title: Anterior knee pain and thigh muscle strength after intramedullary nailing of a tibial shaft fracture: an 8-year follow-up of 28 consecutive cases.
abstract: OBJECTIVE
  Chronic anterior knee pain is a common complication after intramedullary nailing of a tibial shaft fracture. The source of pain is often not known, although it correlates with a simultaneous decrease in thigh muscle strength. No long-term follow-up study has assessed whether weakness of the thigh muscles is associated with anterior knee pain after the procedure in question.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University Hospital of Tampere, University of Tampere.
  
  
  METHODS
  The muscular performance of 40 consecutive patients with a nailed tibial shaft fracture was tested isokinetically in a follow-up examination an average of 3.2 +/- 0.4 (SD) years after the initial surgery. An 8-year follow-up was possible in 28 of these cases.
  
  
  METHODS
  Isokinetic muscle strength measurements were made in 28 patients at an average 8.1 +/- 0.3 (SD) years after nail insertion and an average 6.6 +/- 0.3 (SD) years after nail extraction. All nails were extracted at an average 1.6 +/- 0.2 years after the nailing.
  
  
  RESULTS
  : Seven patients were painless initially and still were at final follow-up (never pain, or NP). In 13 patients, the previous symptom of anterior knee pain was no longer present at final follow-up [pain, no pain (PNP)], and the remaining 8 had anterior knee pain initially and at final follow-up [always pain group (AP)]. With reference to the hamstring muscles, the mean peak torque difference between the injured and uninjured limb was -2.2% +/- 12% in the NP group, 1.6% +/- 15% in the PNP group, and 10.3% +/- 30% in the AP group at a speed of 60 degrees/second (Kruskal-Wallis test; chi(2) = 1.0; P = 0.593). At a speed of 180 degrees/second, the corresponding differences were -2.9% +/- 23% and 7.0% +/- 19% and 4.4% +/- 16% (Kruskal-Wallis test; chi = 1.7; P = 0.429). With reference to the quadriceps muscles, the mean peak torque difference was -2.8% +/- 9% in the NP group, 5.9% +/- 15% in the PNP group, and -13.0% +/- 16% in the AP group at a speed of 60 degrees/second (Kruskal-Wallis test; chi(2) = 7.9; P = 0.019). At 180 degrees/second, the corresponding differences were -9.4% +/- 13% and 4.9% +/- 16% and -1.9% +/- 9%, respectively (Kruskal-Wallis test; chi(2) = 4.8; P = 0.092).
  
  
  CONCLUSIONS
  Based on this prospective long-term follow-up study, it appears that the anterior knee pain symptoms that are present after intramedullary nailing of a tibial shaft fracture disappear in a number of patients 3 to 8 years after surgery. Quadriceps, but not hamstring weakness, and lower functional knee scores are associated with anterior knee pain at 8 years.
authors.affiliation: Medical School, University of Tampere, Finland.
authors.forename: Olli
authors.initials: O
authors.lastname: Väistö
authors.forename: Jarmo
authors.initials: J
authors.lastname: Toivanen
authors.forename: Pekka
authors.initials: P
authors.lastname: Kannus
authors.forename: Markku
authors.initials: M
authors.lastname: Järvinen
mesh_terms: D000328:Adult; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects*; D006801:Humans; D007717:Knee; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D010146:Pain / Q000145:classification / Q000209:etiology*; D011183:Postoperative Complications; D011446:Prospective Studies; D013978:Tibial Fractures / Q000601:surgery*