The patents included in the study were selected from a prospectively-collected database of patients treated for TKA in the years 2008 to 2017 in the department specializing in hip and knee arthroplasties. Beginning in 2014, it was decided to include oral prednisolone in treating the cases characterized by the most severe limitation of motion. It was believed that this modification may improve the range of motion and final result of arthroplasty. The inclusion criteria for the examined group were as follows: (1) primary or secondary knee osteoarthritis with severe ROM limitation before TKA – no more than 80° of the range of motion and 10° of knee flexion contracture, (2) administration of oral prednisolone twice a day after TKA, (3) informed consent for participation in the study. Patients who had experienced previous septic arthritis, revision TKA, allergy to prednisolone, other contraindications to taking prednisolone (severe osteoporosis, uncontrolled diabetes mellitus, active gastrointestinal ulcers, diverticulitis), lost to follow-up and those who did not agree to participate in the study, were excluded.
Thirty eight consecutive patents underwent TKA and were treated with prednisolone postoperatively. Among them two patients did not agreed to participate in the study, and four were lost to follow-up. After the exclusion process, 32 patients (32 knees) were included in the study (prednisolone group). The mean age was 61.2 years (range from 33 to 82, median 63.8) and the mean BMI was 28.6 kg/m2 (range from 22.19 to 45.26, median 29.28). The demographic and clinical data are presented in Table 1.
Prednisolone (Encorton, Polfa S.A., Pabianice, Poland) was administrated in two doses per day, with the 12h interval, the first in the morning at 7 am., and the second in the afternoon at 7 pm. (1 mg per kg of body mass, maximum dose 90mg per day) from the first postoperative day (total dose from 55mg to 90mg). Sudden steroid withdrawal may cause severe side effects (e.g. joint pain, nausea, vomiting, low blood pressure, muscle pain). To avoid these complications, the dose reduction by 2.5-5mg decrements (once from the morning dose and once from the afternoon dose) every 3-7 days until a dose taken by the patient was reached should be applied. The dose was reduced to zero, or to the dose prescribed to patients before the operation (rheumatoid patients). The duration of treatment took no more than three months.
Patients from the study group were matched with patients who did not receive prednisolone administration and were operated before 2014 (control group, non-prednisolone group). The patients were matched in terms of gender, etiology (primary, postoperative, RA OA), range of motion before operation +/-10˚ (but no more than 80° of the range of motion and 10° of knee flexion contracture), type of deformity (varus, valgus or neutral) and age +/- two years.
Pre-operative planning was performed in every case with the use of Orthoview orthopedic digital pre-operative planning software. The software allowed an assessment of whether limb axis correction could be performed only by bone cuts. The surgeon assessed the possibility of soft tissue balancing, deformation severity, quality of posterior capsule and collateral ligaments. The age, weight and activity level of the patients were also taken into consideration when choosing the type of implant. Most of the patients in the analyzed cohort required standard condylar implants, with or without a stem. Older, obese and inactive patients were more likely to receive stemmed condylar or semi-constrained knee implants; however, the final decision was made intraoperatively with regard to knee stability and bone quality. If a full release of the medial collateral ligament was necessary, or severe joint destruction with insufficient collateral ligaments was noted that made joint balancing impossible, a constrained rotating-hinge implant was chosen. Additional reconstruction materials (augments and cones) were used for bone loss management. Information regarding the type of used implant and etiology are presented in Table 2.
All operations were performed by one surgeon, the senior author of the study, with the use of tourniquet through the whole procedure. The mid-line incision and medial para-patellar approach was used for varus and neutral knees, and a lateral approach was used for valgus knees. For severe contractures, extensive exposures including quadriceps snip and/or tibial tubercule osteotomy were performed. No patient underwent metalwork removal during TKA. In all cases, proper patella tracking, full extension and knee flexion were checked by the end of surgery.
For patients who underwent multiple procedures on the operated limb, restorable bone graft substitutes with antibiotic beads (Herafill beads G, Heraeus Medical, Wehrheim, Germany) were inserted to medullary canals as an antibacterial prophylaxis. Allografts were not implanted, but BoneSave (Stryker, USA) bone substitute was needed in one case.
Radiological analysis was used to assess the quality of fixation of the components according to the Knee Society Roentgenographic Evaluation and Scoring System.14 The Knee Society Clinical Rating System (KSS)15 and Western Ontario and McMaster Universities Arthritis Index (WOMAC)16 were used for clinical assessment. Clinical data including preoperative and final follow-up range of motion, septic complications, complications related to prednisolone application, including wound healing problems, were analyzed. The data from the first preoperative assessment and those from a one-year follow-up visit were used for calculations.
Informed consent was obtained from patients for participation in the study. This study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki. This study was approved by Bioethics Committee of the institution of the first author of the study (30/PB/2018).
Statistica version 13.1 (Dell Inc 2016) was used for statistical analysis. Levene’s test was used to test the normality of distribution. Student’s T-test for dependent samples was used to compare demographical data, WOMAC score, functional and clinical KSS score, and range of motion. A p-value <0.05 was considered to be significant.