Subchondral bone remodeling is related to clinical improvement after joint distraction in the treatment of ankle osteoarthritis

Abstract

Objective In osteoarthritis (OA), subchondral bone changes alter the joint’s mechanical environment and potentially influence progression of cartilage degeneration. Joint distraction as a treatment for OA has been shown to provide pain relief and functional improvement through mechanisms that are not well understood. This study evaluated whether subchondral bone remodeling was associated with clinical improvement in OA patients treated with joint distraction. Method Twenty-six patients with advanced post-traumatic ankle OA were treated with joint distraction for three months using an Ilizarov frame in a referral center. Primary outcome measure was bone density change analyzed on CT scans. Longitudinal, manually segmented CT datasets for a given patient were brought into a common spatial alignment. Changes in bone density (Hounsfield Units (HU), relative to baseline) were calculated at the weight-bearing region, extending subchondrally to a depth of 8 mm. Clinical outcome was assessed using the ankle OA scale. Results Baseline scans demonstrated subchondral sclerosis with local cysts. At one and two years of follow-up, an overall decrease in bone density (−23% and −21%, respectively) was observed. Interestingly, density in originally low-density (cystic) areas increased. Joint distraction resulted in a decrease in pain (from 60 to 35, scale of 100) and functional deficit (from 67 to 36). Improvements in clinical outcomes were best correlated with disappearance of low-density (cystic) areas (r=0.69). Conclusions Treatment of advanced post-traumatic ankle OA with three months of joint distraction resulted in bone density normalization that was associated with clinical improvement.

Realignment-lengthening osteotomy for malunited distal fibular fracture

“…In their study, Intema et al demonstrated that treatment of advanced post-traumatic ankle osteoarthritis with joint distraction produced an overall decrease of subchondral bone density, which persisted for at least two years, and resolution of subchondral bone cysts which was correlated to the clinical improvement in their patients [19].…”

Distraction Arthroplasty for Ankle Osteoarthritis

“…Twenty-six patients undergoing ankle distraction arthroplasty for posttraumatic arthritis were evaluated preoperatively and at 1-2 years post surgery with CT and ankle arthritis scores. Clinical improvement was directly correlated with CT changes that demonstrated the disappearance of cystic areas originally present in the subchondral bone (Intema et al 2011 ). Another study confi rmed these fi ndings and added further insight into joint changes induced by distraction.…”

“…Many authors have reported success using this technique with improvement in functional outcome scores (Van Valburg et al 1995Saltzman and Buckwalter 1999 ;van Roermund et al 2002 ;Marijnissen et al 2002Marijnissen et al , 2003Ploegmakers et al 2005 ;Paley and Lamm 2005 ;Paley et al 2008 ;Tellisi et al 2009 ;Intema et al 2011 ). Those that have seen positive clinical effects presume that there is a biological explanation behind these successes.…”

The Role of Mechanical Forces in the Initiation and Progression of Osteoarthritis

“…Distraction and motion of osteoarthritic articular surfaces can promote joint remodeling, decrease pain, and improve joint function in patients with end-stage posttraumatic OA [11]. This result, combined with the observation that chondroprogenitor cells are active in osteoarthritic joints [12], suggests that altered loading creates an environment that promotes beneficial joint remodeling.…”