Question: In patients having total knee arthroplasty,
how do the medial patellar and subvastus approaches compare with
regard to functional outcomes and postoperative recovery?
Design: Randomized (unclear allocation concealment),
blinded (patients and outcome assessors), controlled trial with
3-month follow-up.
Setting: A district hospital in England.
Patients: 89 patients (mean age, 70 years; 53% men)
who had a primary total knee arthroplasty for treatment of osteoarthritis.
Follow-up was complete.
Intervention: Patients were allocated to total knee
arthroplasty with either a standard parapatellar approach (n = 43)
or a subvastus approach (n = 46). The subvastus approach involved
raising a medial flap of the perimuscular fascia of the vastus medialis
until the inferior edge of the muscle underside was reached. The
vastus medialis was eased off the medial intermuscular septum for
a distance of approximately 10 cm proximal to the adductor tubercle.
A transverse incision was made across the medial aspect of the capsule
at the level of the middle of the patella and down to the medial
side of the patellar tendon. To close, the inverted v-shaped capsular
incision was tacked back into place.
Main outcome measures: Time to the patient’s
ability to perform an unassisted straight-leg raise, range of motion,
total blood loss, opiate consumption, and length of hospital stay.
Main results: Patients who had surgery through the
subvastus approach had a shorter time to unassisted straight-leg
raise (P < 0.001), greater knee flexion at 1 week (P < 0.001),
less total blood loss (P < 0.001), and less opiate use
at 1 week (P < 0.001) than did patients who had the parapatellar approach
(table). The
groups did not differ with regard to length of hospital stay (P = 0.068)
(table) or range of knee flexion at 4 weeks (P = 0.052)
or at 3 months (P = 0.070).
Conclusion: Total knee arthroplasty through the
subvastus approach resulted in earlier unassisted straight-leg raise,
less total blood loss, less opiate consumption, and better knee
flexion at 1 week after surgery than did total knee arthroplasty
through the parapatellar approach.