Introduction
This condition is an insertional tendonopathy that affects the tendon at or near the inferior pole of the patella.
Anatomy
Blood supply: It is a paratenon-covered tendon. Blood supply is derived from the infrapatellar fat pad, inferior medial and lateral geniculate arteries.
Pathogenesis
Mechanical: Common in sports that require jumping. Incidence has been reported to be up to 44.6% among high level volleyball players and 31.9% among high level basketball players
.Some feel it is due to micro-tears of tendon followed by chronic inflammatory response. However, others feel that it is not an inflammatory condition
.
Metabolic: Diabetes mellitus may limit blood supply and healing potential. Gout, renal failure, hypothyroidism, chondrocalcinosis.
Fluoroquinolone antibiotics inhibit tenocyte metabolism and alter the extracellular matrix and can influence healing. Ciprofloxacin also induces release of MMP-3.
Natural History
The average duration of symptoms has been reported to be just under three years in one epidemiological study
Patient History and Physical Findings
History: History of participation in sports or activities that involve a significant amount of jumping.
Physical: Tenderness over the patellar tendon (most often at the distal pole of the patella and proximal portion of the patellar tendon). Pain with resisted flexion and pain at terminal passive flexion.
Blazina Staging System:
- Stage I: Pain only after activity
- Stage II: Pain present at beginning of activy and disappears after a warm-up but may reappear with fatigue
- Stage III: Pain is constant at rest and with activity
- Stage IV: Complete rupture of the patellar tendon
Imaging and Diagnostic Studies
Plain X-rays should be obtained during initial evaluation. Potential findings include traction osteophytes, tendon calcification. MRI and ultrasound may be obtained when the patient has failed nonoperative management.
MRI:
Differential Diagnosis
Include a list with links to relevant conditions
Treatment
Nonoperative treatment: Modalities such as rest, ice, electrotherapy, massage, taping, anti-inflammatories, and cortisone injections do not have evidence-based support
A randomized controlled trial has reported that 12 weeks of eccentric strength training was equally as effective as surgical treatment at 12 months followup. ("The eccentric training group performed squats on a 25 degrees decline board as a home exercise program (with three sets of fifteen repetitions being performed twice daily) for a twelve-week intervention period.") Victorian Institute of Sport Assessment (VISA) scores improved from a baseline of 30 to 70 at 12 months followup. Of the 20 knees in the eccentric strengthening group 5 knees did not respond to treatment and underwent surgical treatment at 3 to 6 months. Of the remaining 15 knees, seven had no symptoms and eight had partial symptomatic improvement at 12 months followup
Patients without inferior patellar pole osteophytes and patients without tendon edema on MRI are more likely to respond to nonoperative therapy [1].
The quadriceps muscle places less strain on the patellar tendon at flexion angles between 45 and 120 degrees. Rehabilitation programs may want to be restricted to this flexion arc [1].
Operative treatment – Indicated for patients who have failed at least 3 months of nonoperative treatment and have patellar tendon abnormalities on MRI. Surgery typically consists of open longitudinal tenotomy and removal of degenerative tendon material. Promising results have also been reported in early studies of arthroscopic treatment
Pearls and Pitfalls
Tips and problems to avoid
Postoperative Care
Include immediate postoperative care and rehabilitation
Outcome
Stage I:
Stage II:
StageIII: The Bahr et al study, which included patients with stage III patellar tendonopathy, concluded that approximately half of patients will be able to return to sport within one year after nonsurgical or surgical treatment
Complications
Include overview of complications
References
DeLee, Jesse C., David Drez Jr., and Mark D. Miller, eds.DeLee & Drez’s orthopaedic sports medicine principles and practice. 3rd ed. Vol. 2. Philadelphia: Saunders/Elsevier, 2010.