PurposeTo identify the modes of failure after total knee arthroplasty (TKA) in patients >55 years of age and to compare with those >55 years of age in patients who underwent revision TKA.Materials and MethodsWe retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between the groups.ResultsThirty-one revision TKAs were performed in patients ≤55 years of age at the time of primary TKA, whereas 225 cases were in those >55 years of age at primary TKA. In the ≤55 years of age group, the most common cause of TKA failure was polyethylene wear (45%) followed by infection (26%) and loosening (17%). The interval from primary TKA to revision was 8.6 years (range, 1 to 17 years). There were relatively lower infection rate and higher loosening rate in patients ≤55 years of age, but the difference was not statistically significant.ConclusionsThe main causes of failure after TKA in patients ≤55 years of age were polyethylene wear, infection and loosening, and there was no significant difference in the modes of failure after TKA between the two groups.

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BackgroundWe would like to analyze the risk factors of no thumb test among knee alignment tests during total knee arthroplasty surgery.MethodsThe 156 cases of total knee arthroplasty by an operator from October 2009 to April 2010 were analyzed according to preoperative indicators including body weight, height, degree of varus deformity, and patella subluxation and surgical indicators such as pre-osteotomy patella thickness, degree of patella degeneration, no thumb test which was evaluated after medial prepatella incision and before bone resection (1st test), no thumb test which was evaluated with corrective valgus stress (2nd test, J test), and the kind of prosthesis. We comparatively analyzed indicators affecting no thumb test (3rd test).ResultsThere was no relation between age, sex, and body weight and no thumb test (3rd test). Patellar sulcus angle (p = 0.795), patellar congruence angle (p = 0.276) and preoperative mechanical axis showed no relationship. The 1st no thumb test (p = 0.007) and 2nd test (p = 0.002) showed significant relation with the 3rd no thumb test. Among surgical indicators, pre-osteotomy patella thickness (p = 0.275) and degeneration of patella (p = 0.320) were not relevant but post-osteotomy patellar thickness (p = 0.002) was relevant to no thumb test (3rd test). According to prosthesis, there was no significance with Nexgen (p = 0.575). However, there was significant correlation between Scorpio (p = 0.011), Vanguard (p = 0.049) and no thumb test (3rd test). Especially, Scorpio had a tendency to dislocate the patella, but Vanguard to stabilize the patella.ConclusionsNo thumb test (3rd test) is correlated positively with 1st test, 2nd test, and post-osteotomy patella thickness. Therefore, the more patella osteotomy and the prosthesis with high affinity to patellofemoral alignment would be required for correct patella alignment.

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Purpose:We wanted to assess the relations between age and the outcome of unicompartmental knee arthroplasty (UKA) based on a comparative study of UKA patients younger than 60 years and UKA patients older than 60 years of age. Materials and Methods: Among the patients who underwent a UKA between January 2002 and June 2003, 230 cases (the group of patients with ages under sixty consisted of 89 knees -group I, and the group of patients with ages over sixty consisted of 141 knees -group II) were followed up for at least 5 years after the operation. Clinical assessments were made using the Knee Society Score (KSS) rating system. Results: The average KSS knee and function scores improved from 54.2 and 57.1 preoperatively to 87.3 and 85.2 at the last follow-up in group I, and from 54.7 and 54.3 to 89.5 and 81.7 in group II, respectively. The mean range of knee motion also improved from 129.4 o to 132.9 o in group I and from 126.8 o to 133.2 o in group II, respectively. There were 5 cases of failed UKAs in each group, and the survival rate of the implant at 5 years was 94.7% in group I and 96.6% in group II. Conclusion:The clinical results of UKA were satisfactory in both age groups. Group I had better results on the knee function score at the last follow-up, but there was no significant difference between both age groups. UKA can be a one of the reliable methods for the treatment of osteoarthritis in patients younger than 60 years of age. 7,22,30,32) . 이에 저자들은 60세 미만의 상대적으로 젊은 환자와 60세이상의 고령의 환자에서 시행한 슬관절 부분치환술의 임