Muscle strength recovery and its effects on outcome after open reduction and internal fixation of acetabular fractures.
OBJECTIVE
To determine the relationship between muscle strength recovery and functional outcome in patients who were treated for an acetabular fracture via an anterior approach.


METHODS
Case series.


METHODS
University Medical Center.


METHODS
Fifteen patients with a displaced acetabular fracture treated via an anterior, ilioinguinal approach were studied. Hip muscle strength of these patients was then compared with the muscle strength of a similar group of patients treated via a Kocher-Langenbeck approach (posterior approach). These patient groups were then combined and muscle strength recovery was compared with the functional outcome.


METHODS
Primary outcome measures included hip muscle strength, including work (J/min) and maximum torque (Nm/kg) for abductors/adductors and flexors/extensors. Clinical outcome was assessed with the Musculoskeletal Function Assessment (MFA) questionnaire and the results correlated with muscle strength. Secondary outcome measures included adequacy of fracture reduction, radiographic grade, severity of heterotopic ossification, and range of motion of the affected and unaffected hips.


RESULTS
At an average follow-up of 44 months, patients treated via an anterior approach had an overall muscle strength deficit of 9%. Hip extension strength was affected to the least extent (6% deficit when compared with the unaffected hip) whereas abduction, adduction, and flexion strength was affected to a greater degree. For each measure the affected side was typically weaker than the unaffected side. The average MFA score for the anterior approach group was 17 (range, 0 to 47) with most patients reporting poorest results in those domains assessing activities of the arms and legs, and those involving life changes and feelings. When MFA scores were compared with the muscle strength, a relationship was found between hip extension/flexion work and maximum torque and hip adduction work and maximum torque and MFA score. For each of these muscle groups, patients reported worsening function with decreased muscle strength. Assessment of the most recent radiographs revealed 9 patients with an excellent radiographic grade, 3 patients with a good grade, 1 patient with a fair grade, and 2 patients with a poor grade. Hip range of motion was not statistically different when the affected hip was compared with the unaffected hip, and none of these variables correlated with outcome. Heterotopic ossification was found in 8 patients; 4 with grade 1, and 4 with grade 2.


CONCLUSIONS
Standardized muscle strength determination and completion of an MFA questionnaire provided a thorough evaluation of patients who had undergone open reduction and internal fixation of a displaced acetabular fracture. In these patients, hip muscle strength after operative treatment of a displaced acetabular fracture directly influences patient outcome. Therefore, in order to maximize the outcome of these patients, particular attention must be paid to postoperative muscle strengthening protocols and accurate and validated methods to assess strength and outcomes.
Borrelli
Joseph
J
Department of Orthopaedic Surgery, Barnes-Jewish Hospital, Washington University School of Medicine, St Louis, MO 63110, USA. borrellij@msnotes.wustl.edu
Ricci
William M
WM
Anglen
Jeffrey O
JO
Gregush
Ronald
R
Engsberg
Jack
J
D000077:Acetabulum / Q000293:injuries* / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D005593:Fracture Fixation, Internal / Q000379:methods*; D017102:Fracture Healing; D050723:Fractures, Bone / Q000601:surgery*; D006621:Hip Joint; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D017063:Outcome Assessment, Health Care; D020127:Recovery of Function; D016896:Treatment Outcome