Date Published: February 8, 2012
Publisher: Informa Healthcare
Author(s): Stig Munk, Jesper Dalsgaard, Karin Bjerggaard, Ina Andersen, Torben Bæk Hansen, Henrik Kehlet.
After total knee arthroplasty with conventional surgical approach, more than half of the quadriceps extension strength is lost in the first postoperative month. Unicompartmental knee arthroplasty (UKA) operated with minimally invasive surgery (MIS) results in less operative trauma. We investigated changes in leg-extension power (LEP) in the first month after MIS Oxford UKA and its relation to pain, knee motion, functional performance, and knee function.
In 35 consecutive Oxford UKA patients, LEP was measured 1 week before and 1 month after surgery together with knee motion, knee swelling, the 30-second chair-stand test, and Oxford knee score. Assessment of knee pain at rest and walking was done using a visual analog scale.
30 patients were discharged on the day after surgery, and 5 on the second day after surgery. LEP and functional performance reached the preoperative level after 1 month. Only slight postoperative knee swelling was observed with rapid restoration of knee flexion and function. A high level of pain during the first postoperative night and day fell considerably thereafter. None of the patients needed physiotherapy supervision in the first month after discharge.
Fast-track MIS Oxford UKA with discharge on the day after surgery is safe and leads to early recovery of knee motion and strength even when no physiotherapy is used.
39 patients were scheduled for surgery. 1 patient was excluded because of preoperative cognitive dysfunction and 2 refused to participate. 1 patient with heart disease and anticoagulation therapy developed tense hemarthrosis and subcutaneous wound hematoma postoperatively and was excluded because of deep infection diagnosed 2 weeks after surgery. No other complications were registered. Thus, 35 patients (18 men) with a mean age of 66 (51–81) years completed the study. 13 patients had bilateral knee osteoarthritis and 5 had a prosthesis in the other knee.
Minzer et al. (2005) found that 1 month after TKA, quadriceps muscle strength decreased by 62% relative to the preoperative level. Mancher et al. (2002) found an increase in strength of the quadriceps muscle 18 months after UKA in both operated and non-operated legs, but they did not focus on early recovery. We found that 1 month after Oxford medial UKA with minimally invasive surgery, the average LEP in both legs and the functional performance were comparable to those at the preoperative level. This is different from TKA patients at our own institution, where we have found that LEP after 1 month is 30% lower than in the present study (Aalund P K, personal communcation).