Patellar Tendon Rupture Treatment & Management

Early diagnosis and definitive treatment provide the best results. The type of treatment depends predominantly on the extent of the tear. The most common injury involves acute complete disruption of the tendon with subsequent dysfunction of the extensor mechanism. In this setting, surgical repair is the treatment of choice. In general, repair should be performed as soon as possible after the injury to limit the degree of quadriceps atrophy and prevent any contractures that might make the procedure more difficult.

In some situations, a partial tear of the patellar tendon may occur. The patient may be able to maintain full active extension and normal patellar height. This individual can potentially be treated nonoperatively with immobilization until the tendon has healed. However, one must be certain that the tear is, in fact, partial before initiating this program. Magnetic resonance imaging (MRI) may be useful in this situation (see Workup).

The chronicity of the tear is another factor that must be considered. After approximately 6 weeks, direct repair becomes challenging, if possible at all, with native tissue; other techniques may be necessary to establish continuity of the extensor mechanism.

In a prospective study that included 17 patients (average age, 30 years; range, 22-36 years), Abdou investigated the use of hamstring tendon autograft in the treatment of chronic rupture of the patellar tendon. ^[37]  Patients underwent regular follow-up (average, 21 months; range, 12-30 months) after clinical and radiographic preoperative and postoperative evaluation. The author concluded that hamstring tendon autograft is safe and effective for patellar tendon reconstruction and that it affords good ligament reconstruction.

Regardless of the timing, repair or reconstruction is still the optimal treatment in a patient who has sustained a patellar tendon tear with subsequent patella alta and extensor mechanism dysfunction.

With disruption of the extensor mechanism of the knee, no absolute contraindications have been cited for the acute traumatic patellar tendon rupture. Perhaps in the case of an open, grossly contaminated wound, the need for a staged reconstruction following surgical debridements can be entertained. Nonetheless, the need for reestablishment of the extensor mechanism cannot be underestimated.

Nonoperative treatment has a limited role in the care of patellar tendon ruptures. For the rare patient who has a partial patellar tendon tear with maintenance of patellar height, cast or brace immobilization in full extension for 6 weeks, followed by a therapy program to regain motion and strength, may be appropriate. Progress must be slow to allow for tendon-to-bone healing. Strengthening exercises should be delayed for at least 3 months.

Choice of technical approach

Complete tears of the patellar tendon are best addressed by means of early surgical intervention. This affords the best opportunity for anatomic repair of all the injured structures within the extensor mechanism.

Several techniques have been described for the immediate repair of the acutely ruptured patellar tendon. In general, repair involves suturing the torn tendon through bone tunnels within the patella or tibial tubercle, depending on the location of the disruption. Additionally, retinacular tears are repaired anatomically.

In the unusual case of chronic patellar tendon tears, direct repair may be challenging or impossible. Surgical correction may be performed in stages, depending on the degree of patella alta and peripatellar scarring. Typically, the repair needs augmentation. Alternatively, the patellar tendon can be replaced with allograft or autograft tissue. ^{[38, 39, 40, 37]}

Substantial progress has been made in surgical technique and clinical care for acute patellar tendon ruptures, including the use of the anterior cruciate ligament (ACL) tibial guide, augmentation with Dall-Miles cables ^[29]  or nonabsorbable suture, and aggressive rehabilitation for improved range of motion (ROM) and strength. In the future, suture anchors may alleviate the need for creating tunnels through the patella and could decrease surgical morbidity by allowing the use of a smaller incision and facilitating more consistent anatomic placement of the torn site onto the patella. ^{[41, 42, 43]}

Preparation for surgery

As with any procedure, both the tissues and the patient must be ready for surgical intervention. The ultimate outcome depends not only on the anatomic repair of the extensor mechanism but also on the rehabilitative efforts of the patient. It is important to stress in the preoperative period the importance of participating in the postoperative rehabilitative protocol so that maximal range of motion and strength can be achieved.

Patellar tendon ruptures with concomitant retinacular tears (see the image below) commonly result in diffuse swelling and ecchymosis along the anterior knee. Therefore, delaying surgical intervention until the inflammation begins to diminish may be safer. This 4- to 7-day delay may decrease the risk of wound complications.

Additional issues that should be considered are the extent of pathology within the ruptured tendon, the degree of patella alta, and the possibility of concomitant injuries within the knee. Extensive tendinosis or calcification within the ruptured tendon may compromise the repair. Although no studies have focused specifically on this issue, the surgeon may choose to excise this pathologic tissue and may subsequently need to supplement the repair with additional tissue. Therefore, the patient and the surgeon must be ready to accept this alternative.

Because anatomic repair is the goal, the surgeon must identify the appropriate patellar height for the injured patient. A radiograph of the contralateral knee can serve as a template intraoperatively to assist in recreating the normal patellar position.

Concomitant injuries to the menisci, articular cartilage, or supporting ligamentous structures may be present. Depending on the location and extent of injury to these structures, additional intervention may be necessary. Therefore, the surgeon must consider this possibility in the preoperative period so that surgical incisions are well planned and the material needed for repair or reconstruction is available. ^[44]

The patient is positioned supine on the operating table after a regional or general anesthetic is administered. Because nonabsorbable material is used, a first-generation cephalosporin typically is administered. The procedure begins with an examination of both knees. ROM assessment and ligamentous examination are performed to determine whether any motion deficits or concomitant ligamentous injuries are present.

A tourniquet is placed on the involved leg, and typically, both legs are cleansed and draped free. After the limb is exsanguinated and the tourniquet started, a straight midline longitudinal incision is made that extends from the superior pole of the patella to the medial aspect of the tibial tubercle. Thick medial and lateral subcutaneous flaps are created to the extent of the retinacular tears.

The torn end of the patellar tendon is then mobilized and minimally debrided of friable tissue. Depending on the location of the tear, the tibial tubercle, inferior pole of the patella, or both are debrided of soft tissue and subsequently decorticated with a curette or bur (see the image below).

Troughs are not created. Two No. 5 nonabsorbable sutures are then inserted with a Krackow stitch into each half of the tendon (see the image below). ^[45]  Three parallel tunnels are placed through the patella or tibial tubercle.

The authors advocate the technique described by Ong and Sherman, in which an ACL tibial tunnel guide is used during this aspect of the procedure to maneuver the drill more accurately to the desired endpoint (see the image below). ^[46]  Using the tunnel guide decreases the risk of violating the articular surface, reduces the number of passes required to obtain an optimal position, minimizes injury to the quadriceps tendon, and eliminates the additional step of retrieving sutures through drill holes.

The drill is then replaced with a Beath pin (see the first image below). The inner limbs of each stitch are passed through the central tunnel, and then the outer limbs are passed through the outer tunnels (see the second image below). In certain situations, the authors have used suture anchors in both the patella and the tibial tubercle with good results, but at this time, they still favor the use of tunnels.

A drill hole is then created transversely through the tibial tubercle, and an additional No. 5 nonabsorbable suture is passed through this hole. This suture is then passed superiorly within the quadriceps tendon along the superior pole of the patella (see the image below). This is accomplished by passing a 16-gauge spinal needle along the superior pole and then threading the suture through.

Both knees are then positioned in 30° of flexion. The patellar height is measured from the tibial tubercle to the inferior pole of the patella on the noninvolved leg and recreated in the involved leg by increasing tension in the cerclage suture.

Once the correct position is obtained, the repair sutures are tied and the knee reexamined to assess the degree of knee flexion that can be obtained without causing excessive tension on the repair. Alternatively, an intraoperative radiograph can be obtained on the involved knee, before the repair sutures are tied, and compared with the radiograph of the contralateral knee obtained in the preoperative period.

The repair site is then oversewn with 0 absorbable suture to bring the loose ends remaining on the avulsed side over the repair. The retinacular tears are closed with the same suture material but with the knee held in 30º of flexion to limit the possibility of capturing the knee and thus limiting motion (see the image below).

The wound is then closed in standard fashion, with an effort made to minimize the amount of grasping of the skin edges. Ideally, this should further diminish the risk of wound breakdown in this inflamed tissue. A standard dressing is applied, followed by a self-contained cooling device and hinged knee brace locked in extension.

Situations exist in which acute repair with sutures alone is not adequate. This may be the case when the patient has a midsubstance tear, has a chronic rupture, or has undergone a previous resection of chronic patellar tendinitis or a recent ACL reconstruction with the use of patellar tendon autograft.

In these situations, augmentation or reconstruction may be necessary. Described techniques involve the use of both autograft (eg, hamstrings, ^{[38, 39, 40, 47, 48, 49, 50, 28, 51, 52, 53]}  Regardless of the material used, these techniques generally involve weaving the supplemental tissue through the native patellar tendon or through bone tunnels within the patella, tibial tubercle, or both.

In the individual with a chronic tear, other factors are involved. Because the patella has been retracted for an extended period, significant scarring may develop, which limits the surgeon's ability to recreate normal patellar height and the ability to regain full knee motion. Adequate mobility can usually be obtained after thorough debridement of the medial and lateral gutters and subperiosteal elevation of the vastus intermedius from the anterior femur.

If this is inadequate, a two-stage reconstruction with preoperative traction with the use of a transverse Steinmann pin placed in the patella can be performed. When the remaining tendon is scarred and attenuated, a Z-lengthening of the quadriceps and Z-shortening of the patellar tendon can be performed. This allows sliding of the patella back to the anatomic position. A reconstructive technique as mentioned above then should follow. ^{[47, 48, 49, 54]}

Allograft reconstructive techniques have also been described for care of the chronic patellar tendon rupture. ^{[50, 55]}  The procedure involves placement of the bone-block end of the graft into a trough created in the tibial tubercle. The tendinous end is then split and passed through one or more tunnels within the patella and/or encircling the patella medially and laterally.

The ultimate goal of the surgical repair is the return of normal knee mechanics and strength. To achieve this goal, it is important for the repair to be stable enough to allow early, controlled ROM as described by Marder and Timmerman. ^[5] Provided that a stable repair has been achieved, a standard postoperative protocol may then be followed (see Table 1 below).

Table 1. Standard Postoperative Protocol (Open Table in a new window)

For tenuous repairs, whether for acute or chronic tears, a more conservative program is used and tailored to the situation. Generally, strict immobilization is recommended for 6 weeks, followed by ROM exercises. Strengthening exercises are then started approximately 3 months after the repair, followed shortly thereafter by neuromuscular retraining. Return of quadriceps bulk and strength usually is delayed, and return to premorbid athletic activities may take approximately 9-12 months.

Not infrequently, decreased quadriceps strength and loss of full knee flexion can complicate the overall success of a repair. Prolonged immobilization leads to stiffness. Manipulation under anesthesia or arthroscopic lysis of adhesions may be necessary to improve motion.

Occasionally, the decreased ROM can be attributed to patella infera (sometimes referred to as patella baja). In this condition, the patella lies more distal than normal, which can result when the tendon is relatively shortened by the repair. Patella infera can be a very challenging problem if severe and locked down. If only mild stiffness is noted, manual superior, inferior, medical, and lateral guides performed passively can be helpful. If ROM is severely restricted, the patient should follow up with the surgeon.

Rerupture, failure of fixation, or both also can occur, especially in patients who return to athletic endeavors before the tendon is completely healed. The repeat injury may require a revision of the repair. ^{[56, 57]} Inadequate placement of the suture repair or failure to recreate the appropriate patellar height can cause patellofemoral pain.

Wound breakdown and infections can occur, as with any other surgical intervention. These complications may be slightly more common in this region because of limited soft tissue along the anterior knee and operating through inflamed tissue. To diminish these potential wound complications, perioperative antibiotics and closed-suction drains can be used, the initial incision can be made through uncompromised skin, and grasping of the skin edges can be kept to a minimum.

After an adequate repair allowing for an aggressive postoperative rehabilitative program, the follow-up care goals, with intervals dated as time after surgery, are as follows:

• 3-5 days - Adequate pain control, decrease in swelling and wound check
• 2 weeks - Active flexion to 45º, full passive extension
• 4 weeks - Active flexion to 90º, maintenance of full passive extension
• 6-8 weeks - Full active flexion
• 3 months - Straight leg raise with no extension lag
• 6 months - Symmetric quadriceps size and strength