The Warrior Athlete Part 2-Return to Duty in the US Military: Advancing ACL Rehabilitation in the Tactical Athlete

Impact of Functional Training on Injuries After Anterior Cruciate Ligament Reconstruction for Return-to-Duty Status in U.S. Naval Academy Midshipmen: A Retrospective Analysis

INTRODUCTION

Acute anterior cruciate ligament (ACL) injuries can be disabling because of prolonged rehabilitation process following surgical reconstructions. Rates of ACL injuries among military service members are close to 10 times greater than the general civilian population, likely because of the operation tempo and the unique physical requirements. Studies debated functional testing requirements for return to sports, but no study investigated the impact of functional training and re-injury rates following ACL reconstruction and their association with functional testing outcomes and time to return to full duty in United States Naval Academy (USNA) Midshipmen. Therefore, the purpose of this study was to review all ACL reconstructions with and without meniscal injury at USNA, the functional training and testing, timing of return to military training, and associations with postoperative re-injury rates.

MATERIALS AND METHODS

A retrospective chart review of all Midshipmen who sustained ACL reconstructions between 2015 and 2019 was performed. Demographic variables, type of surgeries, functional training/testing outcomes, timing to return to full duty and postoperative re-injury rates were recorded up to January 1, 2022.

RESULTS

Of 204 ACL reconstructions, 87 were excluded, resulting in a sample size of 117 including 76 (65%) men and 41 (35%) women aged 20.4 ± 1.4 years. Fifty-one (44%) Midshipmen sustained a re-injury to the postoperative knee or complication. Thirty-three out of 76 (43%) men and 18 out of 41 (35%) women sustained complication or re-injury to the surgical knee. Of those re-injuries or complications, 12 Midshipmen (10%) sustained graft failures,12 (10%) anterior arthrofibrosis, 7 (6%) meniscus tears, 17 (15%) patella tendinopathy, and 3% other ligament injuries (MCL, PCL, etc.). Fifty participants (43%) followed a functional training program while 67 (57%) lacked documented functional training. There was a significant difference in Midshipmen who participated in functional training, displaying fewer postoperative anterior cruciate ligament reconstruction (ACLR) re-injuries or complications to the surgical knee as compared to those who did not (0.027). Nineteen Midshipmen (16%) performed functional testing while 98 did not. Of the 98 Midshipmen who did not perform functional testing, 57 (58%) had re-injury or complications to the surgical knee postoperatively compared to 9 (48%) who performed functional testing sustained a re-injury or complication. The average return to full duty was 37.1 ± 25.8 weeks versus 63.8 ± 35.8 weeks for Midshipmen who sustained postoperative injuries. Within 1 year of return to duty, 6 of 12 (50%) ACL graft failures occurred.

DISCUSSION-CONCLUSION

Postoperative injuries and complications following ACLR can delay the ability to return to duty by twice as long, consequently effecting military manpower capability. A functional training and testing program resembling both an athletic and military/operational environment can reduce re-injury and complication rates, resulting in faster return-to-duty rates. Future studies should assess the impact of military rehabilitation participation following ACLR and functional testing protocols to assess physical readiness of Midshipmen to return to full duty. Additionally, methods to assess psychological readiness to return to duty should be further investigated.

Timing of Outcomes and Expectations After Knee Surgery in the US Military: A Systematic Review

CONTEXT

Knee injury and subsequent surgery are widespread in the military setting. Associations between knee surgery and expected outcomes over time have not been consolidated and characterized systematically by procedure type across the body of literature, and the temporal expectations of these outcomes remain unclear.

OBJECTIVE

To summarize common postoperative follow-up times and associated outcomes that determine clinical or surgical failure in US service members after elective knee surgery.

DATA SOURCES

A systematic search was conducted with 3 bibliographic databases of published research reports from 2010 through 2021.

STUDY SELECTION

Studies in US military service members undergoing elective knee surgery, with a minimum of 1-year follow-up, and reporting on a functional/occupational outcome were included. Three reviewers screened all abstracts and full-text articles to determine eligibility.

STUDY DESIGN

Systematic review of longitudinal cohort studies.

LEVEL OF EVIDENCE

Level 2a.

DATA EXTRACTION

Extracted data included military demographics, surgical procedure variables, surveillance period, and outcome measures. The Newcastle-Ottawa Scale and the Grading of Recommendations Assessment, Development, and Evaluation approach were used to determine study quality and risk of bias.

RESULTS

A total of 22 studies (mean follow-up time of 40.7 months) met the inclusion criteria. For cruciate ligament repair, approximately one-third of patients required a second surgery or were medically separated from military service by 2 years from surgery; 100% were reinjured by 4 years, and 85% sustained a new injury within 5 years of surgery. For meniscal repair, nearly one-third of patients were medically separated, and half were placed on activity restrictions within 3 years of surgery. For articular cartilage repair, within 5 years, 39% of patients required a second surgery, 30% were placed on activity restrictions, and 36% were medically separated. For patellar repair, 37% of patients were medically separated and over half were placed on activity restrictions within 5 years.

CONCLUSION

Common knee surgeries can have long-term implications for military careers that may not become apparent with shorter follow-up periods (<2 years). When longer surveillance periods are used (eg, up to 5 years), additional surgical procedures are more common and the likelihood of being injured or medically separated from military service is higher.

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.

Therapy-based expert system on function and postural stability after anterior cruciate ligament reconstruction: a pilot study

PURPOSE

Wii Fit exergames have been less commonly used for the rehabilitation of athletes after Anterior Cruciate Ligament Reconstruction (ACLR). This study aims to investigate the effects of an expert system using Wii Fit exergames compared to conventional rehabilitation following ACLR. A forward-chaining rule-based expert system was developed which proposed a rehabilitation program that included the number and type of exercise in terms of difficulty and ease and the duration of each exercise in a progressive manner according to the patient's physical condition.

MATERIALS AND METHODS

Twenty eligible athletes aged 20-30 who underwent ACLR were enrolled in this study and randomly assigned to two groups; and received 12 sessions of either Wii Fit exergames as Wii group (n = 10) or conventional rehabilitation as CL group (n = 10).

RESULTS

The main outcomes consisted of pain (Visual Analogue Scale (VAS)), knee effusion, knee flexion range (KFR), thigh girth (TG), single-leg hop for distance (SLHD), and for time (SLHT), static and dynamic balance tests. Both groups had considerable improvement in all outcomes, also there were significantly differences between Wii and CL groups as follows; VAS (P < 0.001), knee effusion (P < 0.001), TG (P = 0.001), KFR (P = 0.012), static balance in stable position (P < 0.001) and in unstable position (P = 0.001), dynamic balance in the anterior (P < 0.001), posteromedial (P < 0.001), posterolateral (P = 0.004) directions, symmetry index of SLHD (P < 0.001) and symmetry index of SLHT (P = 0.013).

CONCLUSIONS

The findings showed that using Wii Fit exergames in post-ACLR patients reduced pain and effusion while also improving function and balance significantly. Iranian Registry of Clinical Trials registration number is IRCT20191013045090N1, and the registration date is 03-03-2020.

Survival of anterior cruciate ligament reconstructions in active-duty military populations

PURPOSE

Anterior cruciate ligament tears and anterior cruciate ligament reconstruction (ACLR) are common in young athletes. The modifiable and non-modifiable factors contributing to ACLR failure and reoperation are incompletely understood. The purpose of this study was to determine ACLR failure rates in a physically high-demand population and identify the patient-specific risk factors, including prolonged time between diagnosis and surgical correction, that portend failure.

METHODS

A consecutive series of military service members with ACLR with and without concomitant procedures (meniscus [M] and/or cartilage [C]) done at military facilities between 2008 and 2011 was completed via the Military Health System Data Repository. This was a consecutive series of patients without a history of knee surgery for two years prior to the primary ACLR. Kaplan-Meier survival curves were estimated and evaluated with Wilcoxon test. Cox proportional hazard models calculated hazard ratios (HR) with 95% confidence intervals (95% CI) to identify demographic and surgical factors that influenced ACLR failure.

RESULTS

Of the 2735 primary ACLRs included in the study, 484/2,735 (18%) experienced ACLR failure within four years, including (261/2,735) (10%) undergoing revision ACLR and (224/2,735) (8%) due to medical separation. The factors that increased failure include Army Service (HR 2.19, 95% CI 1.67, 2.87), > 180 days from injury to ACLR (HR 1.550, 95% CI 1.157, 2.076), tobacco use (HR 1.429 95% CI 1.174, 1.738), and younger patient age (HR 1.024, 95% CI 1.004, 1.044).

CONCLUSION

The overall clinical failure rate of service members with ACLR is 17.7% with minimum four-year follow-up, where more patients are likely to fail due to revision surgery than medical separation. The cumulative probability of survival at 4 years was 78.5%. Smoking cessation and treating ACLR patients promptly are modifiable risk factors impacting either graft failure or medical separation.

LEVEL OF EVIDENCE

Level III.

Characteristics of return to running programs following an anterior cruciate ligament reconstruction: A scoping review of 64 studies with clinical perspectives

OBJECTIVE

To (1) describe return to running (RTR) programs used during rehabilitation after anterior cruciate ligament reconstruction (ACLR); and (2) provide clinical guidelines for RTR program after ACLR.

DESIGN

Scoping review.

LITERATURE SEARCH

We searched the MEDLINE (Pubmed), EMBASE, Web of Science and PEDro databases.

STUDY SELECTION CRITERIA

We included randomized controlled trial (RCT), cases series, meta-analyses, both scoping and systematic reviews including a rehabilitation program after ACLR with a specific RTR program. A "Running program checklist" (RPC) was elaborated based on the Template for Intervention Description and Replication (TIDieR), and on the Consensus on Exercise Reporting Template (CERT) checklist.

DATA SYNTHESIS

The percentage and number of studies specifying each of the running program checklist items in their RTR program were reported. Number of items reported in each study and specific analysis item-by-item were also proposed.

RESULTS

The "When (2)" item was the most frequently found (92.19%) and, conversely, the "Who (1)" item appeared only in four studies (6.2%). One-third of the studies presented only one item of the RPC, and 48 of the 64 articles discussed less than three items. Two studies described in detail their RTR program by reporting 8 and 9 items out of the 10, respectively. No study presented 10 of the PRC items.

CONCLUSION

There is a serious lack of information concerning RTR program following ACLR in the literature and further studies are needed to establish a program based on the best evidence.

Anterior Cruciate Ligament Reconstruction Surgery: Creating a Permissive Healing Phenotype in Military Personnel and Civilians for Faster Recovery

Introduction

Anterior cruciate ligament (ACL) rupture in military personnel and civilians can be a devastating injury. A service member is 10 times more likely to suffer an ACL injury than their civilian counterparts, and despite successful surgical stabilization, 4%-35% will develop arthrofibrosis, over 50% will not return to full active duty, and up to 50% will develop post-traumatic osteoarthritis (PTOA) within 15 years. Equally concerning, woman are 2 to 8 times more likely to experience ACL injuries than men, which represents a major knowledge gap.

Materials and Methods

A comprehensive literature search was performed in December 2021 using structured search terms related to prevalence, risk factors, disease progression, and treatment of ACL injury and reconstruction. The literature search was conducted independently by two researchers using PubMed, Cochrane, and Embase databases, with inclusion of articles with military, civilian, and sex relevance, and exclusion of most papers with a publication date greater than 10 years. The resources used for the review reflect the most current data, knowledge, and recommendations associated with research and clinical findings from reliable international sources.

Results

Currently, there is no effective system-based drug therapy that creates a “permissive environment” to reduce synovial and cartilage stress after ACL injury and reconstruction and prevent secondary complications. We argue that progress in this area has been hampered by researchers and clinicians failing to recognize that (1) an ACL injury is a system’s failure that affects the whole joint, (2) the early molecular events define and perpetuate different injury phenotypes, (3) male and female responses may be different and have a molecular basis, (4) the female phenotype continues to be under-represented in basic and clinical research, and (5) the variable outcomes may be perpetuated by the trauma of surgery itself. The early molecular events after ACL injury are characterized by an overexpression of joint inflammation, immune dysfunction, and trauma-induced synovial stress. We are developing an upstream adenosine, lidocaine, and magnesium therapy to blunt these early molecular events and expedite healing with less arthrofibrosis and early PTOA complications.

Conclusions

ACL injuries continue to be a major concern among military personnel and civilians and represent a significant loss in command readiness and quality of life. The lack of predictability in outcomes after ACL repair or reconstruction underscores the need for new joint protection therapies. The male–female disparity requires urgent investigation.

Is Self-reported Return to Duty an Adequate Indicator of Return to Sport and/or Return to Function in Military Patients?

BACKGROUND

In the military, return-to-duty status has commonly been used as a functional outcome measure after orthopaedic surgery. This is sometimes regarded similarly to return to sports or as an indicator of return to full function. However, there is variability in how return-to-duty data are reported in clinical research studies, and it is unclear whether return-to-duty status alone can be used as a surrogate for return to sport or whether it is a useful marker for return to full function.

QUESTIONS/PURPOSES

(1) What proportion of military patients who reported return to duty also returned to athletic participation as defined by self-reported level of physical activity? (2) What proportion of military patients who reported return to duty reported other indicators of decreased function (such as nondeployability, change in work type or level, or medical evaluation board)?

METHODS

Preoperative and postoperative self-reported physical profile status (mandated physical limitation), physical activity status, work status, deployment status, military occupation specialty changes, and medical evaluation board status were retrospectively reviewed for all active-duty soldiers who underwent orthopaedic surgery at Madigan Army Medical Center, Joint Base Lewis-McChord from February 2017 to October 2018. Survey data were collected on patients preoperatively and 6, 12, and 24 months postoperatively in all subspecialty and general orthopaedic clinics. Patients were considered potentially eligible if they were on active-duty status at the time of their surgery and consented to the survey (1319 patients). A total of 89% (1175) were excluded since they did not have survey data at the 1 year mark. Of the remaining 144 patients, 9% (13) were excluded due to the same patient having undergone multiple procedures, and 2% (3) were excluded for incomplete data. This left 10% (128) of the original group available for analysis. Ninety-eight patients reported not having a physical profile at their latest postoperative visit; however, 14 of these patients also stated they were retired from the military, leaving 84 patients in the return-to-duty group. Self-reported "full-time duty with no restrictions" was originally used as the indicator for return to duty; however, the authors felt this to be too vague and instead used soldiers' self-reported profile status as a more specific indicator of return to duty. Mean length of follow-up was 13 ± 3 months. Eighty-three percent (70 of 84) of patients were men. Mean age at the preoperative visit was 35 ± 8 years. The most common surgery types were sports shoulder (n = 22) and sports knee (n = 14). The subgroups were too small to analyze by orthopaedic procedure. Based on active-duty status and requirements of the military profession, all patients were considered physically active before their injury or surgery. Return to sport was determined by asking patients how their level of physical activity compared with their level before their injury (higher, same, or lower). We identified the number of other indicators that may suggest decreased function by investigating change in work type/level, self-reported nondeployability, or medical evaluation board. This was performed with a simple survey.

RESULTS

Of the 84 patients reporting return to duty at the final follow-up, 67% (56) reported an overall lower level of physical activity. Twenty-seven percent (23) reported not returning to the same work level, 32% (27) reported being nondeployable, 23% (19) reported undergoing a medical evaluation board (evaluation for medical separation from the military), and 11% (9) reported a change in military occupation specialty (change of job description).

CONCLUSION

Return to duty is commonly reported in military orthopaedics to describe postoperative functional outcome. Although self-reported return to duty may have value for military study populations, based on the findings of this investigation, surgeons should not consider return to duty a marker of return to sport or return to full function. However, further investigation is required to see to what degree this general conclusion applies to the various orthopaedic subspecialties and to ascertain how self-reported return to duty compares with specific outcome measures used for particular procedures and subspecialties.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Temporal Utilization of Physical Therapy Visits After Anterior Cruciate Ligament Reconstruction

Background:

Physical therapy (PT) rehabilitation is critical to successful outcomes after anterior cruciate ligament reconstruction (ACLR). Later-stage rehabilitation, including sport-specific exercises, is increasingly recognized for restoring high-level knee function. However, supervised PT visits have historically been concentrated during the early stages of recovery after ACLR.

Purpose/Hypothesis:

To assess the number and temporal utilization of PT visits after ACLR in a national cohort. We hypothesized that PT visits would be concentrated early in the postoperative period.

Study Design:

Descriptive epidemiological study.

Methods:

The Humana PearlDiver database was searched to identify patients who underwent ACLR between 2007 and 2017. Patients with additional structures treated were excluded. The mean ± SD, median and interquartile range (IQR), and range of number of PT visits for each patient were determined for the 52 weeks after ACLR. PT visits over time were also assessed in relation to patient age and sex.

Results:

In total, 11,518 patients who underwent ACLR met the inclusion criteria; the mean age was 32.62 ± 13.70 years, and 42.7% were female patients. Of this study cohort, 10,381 (90.4%) had documented PT postoperatively; the range of PT visits was 0 to 121. On average, patients had 16.90 ± 10.60 PT visits (median [IQR], 16 [9-22]) after ACLR. Patients completed a mean of 52% of their PT visits in the first 6 weeks, 75% in the first 10 weeks, and 90% in the first 16 weeks after surgery. Patients aged 10 to 19 years had the highest number of PT visits (mean ± SD, 19.67 ± 12.09; median [IQR], 18 [12-25]), significantly greater than other age groups (P < .001).

Conclusion:

PT after ACLR is concentrated in the early postoperative period. Physicians, therapists, and patients may consider adjusting the limited access to PT to optimize patient recovery.

Clinical Relevance:

As supervised PT visits may be limited, the appropriate temporal utilization of supervised PT visits must be maximized. Strategies to ensure sessions for later neuromuscular and activity-specific rehabilitation are needed.