• Fracture of Pars interarticularis (Narrow isthmus of bone that lies between the two articulating facets - one superior and and one inferior)
  • Usually childhood fracture
  • Usually in Lumber spine
  • Common in sports that require episodes of Hyperextension, especially if combined with rotation. Eg; of common sports - Gymnastics, fast bowling (cricket), Tennis, rowing, dance, weightlifting, wrestling, pole vaulting and high jump and throwing activites
  • Usually at opposite side of activity (that is; In right handed person, fracture is common seen in Left).

Clinical Features

  • Unilateral low back pain, occasionally associated with somatic buttock pain
  • Aggravated by movements involving hyperextension of lumber spine
  • Occasionally asymptomatic


  • Pain maybe reproduced by hyperextension with rotation of Lumber spine
  • And on extension while standing on the affected leg.
  • Associated hamstrings spasm with excessive lordosis may present
  • Tender over fracture site


  • Xray - maybe normal (or) may showScotty dog appearance of a pars defect in Long stranding fracture
  • If Xray Normal, SPECT scan to detect active stress fracture or stress reaction (Increase bone uptake)
  • If SPECT positive - CT (reverse gantry) - to detect fracture line
  • Alternatively - MRI can be used (not as sensitive as combined use of SPECT and CT)

Stages (by Radiology images)

  • Early - Focal bone absorption or Hairline defect
  • Progressive - Wide defect and small fragments
  • Terminal - Sclerotic changes


  • Early and half of progressive type achieved radiological healing
  • Terminal cases - will not heal
  • L4 fracture is better chance of healing than in L5


  • Initially - Rest and avoid aggravating movment (ie; lumber extension and rotatoin)
  • There is no definitely time set period to rest. PAIN should be used as a guide
  • Rehab program aims at painfree progressive exercises
  • When there is no longer local tenderness and aggravating activity is none tender, gradually resume the aggravating activity over 4 - 6 weeks.

Other Management

  • Specific exercise program training on Transverse abdominus and Multifundus (O'Sullivan et al's)
  • Core stability exercises
  • Assessment and modification of biomechanics and technique