This study conducted a systematic review and meta-analysis of comparative studies published since 1990 to compare the fusion rate, operative effectiveness, safety and postoperative outcomes of arthroscopic arthrodesis and open surgery for ankle arthritis. Although there are similar studies comparing ankle arthrodesis and open surgery, this study included the most publications, reflects the latest surgical results, and focuses on the results of arthroscopic arthrodesis and open surgery for ankle arthritis. Considering limitations of a learning curve and insufficient evaluation, the study results might be meaningful. This study evaluated the two procedures using 4 items: days to union, estimated blood loss, and AOS score at 12 and 24 months, unlike the previous study. These items formed a complete evaluation, from primary outcome to postoperative recovery. First, it was noted that there was no significant difference in days to union, which is contrary to previous studies.[3] Patients who underwent arthroscopic arthrodesis did not have a shorter time to union than those who experienced open surgery.
Regarding the rate of fusion, the meta-analysis showed that there was a remarkable difference between arthroscopic arthrodesis and open surgery, and the data support the most recent meta-analysis by Honnenahalli et al.[3] Patients who underwent arthroscopic arthrodesis had a higher fusion rate than those who underwent open surgery. In arthroscopic arthrodesis, the soft tissue envelope is disrupted to a minimum degree, which enables the major functions of soft tissues close to the surgical site. The bone healing cascade is activated rapidly, so the bone heals rapidly and function improves in the early stage due to the minimum degree of soft-tissue envelope disruption [4, 18]. These theories may elucidate the high fusion rate for arthroscopic arthrodesis.
Additionally, this study is the first to assess the estimated blood loss, and the pooled data significantly favoured arthroscopic arthrodesis compared with open surgery. The data were pooled by O’Brien et al.[19] and Townshed et al. [4] Moreover, the tourniquet time during the operation was considerably shorter with arthroscopic arthrodesis than with open surgery. Although Meng et al.[20] mentioned a longer operation time for arthroscopic arthrodesis, this study showed no significant differences in the operating time for the two procedures. There is only one relevant study mentioned in Meng et al.[20], but their pooled data was extracted from a larger sample size from different countries. Therefore, the risk of bias is minimised in the results. As a result, arthroscopic arthrodesis does not take longer to complete than open surgery.
Regarding complications, patients who undergo arthroscopic arthrodesis may require removal of a screw for prominence, superficial infections, deep vein thromboses/pulmonary emboli, fixation revision, stress fracture or deep infections after surgery.[9] However, the study shows no significant difference between these two surgical procedures. It has been reported that patients require reoperation for similar complications in the two groups. This explains why there was no remarkable difference in either group given the similar postoperative radiological alignment.[21]
Moreover, postoperative improvements were studied via the AOS score. The arthroscopic arthrodesis group showed significantly better scores at one year compared with the open surgery groups.[22] However, no significant difference between the groups at 2 years was noted. Since less area was damaged during arthroscopic arthrodesis than during open surgery, the tissues and functions recovered rapidly and in earlier stages, as per Townshend et al. [4] Further study is needed to improve understanding of the clinical picture of the finding, especially with regards to education for patients choosing the best time to undergo reconstruction for their ankle arthritis.[21, 23, 24] This is a new finding compared with the previous study. Thus, patients who underwent arthroscopic arthrodesis recovered in a shorter time but showed similar bone reconstruction in the long term compared with those who underwent open surgery.
There are several limitations despite these findings. First, no randomised controlled trial (RCT) was reported. There is a higher risk of selection and reporting bias in an observational study compared with an RCT study. Second, a larger sample size is needed for some of the results, such as blood loss and functional improvement, which are drawn from few data points because they were not investigated in all the studies that were available for review. Four out of 9 reviews were from the US. This increases the risk of bias towards a specific area. Third, longer follow-up times are needed. A 24-month follow-up cannot show the long-term effects or complications of the procedures.[24–28]