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n sports medicine updateSection Editor: Darren L. Johnson, MD

Two-stage Revision Anterior Cruciate Ligament Reconstruction: Indications, Review, and Technique DemonstrationAaron C. Coats, MD; Darren L. Johnson, MD

Revision anterior cruciate ligament (ACL) recon-

struction is increasing in fre-quency. This is directly related to an overall increase in athlet-ic participation and a desire to return to competition follow-ing primary reconstruction. When compared with primary ACL reconstruction, multiple studies have shown that revi-sion surgery is associated with a higher incidence of meniscus

and cartilage injury, lower re-turn to play percentage, and lower knee outcome scores.1-3

Due to the unique challeng-es associated with revision ACL surgery, certain cases are best addressed with staged surgery to optimize patient outcome. Previous hardware, inaccurate tunnel placement, and tunnel expansion can di-minish outcomes by impair-ing anatomic graft placement

and biological fixation, both of which are important for immediate rehabilitation. In addition, motion restoration surgery should not be con-comitantly performed with revision ACL reconstruction.4 Therefore, when loss of mo-tion is encountered, a motion-restoring procedure should be performed first, followed by revision surgery once motion has returned.

To the authors’ knowledge, no evidence-based guidelines are available for addressing tunnel expansion and tunnel overlap in the revision setting. The purpose of this article is to present indications for staged revision ACL surgery in the setting of tunnel lysis or overlap.

Tunnel lysis, Widening, and expansion

The exact etiology of tun-nel lysis is unknown, but me-chanical and biologic factors are believed to contribute. Although graft motion (asso-ciated with suspensory fixa-tion) is the predominant me-chanical theory, other factors include tunnel expansion at surgery (ie, screw fixation of a soft tissue graft compresses softer cancellous bone), non-anatomic tunnel placement (resulting in nonphysiologic forces on graft during knee motion), accelerated postoper-ative rehabilitation, and stress shielding.5-7 Biologic causes include synovial fluid bathing of the tunnel, graft swelling, and inflammatory cytokines.8,9

Dr Coats is from the Department of Orthopaedic Surgery, American Health Network, Indianapolis, Indiana; and Dr Johnson is from the Depart-ment of Orthopaedic Surgery, University of Kentucky School of Medicine, Lexington, Kentucky.

Drs Coats and Johnson have no relevant financial information to disclose.Correspondence should be addressed to: Darren L. Johnson, MD, De-

partment of Orthopaedic Surgery, University of Kentucky School of Medi-cine, 740 S Limestone, K401 Kentucky Clinic, Lexington, KY 40536-0284 (dljohns@uky.edu).

doi: 10.3928/01477447-20121023-08

Abstract: Revision anterior cruciate ligament reconstruction has inherent technical challenges not encountered during pri-mary reconstruction. Prior tunnel placement and tunnel lysis can significantly alter graft fixation, compromising patient outcome. Preoperative recognition of patients with existing tunnel overlap and severe tunnel lysis will allow appropriate surgical planning and patient counseling, optimizing patient outcome. When single-stage revision is not possible in the presence of significant tunnel overlap and lysis, performing a 2-stage revision is recommended.

Figure 1: Notch view radiograph displaying tunnel expansion (A). Sagittal mag-netic resonance imaging revealing expansion (B).

1A 1B

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n sports medicine update

However, most authors sup-port a multifactorial etiology of tunnel expansion, includ-ing biological and mechanical contributions. The occurrence of various forms of tunnel ly-sis (conical, cavitary, cystic, and linear) further supports a multifactorial theory.

Tunnel widening may ad-versely affect graft placement and fixation in the revision set-ting. Placing a revision graft into a widened tunnel may compro-mise its stability. Preoperative assessment of tunnel width can be achieved using radiographs, magnetic resonance imaging, and computed tomography. These imaging modalities can detect the extent of tunnel wid-ening and allow for proper sur-gical planning. Lesser degrees of tunnel widening may be ad-dressed with the use of a larger graft or additional interference screw fixation in a stacked tech-nique.10 Although no evidence-based guidelines exist for the degree of tunnel lysis requiring a 2-stage revision, authors have suggested that a tunnel diameter greater than 16 to 17 mm is the threshold for necessitating bone grafting.10

Tunnel placemenTPrevious tunnel position may

also affect revision graft integ-rity and, therefore, the ability to perform a single-stage revi-sion. Preoperative evaluation of the tibial and femoral tunnel positions on radiographs, mag-netic resonance images, and computed tomography scans is critical. In addition, previous surgical technique may predict tunnel placement. For example, a transtibial primary ACL recon-

struction commonly results in a posteriorly placed tibial tunnel and an anterior and superiorly placed femoral tunnel. In this scenario, drilling an anatomic femoral tunnel in native bone is often possible; however, it is more common that the tibial tunnel necessitates bone grafting and staged surgery.

Prior tunnel position can be described as anatomically placed (entire tunnel opening is 100% in the native ACL foot-print), nonanatomically placed (commonly seen in transtibial femoral tunnel drilling), or par-tially anatomic (overlapping). The greatest variation in tunnel placement is seen on the femur. When the femoral tunnel is non-anatomically placed, it rarely in-terferes with the revision tunnel placement and can be ignored, leaving the previous fixation hardware in place. Partially overlapping tunnel placement creates the most difficult sce-nario because the existing and revision tunnels will create a figure-of-eight tunnel. Often, re-direction of the tunnel (diverg-ing from the existing tunnel) can address this on the femur, allow-ing for adequate fixation of the new graft. In the authors’ experi-ence, outside-in femoral tunnel drilling has proven successful in this situation. A revision ACL surgeon must be comfortable with multiple techniques to reproduce anatomic tibial and femoral tunnels.

To the authors’ knowledge, no studies have evaluated the outcomes of single- vs 2-stage revision in patients with tunnel overlap. However, Thomas et al3 reported on whether graft integ-rity following a 2-stage revision

was comparable with primary ACL reconstruction. The focus of this study was not to define when tunnel overlap necessi-tated bone grafting but rather to show objective laxity following a 2-stage revision was compa-rable to that of a primary ACL reconstruction.3 Although this study showed comparable knee stability for 2-stage revisions, this approach should be used judiciously to minimize unnec-essary risk to the patient. One obvious risk is the patient’s ex-posure to 2 surgeries. Also, knee instability continues until defini-tive fixation after bone graft in-corporation, which is typically 4 to 6 months. This can result in progressive cartilage and menis-cus damage, potentially affect-ing long-term outcome.11

case RepoRTA 30-year-old woman pre-

sented with knee instability following a noncontact pivot in-

jury. She had undergone 2 pre-vious ACL reconstructions. Her primary ACL reconstruction (hamstring autograft) was per-formed 13 years previously, fol-lowed by a revision ACL recon-struction (Achilles allograft) 6 years prior to presentation.

Significant findings on physical examination included a positive pivot shift and no

Figure 2: Intraoperative arthroscopic images as viewed through the central por-tal (A-C) and through the high, tight anterolateral portal (D). The previous femo-ral tunnel was evaluated (A), prepared (B), and bone grafted (C) with femoral head allograft. The tibial tunnel was bone grafted after tunnel preparation (D).

2A 2B

2C 2D

Figure 3: Anteroposterior radiograph showing graft consolidation 5 months after bone grafting.

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n sports medicine update

endpoint with Lachman exam-ination. Radiographs (Figure 1A) revealed tunnel widen-ing, and magnetic resonance imaging confirmed a retear of the ACL graft and tunnel lysis involving the tibia and femur. Tibial tunnel lysis measured 20 mm in diameter (Figure 1B). Due to significant tunnel widening, a staged revision involving bone grafting of the femoral and tibial tunnels with femoral head allograft was recommended.

Intraoperatively, the femoral tunnel was prepared with cu-rettes and a shaver until bleeding bone was exposed. The femoral tunnel was measured and filled with femoral head allograft dowels that were subsequently

tamped in place (Figures 2A-C). The tibial tunnel was prepared with reamers, curettes, and a shaver. Bleeding bone was vi-sualized, and the tunnel was also filled with femoral head allograft (Figure 2D). After ra-diographs confirmed incorpora-tion at 5 months (Figure 3), de-finitive fixation was performed. An anatomic ACL reconstruc-tion using hamstring allograft (Figure 4) was achieved using the accessory anteromedial por-tal technique.12

conclusionFor all candidates of revi-

sion ACL reconstruction, a comprehensive preoperative evaluation must be performed, including a thorough history,

physical examination, and ap-propriate imaging. As part of the history, special attention should be given to previous surgeries, surgical technique, grafts and implants used, and associated injuries. Physical examination must include evaluation for associated liga-mentous injuries. Preoperative radiographs should include weight-bearing anteroposteri-or, 45° posteroanterior, stand-ing alignment, lateral, and sun-rise views. Special attention must be given to the placement of previous tunnels and tunnel lysis. Magnetic resonance im-aging can identify associated cartilage damage and confirm tunnel lysis and placement.

Revision surgeons should be knowledgeable in advanced tunnel drilling techniques (ie, accessory medial portal and outside-in) when presented with previous tunnels. Often, these techniques will adequate-ly address tunnel overlap sce-narios in the femur. However, when these techniques are in-sufficient in achieving anatomic ACL placement and stable fixa-tion in the setting of significant tunnel lysis or overlap, a 2-stage revision is critical to achieving a successful outcome.

RefeRences 1. Denti M, Lo Vetere D, Bait C,

Schonhuber H, Melegati G, Volpi P. Revision anterior cruciate liga-ment reconstruction: causes of failure, surgical technique, and clinical results. Am J Sports Med. 2008; 36:1896-1902.

2. Diamantropoulos AP, Lorbach O, Paessler HH. Anterior cruci-ate ligament revision reconstruc-tion: results in 107 patients. Am J Sports Med. 2008; 36:851-860.

3. Thomas NP, Kankate R, Wandless F, Pandit H. Revision

anterior cruciate ligament recon-struction using a 2 stage tech-nique with bone grafting of the tibial tunnel. Am J Sports Med. 2004; 32:1986-1995.

4. Getelman MH, Friedman MJ. Revision anterior cruciate liga-ment reconstruction surgery. J Am Acad Orthop Surg. 1999; 7:189-198.

5. Morgan CD, Stein DA, Leitman EH, Kalman VR. Anatomic tibial graft fixation using a retrograde bio-interference screw for endo-scopic anterior cruciate ligament reconstruction. Arthroscopy. 2002; 18:E38.

6. Insalata JC, Klatt B, Fu FH, et al. Tunnel expansion following ante-rior cruciate ligament reconstruc-tion: a comparison of hamstring and patellar tendon autografts. Knee Surg Sports Traumatol Arthrosc. 1997; 5:234-238.

7. Zijl JA, Kleipool AE, Willems WJ. Comparison of tibial tunnel enlargement after anterior cruci-ate ligament reconstruction using patellar tendon autograft or al-lograft. Am J Sports Med. 2000; 28:547-551.

8. Cameron M, Buchgraber A, Passler H, et al. The natural his-tory of the anterior cruciate liga-ment-deficient knee: changes in synovial fluid cytokine and kera-tin sulfate concentrations. Am J Sports Med. 1997; 25:751-754.

9. Clatworthy MG, Annear P, Bulow JU, et al. Tunnel widening in anterior cruciate ligament recon-struction: a prospective evaluation of hamstring and patella tendon grafts. Knee Surg Sports Traumatol Arthrosc. 1999; 7:138-145.

10. Kamath GV, Burks RT, Redfern JC, et al. Revision anterior cruciate ligament reconstruction. Clinical sports medicine update. Am J Sports Med. 2011; 39:199-217.

11. Ohly NE, Murray IR, Keating JF. Revision anterior cruciate ligament reconstruction: timing of surgery and the incidence of meniscal tears and degenerative change. J Bone Joint Surg Br. 2007; 89:1051-1054.

12. Johnson D, Snyder G. Anatomic single bundle ACL reconstruc-tion with quadrupled hamstring Autograft. VuMedi Web site. http://www.vumedi.com/video/ 242096?icn=organic&ici= search-5. Accessed October 8, 2012.

Figure 4: Intraoperative arthroscopic images at the time of revision ante-rior cruciate ligament reconstruction as viewed from the high, tight antero-lateral portal (A, B, E) and the central portal (C, D). Images display tibial tun-nel consolidation (A), tibial guide-pin placement (B), femoral tunnel place-ment (C), and final hamstring allograft placement (D, E).

4A 4B

4C 4D

4E