 33.50; p < 0.001) and at eight weeks (F1,156 = 22.48; p < 0.001), compared with those in whom the knee had greatly improved. The test-retest reliability coefficient (intraclass correlation coefficient[2,1]) was 0.97. These results suggest that the Activities of Daily Living Scale is a reliable, valid, and responsive instrument for the assessment of functional limitations that result from a wide variety of pathological disorders and impairments of the knee.

An electromyographic study of vastus medialis oblique and vastus lateralis activity while ascending and descending steps.

Imbalances in the firing pattern and contraction intensity of the vastus medialis oblique (VMO) and the vastus lateralis (VL) have been considered important factors contributing to patellofemoral joint dysfunction. Vastus medialis oblique and vastus lateralis electromyographic (EMG) activity were measured for 15 individuals without patellofemoral pain (asymptomatic group) and 13 subjects with patellofemoral pain (symptomatic group) while ascending and descending steps. The peak VMO/VL ratios of EMG activity and the difference in peak VMO and VL onset times were measured. Two-way mixed-model analyses of variance (ANOVA) were used to determine the main effects of group (asymptomatic and symptomatic), phase (concentric phase ascending and two eccentric phases descending stairs), and the interaction between group and phase. The ANOVAs indicated no difference between groups for the peak VMO/VL EMG ratio or for the onset timing between peak VMO and VL muscle activity. Combining groups, the peak VMO/VL EMG ratio was less for the eccentric weight acceptance phase of descent compared with the concentric phase of ascent. These findings suggest no differences between asymptomatic and symptomatic individuals, but differences may exist between concentric and eccentric VMO/VL ratios. Further research is needed to determine if VMO and VL muscle imbalances contribute to patellofemoral dysfunction.

Use of the International Knee Documentation Committee guidelines to assess outcome following anterior cruciate ligament reconstruction.

The purpose of this project was to determine if guidelines established by the International Knee Documentation Committee (IKDC) could distinguish differences in outcome, as indicated by the patients' subjective rating of knee function following ACL reconstruction, and to determine if all subgroups included in the IKDC rating system contribute to the prediction of the overall final IKDC rating. A total of 133 patients undergoing ACL reconstruction were evaluated according to IKDC guidelines 1-5 years postoperatively. Each subject was rated in each of four subgroups on the IKDC scale: patient subjective assessment, symptoms, range of motion (ROM), and laxity. The worst rating for the subgroups defined the overall final rating. The outcome from the patient's perspective was determined by asking them to rate the function of their knee on a scale from 0 to 100 with 100 being the level of function before injury. Average length of follow-up was 3.2 years (range 1.1-6.3 years). ANOVA indicated that the patients' subjective rating of knee function on a scale from 0 to 100 differed according to the overall final IKDC rating (F = 16.1, P < 0.001). The average subjective rating of knee function for those with a normal IKDC rating was 95.2, nearly normal was 91.2, abnormal was 84.9, and severely abnormal was 75.4. The average subjective rating of knee function for those who were severely abnormal was significantly different from those rated normal, nearly normal, and abnormal, and the average subjective rating for those who were abnormal was significantly different from those who were normal or nearly normal. There was no significant difference in average subjective rating between those who were rated as normal or nearly normal. Regression analysis indicated that all four subgroups contributed significantly to the prediction of the final IKDC rating (r2 = 0.70), but the majority of the variance (62%) was accounted for by symptoms and laxity. These results appear to indicate that the IKDC guidelines are useful for describing the outcome following ACL reconstruction. Further testing of the IKDC guidelines is necessary to determine if they are capable of detecting a change in the patients over time following treatment and/or surgery of the knee.

Arthroscopic-assisted rotator cuff repair: patient selection and treatment outcome.

Over a 4-year period 24 patients out of 376 who required a rotator cuff repair were selected for arthroscopic-assisted rotator cuff repair. Preoperative selection criteria were refractory pain in the setting of good range of motion and strength (after an impingement test), absence of radiographic superior humeral head translation, and magnetic resonance imaging evidence of minimally retracted tear without rotator cuff muscle atrophy. Intraoperative selection criteria were the findings of an avulsion-type tear configuration with good tendon quality and absence of subscapularis tendon involvement. Based on these intraoperative criteria, 7 of the 24 patients were converted to an open approach to mobilize retracted and friable tendon tissue in a complex tear configuration. The remaining 17 patients underwent a transosseous arthroscopic-assisted rotator cuff repair with an average postoperative follow-up of 23 months. Evaluation by an independent therapist determined the postoperative American Shoulder and Elbow Surgeons Shoulder Function Index of 96 +/- 3 for the operative shoulder. The Functional Rating Scores for Activities of Daily Living and Sports Activity Score were 89% +/- 10% and 87% +/- 12%, respectively. Instrumented isometric strength for abduction and external rotation strength in the operated shoulder were 94% +/- 20% and 93% +/- 20%, respectively, compared with the contralateral unoperated side. Five of eight patients who performed overhead sports returned to a premorbid level of performance, and 14 of 15 patients available for follow-up believed that their result was excellent. We conclude that through careful selection one can identify patients optimally suited for arthroscopic-assisted rotator cuff repair, but some may have to be converted to an open end approach because of the quality of the tendon tissue and configuration of the tear requiring soft tissue releases.