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The Orthopod

The Official Publication of the
American Osteopathic Academy of Orthopedics

Abstracts

The Role of In-Office Diagnostic Needle Arthroscopy for Intra-Articular Knee Symptoms With a Normal MRI: A case report for ACL Insufficiency

Sean Mc Millan, DO1, FAOAO; Elizabeth Ford, BA2; Jim Stenson, DO3

Authors’ Disclosure Statement: Dr. Mc Millan reports that he receives equity, patents, and is an advisory board member for Trice Medical.  Student Doctor Ford reports that she is has equity in Trice Medical.  Dr. Stenson has no conflicts to report.

1Dr. Mc Millan is the Chief of Orthopedics and Vice Chairman of the Department of Surgery at Lourdes Health System in Burlington, NJ.  Furthermore he is a Clinical Professor of Surgery at Rowan University School of Osteopathic Medicine in Stratford, NJ..

2Student Doctor Ford is a medical student at Rowan University School of Osteopathic Medicine in Stratford, NJ.  Furthermore she is the lead clinical research assistant in the department of orthopedics at Lourdes Health System in Burlington, NJ.

3Dr. Stenson is an orthopedic resident at Rowan University School of Osteopathic Medicine in Stratford, NJ.

INTRODUCTION
Anterior cruciate ligament (ACL) injuries are one of the most commonly occurring orthopedic sports medicine injuries.  In the general population, ACL injuries account for approximately 64% of all athletic knee injuries in jumping in pivoting sports.  That translates into over 120,000 to 200,000 ACL reconstructions per year in the United States alone.1-3  Within the clinic setting, ACL injuries are most commonly diagnosed utilizing the combination of a thorough history, physical examination, and advanced imaging modalities.  Currently, the imaging gold standard for the diagnosis intra-articular knee pathology is the use of a magnetic resonance imaging (MRI).4 Together, this combination has been successful and non-invasive in evaluating an ACL injury.

However, the reliability of MRI for diagnostic purposes is not always perfect.  This can be due to a large number of variables including:  poor quality MRI magnets, patient movement during the procedure, metallic artifact, post-surgical changes in the tissues, and static evaluation of the structures rather than dynamic.  In ACL tears alone, various studies have questioned the accuracy of MRI in recognizing the injury.  MRI’s have been reported to have varied sensitivity (90.9%), specificity (84.6%), accuracy (88.6%) and negative predictive value (NPV) (84.6%) of full thickness ACL injuries.5 These percentages are even lower when evaluating partial or chronic tears.  Furthermore, the sensitivity, specificity, accuracy, and NPV of MRI to detect medial meniscus pathology has been shown to be 100%, 52.6%, 64% and 100%, respectively. These limitations of diagnosis do not take into account those patients who cannot obtain an MRI for any reason.  Examples of such reasons include:  claustrophia, metal in the body, body habitus, cost, and or MRI availability.  In this setting, obtaining an accurate and confident diagnosis can be challenging for both the physician and the patient.  Based upon this, many physicians have sought alternative imaging modalities to better obtain the answers to their patient’s pathology.

In-office diagnostic needle arthroscopy offers a minimally invasive option for health care providers to visualize large joints in a painless, safe, and time effective manner.  It has been shown to be a cost-effective rapidly emerging tool that can provide similar or greater diagnostic accuracy compared to MRI.6,7  The ability to provide real-time dynamic visualization of the patient’s anatomy allows for more accurate decision making by the physician and can potentially reduce the time from injury to diagnosis to recovery.  Furthermore a recent study reveals that the risk of major and minor complications to be equivocal or better to that of any standard in office injection. (?)  Indications for use are based off intra-articular pathology.  For the knee, the most commonly identified pathologies include, but are not limited to:  meniscal tears, ACL tears, loose bodies, rotator cuff tears, labral tears, aid in decision making for patient undergoing potential uni-compartmental verses total knee replacements, and second look evaluations of cartilage procedures.

The Mi-Eye2™ is an in-office diagnostic needle arthroscope that allows for real time diagnostic capabilities for both the patient and surgeon (Figure 1).  The hand piece comes as a sterile packaged disposable unit that connects to a Microsoft Surface tablet unit.  It provides a 1200 field of visualization and produces an image that is 00 when viewing, as opposed to the standard arthroscopic 300 view.  The tip of the hand-piece contains a 14 gauge outer sheath that is retractable upon entry to the joint to allow for the optics and light source to be deployed.  The interface between the hand-piece and the tablet can allow for still pictures and or video recordings.  These images are transferable to a memory stick if so desired for the surgeon or the patient.

CASE HISTORY
A 25-year-old competitive female horseback rider presented to clinic with a chief complaint of left knee instability and recurrent swelling, which has progressively worsened over the past year.  History reveals that she underwent a left knee multi-ligamentous reconstruction with medial meniscectomy and medial femoral condyle micro-fracture 6 years ago after an equestrian accident.  A review of her medical records reveals that she had a quadruple stranded hamstring allograft ACL reconstructions performed along with an Achilles allograft PCL reconstruction.  She notes that she was able to return to a high level of functional activity post reconstruction, including a return to horseback riding and marathon running.  Within the past 14 months however she has had several instability episodes without an inciting re-injury event.  Pivoting, jumping and plyometric activities are reported to elicit the most symptomatic instability.  She denies catching or locking. Currently, she reports significant instability during rotational movements and plyometric exercises at the gym.

On physical exam, there was no gross deformity, erythema, or effusion noted.  Range of motion was symmetric to the contralateral leg with -3 degrees extension, and 145 degrees of flexion.  There was 1+ Lachman, positive apprehension with pivot shift testing, and 1+ posterior drawer testing.  There was a negative McMurry’s sign and negative varus/valgus gapping on collateral ligament testing.  Motor testing demonstrates 5/5 quad strength and 5/5 hamstring strength.  Sensation, perfusion, and reflexes were symmetric and equal bilaterally.

The patient had normal radiographs and was sent for an MRI of the left knee (Figure 2).  The radiologist and treating orthopedic surgeon had agreed that the ACL and PCL were intact based upon image review.  The remainder of the joint was unremarkable.  The patient was placed into 3 months of dedicated physical therapy and returned reporting worsening symptoms of instability.  With her examination unchanged the patient was offered an in-office diagnostic needle arthroscopy which she agreed to.

PROCEDURE TECHNIQUE
Informed consent was obtained by the treating physician from the patient after a discussion regarding the pros and cons of an in-office diagnostic needle evaluation under local anesthesia versus an operating room arthroscopic evaluation under anesthesia.  Following this, the patient was positioned sitting up with her knees bent to 900 off the end of the bed.  A standard sterile betadine and alcohol prep was performed and the patient had a medial portal location anesthetized through the injection of 10cc of 1% lidocaine plain.  Care was taken to make sure that both the skin and capsule were numbed in a wheel fashion.  Once the skin was numbed, the procedure was undertaken.  Inspection of the joint included both the medial and lateral compartments of the knee as well as the intercondylar notch.  Access to the medial compartment was facilitated by placing a valgus force on the knee with the physician’s assistant applying a stabilizing force on the patient’s thigh.  This dynamic movement of the leg is the same as is performed in traditional operating room based arthroscopy.   Similarly the lateral compartment was accessed by gently placing the patient’s leg into a figure 4 position.

Once the medial and lateral compartments were inspected attention was turned to the ACL.  Figure 3 demonstrates the ACL with the knee flexed at 900.  The imaged demonstrates a lack of re-vascularization of the graft.  Next, dynamic evaluation of the graft was undertaken by placing the knee into the figure 4 position once again.  Figure 4 demonstrates incompetency of the graft with a clear peeling away of the graft from the femoral wall.  The PCL demonstrated evidence of vascularity without incompetence.

DISCUSSION
Our case demonstrates needle arthroscopy to be a viable diagnostic tool for symptomatic patients with occult imaging findings. MRI is a valuable and minimally invasive diagnostic tool but is limited by artifact, anatomic variations, and misinterpretation of pathology.  Furthermore the benefit seen through dynamic evaluation of the knee cannot be matched through a static MRI.  Highly ordered collagen fibers oriented at 55° to the MRI beam cause the “Magic Angle Phenomenon” and falsely mimic meniscal tears.8 Additionally, MRI misses 1 in 14 patients with ACL pathology.9 The overall gold standard for intra-articular knee pathology continues to be surgical arthroscopy of the knee.10 Through the benefit of in-office needle based arthroscopy, the same benefits can be realized over a traditional MRI through a painless, minimally invasive technique.  Furthermore, recent reports have shown that the complication risk associated with the procedure are at or below those seen with standard in office injections.  Operating room traditional surgical diagnostic arthroscopy can cause a patient to miss work and predisposes them to the medical side effects of anesthesia. Furthermore these same surgical risks can become compounded if the patient must be brought back at a later date for definitive surgical intervention for unanticipated findings, such as an incompetent ACL in the face of a “normal MRI”.   In office needle arthroscopy can bridge the gap between the diagnostic limitations of MRI with the surgical risks of surgical diagnostic arthroscopy within the operating room.

Our findings further validate recent publications that found in-office needle arthroscopy to be superior to MRI in diagnosing intra-articular knee pathology. Deirmengian et. al. compared 106 patients with intra-articular knee pathology and found needle arthroscopy to be more sensitive and specific than MRI in identifying meniscal tears.11 In a blinded, prospective, multi-centered study of 110 patients, Xerogeanes et. al. found needle arthroscopy equivalent to surgical arthroscopy and superior to MRI for diagnosing intra-articular knee pathology. Furthermore, the authors found office-based arthroscopy could result in up to $177 million in savings for the healthcare system per year.12 Additionally, separate studies by both Mc Millan et. al. and Voigt et. al. found significant economic benefit of utilizing office based arthroscopy due to improved accuracy of diagnoses compared to MRI. (Voigt)

In conclusion, we clearly demonstrate a role for diagnostic needle arthroscopy in the management of symptomatic patients with normal imaging studies. In-office diagnostic needle arthroscopy offers a safe, accurate, and cost-effective means to diagnose missed or occult intra-articular knee pathology. Further research is needed to identify the prevalence of missed injuries and the ability of needle arthroscopy to shed light on this problem.

REFERENCES

  1. Stannard JP, Sherman SL, Cook JL. Soft tissues about the knee. In: Grauer JN, editor. AAOS Orthopaedic Knowledge Update 12. Ch. 36. 2017. pp. 1–13.
  2. Ellman MB, Sherman SL, Forsythe B, LaPrade RF, Cole BJ, Bach BR, Jr, et al. Return to play following anterior cruciate ligament reconstruction. J Am Acad Orthop Surg. 2015;23:283–96.
  3. Raines BT, Naclerio E, Sherman SL. Management of Anterior Cruciate Ligament Injury: What’s In and What’s Out? Indian Journal of Orthopaedics. 2017;51(5):563-575. doi:10.4103/ortho.IJOrtho_245_17.
  4. Avcu S, Altun E, Akpinar I, Bulut MD, Eresov K, Biren T. Knee joint examinations by magnetic resonance imaging: The correlation of pathology, age, and sex. North American Journal of Medical Sciences. 2010;2(4):202-204. doi:10.4297/najms.2010.2202.
  5. Laoruengthana A, Jarusriwanna A.  Sensitivity and specificity of magnetic resonance imaging for knee injury and clinical application for the Naresuan University Hospital.  J Med Assoc Thai. 2012 Oct;95 Suppl 10:S151-7.
  6. Siemieniuk RAC, Harris IA, Agoritsas T, et al. Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline. BMJ. 2017;(357):j1982.
  7. Crawford R, Walley G, Bridgman S, Maffulli N. Magnetic resonance imaging versus arthroscopy in the diagnosis of knee pathology, concentrating on meniscal lesions and ACL tears: a systematic review. Br Med Bull. 2007;(84):5-23.
  8. Peterfy, Charles & L Janzen, D & Tirman, P.F.J. & Dijke, Cornelis & Pollack, M & Genant, Harry. (1994). ‘Magic-angle’ phenomenon: A cause of increased signal in the normal lateral meniscus on short-TE MR images of the knee. AJR. American Journal of Roentgenology. 163. 149-54.
  9. Patel KA, Hartigan DE, Makovicka JL, Dulle DL, Chhabra A. Diagnostic Evaluation of the Knee in the Office Setting Using Small-Bore Needle Arthroscopy. Arthrosc Tech. 2018;7(1):e17-e21.
  10. Cullen KA, Hall MJ, Golosinskiy A. Ambulatory surgery in the United States, 2006. Natl Health Stat Rep. 2009;(11):1-25.
  11. Deirmengian CA, Dines JS, Vernace JV, Schwartz MS, Creighton RA, Gladstone JN. Use of a Small-Bore Needle Arthroscope to Diagnose Intra-Articular Knee Pathology: Comparison With Magnetic Resonance Imaging. Am J Orthop. 2018;47(2)
  12. Xerogeanes JW, Safran MR, Huber B, Mandelbaum BR, Robertson W, Gambardella RA. A prospective multi-center clinical trial to compare efficiency, accuracy and safety of the VisionScope imaging system compared to MRI and diagnostic arthroscopy. Orthop J Sports Med. 2014;2(2 suppl):1.
  13. McMillan S, Schwartz M, Jennings B, et al. In-office diagnostic needle arthroscopy: Understanding the potential value for the US healthcare system. Am J Orthop 2017;46:252-256.
  14. Voigt JD, Mosier M, Huber B. Diagnostic needle arthroscopy and the economics of improved diagnostic accuracy: a cost analysis. Appl Health Econ Health Policy. 2014;12(5):523-35.