Results
Table 1.
Table 2.Table 2 lists self-reported activities limited by the affected knee before surgery, and Table 3 lists activity levels after surgery. Return to previous preferred activity was reported by 72.2% of patients, and 52.8% of patients reported returning to the same activity level or to a higher level. There were no differences in age (P = .978) or sex (P = .232) between patients who returned to the same or a higher activity level and patients who did not.
Table 3.
Postoperative knee-specific PROM scores and general pain score (reported by the patient on a scale of 0-10) were statistically significantly improved (P < .001 for all measures) over preoperative scores (Table 4).
Table 4.
After surgery, 1 patient (2.6%) developed a pulmonary embolus, which was successfully identified and treated without incident. Five patients (10.4%) had another surgery on the same knee. Three patients (6.3%) underwent conversion to TKA: 1 for continued symptoms in the setting of newly diagnosed inflammatory arthritis, 1 for arthritic pain, and 1 for patellofemoral instability. Two patients (4.2%) underwent irrigation and débridement: 1 for hematoma and 1 for suspected (culture-negative) infection.
Discussion
Historically, the literature evaluating knee arthroplasty outcomes has focused on implant survivorship, pain relief, and patient satisfaction. Since the advent of partial knee arthroplasty options, more attention has been given to functional outcomes and return to activities after single-compartment knee resurfacing. TKA remains the gold standard by which newer, less invasive surgical options are measured. In a large prospective study, 97% of patients (age, >55 years) who had TKA for patellofemoral arthritis reported good or excellent clinical results, the majority being excellent.11 Post-TKA functional status and activity levels may not be rated as highly. After TKA, many patients switch to lower impact sports or reduce or stop their participation in sports.12 A small study of competitive adult tennis players found high levels of post-TKA satisfaction, ability to resume playing tennis, pain relief, and increased or continued enjoyment in playing.13 In a study of 355 patients (417 knees) who had underwent TKA, improvement in Knee Society function score showed a moderate correlation to an increase in weighted activity score (R = 0.362).14
Unicondylar knee arthroplasty (UKA) is becoming a popular treatment option for single-compartment tibiofemoral arthritis. A systematic review of 18 original studies of patients with knee osteoarthritis found that overall return to sports varied from 36% to 89% after TKA and from 75% to 100% after UKA.15 In another study, return-to-sports rates were similar for UKA (87%) and TKA (83%); the only significant difference was UKA patients returned quicker.16 The authors of a large meta-analysis conceded that significant heterogeneity of data prevented them from drawing definitive conclusions, but UKA patients seemed to return to low- and high-impact sports 2 weeks faster than their TKA counterparts.10 Overall, UKA and TKA patients (age, 51-71 years) had comparable return-to-sports rates at an average of 4 years after surgery.10 A smaller study corroborated faster return to sports for UKA over TKA patients and also found that, compared with TKA patients, UKA patients participated in sports more regularly and over a longer period.17 On the other hand, Walton and colleagues18 found similar return-to-sports rates but higher frequency of and satisfaction with sports participation in UKA over TKA patients.
A large retrospective study found no differences in rates of return to sports after TKA, UKA, patellar resurfacing, hip resurfacing, and total hip arthroplasty.19 Pain was the most common barrier to return. UKA patients who returned to sports tended to be younger than those who did not.20 Naal and colleagues3 found that 95% of UKA patients returned to their activities—hiking, walking, cycling, and swimming being most common. Although 90.3% of patients said surgery maintained or improved their ability to participate in sports, participation in high-impact sports (eg, running) decreased after surgery.
Outcomes of PFA vary because of evolving patient selection, implant design, surgical technique, and return-to-activity expectations.21,22 Most PFA outcome studies focus on implant survivorship, complication rates, and postoperative knee scores.23-28 PFA studies focused on return to activities are limited. Kooijman and colleagues7 and Mertl and colleagues29 reported good or excellent clinical results of PFA in 86% and 82% of patients, respectively. Neither study included a comprehensive analysis of postoperative functional status. Similarly, De Cloedt and colleagues30 reported good PFA outcomes in 43% of patients with degenerative joint disease and in 83% of patients with instability. Specific activity status was not described. Dahm and colleagues31 and Farr and colleagues32 suggested postoperative pain resolution motivates some PFA patients not only to resume preoperative activities but to start participating in new, higher level activities after pain has subsided. However, the studies did not examine the characteristics of patients who returned to baseline activities and did not examine return-to-sports rates.