STUDY DESIGN: Randomized clinical trial. OBJECTIVE: To investigate the clinical and functional efficacy of 2 different non–weight-bearing exercise regimens, proprioceptive training (PrT) versus strength training (ST), for patients with knee osteoarthritis (OA). BACKGROUND: Both strength and proprioceptive training are important interventions for individuals with knee OA. The benefits of weight-bearing exercises are generally recognized in the clinical setting. However, exercising in a standing or weight-bearing position may aggravate symptoms in patients with knee OA. METHODS AND MEASURES: One hundred eight patients were randomly assigned to the PrT, ST, or no exercise (control) group for an 8-week intervention. Both the PrT and ST interventions consisted of non–weight-bearing exercises. Western Ontario and McMaster Universities Osteoarthritis Index-pain (WOMAC-pain) and -function scores, walking time on 3 different terrains, knee strength, and absolute knee reposition error were assessed before and after intervention. Data were analyzed using mixed-model ANOVAs. RESULTS: Both PrT and ST significantly improved WOMAC-pain and -function score after intervention (P<.008). The improvement secondary to ST in the WOMAC-function scores (17.2 points) and for knee extension strength (10.3-14.9 Nm) was greater than the minimally clinically important difference for these measurements. The PrT group demonstrated greater improvement in walking time on a spongy surface and knee reposition error than the other 2 groups. No improvements were apparent in the control group. CONCLUSION: Both types of non–weight-bearing exercises (PrT and ST) significantly improved outcomes in this study. PrT led to greater improvements in proprioceptive function, while ST resulted in a greater increase in knee extensor muscle strength. LEVEL OF EVIDENCE: Therapy, level 1b.

J Orthop Sports Phys Ther 2009;39(6):450-457, Epub 24 February 2009. doi:10.2519/jospt.2009.2923

KEY WORDS: arthritis, randomized clinical trials, tibiofemoral joint, WOMAC

STUDY DESIGN: Controlled laboratory study. BACKGROUND: The effect of quadriceps contraction on patellar alignment in patients with patellofemoral pain syndrome (PFPS) is debated and may vary based on patellar alignment subtypes measured with the quadriceps relaxed. OBJECTIVES: To determine if the effects of quadriceps contraction on patellar alignment differs (1) with respect to patellar alignment subtype in individuals with PFPS and (2) between symptomatic and asymptomatic knees in individuals with unilateral PFPS. METHODS AND MEASURES: Seventy-eight individuals, 47 with bilateral and 31 with unilateral PFPS, participated in the study. On axial computed tomography images with the knee in extension with quadriceps relaxed as well as contracted, patellar lateral condyle index (PLCI) and patellar tilt angle (PTA) were measured and analyzed. Based on the median PLCI and PTA alignment values measured with quadriceps relaxed for the 78 subjects, 4 subgroups of subjects were created: type 1, laterally displaced; type 2, laterally displaced and tilted; type 3, laterally tilted; and type 4, neither. RESULTS: Quadriceps contraction caused an increase in PLCI in all patellar alignment types (P<.01), with no difference in the magnitude of the increase between types (P>.05). PTA decreased with quadriceps contraction in the subjects with the type 3 initial patellar alignment (P<.01), with a significant difference in the change in patellar alignment between the subjects with type 3 and type 1 initial patellar alignment (P = .004). For the 31 subjects with unilateral PFPS, quadriceps contraction caused a similar change in PLCI and PTA in both the symptomatic and asymptomatic knees. CONCLUSIONS: The initial position of the patella with the quadriceps relaxed did not influence the change in PLCI with quadriceps contraction. For the 31 subjects with PFPS, there was no difference in initial alignment as well as in change of alignment with quadriceps contraction between symptomatic and asymptomatic knees.

J Orthop Sports Phys Ther 2009;39(4):264-269, Epub 15 December 2008. doi:10.2519/jospt.2009.2873

KEY WORDS: chondromalacia patellae, imaging, patella, patellofemoral pain syndrome