SPONTANEOUS SIMULTANEOUS BILATERAL PATELLAR TENDON RUPTURE

James Foley, Rawan Elhelali, Dineo Moiloa

Summary

Bilateral patellar tendon rupture is an extremely rare occurrence, especially in otherwise healthy individuals without systemic disease. the authors report the case of a man who presented with simultaneous, spontaneous bilateral rupture of his patellar tendons.
He had a history of unilateral patellar tendinopathy but no other predisposing risk factors such as steroid or fluoroquinolone use. He underwent surgical repair and following intensive rehabilitation, he returned to baseline physical activity 6 months post injury.

Background

Bilateral patellar tendon rupture is extremely rare, with approximately 50 cases reported in English literature. It is usually associated with systemic diseases or medication side effects, and in the absence of these predisposing factors and also the rarity of the injury, clinical suspicion is usually low for this injury. It is reported that up to 38% of patellar tendon ruptures are misdiagnosed initially, so a focused history and clinical examination is important to facilitate early repair.1

Case presentation

We present the case of a 47-year-old man who had no medical history, no known drug allergies and was not on any regular medications. Of note, he had a history of patellar tendinopathy to his left knee, but prior to this presentation, he declared that he was not suffering from any left knee symptoms. He was playing football on an artificial pitch and on making a challenge to an opposing player, lost his footing and landed onto the ground with both his knees in a forced hyperflexion position. He noted immediate pain over his anterior knee, followed by a tearing sensation and noted that both his patellae moved superiorly towards his mid-thigh. He was unable to stand due to pain and was brought to hospital by ambulance.
On examination, he had swelling to the superior aspect of both knees, with a loss of fullness at the anterior knee. There was a positive effusion on both bulge and patellar tap tests. He had no tenderness over the medial or lateral joint lines but difficulty was noted in assessment of his cruciate and collateral ligaments due to pain. A neurovascular examination of both lower limbs was unremarkable. Of note, he was unable to straight leg raise and could not initiate knee extension bilaterally. A presumptive diagnosis of bilateral patellar tendon rupture was made.

Investigations

Plain radiography of both knees revealed bilateral high-riding patellae and avulsion fractures as shown in figures 1 and 2. The patient was referred to the orthopaedic team and a subsequent ultrasound showed ruptures of bilateral proximal patellar tendons with associated avulsion fractures.

Treatment

Both tendons were repaired with the use of an internal brace with a Swivelock anchor and the repair augmented with continuous suture. He was subsequently placed in extension braces with controlled range of motion and weight bearing as tolerated. He began controlled initiation of range of motion at 10 days and subsequently began a rehabilitation programme consisting of heel slides, knee
extension range of motion and patellar mobilisation exercises. At 6 weeks he had full knee extension bilaterally with flexion to 100° bilaterally. He then progressed onto active range of motion without the brace, closed chain quadriceps exercises with squats and subsequently use of a stationary bike.
At his 4-month review he had full range motion of both knee joints, with grade five muscle power of his quadriceps. His discharge advice from the department of orthopaedics was to avoid post-activity swelling and avoid walking with a limp. He continued his rehabilitation with his physiotherapist gradually introducing his sporting demands with static and dynamic neuromuscular exercises and made full return to baseline activity at 6months post-surgery.

Outcome and Follow-up

Following extensive physiotherapy and rehabilitation, he recommenced his pre-injury activities at 6months post-surgery.

Discussion

The knee extensor mechanism consists of the quadriceps muscles converging into a central tendon that attaches to the patella and continues as the patellar tendon which attaches to the tibial tuberosity.2 This allows the leg to extend at the knee following contraction of the quadriceps muscle complex. Disruption of any part of this kinetic chain can create a significant deficiency in functionality.
Patellar tendon ruptures are usually associated with unhealthy patellar tendons, systemic disease such as rheumatoid arthritis, systemic lupus erythematous, chronic renal disease or medications such as fluoroquinolones or systemic steroid use.3 This patient has a history of patellar tendinopathy which could be considered as a predisposing risk factor. Tendon pathology with inflammation may lead to tendon degeneration and subsequent weakness or rupture. ‘Jumpers knee’ with patellar tendinosis has also been described previously as an independent risk factor for patellar tendon rupture.2
While these risk factors may lead to an isolated tendon rupture, it is extremely rare to suffer a bilateral tendon injury without any predisposing factors, and the rarity of this presentation may lead to a misdiagnosis of the condition.4 Clinicians should maintain a high degree of suspicion in patients with a concerning history, examination or radiographic findings. An inability to straight leg raise is a useful test and should be performed in all patients with a suspicion of patellar tendon pathology, while also considering that lack of motion may be due to pain.5 6 Prompt diagnosis is important to facilitate early surgical repair, and a delay may lead to proximal retraction of the patella, with scarring, difficult repairs and diminished functioning.6

Contributors JF: Lead author. re: Case writing. DM: supervising consultant.
Funding The authors have not declared a specific grant for this research from any
funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication obtained.
Provenance and peer review Not commissioned; externally peer reviewed.

References

1 Tarazi N, O’Loughlin P, Amin A, et al. a rare case of bilateral patellar tendon ruptures: a case report and literature review. Case Rep Orthop 2016;2016:1–3.
2 Divani K, Subramanian P, Tsitskaris K, et al. Bilateral patellar tendon rupture. JRSM Short Rep 2013;4:204253331349955.
3 Sibley T, Algren DA, Ellison S. Bilateral patellar tendon ruptures without predisposing systemic disease or steroid use: a case report and review of the literature. Am J Emerg Med 2012;30:261.e3–5.
4 Siwek CW, Rao JP. Ruptures of the extensor mechanism of the knee joint. J Bone Joint Surg Am 1981;63:932–7.
5 Brukner P, Clarsen B, Cook J, et al. Clinical Sports Medicine. 5th edn: McGraw Hill, 2017:893–937.
6 Rose PS, Frassica FJ. atraumatic bilateral patellar tendon rupture, a case report and review of the literature. J Bone Joint Surg Am 2001;83-a:1382–6