Repair of Acute and Chronic Patella Tendon Tears

Thomas M. DeBerardino

Laura E. Scordino

ANATOMY

The patella tendon is approximately 30 mm wide × 50 mm long, with a thickness of 5 to 7 mm.¹
The origin on the inferior pole of the patella is juxtaposed to the articular cartilage on the deep side and becomes confluent with the periosteum of the patella anteriorly.²
The tibial insertion is narrower and invests the entirety of the tibial tubercle.
The overlying peritenon is thought to be the cellular source for healing of tendon injuries.

PATHOGENESIS

Tendon rupture usually is the result of underlying tendinosis.⁶
There is some evidence of genetic predisposition to tendon rupture.
Certain conditions predispose individuals to tendon rupture, including renal dialysis, chronic corticosteroid use, fluoroquinolone antibiotics, and corticosteroid use.

NATURAL HISTORY

The natural history of an untreated patella tendon is complete extensor mechanism dysfunction.
Untreated acute ruptures result in chronic lesions that are more difficult to manage surgically. These often require reconstructive procedures and have inferior functional results.

PATIENT HISTORY AND PHYSICAL FINDINGS

Patients with acute tendon tears may report an audible “pop” or the sensation of their knee giving way.
Patients with chronic injuries may report ambulatory difficulty and pain. These injuries often are treated with bracing before definitive evaluation.
The loss of active knee extension is the key physical examination finding when evaluating for patella tendon rupture.
Loss of tension in the patella tendon with the knee at 90 degrees of flexion and patella alta are indirect signs of rupture.

IMAGING AND OTHER DIAGNOSTIC STUDIES

Plain radiographs may reveal patella alta, avulsion fractures, Osgood-Schlatter lesions, or other concomitant knee injuries.
Magnetic resonance imaging scans may be helpful in determining the exact location of the rupture and evaluating concomitant intra-articular knee lesions.

DIFFERENTIAL DIAGNOSIS

NONOPERATIVE MANAGEMENT

Nonoperative management should be considered only for patients who are not surgical candidates because of medical comorbidities.

SURGICAL MANAGEMENT

Although not considered to be a surgical emergency, prompt surgical management of acute patella tendon ruptures is recommended to avoid the difficulties of repairing a chronic rupture.

Preoperative Planning

Repairs of chronic injuries often require allograft tissue availability and careful surgical planning.
Significant patella alta may require proximal release in conjunction with the repair.

Positioning

Supine positioning is recommended.
Use of a tourniquet may preclude proper repair tensioning in chronic injuries. If one is used, it should only be elevated after flexing the knee.
Prepping and draping of both lower extremities allows use of contralateral limb as a template for patella positioning.

Approach

An anterior approach is used, regardless of the repair technique.
A midline longitudinal incision is made over the patella tendon.
The peritenon is incised longitudinally and sharply dissected away from the underlying tendon.

TECHNIQUES

▪ Acute Repair

Midsubstance

Grossly pathologic tendon tissue is aggressively débrided.
The full length of the patella tendon is exposed.
Two Krackow locking stitches are placed in each tendon stump with no. 2 or no. 5 FiberWire (Arthrex, Inc., Naples, FL; TECH FIG 1A).
Any required retinacular repair stitches are placed with absorbable suture before the tendon repair.
The four proximal core sutures are tied to the four distal core sutures with the knee in full extension.
Integrity of the repair is evaluated by checking the maximal flexion possible prior to gap formation.
The peritenon is closed with absorbable suture.