Early functional outcome after subvastus or parapatellar approach in knee arthroplasty is comparable.
OBJECTIVE
In total knee arthroplasty, tissue-sparing techniques are considered more important, as functional gain could become more advantageous when early mobilization is commenced. The parapatellar approach is most often used, whereas the subvastus approach is a suitable alternative. Presently, it is unknown, according to true objective measurements, which of the two is most advantageous.


METHODS
In this prospective randomized double-blind, short-term trial measurements (KSS, WOMAC, PDI, VAS, ability to perform) were obtained at day 1, day 3, 1 week, 6 weeks, and 3 months.


RESULTS
The subvastus group (n=20) showed only significantly less extension lag direct postoperative (P=0.04) compared with the parapatellar group (n=20). Other scores were not significantly different. The Dynaport®knee test, an objective performance-based tool, could not demonstrate significant differences. A blunt anatomical dissection was carried out in both observational and histological to support findings. A dense innervation of the distal vastus medialis was found. This is at risk employing the subvastus approach. Both approaches harm the suprapatellar bursa. The vastus medialis sheath must be detached distally to open the knee joint. No true separate vastus medialis obliquus could be identified.


CONCLUSIONS
Comparable to literature, only mild advantage employing the subvastus approach was found, but only early postoperative and not objectively. As this approach is also not suitable in every case, we will continue to use the parapatellar approach.
Department of Orthopaedic Surgery and Traumatology, Atrium Medical Centre, PO Box 4446, 6401 CX, Heerlen, The Netherlands. wht02@atriummc.nl
Wouter L W
WL
van Hemert
Rachel
R
Senden
Bernd
B
Grimm
Matthijs J A
MJ
van der Linde
Arno
A
Lataster
Ide C
IC
Heyligers
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D002102:Cadaver; D004210:Dissection; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery; D010147:Pain Measurement; D010329:Patella / Q000601:surgery*; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D052097:Quadriceps Muscle / Q000601:surgery*; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome