Preservation of the rectus femoris origin during periacetabular osteotomy does not compromise acetabular reorientation

Abstract

Background: The early recovery period after periacetabular osteotomy (PAO) can be limited by pain and activity restrictions. Modifications of the Bernese PAO, including sparing the rectus tendon and discontinuing routine arthrotomy, may accelerate early postoperative recovery compared with the standard approach.

Questions/purposes: Does a modified approach for PAO (1) lead to improved pain control immediately after surgery; (2) lead to improved ambulation during the hospital stay; (3) lead to shorter stays, less blood loss, and shorter surgical times; and (4) compromise acetabular correction?

Methods: We retrospectively reviewed all 75 patients who underwent PAO for developmental dysplasia of the hip between August 2009 and May 2013. The control group included 44 consecutive patients who underwent a standard Bernese PAO with rectus takedown (RT). The study group consisted of 31 consecutive patients who underwent PAO using a modified rectus-sparing (RS) approach without routine arthrotomy. The groups were similar in age, body mass index, and American Society of Anesthesiologists score, but the RT group was comprised of a greater percentage of men than the RS group. Outcome variables were collected from patient charts and included inpatient pain, inpatient ambulation as well as length of stay, estimated blood loss, surgical time, and postoperative radiographic measurements. Cohen's f(2) was used to calculate the effect size in the regression analysis and effects were considered small for values<0.15, moderate for 0.15 to 0.34, and large for values>0.35.

Results: Patients who underwent PAO with a RS approach had less overall pain (RT median 4 versus RS median 2); however, the difference may not have been perceptible to the typical patient (p=0.001, f2=0.059). Patients treated with the RS approach ambulated similar distances during the hospital stay with a median 11 feet (interquartile range [IQR], 0-72.5) for the RT group and a median 30 feet (IQR, 0-100) for the RS group (p=0.215, f2=0.095). Patients in the RT group had a median length of stay of 4 days (IQR, 4-5) compared with a median 3 days (IQR, 3-4) in the RS group (p<0.001). The median estimated blood loss was greater (p=0.010) in the RT group (median, 500 mL; IQR, 350-700) versus the RS group (median, 300; IQR, 250-500). The median surgical time was longer (p<0.001) in patients undergoing PAO with the RT approach (median, 159.5 minutes; IQR, 145.5-177) compared with the RS approach (median, 103 minutes; IQR, 75-114). Acetabular reorientation based on postoperative radiographs was not compromised by the modified approach.

Conclusions: The approach modification was straightforward to implement in all patients and did not compromise acetabular fragment mobilization or final positioning. Two of the three key variables that the approach might have influenced-pain and length of stay-were below the minimum clinically important difference and different by only a fraction of a day, respectively. The difference in ambulation was of only modest clinical importance. More definitive evidence for clinical superiority in terms of pain, ambulation, and return of muscle function will likely require more sophisticated instruments such as gait analysis, muscle strength testing, and longer-term outcome studies with sensitive instruments.

Level of evidence: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Figures

Fig. 1

Diagram illustrates the standard Bernese PAO approach with the takedown of the rectus tendon from the AIIS followed by exposure (area in black) of the anterior hip capsule. TFL = tensor fascia latae.

Fig. 2

Diagram illustrates the modified approach sparing the rectus tendon by developing a smaller window (area in black) between the iliopsoas and the rectus muscles. TFL = tensor fascia latae.

Fig. 3

Line graph demonstrates the difference in pain scores between the groups.

Fig. 4

Line graph demonstrates distance ambulated between the groups.