Combined Anterior Cruciate Ligament Reconstruction and Meniscal Allograft Transplantation

Combined Anterior Cruciate Ligament Reconstruction and Meniscal Allograft Transplantation

M. Mustafa Gomberawalla and Jon K. Sekiya

Chapter Synopsis

• Combined meniscal and anterior cruciate ligament (ACL) deficiency alters knee function and predisposes the patient to accelerated degenerative changes. Combined meniscal allograft transplantation and ACL reconstruction has been advocated to treat this combined deficiency. A size-matched meniscus allograft is transplanted into the appropriate compartment. For revision ACL reconstructions, we prefer to use a double-bundle allograft technique. Clinical results have shown normal to near-normal IKDC scores and return to recreational activities in most patients.

Important Points

• Patients should be under 40 years of age with both meniscal and ACL deficiency.

• Transplantation should be avoided in the presence of advanced chondral changes.

• The meniscal allograft is affixed with use of two bone plugs and bone tunnels (for the medial meniscus) or a bone bridge and trough (for the lateral meniscus).

• Patients may return to recreational activities; however, high-impact sports should be avoided indefinitely.

Clinical and Surgical Pearls

• For the medial meniscus, keep the bone plugs relatively short.

• A traction suture is used in the posterior horn of the transplanted meniscus to guide its intra-articular reduction.

• Intercompartment visualization is significantly improved with the use of a femoral distractor.

• One to 2 mm of the native meniscus rim should be left intact and will be used as a bed for fixation.

Clinical and Surgical Pitfalls

• An appropriately size-matched meniscus allograft should be used.

• The tibial ACL tunnel(s) can encroach on the bony fixation sites of the meniscus.

• The bone plugs (medially) or bone trough (laterally) should be created at the anatomic insertion sites to avoid malpositioning of the meniscal transplant.

• Ensure that full range of motion (including extension) is obtainable at the conclusion of the procedure.

• Video 61-1: Allograft preparation

• Video 61-2: Meniscal site preparation

• Video 61-3: Meniscal allograft fixation

• Video 61-4: ACL tunnel preparation and graft passage

The menisci play a crucial role in maintaining the structure and function of the normal knee. They contribute to shock absorption, joint lubrication, knee stabilization, proprioception, and load sharing.1–3 These roles are significant in protecting the articular cartilage. For example, the medial meniscus carries up to 50% of the load in the medial compartment when the knee is extended.⁴ Fairbank showed significant changes in the knee joint after medial and lateral meniscectomies.⁵ Although chondral changes occur more rapidly after lateral meniscectomies, medial meniscectomy more predictably results in degeneration within the knee.^5,6 These findings lead surgeons toward meniscal-preserving treatments whenever possible.⁷ Unfortunately, in certain patients meniscal pathology may be severe enough to necessitate subtotal or total meniscectomy to appropriately address a patient’s symptoms.

The progression toward degeneration in postmeniscectomy knees is accelerated with an associated injury to the anterior cruciate ligament (ACL).8,9 In addition, the results of ACL reconstruction in knees with medial meniscal deficiency are usually worse than in knees with an intact medial meniscus.¹⁰ Thus, the menisci and ACL likely play a synergistic role in preserving knee stability. The medial meniscus acts as a secondary stabilizer to anterior tibial translation. Medial meniscectomy in the ACL-deficient knee increases anterior tibial translation by 58% to 90%.³ With ACL deficiency, forces in the medial meniscus increase from 52% to 197%.¹¹ In addition, a combined ACL and medial meniscal deficiency results in anteromedial rotatory instability of the knee. For this combined deficiency, performance of meniscal allograft transplantation combined with ACL reconstruction has been advocated to diminish pain, to improve knee stability and function, and to delay degenerative changes in the knee. We present our preferred technique to address this challenging condition as well as our clinical outcomes.

Preoperative Considerations

Before any major reconstructive procedure, it is important to thoroughly evaluate the symptoms the patient may be experiencing, the preinjury and postinjury levels of function, and his or her goals for after treatment. The history should include the initial injury, any treatments (conservative and surgical) for the injury, and what symptoms the patient is experiencing. Typically, the patient has a history of an acute knee injury that may include an episode of “giving way.” He or she has likely undergone meniscectomy, and possibly ACL reconstruction. Despite these treatments, pain in the affected compartment and symptomatic instability may persist. Obtaining previous operative reports as well as arthroscopic images from prior surgeries is important to understand the status of the menisci.

Physical Examination

The physical examination should begin with inspection to document the presence of an effusion or visible swelling, trauma, or skin compromise. Next, the range of motion and strength are documented. The patient’s stance, gait pattern, and overall limb alignment should be evaluated and compared with the contralateral side. Joint line tenderness and degree of quadriceps atrophy (if any) should also be noted. Ligamentous stability of the knee should be assessed and compared with uninjured side. Specific attention should be paid to evaluation of the ACL with the Lachman, pivot-shift, and anterior drawer tests. Increased anterior tibial translation during the anterior drawer test that is equal to or greater than translation noted during the Lachman test suggests a loss of secondary stabilizers, most commonly from a deficient posterior horn of the medial meniscus, but also from posteromedial or posterolateral insufficiency.12,13

Imaging

Bilateral weight-bearing posteroanterior (PA) views at 45 degrees of flexion, lateral views, and sunrise views are obtained. Long-leg films are used to evaluate mechanical axis alignment and are essential if meniscus replacement surgery is being considered.

Magnetic Resonance Imaging

The integrity of the ACL, subchondral bone, meniscal tissue, and other ligamentous structures is assessed. T1-weighted coronal and sagittal images are specifically used to evaluate the remaining meniscus (Fig. 61-1).

Figure 61-1 Magnetic resonance image (T1-weighted, sagittal view) of the knee demonstrating a deficient medial meniscus (A) and a complete anterior cruciate ligament tear (B).

Indications and Contraindications

Candidates for combined ACL reconstruction and meniscal transplantation are patients under 40 years of age with symptomatic instability (despite previous ACL reconstruction) and meniscal deficiency with pain localized to the affected compartment. Ideally, patients should have intact cartilage surfaces with minimal chondral wear (grade I or II changes) and should not have limb malalignment. If the affected limb is malaligned, this should be addressed with an osteotomy to realign the weight-bearing axis before or concomitantly with the reconstruction-transplantation. Large grade IV lesions can be concomitantly reconstructed with fresh osteochondral allograft replacement. Nonoperative treatment including bracing and activity modification will likely have failed. Significant chondral changes (grade III or higher), inflammatory arthritis, history of previous infections, or a body mass index greater than 35 should be considered contraindications to the procedure. Before surgery, the patient’s willingness to cooperate with a comprehensive rehabilitation program should be assessed. In addition, given the complexity of this problem, staged diagnostic scope is usually indicated to determine what will need to be done.

Surgical Technique

Allograft Selection

Appropriate sizing of the meniscal allograft facilitates healing of the graft after transplantation. Thus meniscal grafts should be matched in both size and laterality. Measurements from the PA and lateral radiographs of the knee are used to size the meniscus, as described by Pollard and colleagues—the most common technique used by American Association of Tissue Banks (AATB)–certified tissue banks.¹⁴ This sizing method allows for an accurate estimate (within 3 to 4 mm) of the graft¹⁴ without the need for additional imaging. This size is given to the tissue bank, and an appropriately matched graft is obtained. The meniscal allografts are sterility harvested and fresh-frozen. They should not be irradiated before transplantation.

To reconstruct the ACL concomitantly with meniscal transplantation, we prefer to use a tibialis anterior allograft tendon. In revision procedures we prefer to reconstruct the ACL with a double-bundle technique. Alternatively, bone-patellar tendon-bone allograft may also be used. We prefer allograft in these situations as opposed to autograft, because it hastens postoperative recovery and decreases donor site morbidity in general in knees that have undergone multiple or previous operations. The allograft should be fresh frozen and may be irradiated before use.

Anesthesia and Positioning

We prefer to use general anesthesia for most procedures (unless contraindicated). Often, a femoral and sciatic nerve block will also be used to aid in postoperative pain control. The patient is positioned supine on the operating room table. A sandbag is taped onto the bed under the foot to help support the knee at approximately 70 degrees of flexion. A tourniquet is applied high on the thigh, along with a lateral post at the level of the tourniquet.

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Sep 11, 2016 | Posted by admin in SPORT MEDICINE | Comments Off

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