Patellofemoral and tibiofemoral bone marrow lesions over four years: Associations with pain and compartment-specific changes

Abstract

x Mexico's Children Hosp. Federico Gomez, Mexico City, MexicoPurpose: Malalignment plays a major role in knee osteoarthritis (OA) and one therapy that is designed to modify malalignment in the context of knee OA is bracing. We hypothesize that the effect of bracing in persons with knee OA will be dependent on the extent of malalignment. Methods: Participants from the Osteoarthritis Chronic Care Program (OACCP) were followed for up to 52 weeks from March 2012 to March 2013 as part of a multidisciplinary approach to knee OA. The multidisciplinary approach consists of a physiotherapist, medical officer, rheumatologist, social worker, occupational therapist, orthotist, and dietician providing individually tailored interventions to participants. Participants with radiographic evidence of unicompartmental femorotibial OA and evidence of genu varum, plus or minus adductor thust through stance phase of gait were referred to the orthotist. X-rays of participants with femorotibial OA referred to an orthotist for consideration of bracing (Unloader One Knee Brace from Ossur) were analyzed. Radiographic measurements including the anatomical axis, condylar angle, tibial plateau angle and condylar plateau angle (Figure 1) were obtained from the initial knee x-rays before the participants knees were braced. In participants who had a knee brace, we tested if malalignment from the x-rays before bracing took place for was associated with the change in KOOS pain score at week 26. Results: The 72 participants had a mean age of 66 years, were 57% female and had a BMI of 30.6 kg/m 2 . 47 participants had complete data at week 26 and are the focus of this analysis. Multiple regression was used with change in pain at 26 weeks as the dependent variable, tibial plateau angle and condylar plateau angle were used as co-variables and the model was adjusted for age. The greater the tibial plateau angle, the greater the pain response (b¼2.27, SE¼0.94, p¼0.019), and the greater the condylar plateau angle the lower the pain response was SE¼1.22, p¼0.022). When the 72 patients who underwent bracing were analyzed for week 26 pain response, the greater the anatomical axis angle, the greater the pain response (b¼1.81, SE¼0.63, p¼0.01). There was no trend suggestive of a relationship to condylar angle. Conclusions: In our cohort, participants who were eligible for bracing had improved knee pain from week 0 to 26. Tibial plateau, condylar plateau and anatomical axis angles in participants with varus malalignment who undergo bracing were associated with improvement in pain. These measures may assist in identifying those most likely to redeem an effect from knee bracing.