Pain in Osteochondral Lesions of the Ankle - an Investigation Based on Data from the German Cartilage Registry (KnorpelRegister DGOU).

BACKGROUND: The aim of the study was to investigate parameters influencing the preoperative pain intensity in patients with osteochondral lesions of the ankle. The evaluation covered patient-related parameters such as age, sex, body mass index (BMI), as well as defect-related parameters, such as localisation, size and stage (according to the classification of the International Cartilage Repair Society [ICRS] and the Berndt-Harty-Loomer classification). We also examined the correlation between the different surgical techniques and additional factors, such as debridement of an impingement or stabilisation of the ankle on the one hand, and the preoperative pain intensity on the other.

MATERIAL AND METHODS: 259 patients with osteochondral lesions of the ankle were operated in 32 clinical centres between October 2014 and December 2016 and enrolled consecutively in the German Cartilage Registry (KnorpelRegister DGOU). 151 patients were available for analysis. The preoperative pain intensity was assessed at the time of surgery with online questionnaires, using the Numeric Rating Scale for pain (NRS).

RESULTS: The median preoperative pain intensity in the complete study population (n = 151) was 3 (range 0 - 10). There was no correlation between the age and the preoperative pain intensity (ρ = - 0.06). Further, there was not detected a difference between the two genders according to the preoperative pain intensity (p = 0.31). In female patients a higher BMI correlated with a higher preoperative pain intensity (ρ = 0.16). Within the group of patients with a solitary treated talus lesion there was no difference according to the preoperative pain intensity between the different localizations of the defect (medial vs. lateral talus) (p = 0.82). Within the group of patients with a solitary treated talus or tibia lesion there was no correlation between the defective area or the lesion stage according to the ICRS classification on the one hand, and the preoperative pain intensity on the other (ρ = 0.09, and ρ = 0.04, respectively). According to the Berndt-Harty-Loomer classification a higher lesion stage (stage four and five) was associated with a higher preoperative pain intensity (ρ = 0.13). There was no difference according to the preoperative pain intensity between the group of patients that received a debridement of a bony or soft tissue impingement in addition to the cartilage therapy and the group of patients without this kind of additional therapy (p = 0.10). Further, there was no difference according to the preoperative pain intensity between the group of patients that received a stabilisation of the ankle joint in addition to the cartilage therapy and the group of patients without a stabilisation procedure (p = 0.83).

CONCLUSION: Osteochondral lesions of the ankle can be associated with a moderate and in some cases high pain intensity. In female patients a higher BMI is associated with a higher pain intensity. Further, a higher lesion stage according to the Berndt-Harty-Loomer classification is associated with a higher pain intensity, which highlights the clinical relevance of this classification.