Last month while in the park you injured your knee. You heard a pop followed by an immediate onset of intense pain and swelling. Walking was impossible. The swelling has continued and you have noticed bruising. Your doctor thinks you may have injured your patellar tendon. What is a Patellar tendon? Are there different types of Patellar tendon tears? What are the symptoms of a Patellar tendon tear? What are the five most common causes of Patellar tendon tears? How to diagnose a Patellar tendon tear?
Patellar Tendon Tear: Why you Should Care
Tendons are thick pieces of connective tissue that connect muscle to bone. They are important for the movement and stability of our joints. Small tears of a tendon can make it difficult to walk. Large tears can be debilitating preventing activity. Is a Patellar tendon tear responsible for your ongoing knee pain and dysfunction?
What Is a Patellar Tendon ?
The Patellar tendon is the thick connective tissue that starts at the base of the kneecap (Patella) and extends down to the shin. The is an extension of the Quadriceps tendon (1). The Quadricep is the large thick muscle that is often referred to as our thigh. The Patellar tendon works together with the Quadriceps muscle to straighten (extend) the knee. It is easy to touch your Patellar tendon as it is immediately below the knee cap.
Are there Different Types of Patellar Tendon Tears? (Strain, Partial and Complete Tear)
Yes! There are three principal types of Patellar tendon tears which are graded 1-3.
Grade 1: Stretching of the Patellar tendon fibers. Also referred to as a sprain.
Grade 2: Partial-thickness tear. A portion of the Patellar tendon is torn but the surrounding fibers are intact.
Grade 3: Complete tear. Tear has extended across all the Patellar tendon fibers and the tendon ruptures. A rupture is similar to when a rubber band breaks when overstretched. There are two loose ends that are physically separated. When the Patellar tendon is completely torn, the tendon is separated from the kneecap. Without this attachment, you cannot straighten your knee.
Symptoms of Patellar Tendon Tear
Symptoms will vary depending upon the severity of the injury (2). Many patients report a snapping or popping sensation at the time of the injury. Common symptoms include:
- Difficulty or inability to walk
- Tenderness to the touch
Five Most Common Causes of Patellar Tendon Tear
There are many different causes of Patellar tendon tears. Patellar tendon tears are a common sport injury but can also occur from overuse or a motor vehicle injury. The tendon is typically injured in the area where the blood flow is poor and the tendon is the weakest. This area is also called the watershed region. The most common causes of Patellar tendon tears are:
Impact from Running and Jumping
Continued running and jumping can place significant strain on the Patellar tendon. Increasing mileage in preparation for a competition or event can place additional stress on the tendon. Chronic tendon overload is thought to be a leading cause of Patellar tendon tears (3). Patellar tendinosis, inflammation of the tendon can easily progress to Patellar tendon tears if not treated successfully in the acute phase. Chronic Patellar tendinosis oftentimes leads to Patellar tendon tears as the tendon fibers are weakened and susceptible to injury.
The Patellar tendon may be weakened which makes it susceptible to tearing and possible rupture. Medical conditions that can weaken tendons include:
- Rheumatoid Arthritis
- Chronic Renal Failure
- Systemic Lupus
Tendons can also be weakened by steroids and certain antibiotics. Ciprofloxacin and other Fluoroquinolones have black-boxed warnings issued by the FDA for their known association with tendon ruptures (4). Sport experts have identified nine risk factors that contribute to Patellar tendon weakness (5). they include weight, increased body mass index, leg length differences, the arch height of the foot, quadriceps flexibility, and hamstring flexibility.
Soccer, Lacrosse, and other field sports are rich in forceful contacts in addition to abrupt starts and stops. These forces can lead to Patellar tendon injuries. Trauma can also occur off the playing field and include simple falls around the house or cabin or motor vehicle accidents. Some patients when rear-ended are forcefully pushed forward striking their knee on the dashboard or steering wheel leading the Patellar tendon tears.
Aging is an unfortunate process when there is a general decline in bodily function. This includes the integrity of tendons and the overall function of the knee. As we age the Patellar tendon does not fold back upon itself during extension which puts it at risk for strain and tearing (6).
Prior Knee Surgery
Prior knee surgery increases the risk of a Patellar tendon tear. Often times orthopedic knee surgeries weaken the stability of the knee joint, changing the biomechanics of the knee and placing additional stress and strain on the Patellar tendon.
How to Diagnose Patellar Tendon Tear
Clinical presentation will vary depending upon the severity of the injury. Pain, swelling, and inability to walk are the most common hallmarks. Diagnosis of a patellar tendon tear requires a review of past medical history, physical examination, and possible imaging studies.
Your doctor will discuss your past medical history, medications, and current symptoms. Questions you might be asked include:
- Have you had previous knee injuries?
- Have you had tendonitis?
- Have you had knee surgery?
Examination of the knee will include an inspection to identify swelling, redness, and bruising. You will be asked to bend and extend the knee to assess its range of motion. Special physical examination maneuvers may be performed to assess knee function and integrity.
To confirm a Patellar tendon tear imaging tests may be ordered. An x-ray is useful to identify a Patellar tendon rupture as the knee cap will slide up as it is no longer tethered by the tendon. MRI is useful to evaluate the location and size of Patellar tendon tears. At the Centeno-Schultz Clinic, ultrasound is used in our evaluation and management of patients with knee pain. Ultrasound is a powerful imaging modality that is readily available in the clinic, does not need prior authorization or scheduling, and can easily identify Patellar tendon tears.
Common Treatments for Patellar Tendon Tear
Treatment options will depend the severity of the injury, past medical history and access to care. When appropriate conservative care should alwasy be first line treatment. Treatment options include
During the acute phase, your physician may recommend you wear a knee immobilizer. This will keep the knee straight, limit additional injury, and allow the swelling to decrease. It will also allow for the healing to start.
Physical therapy is a cornerstone in the treatment of most Patellar tendon tears. Therapy will focus on increasing strength, stability, and range of motion. The most popular physical therapy involves eccentric exercise (7).
When physical therapy, immobilization, and other conservative treatments fail to provide significant benefits some patients are referred for a steroid injection. Steroids are powerful anti-inflammatory agents which can reduce swelling and pain. Unfortunately, they are toxic to most orthopedic tissue and have been demonstrated to damage cartilage, tendons, and ligaments (8). Steroids can cause tendon rupture (9). For this reason, steroids should be avoided.
Surgery is rarely indicated with the exception of the complete tear. When this occurs the tendon ruptures into two pieces. Surgery is required to unite the two ends together. If the patellar tendon has ruptured from the patella bone, surgery may require the surgeon to drill a series of small holes into the patella bone in order to create a new anchor site. Complications exist and include weakness, loss of range of motion, and Patellar tendon re-tears (10).
The Physicians at the Centeno-Schultz Clinic are experts in the management of Patellar tendon tears. Treatment options include the use of PRP or Bone Marrow Concentrate. PRP is rich is growth factors that can decrease inflammation and increase blood flow both of which can accelerate healing. Bone Marrow Concentrate contains stem cells which are the body’s powerhouses of healing. All injections are performed under ultrasound guidance. This ensures accurate placement of the PRP or Bone Marrow Concentrate into the patella tendon tear.
We also pioneered the successful use of Bone Marrow Concentrate in the treatment of ACL tears. Much of the same technology is used in the treatment of Patellar tendon tears.
Rehab and Recovery from a Patellar Tendon Tear
Rehabilitation and recovery will vary depending upon the severity of the injury, past medical history, level of activity and access to care. Physical therapy is essential and progressive over the course of treatment. Strengthening and range of motion is critical. Recovery can take between 6 weeks and 6 months. The advantage of PRP is that it can promote the acceleration of healing and recovery (11).
Tendons are thick pieces of connective tissue that connect muscle to bone.
The Patellar tendon is the thick connective tissue that starts at the base of the kneecap and extends down to the shin.
The Patellar tendon works together with the Quadricep to extend (straighten) the knee.
There are three different types of Patellar tendons tears which are graded 1-3.
Grade 1 is a stretching of the Patellar tendon whereas Grade 2 is a partial thickness tear.
Grade 3 is a complete tear.
Common symptoms include pain, swelling, bruising, difficulty walking, and tenderness to the touch.
The five most common causes of a Patellar tendon tear are:
- Repetitive Running and Jumping
- Tendon Weakness
- Prior Knee Surgery
A Patellar tendon tear is diagnosed by reviewing medical history, physical examination, and imaging.
Treatment options for Patellar tendon tear depend upon the severity of the injury. Common options include
- Physical Therapy
- Steroid Injections
- Regenerative Options which include precise injections of PRP and Bone Marrow Concentrate.
If you or a loved one has sustained an injury with a Patellar tendon tear that has not responded to conservative care please schedule a telephone candidacy discussion with a board-certified, fellowship-trained physician. At the Centeno-Schultz Clinic in Broomfield and Denver, Colorado we are experts in the evaluation and treatment of knee injuries. From the comfort of your home or office learn what treatment options for knee pain are available for you.
1.Reinking MF. CURRENT CONCEPTS IN THE TREATMENT OF PATELLAR TENDINOPATHY. Int J Sports Phys Ther. 2016;11(6):854-866. [Google Scholar]
2.Rosso F, Bonasia DE, Cottino U, Dettoni F, Bruzzone M, Rossi R. Patellar tendon: From tendinopathy to rupture. Asia Pac J Sports Med Arthrosc Rehabil Technol. 2015;2(4):99-107. Published 2015 Aug 7. doi:10.1016/j.asmart.2015.07.001
3.Lavagnino M, Arnoczky SP, Elvin N, Dodds J. Patellar tendon strain is increased at the site of the jumper’s knee lesion during knee flexion and tendon loading: results and cadaveric testing of a computational model. Am J Sports Med. 2008 Nov;36(11):2110-8. doi: 10.1177/0363546508322496. Epub 2008 Sep 3. PMID: 18768702.
4.Tanne JH. FDA adds “black box” warning label to fluoroquinolone antibiotics. BMJ. 2008;337(7662):a816. Published 2008 Jul 15. doi:10.1136/bmj.a816
5.van der Worp H, van Ark M, Roerink S, Pepping GJ, van den Akker-Scheek I, Zwerver J. Risk factors for patellar tendinopathy: a systematic review of the literature. Br J Sports Med. 2011 Apr;45(5):446-52. doi: 10.1136/bjsm.2011.084079. Epub 2011 Mar 2. PMID: 21367808.
6.Slane LC, Dandois F, Bogaerts S, Vandenneucker H, Scheys L. Patellar tendon buckling is altered with age. Med Eng Phys. 2018;59:15-20. doi:10.1016/j.medengphy.2018.04.024
7. Visnes H, Bahr R. The evolution of eccentric training as treatment for patellar tendinopathy (jumper’s knee): a critical review of exercise programmes. Br J Sports Med. 2007 Apr;41(4):217-23. doi: 10.1136/bjsm.2006.032417. Epub 2007 Jan 29. PMID: 17261559; PMCID: PMC2658948.
8. Wernecke C, Braun HJ, Dragoo JL. The Effect of Intra-articular Corticosteroids on Articular Cartilage: A Systematic Review. Orthop J Sports Med. 2015;3(5):2325967115581163. Published 2015 Apr 27. doi:10.1177/2325967115581163.
9. Paavola M, Kannus P, Järvinen TA, Järvinen TL, Józsa L, Järvinen M. Treatment of tendon disorders. Is there a role for corticosteroid injection? Foot Ankle Clin. 2002 Sep;7(3):501-13. doi: 10.1016/s1083-7515(02)00056-6. PMID: 12512406.
10. Volk WR, Yagnik GP, Uribe JW. Complications in brief: Quadriceps and patellar tendon tears. Clin Orthop Relat Res. 2014;472(3):1050-1057. doi:10.1007/s11999-013-3396-6.
11.Dragoo JL, Wasterlain AS, Braun HJ, Nead KT. Platelet-rich plasma as a treatment for patellar tendinopathy: a double-blind, randomized controlled trial. Am J Sports Med. 2014 Mar;42(3):610-8. doi: 10.1177/0363546513518416. Epub 2014 Jan 30. Erratum in: Am J Sports Med. 2016 Jul;44(7):NP38. PMID: 24481828.