Arthroscopic Patellar Tendon Debridement and Distal Pole Osteoplasty for Recalcitrant Patellar Tendinopathy

Abstract

Background:

Chronic patellar tendinosis is an overuse injury of the patellar tendon that commonly afflicts jumping athletes.

Indications:

For patients with refractory symptoms that do not respond to extensive physical therapy and rest, surgical management may be considered. Although both open and arthroscopic treatments have been described, arthroscopic treatment allows for more direct access to the diseased dorsal portion of the tendon and allows for faster return to activities and sport.

Technique Description:

Arthroscopic treatment involves debridement of the diseased portion of the patella tendon and osteoplasty of the distal pole of the patella. The infrapatellar fat pad is first debrided using an arthroscopic shaver and radiofrequency ablation device to the level of the dorsal surface of the patellar tendon. Under direct arthroscopic visualization and corresponding to the location of edema noted on the magnetic resonance image, the diseased portion of the patellar tendon is gently debrided with an arthroscopic shaver. Next, an osteoplasty of the distal pole of the patella is performed to facilitate bleeding and healing of the diseased tendon as well as eliminate any mechanical impingement. Any calcifications within the enthesis can be removed using an arthroscopic biter and resector. An arthroscopic resector is then used to decorticate and smoothen the distal pole of the patella to the level of healthy, bleeding cancellous bone.

Results:

Significant improvements in pain and function have been reported with arthroscopic treatment for chronic patellar tendinosis. Patients can expect a 90% return to sport rate following the procedure, with return to preinjury function as soon as 3 to 5 months. This procedure is well tolerated with minimal complications reported.

Discussion:

Arthroscopic patellar tendon debridement and distal pole osteoplasty can be used to treat chronic patellar tendinosis refractory to nonoperative treatment. Improvements in pain and function have been reported with this technique, along with a faster return to sport compared with traditional open techniques.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

In the following video, we present an arthroscopic surgical technique for the treatment of chronic patellar tendinosis. The authors’ disclosures are seen here.

Chronic patellar tendinosis is an overuse, degenerative injury of the patellar tendon resulting in anterior knee pain at the inferior pole of the patella. It is common in athletes who engage in repetitive jumping, kicking, or other maneuvers that involve high-impact loading of the knee extensors. Intrinsic risk factors for this condition include male sex, strength imbalance, postural alignment, and foot structure. A longer nonarticular patella and a higher ratio of nonarticular to articular patella surface have been postulated as risk factors for patellar tendinosis. The senior authors have also observed that patients with chronic patellar tendinosis frequently exhibit genu recurvatum. The patellar articular surface ratios are demonstrated in the following images, with “A” being the articular portion of the patella and “B” being the nonarticular portion of the patella.

Currently, nonoperative management consists of a physical therapy program focused on eccentric training, jumper’s knee straps, and activity modification with rest. For athletes with chronic patellar tendinopathy who have failed nonoperative management, treatment options are limited. Inconsistent results have been reported with shock wave therapy, platelet-rich plasma injections, and other injection treatments. Therefore, for those with chronic symptoms (>6 months), surgical intervention may be considered. Historically, open surgical techniques have consisted of a longitudinal split in the patellar tendon and resection of the diseased portion of the tendon. However, an arthroscopic technique may allow for more direct access and debridement of the diseased tendon, which is most often on the dorsal, intra-articular side. Open and arthroscopic treatments cover the same range of possible pathologies encountered with chronic patellar tendinopathy, and there are no indications to convert from arthroscopic to open.

In addition, while studies have shown that both open and arthroscopic treatment can result in significant improvements in pain and activity levels, arthroscopic treatment has been reported to result in a faster return to sport. With the return to sport benefits and sparing the risks associated with arthrotomy, our senior authors typically elect to treat this condition arthroscopically.

Here we present a case of a 25-year-old man with chronic patellar tendinosis who did not respond to extensive physical therapy, activity modification, and rest. He was unable to participate in running or mixed martial arts fighting due to his symptoms. Physical examination and advanced imaging were consistent with chronic patellar tendinosis. A small calcification of the enthesis was noted on radiographs and magnetic resonance images (MRIs). He was therefore indicated for arthroscopic patellar tendon debridement and osteoplasty of the distal pole of the patella.

Our surgical technique is presented here. The patient is positioned supine with a lateral knee post. A nonsterile tourniquet may be applied and inflated if necessary. The knee and lower extremity are then prepped and draped in the usual sterile fashion.

Standard anterolateral and anteromedial portals are created. These portals should not be placed too close to the patellar tendon, which would make it more difficult to access the dorsal surface of the patellar tendon with arthroscopic instruments. To avoid violating the integrity of the patellar tendon, portals should be created 1 cm from the patellar tendon or in the “soft spot” of the joint line. All pathologies encountered with chronic patellar tendinopathy can be addressed via these portals. A diagnostic arthroscopy is then performed.

Attention is first turned to the patellar tendon debridement. The knee is flexed approximately 90° over the table on a padded bump. Through the anterolateral portal, the arthroscope is directed anteriorly to visualize the infrapatellar fat pad covering the enthesis. The fat pad is debrided using an arthroscopic shaver and radiofrequency ablation device to the level of the dorsal surface of the patellar tendon. The dorsal patellar tendon fibers, which run longitudinally from the distal pole of the patella to the tibial tubercle, can be easily visualized. The camera is then inserted into the anteromedial portal, and the lateral portion of the fat pad can be similarly debrided to expose the entire dorsal surface of the patellar tendon.

A spinal needle can be inserted percutaneously in the center of the patella tendon to gain proper arthroscopic perspective of the entire width of the patellar tendon. Macroscopically, the diseased area of the tendon appears yellow-brown and more disorganized compared with healthy fibers.

Under direct arthroscopic visualization and corresponding to the location of edema noted on the MRI, the diseased portion of the patellar tendon is gently debrided with an arthroscopic shaver.

The amount of tendon that can be safely debrided is case-dependent, and no literature has provided definitive cutoffs or guidelines for this portion of the procedure. A careful understanding of how diseased and healthy patellar tendon appears under arthroscopy aids with resection. Dissection must be performed carefully as overresection can place the patellar tendon at risk of rupture.

Next, an osteoplasty of the distal pole of the patella is performed to facilitate bleeding and healing of the diseased tendon, as well as elimination of any mechanical impingement. A radiofrequency ablator is used to expose the inferior pole and prepare the area of planned bony resection. With care taken to avoid violation of the inferior articular cartilage of the patella, a 5.5-mm arthroscopic resector is then used to decorticate and smoothen the distal pole of the patella to the level of healthy, bleeding cancellous bone. Any calcifications within the enthesis can be removed in a controlled fashion using an arthroscopic biter and resector.

The area is then probed to ensure that all bony prominences have been resected.

Postoperatively, the knee is placed in a hinged knee brace. The patient is allowed to weight bear as tolerated in the brace locked in extension. The brace is discontinued as soon as sufficient quad strength returns. This can be determined by gait analysis performed by the physical therapy team. In phase I (0-6 weeks), the patient is returned to activities of daily living, including normal gait and stairs. In phase II (6-12 weeks), closed chain strengthening can progress, and proprioception and hamstring work can commence. In phase III (12+ weeks), strengthening exercises are advanced, and running, plyometrics, and sport-specific drills are initiated when it is deemed safe by the physical therapist and surgeon. Return to sport is allowed when there is evidence of good dynamic muscular control of the lower extremity with multiplane activities at full exertion.

Patients can expect a 90% return to sport rate following the procedure, with return to preinjury function as soon as 3 to 5 months.

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