Abstract
Background:
Re-revision anterior cruciate ligament reconstruction (ACLR) is a challenging clinical problem. A multifactorial approach to this situation is necessary to address each patient’s needs fully.
Indications:
Persistent instability.
Technique Description:
Contralateral bone–patellar tendon–bone ACLR with tibial bone defect bone grafting and postfixation of the tibial bone plug. Concomitant lateral extra-articular tenodesis was also performed.
Results:
At the 12-week follow-up, the patient had regained full range of motion and demonstrated sagittal stability on examination. However, with published data consistently demonstrating low return to preinjury level of activity, we remain cautiously optimistic with regard to her eventual outcome.
Discussion/Conclusion:
While it is important to be privy to the latest literature, it is also important to consider each patient’s case individually. Consideration should be given to the patient’s pertinent history and physical examination findings and not just radiographic parameters. Revision situations often present unforeseen challenges, so it is important to have contingency plans in place. Adopting techniques that minimize potential challenges, such as tunnel convergence, can be critical in successfully completing a surgery.
Patient Consent Disclosure Statement:
The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.
This is a visual representation of the abstract.
Video Transcript
This is Hansel Ihn, Elaine Shing, and Travis Maak from the University of Utah, presenting on preoperative assessment and intraoperative management of a revision anterior cruciate ligament reconstruction (ACLR) case. Our disclosures are listed here. Here is a brief overview of what we will cover in this video.
Background
The patient is a 30-year-old woman in the military who reported persistent instability of her left knee even with walking and straight-line running over a 5-year period. She had an extensive surgical history to this knee. All prior surgeries were performed by another physician. She sustained her primary ACL injury in 2015 and subsequently underwent reconstruction using a hamstring autograft. This lasted her another 3 years before she retore her ACL during a military drill. She underwent her first revision ACLR at that time using the ipsilateral bone–patellar tendon–bone (BTB) autograft. She sustained a repeat injury 1 year later after returning to duty. There was reported concern about varus knee alignment, which is a potential contributing factor for 2 failed ACLRs. Consequently, she underwent bone tunnel grafting with a medial opening wedge high tibial osteotomy (HTO). A medial meniscal tear that was irreparable was also treated with a partial medial meniscectomy at that time. There were plans to return to the operating room after adequate time had passed for osteotomy and bone tunnel healing. Unfortunately, the patient’s postoperative recovery was complicated by the development of chronic regional pain syndrome (CRPS). During this time, the COVID-19 pandemic and other personal life events led to her delaying her revision surgery. Since that time, the patient had been managing her symptoms conservatively. When she presented to our clinic, the patient’s CRPS was resolved without needing pain medication. She desired to return to full military duty as well as partake in cutting and pivoting sports.
On examination, the patient had an equivalent range of motion to her contralateral limb with an overall neutral alignment with trace effusion. She had tenderness to palpation right over the area of the known plate. She also had an impressive pivot shift with a 2B Lachman.
On radiographic assessment, the patient’s left knee was noted to have a well-maintained joint space along with prior HTO hardware. The osteotomy and bone tunnels appeared to be healed. She was also noted to have a posterior tibial slope of a little over 13°. On advanced imaging, the osteotomy site and bone tunnels appeared to have healed but were somewhat limited by metal artifact. Magnetic resonance imaging also revealed ACL insufficiency without concern for new meniscal pathology or cartilage loss.
Indications
This patient’s functional instability, even with walking and straight-line running, indicated her for a revision reconstruction. The question now is what exactly needs to be done. Revision ACLR is a challenging problem that warrants multifactorial consideration. The MARS group broadly defined 3 different modes of ACLR failure: technical, traumatic, and biological. 8 Scores of studies have looked at such variables. Our patient’s risk factors include female sex, high-demand activity, residual anterolateral laxity, and elevated posterior tibial slope. Given that a prior soft tissue autograft failed, another soft tissue graft seems out of the question. Consideration could be given to an ipsilateral quadriceps tendon bone block autograft; however, a second hit to the extensor mechanism is something we wanted to avoid. Consequently, we decided on a contralateral BTB autograft.
Over the past decade, there has been an increase in the literature supporting the use of deflexion osteotomy or anterior closing wedge osteotomy to address an increased posterior tibial slope in patients with ACL deficiency. Based on many prior studies, a posterior tibial slope of 12° has been implicated as a threshold for increased risk for ACLR graft failure and a determining factor in performing an anterior closing wedge osteotomy.7,10,11 However, a comprehensive literature review reveals that that number may not be reliable. A recent systematic review by Duerr et al 3 demonstrated that while posterior tibial slope certainly appears to be associated with an increased risk for ACL graft failure, a wide range of posterior tibial slope values are reported. Consequently, while most of the literature would suggest that our patient may be indicated for a slope-correcting osteotomy with a 13.3° posterior tibial slope, we decided against this intervention for 2 reasons. First, based on the best available evidence, there is no true threshold for an increased posterior tibial slope. Second, the patient’s history must be considered in any decision-making. Her history was significant for CRPS after her HTO procedure. It is impossible to know whether this was a direct cause, but with that history and a posterior tibial slope not that far off from the quoted threshold, we did not believe it was in her best interest to perform a slope-correcting osteotomy.
Our patient had an explosive pivot shift, suggesting compromise of the anterolateral complex. The STABILITY trial was a multicenter randomized controlled trial in which nearly 600 patients undergoing primary ACLR with hamstring autograft were allocated to receiving or not receiving a lateral extra-articular tenodesis (LET). 4 At the 2-year follow-up, the patients who had received the LET had a 33% reduction in graft rerupture. This was in the primary setting and with hamstring autograft. One randomized controlled trial specifically looking at BTB autografts was performed by Castoldi et al. 1 Their notable finding was that at a mean 19-year follow-up, there was no statistically significant difference in clinical outcomes, including graft rerupture, between the groups that had and had not received an LET. It should be noted that the study was underpowered, and the follow-up rate was poor. Nevertheless, there was a trend toward the LET group having fewer reruptures. A potential area of further inquiry is whether an LET can adequately mitigate the increased risk of anterior subluxation associated with a steeper tibial slope. Marcel Lemaire observed that the extra-articular procedure was effective in stabilizing rotational instability but had a minimal impact on sagittal instability. 9 Conversely, a recent biomechanical study by Xu et al 12 showed that adding a lateral extra-articular procedure to an ACLR can significantly reduce anterior translation. Consequently, we planned on performing a hardware removal of the prior HTO plate, revision ACLR using a contralateral BTB autograft, and an LET procedure.
Technique Description
We began by simultaneously removing the HTO plate from the operative limb and contralateral BTB harvest. Notably, the bone underlying the HTO plate was noted to be in continuity without any defect other than the one left from the metal block spacer that is a part of this particular HTO plate variety as well as the prior screw holes.
We then performed a diagnostic arthroscopy. We were able to confirm the patient had no evidence of chondromalacia or cartilage defect in all 3 compartments. The medial meniscus that remained from the prior partial meniscectomy was intact without tear. The ACL was confirmed to be deficient with a drive-through sign present. We then cleared off the soft tissue from the lateral femoral wall and over the approximate area of the tibial aperture to visualize the femoral and tibial tunnels. The tunnels were noted to have healed bone graft.
We started with the tibial side by placing a guidewire through the anatomic position. A 10-mm reamer was used to ream over this wire. Upon removal of the reamer, a sizable medial tibial cortical defect was noted juxtaposing the tibial tunnel where the prior HTO plate and screws had been. This measured about 2 cm from medial to lateral and 2.5 cm from proximal to distal. The intraosseous, cancellous portion of the tibial tunnel created by our reamer was notably in continuity and had not collapsed. Given the structural integrity of the tibial tunnel, we moved forward with the operation and onto the femoral side.
A microfracture pick was used to mark the approximate anatomic center of our femoral tunnel. The knee was then hyperflexed and a flexible guidewire was advanced at the demarcated spot up the lateral thigh. A 10-mm flexible reamer was used to gently ream to about 5 mm in depth. The reamer was then removed to once again confirm that the planned tunnel would be well positioned with respect to the posterior femoral condyle without risking blowout. Once this was confirmed, the femoral tunnel was reamed to a little more than a 20-mm depth. We confirmed the lateral femoral cortex was still intact. The BTB autograft was then delivered intra-articularly, and the femoral bone plug was fixated using a metal interference screw. We then turned our attention to the tibial side. While the intraosseous tibial tunnel was in continuity, we did not believe it would be safe to perform an interference screw fixation. Instead, we filled the bony defect using 15 cc of freeze-dried cancellous chips. We made sure not to violate the position of the tibial bone plug, and this remained anterior and proximal to the bone graft. Once we were satisfied with the bone grafting, the tibial bone plug was fixated using a 4.5-mm × 25-mm cancellous post screw. This was placed 1 cm below the bone defect and was not fully seated so that the smooth portion of the partially threaded screw was still above the cortical surface. The previously placed 3 sets of high-strength suture through the tibial bone plug were then secured around the post screw. These sutures were placed to help with graft passage but also for situations like this where noninterference fixation is required. Each set was individually tied around the smooth part of the post screw with the knee in 15° of flexion. The knee was then fully ranged and stability was assessed. Once satisfied, final tightening of the screw was performed. Here is our final construct on the tibial side.
Finally, we turned our attention to performing the LET. A 7-cm incision was made over the lateral epicondyle and extending toward Gerdy’s tubercle. Once down onto the iliotibial band, the center of the iliotibial band was identified at the level of the lateral epicondyle, and a fresh blade was used to make an anterior and posterior nick approximately 10 mm wide. Metzenbaum scissors were introduced into the nicks and bluntly spread to lengthen the graft.
We typically transect the graft about 4 cm proximal to the lateral epicondyle. Careful dissection is carried through the soft tissue deep to the iliotibial band and superficial to the lateral collateral ligament. Dissection is carried down distally to the Gerdy’s tubercle. We then delineate the lateral collateral ligament using a blade. We bluntly develop this delineation to allow smooth passage of the graft. The graft is passed using a passing suture. A position posterior and proximal to the lateral collateral ligament is cleared of soft tissue using electrocautery. We use a double-loaded all-suture anchor, so there is no concern with tunnel convergence.
The implant was placed proximal and posterior to the lateral collateral ligament. The iliotibial band graft was then secured with the knee in 30° of knee flexion with the foot in a neutral position. Once secured through the first knotless suture, the graft was doubled back on itself through the second knotless suture loop and secured. The 2 suture limbs were then overtied for additional security. The remainder of the graft was then amputated. The knee was then checked a final time for range of motion and stability. Immediate postoperative radiographs are shown here demonstrating a well-positioned graft and implants.
Results
Given that the bone defect was filled with bone allograft, we protected the patient’s weightbearing with toe-touch precautions with a plan for 4 weeks duration. Range of motion was locked in full extension for the first 10 days while the wound healed. The patient will then enter into physical therapy with a focus on range of motion to reach full range of motion by 6 weeks. We plan on the patient starting strengthening at 12 weeks postoperatively, followed by a slow return to sport activity with pivoting and cutting starting no sooner than 9 months.
At the time of submission, the patient had been seen for her 12-week postoperative visit. She had full range of motion and a 1A Lachman. With the literature consistently demonstrating that less than 30% of patients undergoing revision ACLR are able to return to preinjury level of activity, we remain cautiously optimistic about her eventual outcome.2,5,6
Discussion/Conclusion
While we do not know what the patient’s final outcome will be at this time, several tips and pearls can be gleaned from this case. The intraoperative bone defect may have been avoidable had a computed tomography scan been performed preoperatively. The metal artifact from the HTO plate made complete assessment of the osteotomy site impossible, so it is possible we may have picked up on bony insufficiency preoperatively. Nevertheless, unexpected events occur all the time during surgery and should be anticipated with contingency plans. Fortunately, we had this in place with the high-strength sutures that were already threaded into the tibial bone block and the cancellous post screw. Additionally, the use of aperture ACL fixation on the femoral side along with cortical fixation of the LET graft renders any concern about tunnel convergence moot. This is a worthy fixation strategy for concomitant LET procedures that surgeons should consider having in their armamentarium.
Footnotes
Submitted July 3, 2024; accepted November 11, 2024.
One or more of the authors has declared the following potential conflict of interest or source of funding: T.M. received consulting fees from Arthrex and support for education from Active Medical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
