Retensionable All-Suture Anchor Extensor Mechanism Repair

Abstract

Background:

Extensor mechanism tendon ruptures, including the quadriceps and patellar tendons, are devastating injuries that most often require acute surgical repair to restore knee mechanics and function. There are 2 well-described categories of quadriceps repair techniques, including superior pole suture anchor repairs and transosseous repairs, with recent studies reporting similar overall outcomes. However, failure rates have been reported to be as high as 18% and 21%, respectively.

Indications:

Extensor mechanism ruptures.

Technique Description:

The described technique utilizes 2 transosseous patellar tunnels. Retensionable all-suture anchor loops are then passed from the distal cortex to the near cortex, setting the suture anchors at the distal cortex. A Krakow stitch is passed from proximal to distal along the medial tendon, through the suture loop, and then distal to proximal through the central tendon and tied. This is repeated for the lateral half of the tendon. The suture loops are then tensioned to reduce the quadriceps tendon to the patella. The knee is cycled to remove creep from the Krakow suture, and the anchors are retensioned as needed to avoid gapping. This technique can also be utilized for patellar tendon ruptures in a similar fashion, with passage of the loops from proximal to distal and setting of the all-suture implant at the superior pole.

Results:

In our experience, patients undergoing extensor mechanism repair with knotless retensionable all-suture anchors have achieved successful outcomes. The transosseous adjustable all-suture anchor has been shown to be biomechanically superior to a traditional transosseous suture repair, with significantly less gap formation, higher load-to-failure, and greater stiffness. Furthermore, the adjustable knotless anchor allows retensioning that may improve compression, minimize laxity both intra- and postoperatively, and allow more aggressive flexion range of motion during the early postoperative course. The all-suture anchor may also potentially limit complications related to hardware irritation when metal buttons are used for bicortical fixation or hard-bodied anchors are utilized at the superior pole.

Discussion/Conclusion:

Transosseous retensionable all-suture anchors offer an alternative high- strength construct for extensor mechanism repairs, with a unique ability to minimize creep within repair constructs intraoperatively.

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.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

We present our surgical technique for a retensionable all-suture anchor extensor mechanism repair. This technique can be utilized for both quadriceps and patellar tendon ruptures.

Background

Extensor mechanism injuries, including both patellar tendon and quadriceps tendon ruptures, are relatively uncommon yet devastating injuries, most often seen in males >40 years.^2,3,7 Quadriceps tendon ruptures occur slightly more often; however, recent trends have revealed that the incidence of extensor mechanism injuries has continued to rise over the last decade. Extensor mechanism ruptures result after forceful knee flexion on an eccentrically loaded quadriceps, and risk factors—including overuse, participation in jumping sports, and local steroid injections.^2,6

Several repair techniques have been described in the literature.^1,2,5,9,10 The most extensively studied techniques include the transosseous tunnel repair and the suture anchor repair with hard-bodied suture anchors. The transosseous repair typically involves 3 transpatellar tunnels with a Krakow suture passed through each tunnel and tied over the far cortex. Hard-bodied suture anchor repairs utilize biocomposite or titanium anchors to anchor the repair to the near cortex, historically requiring knots for fixation or the utilization of a knotless anchor with an interference fit of the repair suture, which is tensioned at the time of anchor insertion. Biomechanical studies have shown that suture anchors can reduce gap formation and initial displacement compared with transosseous techniques, with similar ultimate loads to failure. ¹ More recently, adjustable, transosseous all-suture anchor repair has been shown to reduce gap formation and increase yield and ultimate load compared with transosseous repair, making adjustable, knotless all-suture anchor repairs a viable fixation alternative. ¹⁰ Suture-button repair techniques have also been described, but are less commonly studied in the literature.

Indications

Extensor mechanism repairs with the retensionable all-suture anchor technique are indicated for patients with complete avulsion ruptures of the patellar or quadriceps tendon, resulting in loss of the extensor mechanism. Early intervention is preferable to avoid tendon retraction and scarring, which may make primary repair more challenging.

Technique Description

In this case, the patient was a 67-year-old male who presented with a chief complaint of right knee instability, pain, and difficulty ambulating. Briefly, the patient experienced an acute onset of knee pain, swelling, and difficulty ambulating after a fall at the gym and reports an episode of knee buckling when trying to weightbear. He was seen by an emergency department provider with concern for quadriceps tendon rupture, placed in a knee immobilizer, and referred to our clinic 10 days later. In our clinic, physical examination was significant for a mild knee effusion and palpable defect just proximal to the patella. The patient was unable to actively straight-leg raise or hold his knee in extension against gravity. Ligamentous examination was stable, and neurovascular examination was intact distally.

On imaging, anteroposterior and lateral radiographs of the right knee revealed patellar baja and knee effusion. A magnetic resonance imaging (MRI) without contrast of the right knee was then obtained, which demonstrated a full-thickness quadriceps rupture with approximately 9 mm of retraction. Mild tricompartmental degenerative changes were also noted.

The patient was now over 10 days from the inciting injury with continued pain, instability, and difficulty ambulating, with clinical examination and MRI findings consistent with quadriceps tendon rupture. The risks and benefits of surgical repair were discussed, and the patient elected to proceed.

In the preoperative area, a femoral nerve block was placed by the anesthesia team, and the patient was taken to the operating room and positioned supine on a standard table with a blanket bump under the hip. No tourniquet was used. The right lower extremity was prepped and draped in standard fashion, and a sterile towel bump was placed under the knee before incision.

A 10-cm midline incision was made, and the quadriceps tendon was identified. The superior pole of the patella was rongeured down to a bleeding bony surface. The quadriceps tendon was grasped with an Allis clamp and mobilized. At this point, 2 tunnels were made with a 2.4-mm Beath pin from proximal to distal, with starting points located at the medial and lateral junctions of the central third of the patella. The lead suture was then passed through the eyelet of the Beath pin and passed through each bone tunnel from proximal to distal. The lead suture was then used to load and pass a knee FiberTak suture anchor (Arthrex) back from distal to proximal, such that the fiber tacks were lodged at the inferior pole of the patella at the medial and lateral junction of the central third of the inferior patella. This delivered the tensionable suture loops to the superior pole, while anchoring the all-suture anchor to the cortex of the inferior pole of the patella, shown here.

At this point, Krakow sutures were placed in a proximal to distal direction along the medial quadriceps tendon. While holding traction on the safety stitch, the all-suture anchor loop was then tensioned until approximately 1 cm of the loop was left out of the bone. The Krakow suture tail was then passed through the medial tensionable suture loop and then retensioned, bringing the looped Krakow suture tail into the bone tunnel. Next, the Krakow suture tail was passed from distal to proximal along the central aspect of the tendon. The 2 suture tails were then tied proximally. This was then repeated for the lateral aspect of the quadriceps tendon. The tensionable suture loops were then tensioned in alternating fashion to pull the tendon down to the superior pole of the patella, ensuring good apposition. The knee was cycled through range of motion, and then again, the loops were retensioned to account for creep within the Krakow suture. Repeat knee cycling and retensioning can be performed as needed. Finally, the 4 proximal suture tails from the tensionable suture loops were passed through the residual tissue at the superior pole, and these tails were tied. Medial and lateral retinacular closures were done with a running locking suture with No. 2 suture tape (Arthrex).

Results

Surgical Keys

Successful repair using the retensionable all-suture anchor technique requires care to avoid violation of the patellar cartilage. An anterior cruciate ligament tibial guide can also be used to aid with the trajectory to avoid this complication, as needed. Furthermore, maintenance of the safety stitch is key to avoiding losing the suture loop within the bone tunnel before passing the repair stitch. Alternating retensioning and knee cycling minimizes residual gapping at the time of repair and maximizes the degree of flexion without gapping. Lastly, it is important to ensure that the suture anchor is flush with the far cortex and does not tether to soft tissue, which may affect adequate tensioning.

Postoperative Care

Our postoperative protocol allows patients to weightbear as tolerated in a hinged knee brace locked in extension, beginning on postoperative day 1 for 6 weeks. From 0 to 2 weeks, flexion is allowed to 30°, and quadriceps isometrics and assisted extension exercises are started. At 2 to 4 weeks, range of motion is further increased to 0° to 45°, and then 0° to 90° from 4 to 6 weeks. At week 6, the hinged knee brace may be opened from 0° to 50° while ambulating to facilitate return of normal gait function, range of motion is advanced to tolerance, and active extension exercise may begin gradually. Bracing is discontinued at 8 weeks after surgery, with adequate quadriceps control. Here is an example of a similar case demonstrating intact straight leg raise, active knee extension, and the ability to hold a single-leg stance at 12 weeks after quadriceps repair with this technique.

Discussion/Conclusion

Several systematic reviews have evaluated outcomes after patellar and quadriceps tendon repairs. Overall, the mean rerupture rates are low, although they have been reported as high as 18% and 21%, respectively.^4,8 Commonly cited complications can include anchor pull-out, knot slippage, patellar fracture, and repair gapping.^4,8 Overall, functional outcomes and rerupture rates are similar between transosseous and suture anchor techniques,^5,9 but some studies have reported higher complication rates after suture anchor repair. ² In our experience, patients undergoing extensor mechanism repair with knotless retensionable all-suture anchors have been successful, although clinical outcomes have yet to be critically evaluated. We theorize that the adjustable knotless anchor allows retensioning, which may improve compression, minimize laxity both intra- and postoperatively, and increase the early permissible flexion range of motion due to reduced gapping. The all-suture anchor may also help limit complications related to hardware irritation when metal suture buttons or hard-bodied anchors are used.

Thank you.