Incidence of ankle arthrodesis and total ankle replacement between 1997 and 2018: A nationwide registry study in Finland.

BACKGROUND: Surgical treatment options for end-stage ankle osteoarthritis (OA) include ankle arthrodesis (AA) and total ankle replacement (TAR). We investigated the national incidence of AA and TAR and assessed trends in the surgical management of ankle OA in Finland between 1997 and 2018. METHODS: The Finnish Care Register for Health Care was used to calculate the incidence of AA and TAR based on sex and different age groups. RESULTS: The mean age (SD) of patients was similar, 57.8 (14.3) years for AA and 58.1 (14.0) for TAR. TAR showed a 3-fold increase from 0.3 per 100 000 person-years in 1997 to 0.9 per 100 000 person-years in 2018. The incidence of AA operations decreased during the study period from 4.4 per 100 000 person-years in 1997 to 3.8 per 100 000 person-years in 2018. TAR utilization increased notably at the expense of AA between 2001 and 2004. CONCLUSION: TAR and AA are both widely used procedures in the treatment of ankle OA, with AA being the favored option for most patients. The incidence of TAR has remained constant for the past 10 years, indicating appropriate treatment indications and utilization.

Structural validity of the foot and ankle outcome score for orthopaedic pathologies with Rasch Measurement Theory.

BACKGROUND: The Foot and Ankle Outcome Score (FAOS) is one of the most frequently used patient-reported outcome measures for foot and ankle conditions. The aim is to test the structural validity of the Finnish version of the FAOS using Rasch Measurement Theory. METHODS: FAOS scores were obtained from 218 consecutive patients who received operative treatment for foot and ankle conditions. The FAOS data were fitted into the Rasch model and person separation index (PSI) calculated. RESULTS: All the five subscales provided good coverage and targeting. Three subscales presented unidimensional structure. Thirty-eight of the 42 items had ordered response category thresholds. Three of the 42 items had differential item functioning towards gender. All subscales showed sufficient fit to the Rasch model. PSI ranged from 0.73 to 0.94 for the subscales. CONCLUSIONS: The Finnish version of the FAOS shows acceptable structural validity for assessing complaints in orthopaedic foot and ankle patients.

Minimal important change for Foot and Ankle Outcome Score (FAOS).

BACKGROUND: Although Foot and Ankle Outcome Score (FAOS) is a widely used patient-reported outcome measure (PROM) for foot and ankle conditions, research on its longitudinal validity is still needed. Minimal important change (MIC) values for the FAOS were determined using predictive modeling. METHODS: Overall, 134 patients that underwent operative treatment for foot and ankle conditions were included. An anchor based predictive logistic modeling method was used for estimating the MIC values for the FAOS subscales after surgery. RESULTS: Mean score changes in the improved and the unimproved groups were 17.7 and 0.43 points for Pain, 3.9 and -3.3 points for Symptoms, 21.3 and 1.8 points for Activities and daily living (ADL), 8.7 and -2.8 points for Sport, and 12.5 and -3.3 points for quality of life subscale, respectively. MIC was successfully determined to four out of five subgroups as follows: Pain 9.5 (94% CI -6.4 to 24.6); ADL 11.7 (95% CI -19.6 to 46.6); Sport (95% CI -10.4 to 15.4); QoL 5.0 (95% CI -2.6 to 12.9). The Symptoms subgroup presented with low MIC of 0.3 (95% CI -11.7 to 13.4) fitting to the measurement error. CONCLUSION: ADL, Sports, Pain, and QoL subscales of the FAOS presented logical MIC values. The MIC can be further evaluated for specific conditions.