extensor mechanism

·      includes

·      quadriceps muscle

·      quadriceps tendon

·      medial and lateral retinaculum

·      patellar tendon

·      tibial tubercle

Injuries

aetiology

·      active extension prevented by obstacle

location

·      depends on age

·      10-15 - avulsion of tibial tuberosity

·      20-40 - rupture of patellar tendon

·      40-60 - fracture of patella

·      60-80 - rupture of quadriceps tendon

above patella
Epidemiology

·      usually occurs in elderly patient or patient on prolonged corticosteroids

·      due to decreased vasculature and collagen weakness

·      occasionally occurs in young athlete

·      due to excessive contracture

Location

·      occurs as

·      rupture of belly of rectus femoris

·      avulsion of quadriceps tendon from superior patella

·      rupture at musclulotendinous junction (athlete)

Clinical

·      presents with

·      palpable gap in tendon

·      haemarthrosis

·      extensor lag or deficit

·      often difficult to diagnose once acute features settle

·      function usually good if tear incomplete

Treatment

·      incomplete

·      immobilise for 4 weeks in extension

·      then rehabilitate

·      complete

·      surgical repair

·      athlete

·      surgical repair

Technique

·      midline incision

·      Bunnell type repair

·      can reinforce with

·      piece of proximal quadriceps aponeurosis

·      wire around patella

·      postoperative

·      brace for 4 weeks

·      crutches for 8 weeks

·      start static quadriceps exercises at 10 days

·      start flexion at 3 weeks

·      start active extension at 6 weeks

below patella
Epidemiology

·      less common

·      usually occurs in young people

·      often previous history of tendonitis +/- steroid injections

Location

·      most common at level of inferior pole of patella

·      less common at tibial tubercle

·      midsubstance ruptures rare

Clinical

·      severe pain

·      palpable defect

·      extensor deficit

·      patella alta

Treatment

·      requires operative repair

·      midsubstance tears sutured directly

·      avulsions reattached through drillholes

·      may be reinforced with wire loop

·      immobilised for 6 weeks

·      then gradual ROM

Aophysitis

Osgood-schlatter’s disease
Definition

·      condition of apophysis into which part of patellar tendon inserts

Epidemiology

·      occurs in teenagers

·      males more common

·      corresponds with growth spurt

·      age 12-14 in boys

·      age 11-13 in girls

·      may be bilateral

·      20-30%

Aetiology

·      traction injury

·      due to recurrent microtrauma

·      usually no history of injury

Clinical features

Symptoms

·      pain after activity

·      esp. kicking and jumping

·      tender lump

·      pain on direct blow

·      difficulty kneeling

Signs

·      tender lump over tibial tuberosity

·      pain on active extension

Radiology

·      important to exclude other causes

·      shows enlarged fragmented tibial tuberosity

·      CT scan may define ossicle in patellar tendon

Treatment

·      usually resolves spontaneously

·      restriction of provocating activities

·      removal of ossicle if unresponsive

sinding-Johansson-larsen’s disease

·      similar condition

·      traction injury of lower pole of patella where patellar tendon inserts

·      common in high jumpers

·      differential diagnosis

·      patellar tendinitis

·      patellar stress fracture

·      bipartite patella

·      usually recovers with rest

Other

patellar tendinitis
Epidemiology

·      most common in athletes

·      esp. if involved in running, jumping and kicking

Clinical features

·      insidious onset of pain at inferior pole of patella

·      pain may

·      occur after activity only

·      be present also during activity

·      interfere with participation

·      localised tenderness at inferior pole

·      no effusion or joint abnormality

·      may progress to rupture

Radiology

·      usually normal

·      may show

·      traction spurs

·      calcification of patellar tendon

Treatment

Nonoperative

·      activity modification

·      warmup and stretching

·      ice and NSAIDs

·      HCLA should be avoided as weakens tendon

Operative

·      if fails to resolve and interferes with activity

·      involves resection of degenerative part of tendon

bipartite patella

·      patella may develop from one or multiple ossification centres

·      failure of centres to fuse may produce bipartite or tripartite patella

·      usually bilateral and painless

·      accessory fragments are usually

·      superolateral (75%)

·      lateral (20%)

·      inferior (5%)

·      pain may result from repetitive microtrauma with injury to synchondrosis

·      treated with immobilisation for 4 weeks

·      excision or internal fixation may be indicated for lesions that fail to settle