• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.427-434
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• 2019

Purpose: This study evaluated the long term clinical and radiographic results and the survival rates of unicompartmental knee arthroplasty (UKA). In addition, the factors affecting the survival of the procedure were analyzed and the survival curve was compared according to the affecting factors. Materials and Methods: Ninety-nine cases of UKA performed between December 1982 and January 1996 were involved: 10 cases with Modular II, 44 cases with Microloc, and 45 cases with Allegretto prostheses. The mean follow-up period was 16.5 years. Clinically, the hospital for special surgery (HSS) scoring system and the range of motion (ROM) were evaluated. Radiographically, the femorotibial angle (FTA) was measured. The survival rate was analyzed using the Kaplan-Meier method. Cox regression analysis was used to identify the factors affecting the survival according to age, sex, body mass index, preoperative diagnosis, and type of implant. The Kaplan-Meier survival curves were compared according to the factors affecting the survival of UKA. Results: The overall average HSS score and ROM was 57.7 and 134.3° preoperatively, 92.7 and 138.4° at 1 year postoperatively, and 79.1 and 138.4° at the last follow-up (p<0.001, respectively). The overall average FTA was varus 0.8° preoperatively, valgus 4.1° at postoperative 2 weeks, and valgus 3.0° at the last follow-up. The overall 5-, 10-, 15- and 20-year survival rates were 91.8%, 82.9%, 71.0%, and 67.0%, respectively. The factors affecting the survival were the age and type of implant. The risk of the failure decreased with age (hazard ratio=0.933). The Microloc group was more hazardous than the other prostheses (hazard ratio=0.202, 0.430, respectively). The survival curve in the patients below 60 years of age was significantly lower than those of the patients over 60 years of age (p=0.003); the survival curve of the Microloc group was lower compared to the Modular II and Allegretto groups (p=0.025). Conclusion: The long-term clinical and radiographic results and survival of UKA using old fixed bearing prostheses were satisfactory. The selection of appropriate patient and prosthesis will be important for the long term survival of the UKA procedure.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.89-94
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• 2009

Purpose: The purpose of this study was to evaluate the factors affecting the treatment results of medial meniscus posterior horn tear. Materials and Methods: Forty seven patients who had been performed the arthroscopic surgery for medial meniscus posterior horn tear were enrolled in this study. We analyzed the clinical outcomes with Lysholm score and Tegner activity score in accordance with the factors such as patients' age, tibiofemoral angle, uptake in bone scintigraphy, surgical methods and patterns of meniscal tears, respectively. Results: The patients' age didn't affect to the results, but the preoperative tibiofemoral angle over valgus $4^{\circ}$ and the preoperative normal uptake in scintigraphic assessment showed a positive influence on the clinical outcomes. The partial meniscectomy and repair in surgical methods had no statistically significance. In addition, the pattern of meniscal tear did not have an effect on the clinical results. Conclusion: We can conclude that many factors should be considered to get satisfactory results. Among them, preoperative bone scintigraphy may be a good assessment factor for the postoperative prognosis, reflecting the condition of meniscal tear and the periarticular bone and soft tissue.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.31-38
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• 2011

This study aimed to determine the effects of the blockage of visual feedback on joint dynamics of the lower extremity. Fifteen healthy male subjects(age: $24.1{\pm}2.3\;yr$, height: $178.7{\pm}5.2\;cm$, weight: $73.6{\pm}6.6\;kg$) participated in this study. Each subject performed single-legged landing from a 45 cm-platform with the eyes open or closed. During the landing performance, three-dimensional kinematics of the lower extremity and ground reaction force(GRF) were recorded using a 8 infrared camera motion analysis system (Vicon MX-F20, Oxford Metric Ltd, Oxford, UK) with a force platform(ORG-6, AMTI, Watertown, MA). The results showed that at 50 ms prior to foot contact and at the time of foot contact, ankle plantar-flexion angle was smaller(p<.05) but the knee joint valgus and the hip flexion angles were greater with the eyes closed as compared to with the eyes open(p<.05). An increase in anterior GRF was observed during single-legged landing with the eyes closed as compared to with the eyes open(p<.05). Time to peak GRF in the medial, vertical and posterior directions occurred significantly earlier when the eyes were closed as compared to when the eyes were open(p<.05). Landing with the eyes closed resulted in a higher peak vertical loading rate(p<.05). In addition, the shock-absorbing power decreased at the ankle joint(p<.05) but increased at the hip joints when landing with the eyes closed(p<.05). When the eyes were closed, landing could be characterized by a less plantarflexed ankle joint and more flexed hip joint, with a faster time to peak GRF. These results imply that subjects are able to adapt the control of landing to different feedback conditions. Therefore, we suggest that training programs be introduced to reduce these injury risk factors.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.1
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• pp.66-72
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• 2004

Purpose: To evaluate the compensatory mechanism in vivo and develop the treatment guide by performing the comprehensive functional tests of the posterior cruciate ligament (PCL) deficient subjects. Material and Methods: 10 PCL deficient subjects and 10 healthy control group were evaluated. Performed functional tests were range of motion, posterior drawer test, Telos, 30$^{\circ}$ flexion wt-bearing view, KT-1000 arthrometer, gait analysis, EMG test and isokinetic tests. Results: Physical, KT-1000, Telos posterior tests showed significant differences, but 300 full weight bearing lateral view, muscle strength test revealed no difference between two groups. Less knee flexion at initial contact and reduced maximum valgus moment were observed in PCL deficient group. In vertical drop landing, PCL group had increased plantar flexion angle at initial contact. Conclusion: Compensatory mechanisms such as reduced unstable components and absorbing the maximal load of the joint were occurred after PCL insufficiency, which result in good clinical and functional outcomes. Further investigations would be needed to understand the functional adaptations of PCL deficient subjects.

• Journal of the Korean Arthroscopy Society
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• v.12 no.2
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• pp.107-111
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• 2008

Purpose: To evaluate the clinical and radiographical results of arthroscopic meniscectomy in patients aged over 50 with minimum 3-year follow-up. Materials and Methods: Of the patients who had undergone arthroscopic meniscectomies between Dec. 1997 and Dec. 2003, 36 patients(36 knees) were available for retrospective evaluation. The average age at the time of surgery was 56.4 years and the mean follow-up period was 63 months. According to the Kellgren-Lawrence classification, grade I change were noted in 16 patients, II in 12, III in 6 and IV in 2. According to Outerbridge classification, grade I articular lesions were noted in 16 patients, II in 10, III in 7 and IV in 3. Postoperative Lysholm score, patient s subjective satisfaction and radiographic changes were evaluated retrospectively. Results: Twenty-four patients(66.7%) were good or excellent for the Lysholm score and 26 patients(72.2%) were satisfied at final follow-up. Tibiofemoral angle was changes from mean valgus 3.9 degrees to mean valgus 2.6 degrees and 22 patients(61.1%) showed the progression of osteoarthritic changes. Conclusion: The satisfactory results could be obtained in 72.2% of patients aged over 50 with a minimal follow-up of 3 years after arthroscopic meniscectomy. The results tended to be worse in patients with moderate or severe tibiofemoral osteoarthritic changes or with articular cartilage lesions.