Authors: Adam V. Daniel, Griffin R. Rechter, Logan A. Reed, Warren A. Williams, Andrew D. Carbone, Abhishek S. Kannan
Categories: Technical Note
Source: Arthroscopy Techniques
Authors: Adam V. Daniel, Griffin R. Rechter, Logan A. Reed, Warren A. Williams, Andrew D. Carbone, Abhishek S. Kannan
Patellar tendon ruptures are relatively uncommon injuries that often occur in the setting of chronic patellar tendinopathy, particularly in those participating in high-level pivoting sports and jumping athletics secondary to overuse. Tear patterns vary, with the most common being avulsions from the inferior pole of the patella. For complete tears resulting in extensor mechanism compromise, surgical treatment typically entails acute repair. In this technique, we describe the use of a bioinductive bovine collagen implant to augment a patellar tendon repair in the setting of chronic patellar tendinopathy.
In the United States, patellar tendon ruptures have an overall incidence of <1 per 100,000 people and account for 13.5% of all extensor mechanism injuries.^1^ Oftentimes, patellar tendon ruptures occur following a prolonged period of patellar tendinopathy that was treated conservatively.^2^ Studies have shown that, in the case of competitive athletes, hypertrophied patellar tendons and partial tears exceeding 50% of the patellar tendon, as seen on axial magnetic resonance imaging, are less likely to benefit from nonoperative management.^3^ Additionally, continuing to participate in competitive sports with this pathology risks progression to a complete patellar tendon tear.
Recently, augmented patellar tendon repairs have garnered increased interest with promising outcomes, especially in the acute-on-chronic setting.^2^^,^4, 5, 6, 7 Herein we describe a technique, using a bioinductive bovine collagen implant (Regeneten; Smith & Nephew), for the augmentation of patellar tendon repair following acute rupture in the setting of chronic patellar tendon tendinopathy.
A narrated video of the technique is shown in Video 1.
The patient is placed on a standard operating table supine, and a nonsterile tourniquet is applied to the proximal thigh and left uninflated. A small radiolucent triangle is placed under the knee. The leg is then prepped and draped in sterile fashion, with 2 g Ancef given before surgical timeout. Using a No. 15 blade, a 10-cm parapatellar incision is made starting at the infrapatellar pole and extending to the level of the tibial tuberosity. Full-thickness skin flaps are then developed medially and laterally. A combination of blunt and sharp dissection is utilized to remove adhesions and scar tissue around the patellar tendon. The tendinous edge is located, and the avulsion from the inferior pole of the patella is confirmed (Fig 1).Fig 1Intraoperative view of a left knee showing a proximal patellar tendon avulsion with a residual tendinous stump (asterisk). (M, medial retinaculum; P, patella.)
The residual patellar tendon stump and surrounding soft tissue are debrided from the inferior pole of the patella. Subsequently, the knee joint is thoroughly irrigated with normal saline. The entire defect following irrigation and debridement can be visualized in Figure 2.Fig 2Intraoperative view of a left knee showing a primarily proximal avulsion patellar tendon rupture (asterisk) with a residual proximal patellar tendon stump (S). (F, anterior fat pad; L, lateral femoral condyle; P, patellar articular surface.)
Next, a 1.7-mm suture tape (Arthrex) is utilized in standard Krackow fashion from proximal to distal, using full-thickness suture passes through the patellar tendon substance. In total, 3 separate rows of stitches with 6 free limbs of suture tape will be present (Fig 3).Fig 3Intraoperative view of a left knee showing 3 suture tapes in a full-thickness Krackow fashion (white arrowheads) within the avulsed patellar tendon (asterisk). (L, lateral femoral condyle; P, patella; R, medial retinaculum; S, proximal patellar tendon stump.)
Attention is then directed toward the inferior pole of the patella. Debridement of the inferior pole is achieved with a combination of sharp dissection and use of a rongeur to coarsen the bony edges and create a bleeding bed for eventual tendo-osseous healing. Utilizing a Beath pin, 3 equally spaced transosseous tunnels are drilled inferior to superior. Intraoperative fluoroscopy is used to ensure appropriate positioning of the pins (Fig 4).Fig 4Intraoperative fluoroscopic lateral view of a left knee showing pin insertion (asterisk) through the patella (P) from distal to proximal. (F, femur; R, retractor; T, tibia.)
No. 3-0 Vicryl sutures (J&J MedTech) are used as shuttling sutures through the transosseous tunnels. The medial-most suture strand is passed through the medial patellar tunnel. The most lateral suture strand is passed through the lateral transosseous tunnel. The central and sister strands of both medial and lateral rows of Krackow sutures are passed together through the central transosseous tunnel (Fig 5).Fig 5Intraoperative view of a left knee following the shuttling of the 6 suture limbs (white arrows) through the 3 patellar tunnels, with the medial tunnel involving the most medial suture limb (black arrowhead), the lateral tunnel involving the most lateral suture tape limb (white arrowhead), and the central tunnel involving the central row as well as the lateral suture limb of the medial row and the medial suture limb of the lateral row (black arrows). Asterisk, patellar tendon. (P, patella; S, proximal patellar tendon stump.)
With the knee held in full extension, the medial row strands are tied together with alternating half-hitches, and the same is completed for the lateral side. The knee is then ranged passively to ensure no gapping is present between the tendon and its footprint. The medial and lateral retinaculum are repaired with No. 1 Vicryl suture (J&J MedTech). Once completed, the knee is, again, taken through passive range of motion to ensure normal patellar tracking.
Given chronic tendinosis and concerning tissue quality, it was decided to augment the repair with a bioinductive collagen implant (Regeneten; Smith & Nephew). The implant is sewn onto the tendon with 0 Vicryl suture (Fig 6, Table 1).Fig 6Intraoperative view of a left knee showing a bioinductive patch (B) sutured on top of the repaired patellar tendon. White arrows indicate tied-down patellar tendon repair sutures. (P, patella; S, proximal patellar tendon stump.)Table 1Pearls and PitfallsPearlsPitfallsBioinductive collagen implant should be placed directly on the primary repair, ensuring maximum surface area contactBioinductive implant does not provide structural augmentation, such as would be required in the setting of tissue loss or deficiencySuture repair sufficient for incorporation the repair siteUse of fluoroscopy to ensure proper trajectory and avoidance of intra-articular violation
The remnant patellar tendon, attached to the inferior pole of the patella, is then draped over the repair. This construct effectively “sandwiches” the implant in between the deep (distal) and superficial (proximal) layers, which are then sutured over with 3-0 Stratafix Monocryl suture (J&J MedTech) (Fig 7).Fig 7Intraoperative view of a left knee showing the final patellar tendon repair with the proximal remnant patellar tendon (asterisk) completely covering the bioinductive patch. White arrows indicate tied-down patellar tendon repair sutures. (P, patella.)
Next, the surgical wound is thoroughly irrigated with normal saline. The deep layer is closed with 0 Vicryl, followed by a standard closure technique. Sterile dressings are applied to the incision, and the extremity is wrapped in a sterile cast padding. A 6-inch Ace wrap is wrapped from the level of the foot to the mid-thigh, and a hinged knee brace is applied, which is locked in full extension.
The patient is made flat foot weightbearing with crutches, and the hinged knee brace is locked in extension for 6 weeks. Initially, physical therapy should focus on range of motion (ankle pumps, heel prop, and contralateral leg exercises), functional mobility, and positioning when in bed. At postoperative 4 weeks, the patient is allowed to progress to full weightbearing with the brace locked in extension, followed by full weightbearing with the brace unlocked to 90° at postoperative week 6. Discontinuation from brace or progression to an alternate brace is acceptable beginning postoperative weeks 8 to 10. Limited-depth closed-chain exercises are utilized for the first 16 weeks, and light running is permitted between weeks 16 and 24 once the quadriceps have <30% deficit. Full-depth closed-chain strengthening (≥90°) may begin at no later than 6 months postoperatively. Lastly, return to sport is permissible at 6 to 8 months—if the patient is symptom-free and has passed a functional evaluation.
The described technique utilizes a bioinductive bovine collagen implant that is sutured between 2 patellar tendon remnants, with the hope of increasing the healing potential of a chronically injured tendon that progressed to a complete rupture (Table 2). There has only been one other patellar tendon repair technique described utilizing the Regeneten patch; however, the authors performed a concomitant suture tape augmentation (“internal brace”) technique with the patch resting directly on top of the repaired patellar tendon.^8^Table 2Advantages and DisadvantagesAdvantagesDisadvantagesPotential for improved biology and healing potential of repaired tendon, particularly in the setting of tendinosisIncreased cost associated with bioinductive implantDoes not require staple fixation as in the setting of arthroscopic tendon repair applicationsIncreased surgical time associated with additional step of securing augment
Historically, patellar tendinopathy and partial patellar tendon tears have been treated conservatively. However, evidence shows that those who are more active and participate in competitive sports may not tolerate conservative management the same way the general population does, as their activity demand is significantly higher.^3^^,^^9^ Unfortunately, prolonged periods of conservative management may result in further tendinous degradation, resulting in poor patellar tendon tissue quality.3, 4, 5, 6, 7 Therefore, additional augmentation, either with orthobiologics or synthetics, or a combination of the two for patellar tendon repair, has been proposed and implemented with promising results. Additionally, these technologies may afford less reliance on autograft or allograft augmentation in the setting of acute repairs with concerning native tissue quality. While some studies have advocated for the use of hamstring autograft augmentation, such morbidity would be suboptimal in a highly competitive athlete.^10^^,^^11^
Bioinductive collagen implant augmentation using the Regeneten patch has shown positive results in the setting of rotator cuff repair augmentation.^12^^,^^13^ However, there is a paucity of literature describing such efficacy in the setting of patellar tendon repairs for a complete rupture, particularly in young and active patients who had chronic patellar tendinosis before their rupture.
The authors declare the following financial interests/personal relationships which may be considered as potential competing A.D.C. has received speaking and lecture fees from Arthrex, Smith & Nephew, Medwest Associates, Micromed, and Saxum Surgical; has received finding grants from Arthrex and Medical Device Business Services; and has received travel reimbursement from Arthrex, Smith & Nephew, Medwest Associates, and Stryker. A.S.K. has received consultation fees from Linvatec. All other authors (A.V.D., G.R.R., L.A.R., W.A.W.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.