History
In most instances, the history, the physical examination, and standard radiographs suffice for making a diagnosis of acute patellar tendon rupture.
Disruption of the patellar tendon is associated with immediate disabling pain. Acute rupture frequently results in an immediate "pop" or tearing sensation. The patient usually notes immediate swelling and difficulty with rising and weightbearing after the injury.
Physical Examination
On physical examination, diffuse swelling in the anterior knee with ecchymosis, hemarthrosis, and patella alta is observed. Tenderness exists along the anterior knee and retinacula, and a defect at the level of the rupture is usually palpable (see the image below), though significant swelling can make this difficult to appreciate initially. The patella may also feel proximally displaced as compared with the contralateral side.
Patellar tendon rupture. This image depicts the defect within the patellar tendon at the inferior pole of the patella.
The patient is usually unable to bear weight, especially in a single-leg stance, and has a tense hemarthrosis. With a tendon rupture extending through the medial and lateral retinacula, active extension is completely lost, and the patient is unable to maintain the passively extended knee against gravity. If the rupture involves only the tendon and the retinacular fibers remain intact, some extension is possible, though an extensor lag is noted.
Occasionally, a deceleration injury can cause a disruption of the extensor mechanism. In this setting, it is also important to assess both the integrity of the meniscal cartilage with palpation of the joint line and the anterior cruciate ligament (ACL) with a Lachman test. [32]
If the diagnosis of tendon rupture is delayed, scar tissue may obliterate what previously had been a palpable defect. In this scenario, some degree of active extension may be possible, but with weakness and some degree of extensor lag. Quadriceps atrophy may also be noted, with considerable weakness, especially with weightbearing, stair climbing, and rising from a seated position. The weakness can exist to such a degree that the patient performs a forward thrusting motion of the limb in the swing phase of gait and complains of stance instability.
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Patellar tendon rupture. This image depicts the defect within the patellar tendon at the inferior pole of the patella.
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Patellar tendon rupture. A lateral radiograph of the right knee from a patient with an acute patellar tendon rupture. Note the superior patellar migration as well as the calcification below the inferior pole of the patella. This represents preexisting calcification within the patellar tendon, which likely contributed to the rupture.
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Patellar tendon rupture. This intraoperative picture depicts a rupture of the patellar tendon from the inferior pole of the patella with associated medial and lateral retinacular tears.
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Patellar tendon rupture. Two Krackow stitches with number 5 nonabsorbable sutures are sewn through the patellar tendon.
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Patellar tendon rupture. The inferior pole of the patella is debrided of soft tissue, then decorticated.
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Patellar tendon rupture. An anterior cruciate ligament tibial tunnel guide is positioned along the anterior half of inferior pole and angled such that the drill exits along the superior pole of the patella. A total of 3 parallel tunnels are created. Note the contralateral knee within the operative field, which later serves as the guide in recreating normal patellar height.
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Patellar tendon rupture. The Beath pin replaces the drill bit. The suture is then placed through the eyelet.
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Patellar tendon rupture. All of the suture ends are now along the superior pole of the patella. The inner limbs of the stitches are within the central tunnel while the outer limbs are within the corresponding outer tunnels.
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Patellar tendon rupture. A cerclage stitch was passed along the superior pole of the patella and through a tunnel within the tibial tubercle. This is now being tensioned to maintain normal patellar height so that the repair sutures can now be tied.
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Patellar tendon rupture. The repair is now complete with recreation of normal patellar height. The retinacular tears were repaired with absorbable suture with the knee positioned in 30° of flexion.
Tables
Time After Surgery |
Weightbearing |
Immobilization |
Therapy |
0-3 d |
None, with use of crutches |
Hinged knee brace locked in extension |
1. Motion - None 2. Modalities and/or exercises - None |
4-13 d |
Toe touch with crutches |
Hinged knee brace locked in extension |
1. Motion - Active flexion to 45° and passive extension to 0° (no active extension) 3 times a day 2. Modalities and/or exercises - Swelling control with ice, gentle medial and lateral patellar mobilization, gentle isometric hamstring exercises, contralateral isometric quadriceps exercises 3 times a day |
2-4 wk |
Partial (25-50%) with crutches |
Hinged knee brace locked in extension |
1. Motion - Active flexion to progress to 90° and passive extension to 0° (no active extension) 3 times a day 2. Modalities and/or exercises - Swelling control with ice, gentle medial and lateral patellar mobilization, gentle (~25%) isometric quadriceps exercises (sets, no straight leg raises), continue with ipsilateral hamstring exercises and contralateral quadriceps exercises 3 times a day |
4-6 wk |
Progress to weightbearing as tolerated, crutches discontinued when good quadriceps control is obtained |
Hinged knee brace locked in extension |
1. Motion - Active flexion to progress as tolerated and passive extension to 0° (no active extension) 3 times a day 2. Modalities and/or exercises - Swelling control with ice, gentle medial and lateral patellar mobilization, gentle (~25%) isometric quadriceps exercises (sets, no straight leg raises), continue with ipsilateral hamstring exercises and contralateral quadriceps exercises 3 times a day |
6-12 wk |
Weightbearing as tolerated |
Hinged knee brace locked in extension until good active quadriceps control and normal gait are obtained |
1. Motion - Progress to full 3 times a day 2. Modalities and/or exercises - Swelling control with ice, more aggressive medial and lateral patellar mobilization, begin straight leg raises without resistance, continue with ipsilateral hamstring exercises and contralateral quadriceps exercises 3 times a day; start stationary cycling at 8 weeks |
12-16 wk |
Complete weightbearing |
No immobilization |
Progress with quadriceps strengthening (isokinetic) exercises and start neuromuscular retraining |
16-24 wk |
Complete weightbearing |
No immobilization |
May start running and sport-specific training |
>6 mo |
Complete weightbearing |
No immobilization |
May return to jumping and contact sports when obtain 85-90% of strength of contralateral extremity on isokinetic strength testing |
