Patellar Tendinitis-Jumper’s Knee

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Current Concepts in Patellar Tendinopathy

 

• Also known as JUMPER’S KNEE

ETIOLOGY-Multifactorial

• chronic, repeated stress to the posterior fibers of the tendon, particularly near the inferior pole of the patella.
• increased stress-drives fibroblasts -stimulate prostaglandin E2 and leukotriene B4- lead to tendinopathy

INTRINSIC FACTORS

• laxity, weight, strength and flexibility of the quadriceps and hamstrings,
• Abnormal arch height of the foot.
• leg length difference,
• waist-to-hip ratio,
• vertical jump performance

EXTRINSIC FACTORS

• Excessive training volume and frequency,
• environmental conditions such as irregularities on the ground,
• inappropriate footwear choices

Histology

• Absence of inflammatory cells. !

Instead,

• neovascular proliferative changes
• hypercellularity with atypical fibroblasts resulting in abnormal collagen distribution

Symptoms

• pain at the proximal insertion of the patellar tendon during athletic activities
• less frequently at the tibial insertion.
• Pain is typicall triggered by running, jumping, crouching,

duration of symptoms

• acute (less than 6 weeks),
• subacute (6 to 12 weeks),
• chronic (more than 3 months).

Diagnosis and evaluation

• accurately pinpoint the location of pain

Basset sign

• “passive extension—flexion sign”
• patient is lying down
• palpating the anterior aspect of the fully extended knee
• identifying the tender point (typically at the inferior pole of the patella and proximal part of the patellar tendon)
• A positive test is indicated by reduced tenderness on palpation as the knee is flexed to 90°

Standing Active Quadriceps Sign

• the patient is standing on both extremities
• palpating the entire patellar tendon
• repeat the test with the patient standing only on the affected extremity with 30° of knee flexion.
• If pain significantly lessens in the latter position, the test is considered positive.

INVESTIGATIONS

• Radiographs- overall view of the joint , rule out significant bony involvement or concomitant disorders

Ultrasound

• provides detailed visualization of the tendon
• focal tendon thickening,hypoechogenicity,increased extracellular fluid

MRI

• intrasubstance edema in the tendon
• In chronic cases-reveal cortical irregularities affecting the inferior patellar pole

Blazina Classification

• I  -Pain after sports activity
• II -Pain at the beginning of activity, disappearing after warming up, and reappearing at the end of the activity
• III -Pain during and after activity with the patient being unable to participate in sports
• IV -Complete tendon rupture

TREATMENT- Conservative Management

• Eccentric and isometric exercises (45 min )
• patellar strapping (2 hours)
• sports taping (2 hours)
• platelet-rich plasma (PRP) injections- optimal infiltration site –
• autologous whole-blood injections
• dry needling
• Steroid injections-not advised; potential risk of tendon rupture
• Emerging therapeutic alternatives–Ultrasound-guided percutaneous needle tenotomy (PNT) with a well-structured rehabilitation program

 

SURGICAL OPTIONS

 

Open Surgery

involves:

• making a 5-cm longitudinal incision on the midline of the patellar tendon,
• carefully dissecting the paratenon,
• Performing a posterior central tenotomy to expose the deepest layers of the tendon
• complete the debridement,
• drilling multiple holes in the inferior pole of the patella
• Direct suture of the tendon.

 

Arthroscopic Surgery

 

• introduced by Johnson,
• excision of 25% to 30% -nonarticular portion of the inferior patellar pole – a 5-mm spherical arthroscopic burr.

 

• both open and arthroscopic surgical approaches- favorable success rates .
• arthroscopic treatment may lead to faster Return to sports..

the use of ultrasound guidance with Doppler during arthroscopic surgery -valuable resource

 

RECENT DEVOLOPMENT-collagen-based bioinductive patch and a PRP membrane in addition to an intratendinous leukocyte-rich PRP injection.