The Effect of a Lumbar Spinal Lesion on the Clinical Results of Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: Patients with osteoarthritis of knee joint often concomitantly suffer from degenerative disease of the spine. Furthermore, resulting spinal problems could influence function and pain after total knee arthroplasty (TKA), and hence, cause the results of TKA to be misinterpreted. The purpose of this prospective study was to evaluate the effect of spinal disorders, as assessed by Swiss Spinal Stenosis score (SSS scores), on knee function as assessed by knee scores, the Hospital for Special Surgery scale (HSS scale) and Western Ontario & McMaster Osteoarthritis Index scores (WOMAC scores) in patients that after TKA. MATERIALS AND METHODS: One hundred and forty nine osteoarthritic knees of 87 patients were enrolled in this study. All patients received TKA by single surgeon (W-S Cho) from August 2009 to May 2010. Preoperative and postoperative 1- and 2-years HSS scale, Knee, WOMAC, and SSS scores were recorded and analyzed. RESULTS: Postoperative HSS scale, Knee, and WOMAC scores showed marked improvements versus preoperative scores, and scores at 2 years postoperatively were better than at 1 year postoperatively. No significant correlation was found between postoperative Knee scores and SSS scores. On the other hand, statistically significant correlations were found between HSS and SSS scores and between WOMAC and SSS scores. Interestingly, differences between Knee scores and HSS scores were found to be significantly correlated with SSS scores. CONCLUSION: When evaluating outcome after TKA, spinal problems should be investigated concomitantly. SSS scores appear to provide a suitable means of assessing spinal problems.

Results of Two Stage Revision of Infected Total Knee Arthroplasty (A Minimum 5-year Follow-up Analysis) / 대한정형외과학회잡지

PURPOSE: We report the results of 26 cases of revised total knee joint arthroplasty (TKA) that were followed up for more than 5 years. MATERIALS AND METHODS: On a retrospective basis, we reviewed 26 cases of infected TKA that underwent 2-stage revision between January 1993 and June 2005. All cases were followed up for more than 5 years. Clinical results were evaluated using Range Of Motion (ROM), Hospital for Special Surgery (HSS) score and radiographic results as part of the Knee Society Roentgenographic evaluation and Scoring system. The mean follow-up period was 70 months (ranging from 60 to 108 months). RESULTS: Infection recurred in 3 out of 26 cases. Patients without recurrence of infection showed improvement in ROM and HSS score, which had decreased with time (p<0.001) (ROM: pre-op. 47.1degrees, 1-year 89.5degrees, 2-year 87.1degrees, last follow-up 79.2degrees and HSS score: pre-op. 54.5, 1-year 85.7, 2-year 84.5, last follow-up 80.7). CONCLUSION: Infection recurred in 11.5% after revision arthroplasty. Outcomes of stage 2 revision arthroplasty were satisfactory at early follow-up, but worsened at the last follow-up.

Evaluation of the Chondromalacia Patella Using a Microscopy Coil: Comparison of the Two-Dimensional Fast Spin Echo Techniques and the Three-Dimensional Fast Field Echo Techniques

OBJECTIVE: We wanted to compare the two-dimensional (2D) fast spin echo (FSE) techniques and the three-dimensional (3D) fast field echo techniques for the evaluation of the chondromalacia patella using a microscopy coil. MATERIALS AND METHODS: Twenty five patients who underwent total knee arthroplasty were included in this study. Preoperative MRI evaluation of the patella was performed using a microscopy coil (47 mm). The proton density-weighted fast spin echo images (PD), the fat-suppressed PD images (FS-PD), the intermediate weighted-fat suppressed fast spin echo images (iw-FS-FSE), the 3D balanced-fast field echo images (B-FFE), the 3D water selective cartilage scan (WATS-c) and the 3D water selective fluid scan (WATS-f) were obtained on a 1.5T MRI scanner. The patellar cartilage was evaluated in nine areas: the superior, middle and the inferior portions that were subdivided into the medial, central and lateral facets in a total of 215 areas. Employing the Noyes grading system, the MRI grade 0-I, II and III lesions were compared using the gross and microscopic findings. The sensitivity, specificity and accuracy were evaluated for each sequence. The significance of the differences for the individual sequences was calculated using the McNemar test. RESULTS: The gross and microscopic findings demonstrated 167 grade 0-I lesions, 40 grade II lesions and eight grade III lesions. Iw-FS-FSE had the highest accuracy (sensitivity/specificity/accuracy = 88%/98%/96%), followed by FS-PD (78%/98%/93%, respectively), PD (76%/98%/93%, respectively), B-FFE (71%/100%/93%, respectively), WATS-c (67%/100%/92%, respectively) and WATS-f (58%/99%/89%, respectively). There were statistically significant differences for the iw-FS-FSE and WATS-f and for the PD-FS and WATS-f (p < 0.01). CONCLUSION: The iw-FS-FSE images obtained with a microscopy coil show best diagnostic performance among the 2D and 3D GRE images for evaluating the chondromalacia patella.

Patellar Thickness in Korean Osteoarthritic Women

PURPOSE: The patellar thickness is one of the most important factors that affect patellar tracking in patients who undergo total knee arthroplasty (TKA). The purpose of this study is to help the surgeons who perform TKA by presenting basic data on the patellar thickness of the osteoarthritic Korean women. MATERIALS AND METHODS: From January 2006 to May 2007, we measured the patellar thickness of 330 patients (538 cases) who were undergoing TKA. The thickest portion of the patella was measured on a scale of 0.01 mm with using an electronic caliper before patellar osteotomy. We analyzed the data to determine the relationships between the patellar thickness and the patients' age, height, weight and BMI, and the osteoarthritic change of the patella. RESULTS: The average thickness was 21.37+/-1.43 mm. There was a statistically significant positive relation of patellar thickness with weight and height and a negative relation with the degree of osteoarthritis. Age and BMI were not related with the patellar thickness. CONCLUSION: The average thickness was 21.37+/-1.43 mm and it was closely related with weight and height and the osteoarthritic change of the patella.

Unstable Total Knee Arthroplasty

Instability after total knee arthroplasty (TKA) is directly related with the success of an operation. It has been reported that about 10~22% of revisions are caused by instability. The patient's satisfaction is diminished from the early stage of the postoperative period due to pain, recurrent swelling and difficulty when walking. Complications such as infection, wear and the loosening rate are also increased. There are many factors causing unstable TKA. Among the patients factors, neuromuscular pathology, other joint deformity and clinical obesity may play a role. These factors can be avoided by careful preoperative evaluation of patients. Yet the most common causes of instability are from the surgical technique, including the size of the implant, the alignment, gap balancing, soft tissue release and the patella tracking. Surgeons can achieve stable joint by performing a proper surgical procedure. Postoperatively trauma and overuse may provoke instability and patients can feel an unstable knee as a result of wear and loosening. Knee instability can be classified into the instability of flexion and extension, genu recurvatum and global instability. The first step to treat instability is to detect the causes of instability. The second step, of course, is to correct the causes. Either conservative treatment or revision surgery can be chosen according to the degree and causes of instability. Because the result of revision treatment is not as successful as primary TKA, careful evaluation of the patient as well as a meticulous surgical procedure should done for revision TKA.

Pain in Patients Evaluated in Outpatient Orthopaedic Clinics

PURPOSE: We performed this study to assess pain in patients seen in member outpatient orthopaedic clinics of the Korean Knee Society (KKS). MATERIALS AND METHODS: We organized a committee for the study of knee joint pain. The committee designed a questionnaire form consisting of 11 items related to pain. One hundred thirty-five regular members of the KKS asked all patients visiting their respective outpatient clinics during May 2007 to complete the questionnaire form. Although 12,418 patients agreed to fill out the questionnaire form, we only analyzed the questionnaire forms of 9,578 patients who answered completely. RESULTS: 1. Approximately 85% of patients visiting outpatient orthopaedic clinics complained of pain. 2. The average degree of pain was more than moderate, and 72% of patients simply desired to be free of pain. 3. Seventeen percent of patients thought their physicians underestimated their pain. 4. Regarding agreement in the assessment of pain between physicians and patients, there was low level of agreement by numeric rating scale, but a high level of agreement based on a mild/moderate/severe grading scale. 5. Approximately one-third (36.2%) of patients had used additional treatments for pain relief on top of their prescribed medications. CONCLUSION: Eighty-five percent of patients complained of pain, and two-thirds of them were primarily focused on its relief in their visit to the outpatient clinic. Hence, we should heed pain management itself as an important goal in treating orthopaedic patients.

Bonding Strength between Cement and an Implant according to the Cementing Time / 대한정형외과학회잡지

PURPOSE: The objective of this study was to compare the bonding strength between cement and an implant according to the cementing time. MATERIALS AND METHODS: The two types of cement used were CMW(R) 1 and 3 (Depuy Ltd., Blackpool, UK). Plastic molds containing CMW(R) 1 were pressed onto metal blocks at 2, 4, 5 or 6 minutes after mixing the cement, while molds containing CMW(R) 3 were pressed onto blocks at 3, 5, 6 or 7 minutes after mixing the cement. Tensile strength was tested with using an Instron Model 8874 (Instron Corp., Canton, MA, USA). Tensile strengths were compared using the Kruskal-Wallis test and the Mann-Whitney U test. RESULTS: The strongest bonding strengths for the tensile load were at 2 minutes post-mixing for CMW(R) 1, and at 3 minutes post-mixing for CMW(R) 3. The strength rapidly decreased after 5 minutes for CMW(R) 1 and after 6 minutes for CMW(R) 3. CONCLUSION: This study suggests that the risk of loosening between cement and an implant is likely to be minimized by the surgical technique that considers the bonding strength according to time.

The Methods and Results of Revision Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: To suggest operative methods for revision total knee arthroplasty (TKA) according to the causes of revision surgery. MATERIALS AND METHODS: The operative methods of 70 revision total knee arthroplasties in 64 patients between December 1996 and December 2004 were analyzed according to the causes. The mean follow-up period was 65 months (25-120 months). The range of motion and Hospital for Special Surgery (HSS) score were used for the clinical evaluation and the scoring system of American Knee Society was used for the radiographic evaluation. RESULTS: The mean periods of revision surgery from the initial operation was 59 months (1 month-20 years). Posterior cruciate retaining prosthesis was used in 8 cases, posterior cruciate substituting prosthesis in 14 cases, and constrained type prosthesis in 48 cases. The extension stem was required in 51 cases, metal augmentation in 34 cases, and structural allograft in 15 cases for bone defect treatment and firm fixation. The average range of motion improved from 88.8o preoperatively to 105.8o at the final follow-up. HSS score also improved from 60.5 to 87.6 points. The complications after revision TKA were 3 infections (4.3%), 1 patellar dislocation (1.4%), and 1 polyethylene dislocation (1.4%). CONCLUSION: Constrained type prostheses were needed in many cases of revision TKA. Satisfactory results were obtained using an additional structural allograft, metal augmentation, and extension stem for bone defect treatment and firm fixation.

The Causes of Revision Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: To assess the causes of revision total knee arthroplasty (TKA). MATERIALS AND METHODS: The causes of 90 revision total knee arthroplasties were analyzed in 84 patients between December 1996 and June 2006. The patients' history, medical records and radiographs were reviewed in order to detect the main cause of failure of the primary TKA. RESULTS: The causes of revision TKA are as follows: 34 infections (37.8%), 26 loosenings (28.9%), 17 polyethylene wears or breakages (18.9%), 5 stiffness (5.6%), 4 polyethylene dislocations (4.4%), 2 patellar dislocations (2.2%), 1 patellar component failure and 1 instability (1.1%). The mean interval from the index operation to the revision surgery was 59 months (1 month-20 years). CONCLUSION: Infection was the most common causes of revision TKA followed by loosening, wear or breakage of the polyethylene, stiff knee, and dislocation of the polyethylene.

Mucoid Degeneration of Anterior Cruciate Ligament: Correlation between MR Imaging and Pathologic Findings in Patients with Osteoarthritis of the Knee

PURPOSE: To evaluate the mucoid degeneration (MD) of the anterior cruciate ligament (ACL) of the knee by correlation of MRI findings with pathology, in the patients with osteoarthritis (OA). MATERIALS AND METHODS: This study included 17 patients (mean 68.8 years old) who underwent preoperative MRI. In proton density-weighted sagittal and coronal images ACLs were evaluated for the thickness and signal intensity (SI). Total knee replacement arthroplasty was performed and the pathologic findings of ACL were evaluated. MD was classified as 3 grades according to the degenerated amount in microscopy. Thickness and SI was evaluated as normal or increased on MRI. RESULTS: All of the 4 patients who showed thickened ACL showed increased SI on MRI. All of the 8 patients with increased SI of the ACL on MRI had MD in the ACL. However, remained 9 patients also had MD, in spite of their normal thickness and SI on MRI. Calcification was seen in 5 patients. CONCLUSION: Eight cases who showed ACL thickening or increased SI on MRI were well correlated with MD, however, because the other nine cases who showed normal thickness and normal SI of ACL on MRI also showed MD in pathology, normal MRI finding should not exclude the possibility of MD of ACL.

Anterior Knee Pain in Osteoarthritis of the Knee

PURPOSE: The purpose of this study were to evaluate the relationship between anterior knee pain and changes of patellofemoral joint in osteoarthritic knee. MATERIALS AND METHODS: We analyzed 200 patients who had undergone total knee arthroplasty and divided them into two groups ; the group 1(100 cases) with anterior knee pain and the group 2(100 cases) without it. We prospectively measured congruence angle and patellar height, and compared radiologic degenerative changes and operative findings(Outerbridge classification) of patella. RESULTS: The average congruence angle of patella was 11.2+/-1.6degrees in the group 1 and 2.8+/-1.3degrees in the group 2(p<0.05). Patellar height had no significant difference between two groups(p=0.62).For radiologic patellofemoral(PF) degenerative change, the group 1 showed mild degenerative change in 16 , moderate change in 47 and severe change in 37 in plain radiographs. The group 2 showed mild degenerative change in 53 and moderate change in 47 in plain radiographs(p<0.05). For cartilage degenerative change in patella(Outerbridge classification), whereas grade 3&4 were dominant in the group 1 with 71 cases, grade 1&2 were representative in the group 2 with 91 cases(p<0.05). CONCLUSION: Anterior knee pain seemed to be related with congruence angle and degenerative changes in radiologic and operative findings.

Pain after Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: This study examined the factors affecting pain, the pattern of pain, as well as the intensity and duration after a total knee arthroplasty. MATERIALS AND METHODS: As a prospective study, 69 osteoarthritic knee patients who underwent total knee arthroplasty from Jan. 2004 to Nov. 2004, were examined using a visual analogue scale (VAS) in order to determine the pain intensity, duration, pain character and pattern at 6 weeks, 3 months, 6 months and 1 year after surgery. We checked for possible factors such as height, body weight, body mass index (BMI), HSS score, deformity, range of motion preoperatively, prosthesis type and operation procedure intraoperatively, the HSS score and range of motion at postoperative one year. The Pearson correlation test and Kruskal-Wallis test were used for statistical analysis. RESULTS: The mean preoperative and 1-year postoperative HSS score was 61.4 and 94.6, respectively. The height, body weight, body mass index (BMI), HSS score, deformity, range of motion, prosthesis type and surgical procedure were not related to the intensity and duration of the pain. The mean postoperative VAS score at 6 weeks and 3, 6 and 12 months was 4.3+/-1.0, 2.7+/-0.9, 1.6+/-0.4, 1.3+/-0.4, respectively. Five patients had mild pain until postoperative one year. CONCLUSION: The pain after total knee arthroplasty disappeared with time. However, mild knee pain sometimes remained even 1 year after surgery.

The Effect of Intraoperative Regional Analgesic Injection in Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: This study was performed to evaluate the effect and complications of an intraoperative regional analgesic injection in primary total knee replacement arthroplasty (TKRA). MATERIALS AND METHODS: As a prospective study, 50 patients who underwent bilateral TKRA were injected with 50 cc of mixed analgesics (morphine, norepinephrine and epinephrine) into the joint capsule, muscles around the knee joint on one side (study side) and the same amount of the normal saline on the other side (control side) before closure. The level of postoperative pain was evaluated in the visual analogue scale (VAS) at postoperative 4 hours, 12 hours, 1, 2, 4, 7, 14 days. The range of motion at postoperative 4, 7, and 14 days, the amount of hemovac drainage and the patients preference were also evaluated. RESULTS: There was a significant decrease in the VAS on the study side at postoperative 4 hours, 12 hours and 1 day (p0.05). CONCLUSION: An intraoperative regional analgesic injection in primary TKRA is effective in reducing the level of acute postoperative knee pain with minimal complications with the majority of patients preferring it.

The Effect of Elastic Stocking Application after Total Knee Arthroplasty

PURPOSE: To know the effect of elastic stocking on reducing edema and preventing deep vein thrombosis(DVT) after total knee arthroplasty(TKA). MATERIALS AND METHODS: One hundred patients who had received simultaneous bilateral TKA was prospectively evaluated. One extremity was accoutered with elastic stocking while the other, not. The lower extremity circumference was measured at postopertive 2, 5, 7 and 10 days. The patient's satisfaction was asked by means of a questionnaire. We evaluated the DVT case also. RESULTS: The thigh and calf circumferences of elastic stocking side were average 0.70 cm and 0.58 cm shorter than those of non-stocking side, this was found to be statiscally insignificant(p>0.05). Satisfaction rate was 76%. One case of DVT occurred in each of the two groups. CONCLUSION: Elastic stocking application after TKA cannot be expected to reduce lower extremity edema or to prevent DVT. However, the satisfaction rate was high.

Gap Discrepancy in Posterior Cruciate Ligament-Sacrificing Total Knee Joint Arthroplasty

PURPOSE: To evaluate the effects of PCL (posterior cruciate ligament) resection on the flexion and extension gap during TKA (total knee joint arthroplasty). MATERIALS AND METHODS: From December 2002 to August 2003, we quantitatively measured and ana-lyzed prospectively the flexion and extension gap before and after PCL resection during TKA in 26 cases among 23 patients of osteoarthritis. A tensioning device was used to measure the gap and a torque wrench attached to the device was used to apply constant force. RESULTS: Before resection, the average flexion gap was 24.9 mm and the average extension gap was 25.3 mm. After resection, the average flexion gap was 29.8 mm and average extension gap was 27.6 mm. The extension gap was increased 2.2 mm and the flexion gap was increased 4.9 mm which implies that using a thicker polyethylene insert would be favorable after PCL resection. CONCLUSION: After PCL resection, both flexion and extension gaps were increased but the flexion gap was increased more than the extension gap.

Effect of Norepinephrine Irrigation in Primary Total Knee Replacement Arthroplasty / 대한정형외과학회잡지

PURPOSE: We studied the effect of norepinephrine irrigation during total knee replacement arthroplasty (TKRA) on blood loss reduction. MATERIALS AND METHODS: A prospective study of 30 patients who received TKRA from the same surgeon between March 2003 and November 2003, was done. Patients were alternately allocated into two groups. The study group included 15 cases in which 1: 200, 000 diluted norepinephrine was used for irrigation intra-operatively, whereas the control group included 15 cases received normal saline irrigation. Postoperative drain and transfusion amounts were compared between the two groups using the independent t-test. RESULTS: Early bleeding amounts for 6 hours after surgery were a significant difference between the two groups (study group 410.3 cc, control group 517.3 cc, p-value=0.03). However, delayed bleeding amounts during postoperative 6-48 hours (study group 163.8 cc, control group 244.7 cc, p-value=0.05) and transfusion amounts (study group 0.80 unit, control group 1.47 unit, p-value=0.07) were smaller in the study group, but showed no significant differences. CONCLUSION: Using norepinephrine diluted in normal saline as an irrigation solution during TKRA can be considered for reducing early post operative bleeding.

Total Knee Arthroplasty in Stiff Knee

PURPOSE: To evaluate the results of TKRA (Total knee replacement arthroplasty)for the treatment of stiff knee. METHODS & MATERIALS: TKRA has been performed for 18 cases of stiff knee ( ROM < 50 degrees ) between January 1994 and December 2000. 16 cases which have been followed up for more than 2 years were analysed. Average follow-up was 3.3 years(2-6 years). 3 were male and 13 were female. The average age was 55.8 years(34-75years). Sequales of infection were most with 6 cases and followed by osteoarthritis (4 cases, 2 cases had been performed arthroscopic debridement) and rheumatoid arthritis (3 cases) and traumatic arthritis (3 cases) in order. TKRA was performed on average 12.2 years (1-40 years) after knee stiffness has been developed. We evaluate the results with ROM, HSS score and complications. RESULTS: Average ROM was increased from 31.6 degrees(0 degrees-50 degrees) preoperatively to 95.4 degrees(80 degrees-120 degrees) postoperatively. 5 degrees of flexion contracture was present in only 1 case. Average HSS score was improved from 59.6 points preoperatively to 84.6 points postoperatively. The patella tendon was partially ruptured in 1 case during surgery, but by brace application and rehabilitative exercise, ROM was improved to 90 degrees, 1 year post operatively. There were 1 superficial skin infection which was resolved by revision of wound and skin graft, and deep infection in 3 cases, which needed knee fusion finally. CONCLUSION: TKRA is a good method for improving function in knee stiffness although infection risk is high.

Mobile bearing joint in Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: To assess the clinical and radiological results of mobile bearing total knee arthroplasty using the LCS system and to analyse complications arising. MATERIALS AND METHODS: From Oct. 1992 to Dec. 1998, 135 cases of total knee arthroplasty was performed using the LCS mobile bearing system. Among those are evaluated 108 cases which were followed up for a mean of 4.8 years (3-9.2 years). Retrospective analysis was done by the clinical and radiological evaluations usinga ROM, tibio-femoral alignment, HSS score and radiological loosening. RESULTS: The preoperative mean HSS score (58.6) was improved to 89.5 at final follow up. Tibio-femoral angle changed from a varus of 3 degrees to a valgus of 5 degrees. Arc of motion was reduced from 121 degrees to 116 degrees in osteoarthritis and increased from 111 degrees to 118 degrees in rheumatoid arthritis. There were 16 cases of osteolysis, but no case provoked clinical problems or more than 4 points in the radiolucent score. Complications were one polyethylene dislocation and one intraoperative tibia plateau fracture. CONCLUSION: Mobile bearing knee system showed excellent and predictable clinical and radiological results at a mean 4.8 years follow-up.

Factors Affecting Range of Motion after Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: Restoration of range of motion (ROM) after total knee arthroplasty (TKA) greatly affects post-operative results. We analyzed various actors, including implant systems, to identify those factors affecting ROM in TKA. MATERIALS AND METHODS: 645 knees of 418 patients who received TKA from the same operator between June 1990 and May 1999 were analyzed. Knees were sorted according to patient (age, sex, body mass index, symptom duration, pre-operative ROM, and deformity), disease (osteoarthritis, rheumatoid arthritis, and osteonecrosis), implant (implant system, and thickness of spacer), operation (preservation or resection of the posterior cruciate ligament (PCL), and lateral release or not). Post-operative ROM was evaluated with a minimum 3 years of follow-up. RESULTS: Within 1 year after TKA, BMI, symptom duration, pre-opeative deformity, pre-operative ROM, and lateral release were found to significantly (p-value<0.05) affect post-operative ROM. At 2 years after TKA, BMI, pre-operative deformity, and pre-operative ROM were found to significantly affect post-operative ROM. At 3 years after TKA, post-operative ROM was significantly better for a wider pre-op. (p<0.0001), and in patients without lateral release (p<0.018). Underlying disease, the implant system used, and PCL treatment showed no significant difference. CONCLUSION: A better pre-operative ROM and no lateral release of the retinacular ligament showed a better post-operative ROM at 3 years after TKRA.

Modified Elmslie-Trillat Operation in Recurrent and Habitual Patella Dislocation

PURPOSE: To evaluate the effectiveness of the modified Elmslie-Trillat operation on recurrent and habitual patella dislocation. MATERIALS AND METHODS: From November 1993 to December 2000, 16 cases of modified Elmslie-Tril-lat operation were performed in 13 patients. Recurrent dislocation were 10 cases, habitual were 6 cases. Mean age was 26 years old(15~46) and male was 1 patient, female were 12 patients. We checked the Q angle and congruence angle to compare the postoperative state with the preoperative result by radiologic finding. Crosby and Insall's criteria was used to evaluate the clinical results. RESULTS: The congruence angle and Q angle were improved from average 46 degrees (10 degrees ~ 77 degrees) and 20.2 degrees(16 degrees ~35 degrees) in preoperative state to average -5 degrees (-10 degrees ~4 degrees) and 9.5 degrees(4 degrees~15 degrees) in postoperative state. Patella alta were 2 cases and patella baja was none in preoperative measurement. There was no change of patella alta in postoperative measurement. In Crosby and Insall 's criteria, 5 cases showed excellent, 10 cases good, l case poor result. At final follow-up, there were no postoperative complications such as degeneratve arthritis, nonunion, ROM limitation except 1 case of patellar redislocation. CONCLUSION: Modified Elmslie-Trillat operation is good alternatives to the recurrent and habitual patella dislocation.