The Role of Distraction Arthroplasty in Managing Ankle Osteoarthritis

Low annual revision rate in ankle distraction for ankle osteoarthritis: A systematic review and meta-analysis

PURPOSE

Ankle osteoarthritis severely impacts patients' mental and physical quality of life. Besides total ankle replacement and ankle arthrodesis, ankle distraction has been shown to be a promising alternative. The primary aim of the present study was to determine the annual revision rates (ARRs) after ankle distraction. The secondary aim was to obtain an overview of patient-reported outcome measures and functional outcomes.

METHODS

A literature search until November 2023 was performed. Methodological quality was assessed using the methodological index for non-randomised studies criteria. Primary outcome was the ARR which was log-transformed and pooled using a random effects model. Secondary outcomes were pooled using a simplified pooling technique and included the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale (AOFAS), range of motion (ROM) and post-operative complications.

RESULTS

The literature search resulted in 287 articles, of which 10 studies, comprising 602 patients, were included. The patients had a pooled mean age of 47 years (range of means: 40-68) and a mean follow-up of 35 months (range of means: 24-48). The overall methodological quality was moderate to fair. The pooled ARR after ankle distraction was 4% (95% confidence interval [CI], 3%-7%). Pooling of AOFAS showed mean 26-point improvement (from 54 to 80). Additionally, ROM dorsiflexion improved at 5°, and the plantarflexion remained at 31°. The overall complication rate was 41% (95% CI, 35%-48%), of which 77% (95% CI, 67%-85%) were pin-tract infections.

CONCLUSION

Ankle distraction results in an ARR of 4% (95% CI, 3%-7%) with clinically relevant improved AOFAS scores. The overall complication rate is 41% and is mainly attributable to treatable pin-tract infections (77% of recorded complications).

LEVEL OF EVIDENCE

Level IV, Systematic Review and Meta-Analysis.

[Mid- and long-term effectiveness analysis of distraction arthroplasty in treatment of moderate to severe ankle arthritis]

OBJECTIVE

To investigate the mid- and long-term effectiveness of external fixator distraction arthroplasty in the treatment of moderate to severe ankle arthritis.

METHODS

The clinical data of 23 patients with moderate to severe ankle arthritis treated with external fixation distraction arthroplasty who met the selection criteria between January 2007 and November 2019 were retrospectively analyzed. There were 20 males and 3 females; the age ranged from 21 to 65 years, with an average age of 43.7 years. Etiology included 8 cases of primary ankle arthritis, in which 5 cases combined with varus deformity; 15 cases of traumatic ankle arthritis, the cause of injury was 5 cases after ankle fracture surgery, 3 cases after Pilon fracture surgery, 5 cases of chronic ankle instability and repeated sprain, and 2 cases of other causes. According to Takakura staging system, there were 4 cases of stage ⅢA, 12 cases of stage ⅢB, and 7 cases of stage Ⅳ; according to Giannini staging system, there were 5 cases of stage Ⅱ and 18 cases of stage Ⅲ; according to Cheng staging system, 16 cases were in stage Ⅲ, and 7 cases stage Ⅳ. American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and visual analogue scale (VAS) score were used to evaluate the improvement of ankle pain and function before operation and at last follow-up, and the data were analyzed according to different etiological groups. At last follow-up, the surgical results were evaluated subjectively and objectively. The changes of ankle joint space before operation and at last follow-up were compared. The patients were divided into two groups according to their age: ≤45 years old group [young group, 10 cases, aged (35.62±7.41) years old] and >45 years old group [middle-aged and elderly group, 13 cases, aged (54.20±6.20) years old]. The AOFAS ankle-hindfoot score and VAS score were compared before and after operation between the two groups, and the influence of age on distraction arthroplasty was analyzed.

RESULTS

The external fixator was removed after 3 months of continuous distraction,12 patients got infection around the wire tunnels. All the 23 patients were followed up 13-143 months, with an average of 56.9 months; the follow-up time was (43.46±32.77) months and (69.80±37.79) months in the young group and middle-aged and elderly group, respectively. At last follow-up, the AOFAS ankle-hindfoot score and VAS score significantly improved when compared with those before operation ( P<0.05). According to etiological analysis, there was no significant difference in AOFAS ankle-hindfoot score and VAS score before and after operation ( P>0.05) in Pilon fracture patients, while the significant difference was found in remaining patients ( P<0.05). There was significant difference in AOFAS ankle-hindfoot score before operation between the young group and the middle-aged and elderly group ( t=2.110, P=0.040), but no significant difference in preoperative VAS score and the differences in VAS score and AOFAS ankle-hindfoot score before and after operation between the two groups ( P>0.05). The subjective and objective results of pain evaluation at last follow-up showed that 4 patients had no pain, 12 patients had moderate pain relief, 5 patients had mild pain relief, and 2 patients had no significant pain relief; among the 10 patients who were followed up more than 5 years, there were 2, 5, 2, and 1 patient, respectively; 2 patients who were followed up more than 10 years had moderate pain relief. At last follow-up, the ankle joint space was (3.7±0.4) mm, which significantly increased when compared with before operation [(1.5±0.2) mm] ( t=1.791, P=0.002). The ankle joint space was (2.9±0.5) mm in 10 patients who were followed up more than 5 years, and 3.3 mm and 3.0 mm in 2 patients who were followed up more than 10 years.

CONCLUSION

Distraction arthroplasty of the ankle joint can achieve satisfactory results in patients with moderate to severe ankle arthritis (except for arthritis caused by Pilon fracture), and age has no significant effect on distraction arthroplasty.