Is Scapular Stabilization Exercise Effective for Managing Nonspecific Chronic Neck Pain?: A Systematic Review

Scapular stabilization is thought to have an important role in improving pain and dysfunction around the neck and shoulders, but evidence of this is lacking. We aim to systematically review the effect of a scapular stabilization exercise (SSE) on pain and dysfunction in patients with nonspecific chronic neck pain (NP). We searched the PubMed, EMBASE, CINAHL, and Cochrane Library databases using the terms (NP [MeSH] OR NP OR cervical pain OR neck ache OR cervicalgia) AND (scapular exercise OR periscapular exercise OR SSEs). We included suitable studies that met the study’s inclusion criteria. Among the 227 studies identified by our search strategy, a total of four (three randomized controlled studies and one prospective study) met the inclusion criteria. The SSE was intense. It included three sets of 10 repetitions. In most of the studies, the exercises were conducted 3 times per week. Most studies reported that the SSE improved pain and dysfunction in patients with nonspecific chronic NP; however, the reviewed articles did not use the same variables for measurement. Additionally, the sample size was small. Although several studies show that SSE might improve NP and dysfunction, the effects of SSE on pain and dysfunction in the neck region remain unclear because the number of studies was small. Further high-quality studies are necessary to identify the detailed effects of SSE in patients with NP.

Lumbar Extensor Muscle Size and Isometric Muscle Strength in Women with Symptomatic Lumbar Degenerative Diseases

STUDY DESIGN: A cross-sectional design. PURPOSE: To determine the characteristics of lumbar extensor muscle (LEM) size and isometric muscle strength and examine their correlations in women with lumbar degenerative diseases (LDDs). OVERVIEW OF LITERATURE: Many studies have evaluated the relationship between muscle size and strength, but the results have been controversial. METHODS: Seventy-four female patients (mean age, 66 years) who consecutively underwent posterior lumbar interbody fusion (L1–S1) were recruited. The cross-sectional area (CSA) of the back extensor muscles was measured between L1–2 to L5–S1, and the total sum of the CSAs at each disc level was calculated. Back extensor muscle strength was evaluated using a MedX lumbar extension machine. The Oswestry Disability Index (ODI, 0–100) and Visual Analog Scale (VAS, 0–10) of lower back pain were determined. RESULTS: The mean CSAs of the LEM at each level (L1/2–L5/S1) and the total sum were 34.3, 36.3, 35.1, 31.4, 21.9, and 156.2 cm2, respectively. The mean isometric strength at each angle (range, 0°–72°) was 32.5, 50.1, 72.0, 88.7, 100.7, 112.2, and 126.2 ft-lb, respectively. The mean ODI and VAS scores were 54.6 and 6.6, and the mean body weight and body mass index (BMI) were 59.9 kg and 24.9 kg/m2, respectively. The CSAs of the upper lumbar level (L1–4) and the total sum of the CSAs were associated with isometric strength, which was negatively correlated with patients’ age and ODI and positively associated with body weight and BMI, mainly at higher lumbar flexion angles (48°–72°). CONCLUSIONS: In women with LDD, LEM sizes of the upper lumbar levels (L1–4) were larger than those of the lower levels (L4–S1) and were positively associated with muscle strength. The upper lumbar levels in patients with LDDs appear to play a compensatory role when degenerative lesions are present in the lower lumbar levels.

The Effect of Individualized Exercise Parameters Applied to Two Patients Recovering from Implanted Left Ventricular Assist Devices in Korea / 대한스포츠의학회지

Left ventricular assist devices (LVADs) are a treatment option for patients with severe chronic heart failure. These patients are referred to an inpatient cardiac rehabilitation after implantation to improve an aerobic capacity and quality of life (QOL). Several studies have reported that an exercise therapy, which is a component of cardiac rehabilitation, improves exercise capacity and QOL. The LVADs were implanted successfully in a destination therapy in two Korean patients, and these patients were enrolled in the cardiac rehabilitation. After an individualized intervention, they were discharged from improved exercise functional capacity and QOL. This is the first report showing a benefit of the individualized exercise therapy using different parameters after LVADs implantation in Korea.

How to Minimize Rotational Conflict between Femoral & Tibial Component in Total Knee Arthroplasty: The Use of Femoro-Tibial Axial Synchronizer (Linker)

PURPOSE: The purpose of this study was to investigate the correlation between rotational axes of femur and tibia with the use of Linker. MATERIALS AND METHODS: This study was carried out from August 2009 to February 2010 on 54 patients (106 knees), who were diagnosed with simultaneous bilateral total knee arthroplasty. With the use of postoperative computed tomography scans, it was investigated how much the rotational angle of femoral and tibial components matched. RESULTS: The tibial component was internally rotated for the femoral component at an angle of 0.8degrees. The femoral component was externally rotated for the surgical transepicondylar axis (TEA) at an angle of 1.6 (range: from 4.8degrees of internal rotation to 7.9degrees of external rotation, SD=2.2degrees), and the tibial component was externally rotated for the surgical TEA at an average angle of 0.9 (range: from 5.1degrees of internal rotation to 8.3degrees of external rotation, SD=3.1degrees). CONCLUSION: The femoro-tibial synchronizer helped to improve the orientation and positioning of both femoral component and tibial component, and also increase the correlation of the rotational axes of the two components.

How to Minimize Rotational Conflict between Femoral & Tibial Component in Total Knee Arthroplasty: The Use of Femoro-Tibial Axial Synchronizer (Linker)

PURPOSE: The purpose of this study was to investigate the correlation between rotational axes of femur and tibia with the use of Linker. MATERIALS AND METHODS: This study was carried out from August 2009 to February 2010 on 54 patients (106 knees), who were diagnosed with simultaneous bilateral total knee arthroplasty. With the use of postoperative computed tomography scans, it was investigated how much the rotational angle of femoral and tibial components matched. RESULTS: The tibial component was internally rotated for the femoral component at an angle of 0.8degrees. The femoral component was externally rotated for the surgical transepicondylar axis (TEA) at an angle of 1.6 (range: from 4.8degrees of internal rotation to 7.9degrees of external rotation, SD=2.2degrees), and the tibial component was externally rotated for the surgical TEA at an average angle of 0.9 (range: from 5.1degrees of internal rotation to 8.3degrees of external rotation, SD=3.1degrees). CONCLUSION: The femoro-tibial synchronizer helped to improve the orientation and positioning of both femoral component and tibial component, and also increase the correlation of the rotational axes of the two components.

Investigation of Emergency Department Violence: Resident Survey

PURPOSE: The Korean Intern Resident Association and Korean Society of Emergency Medicine announced the 'Hospital violence response system' to secure patient safety and provide a health care provider countermeasures against hospital violence. The aim of this study is to investigate the response to hospital violence in the ER and which measures could improve the current status. METHODS: Emergency medicine residents in the Seoul, Incheon, Kyung-gi area participated in the survey. The questionnaire included 4 categories (1. Awareness of protocol, 2. Experience and countermeasure for hospital violence, 3. Understanding of protocol, 4. Suggestions to improve against hospital violence) RESULTS: Among 362 candidates, 236 (65.2%) participated in the survey. Only 7.6% of residents have not experienced hospital violence. In the group of people who were aware of the protocol, participants tended to be more familiar with processes of the hospital violence response protocol, and willing to deal with violence using a better systematic support. People did not counteract to hospital violence because the process was thought to be too complicated. Only 63 participants were actively involved in an official course for countermeasure. Participants suggested that police should deal more appropriately with hospital violence. CONCLUSION: The hospital violence response protocol is thought to have a positive effect on appropriate management of hospital violence. However, a multi-disciplinary approach to hospital violence from the hospital, police, and judicial authority should be developed.

Is Total Knee Arthroplasty a Viable Treatment Option in Octogenarians with Advanced Osteoarthritis?

PURPOSE: This study directly compared clinical assessment scores and short-term systemic complications after total knee arthroplasty (TKA) between a group of patients aged 80 or older (141 patients) and another group of patients aged between 65 and 70 years (616 patients) with advanced osteoarthritis. MATERIALS AND METHODS: We retrospectively investigated 757 osteoarthritic patients who underwent primary TKA from January 2007 to January 2011 with a follow-up of 1 year. The surgery was performed using an extramedullary alignment guide instrument without invasion of the intramedullary canal to decrease embolic load and blood loss. RESULTS: At 1 year after surgery, the mean Knee Society knee score was improved in both groups (from 63.6 to 83.2 in octogenarians and from 68.3 to 89.0 in the younger group) and the level of satisfaction was excellent in both groups (8 in octogenarians and 8.3 in the younger group), even though there was no notable change in function score in the octogenarians (from 61.0 to 61.9 in the octogenarians and from 62.3 to 73.6 in the younger group). The total incidence of systemic complications (3.4% vs. 1.2%, p=0.400) and surgical complications (2.1% vs. 0.5%, p=0.229) showed no significant difference between groups. CONCLUSIONS: TKA yielded favorable clinical outcomes with a comparatively low postoperative complication rate in octogenarians despite the negligible functional improvement.

The Clinical Outcomes of Exercise Therapy for a Soccer Player with Stress Fracture of Superior Pubic Ramus / 대한스포츠의학회지

Stress fractures are common injuries that begin with repetitive and excessive stress on the bone. It is very rare that stress fracture was occurred in pubis superior ramus in athletics, and the report concerning the exercise therapy for this fracture was not sufficient in the literature. We report of a case of a 17-year-old male soccer player who suffered from left inguinal pain due to the stress fracture of pubis superior ramus. He was conducted an exercise program that consisted of muscle strength, stretching, aerobic and functional exercise for 2 months. After this intervention, all muscle strength was significantly improved (17%) compared to baseline data, and also flexibility and range of motion were improved. This case shows that exercise therapy considered the cause and cyclic formation of bone remodeling is benefit to improve the exercise performance for a soccer player with superior ramus stress fracture.

Change of Lumbar Isometric Extensor Strengths after Posterior Lumbar Interbody Fusion in Patients with Lumbar Degenerative Disease

STUDY DESIGN: Prospective cohort study. OBJECTIVES: This study was undertaken to examine changes in lumbar isometric extensor strength after posterior lumbar interbody fusion (PLIF) surgery. SUMMARY OF LITERATURE REVIEW: In most reports, the patients that have undergone PLIF surgery have been shown to have muscle weakness and atrophy. However, the research conducted regarding the changes in muscle strength throughout a follow up period is insufficient. MATERIALS AND METHODS: Forty-nine patients (mean age, 65 years (range, 45 to 77)), scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases, were enrolled. Preoperatively and 3, 6, and 12 month after surgery, lumbar isometric extensor strength was assessed using a MedX instrument in 7 angular positions (0-72degrees). The mean isometric strength and rate of increase were calculated. Isometric strengths were compared according to patients' age ( or =70 years) and fusion level (short: or =3) and the respective relationships were analyzed. RESULTS: The mean isometric strength changed from 89.0 preoperatively to 85.3, 110.4, and 120.8 ft-lb at each follow-up, respectively. The rate of increase of strength was significantly greater at 0degrees(36.1 %) than at 72degrees(24.2 %) (p=0.019). Preoperative isometric strengths were similar in each age and fusion level group, but isometric strengths at the final follow-up were significantly lower in older patients and in the long level fusion group (p=0.002 and 0.043, respectively). Mean isometric strength at the last follow-up showed significant associations with age and fusion level (r=-0.431 and -0.317, p=0.002 and 0.030, respectively). CONCLUSION: After lumbar fusion surgery, back muscle strength slightly decreased until 3 months and then significantly increased. However, postoperative strength increases were lower in older patients and those in the long level (>3) fusion group. These results could be basic data for a rehabilitation program after lumbar fusion.

Characteristics of Back Muscle Strength in Patients with Scheduled for Lumbar Fusion Surgery due to Symptomatic Lumbar Degenerative Diseases

STUDY DESIGN: Cross sectional study. PURPOSE: To evaluate characteristics of back muscle strength in patients scheduled for lumbar fusion surgery. OVERVIEW OF LITERATURE: Little is known regarding muscle strength in patients with symptomatic lumbar degenerative diseases who require fusion surgery. METHODS: Consecutive 354 patients scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases were approached for participation. 316 patients were enrolled. Before surgery, muscle strength was assessed by measuring maximal isometric extension strength at seven angular positions (0degrees, 12degrees, 24degrees, 36degrees, 48degrees, 60degrees, and 72degrees) and mean isometric strength was calculated. The Oswestry Disability Index (0-100) and visual analogue scale (0-100) for back pain were recorded. Muscle strength was compared according to gender, age ( or =70 years) and scheduled fusion level (short, or =3). RESULTS: Isometric strength was significantly decreased compared with previously reported results of healthy individuals, particularly at extension positions (0degrees-48degrees, p0.05). Isometric strengths showed significant, but weak, inverse correlations with age and Oswestry Disability Index (r<0.4, p<0.05). CONCLUSIONS: In patients with symptomatic lumbar degenerative diseases, back muscle strength significantly decreased, particularly at lumbar extension positions, and in females and older patients.

Exercise Therapy for an Older Patient With Left Ventricular Assist Device

A left ventricular assist device (LVAD) is a mechanical circulation support implanted for patients with end-stage heart failure. It may be used either as a bridge to cardiac transplantation or as a destination therapy. The health of a 75-year-old man with a medical history of systolic heart failure worsened. Therefore, he was recommended to have implanted a LVAD (Thoratec Corp.) as a destination therapy. After the surgery, he was enrolled in patient cardiac rehabilitation for the improvement of dyspnea and exercise capacity. In results, there is an improvement on his exercise capacity and quality of life. For the first time in Korea, we reported a benefit of exercise therapy after being implanted with a LVAD.

Easy Identification of Mechanical Axis during Total Knee Arthroplasty

PURPOSE: We devised an intraoperatively identifiable mechanical axis (IIMA) as a reference of alignment in total knee arthroplasty (TKA). MATERIALS AND METHODS: Between February 2010 and January 2011, primary TKAs were consecutively performed on 672 patients (1007 knees) using an IIMA as a reference in the coronal plane. RESULTS: The alignment of the lower extremity improved from a mean of 11.4+/-6.7degrees (-10.3-34.4degrees) of varus preop. to 0.7+/-3.5degrees (-5.2-8.6degrees) immediately after surgery. Mean alignment of the femoral component in the coronal plane was 89.3+/-2.3degrees (83.4-97.2degrees) postop. and mean alignment of the tibial component was 90.4+/-2.2degrees (85.1-94.2degrees) postop. CONCLUSION: This study showed that IIMA could be of considerable value as a new guider of alignment that is easily accessible and highly effective during total knee arthroplasty.

Soft Tissue Balancing of Varus Arthritic Knee in Minimally Invasive Surgery Total Knee Arthroplasty: Comparison between Posterior Oblique Ligament Release and Superficial MCL Release

PURPOSE: To assess proper soft tissue balancing of the varus arthritic knee between posterior oblique ligament (POL) release group and superficial medial collateral ligament (SMCL) release group. MATERIALS AND METHODS: This retrospective study was performed on 186 patients who underwent minimally invasive surgery (MIS) total knee arthroplasty (TKA) from January 2011 to December 2011. Eighty-three patients were in the group of SMCL release and 103 patients were in the POL release group. We intended to use a 10 mm polyethylene insert (PE) during TKA, and retrospectively compared the actual thickness of PE between POL release group and SMCL release group. RESULTS: The mean PE thickness was 10.59+/-1.3 mm (range, 8 to 15 mm) in POL group and 11.88+/-1.8 mm (range, 10 to 18 mm) in SMCL group (p=0.001). We found a significant difference in the mean PE thickness between POL release group and SMCL release group. CONCLUSIONS: POL and deep MCL releases in MIS-TKA would be beneficial for varus deformity correction in the osteoarthritic knee.

Clinical Outcome of IM-Guided Total Knee Arthroplasty with Inappropriate Femoral Resection in Coronal Plane

PURPOSE: The purpose of this study was to evaluate clinical results and accuracy of femoral cutting in the coronal plane in total knee arthroplasty (TKA) using a fixed length intramedullary guide. MATERIALS AND METHODS: From 2005 to 2008, 101 patients (154 knees) underwent TKA (NexGen LPS implant). The minimal follow-up period was 3 years (mean, 4.4 years). The patients were divided into two groups (group 1, 94alpha, 98 or =2degrees MAD was 65 in group 1 and 24 in group 2. The mean PTA, KSKS, and KSFS were 10.17degrees, 96.0, and 96.6, respectively, in group 1 and 11.58degrees, 84.5, and 85.5, respectively, in group 2. CONCLUSIONS: The percentage of coronal alignment outliers was relatively high (34 in 154 cases, 22%) after TKA using a fixed length intramedullary guide. However, there was no statistically significant intergroup difference in clinical results (KSKS, p=0.67; KSFS, p=0.56).

Factors Correlated with the Reducibility of Varus Deformity in Knee Osteoarthritis: An Analysis Using Navigation Guided TKA

BACKGROUND: We hypothesized that a number of clinical and radiologic parameters could influence the reducibility of varus deformity in total knee arthroplasty. The aim of this study was to identify the factors correlated with reducibility of varus deformity and predict more accurately the amount of medial soft tissue release required in varus deformity total knee arthroplasty. METHODS: One hundred forty-three knees with preoperative varus alignment and medial osteoarthritis were included in this retrospective study. The total knee arthroplasties were performed using a navigation system (OrthoPilot) by single surgeon. To assess varus deformity, the authors measured preoperative mechanical axis angles and valgus stress angles. Mechanical tibial angles, mechanical femoral angles, femoral osteophyte sizes, and tibial osteophyte sizes were measured. The Ahlback grading scale was applied for radiologic parameters, and clinical parameters (age, body mass index, sex, duration of pain, and preoperative range of motion) were documented. Correlations between these factors and preoperative valgus stress angle were analyzed. RESULTS: A negative correlation was found between preoperative mechanical axis angle and preoperative valgus stress angle (p < 0.01, r = -0.38), and a positive correlation was found between the preoperative mechanical tibial angle and preoperative valgus stress angle (p = 0.01, r = 0.19). CONCLUSIONS: The present study shows that preoperative varus deformity and proximal tibial vara (measured by preoperative mechanical axis angle and mechanical tibial angle, respectively) are correlated with reducibility of varus deformity (measured by preoperative valgus stress angle), and clinical parameters (age, range of motion, duration of pain and body mass index) and other radiologic parameters (osteophyte size, severity of osteoarthritis and angulation of distal femoral joint surface) were not significantly correlated with reducibility of varus deformity.

Augmentation with Transcortical Wiring of an Onlay-type Prosthesis for a Deficient Patella during Revision Total Knee Arthroplasty

The management of patellae with a severe bony deficiency during revision total knee arthroplasty is a challenging problem. However, using a technique of augmentation with transcortical wiring of an onlay-type prosthesis allowed the authors to revise a deficient patellae successfully. After making the decision to revise the existing patellar component, the procedure was found to be technically straightforward. Furthermore, the procedure does not require sophisticated instruments, only an onlay-type prosthesis, cement and wires. This technique entails fixing wires to the three pegs of the patellar component, passing the wires through drill holes in the anterior cortex and, after compression of a cemented prosthesis, augmenting the fixation by twisting the wires anteriorly. We believe that stable fixation and painless articulation will be obtained with the described technique for deficient patellae.

Short-term Follow-up of Posterior Cruciate Ligament-sacrificed Total Knee Arthroplasty Using a Mobile Polyethylene Insert: Navigation-aided Technique

PURPOSE: Recently, a mobile ultracongruent polyethylene insert was used to increase joint stability in the posterior cruciate ligament sacrificed total knee arthroplasty with non-posted mobile bearing. However, as yet there have been no reports about this implant. In this study, the clinical and radiological results of surgery using the implant were analyzed through a navigation system. MATERIALS AND METHODS: The subjects included 95 cases of 70 patients to whom the rotating tibial implant was applied after posterior cruciate ligament resection among the patients who underwent total knee arthroplasty from September 2006 to December 2008. The follow-up duration was at least 24 months, and 40 months on average. For clinical evaluation, the knee score and functional scores were measured preoperatively and at the time of final follow-up. With reference to a 5 mm joint line change measurement recorded by the navigation system, which can affect the clinical result, the comparison and evaluation were performed by dividing the subjects into group I (5 mm). Radiological evaluation was performed by measuring the angle of the mechanical axis of the lower extremities and the patella tilting angle preoperatively and at the time of final follow-up using plain radiographs. RESULTS: Seventy subjects (95 cases) were followed up for at least 24 months. According to the clinical results, the mean KSS knee score improved from a preoperative score of 43.4 to a final follow-up score of 90.6 (p<0.0001). In addition, the mean functional score improved from a preoperative score of 51 to a final follow-up score of 88.4 (p<0.0001). Finally, the mean joint line change, which can affect the clinical result, was 5.82 mm, ranging from -1 to 12 mm. The clinical and radiological evaluations were performed by dividing the subjects into two groups in relation to the reference value of 5 mm, but no significant difference was found. The mechanical axis angles of the lower extremities improved from the preoperative value of varus 10.01degrees to the final follow-up value of varus 1.89degrees, and the difference was significant (p<0.0001). The mean patella tilting angles were 8.8degrees and 9.3degrees, respectively, at the time before the operation and after the final follow-up; this difference was not significant (p=0.89). CONCLUSION: Good clinical and radiological results were observed after at least two years of follow-up subsequent to total knee arthroplasty, in which a rotating ultracongruent polyethylene insert was applied after posterior cruciate ligament resection using a navigation system.

Accuracy of Inter Femoral Head Center Distance Measurement and Evaluation for Coronal Alignment of Femoral Component during Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: Alignment is an important factor in the long-term success of total knee arthroplasty. In the total knee arthroplasty, the conventional extramedullary femoral alignment system has significant error in femoral coronal alignment, since it is difficult to find the femoral head center and it is time consuming to determine during the operation. The purpose of our study was to evaluate the accuracy of the newly-designed marker system for extramedullary femoral alignment that uses radiologic distance between the 2 femoral head centers. MATERIALS AND METHODS: Between July 2008 and July 2009, 90 patients (100 knees) with knee osteoarthritis underwent total knee arthroplasty using the femoral extramedullary femoral guide system. We measured the distance between the femoral head centers using the radiologic picture archiving and communication system (PACS, General Electric, Milwaukee, WI) system preoperatively, then plastic rods and metal pegs were used to simulate the inter femoral head center distance. By placing the center of the plastic rod after marking the inter femoral head center distance on the central body line, we could trace the coronal mechanical axis. We measured the angle between the femoral mechanical axis and the femoral component in standing long leg antero-posterior radiograph to assess radiologically the accuracy of coronal alignment postoperatively. RESULTS: The average femoral length in the study group was 402.5+/-16.2 mm. The mean distance between the femoral head and the center of the marker was 49.6+/-17.9 mm. The average error in estimation of the distance between the femoral head center and the metal peg of the marker was 3.78+/-3.14 mm. The positional error in alignment was 1degrees or less in 90% and 2degrees or less in 100% of knees. The average angle of femoral component to femoral mechanical axis was 89.9+/-1.5degrees (range 84.4-93.6degrees). The coronal alignment of the femoral components was within 90degrees+/-3degrees in -96% of cases. CONCLUSION: Our results suggest that the clinical method reported here is a simple and reliable method to localize the center of the femoral head during total knee arthroplasty.

An Extramedullary Femoral Alignment System in Total Knee Arthroplasty Using the Inter-Femoral Head Center Distance / 대한정형외과학회잡지

PURPOSE: Total knee arthroplasty using the extramedullary technique for alignment has some difficulty for detecting the center of the femoral head intra-operatively. In this study we tried to evaluate the usefulness and accuracy of a newly developed Mechanical Axis Marker that synchronizes the center of the knee joint and femoral head with the mechanical axis for the distal femoral cutting and femoral prosthesis alignment. MATERIALS AND METHODS: Between October 2008 and January 2009, 255 knees in 156 patients underwent total knee arthroplasty. We measured the distance between each centers of the femoral head using the PACS system and we applied the distance to the newly developed Mechanical Axis Marker. Subsequently, we applied the new marker to patients to align the centers of knee, the femoral head and the marker in line with the mechanical axis intra-operatively. The accuracy of the marker was validated with C-arm fluoroscopy pre-operatively in 20 patients. Post-operatively we measured and analyzed the frontal femoral component angle to evaluate the coronal alignment of the femoral implant. The accuracy was rated as excellent when the alignment was 5degrees. RESULTS: The pre-operative validation study with the C-arm fluoroscopy showed that the distance between the femoral head center and the metal peg of the marker was within 5 mm in 95% of the patients, which implied acceptable accuracy. The average frontal femoral component angle against the mechanical axis was 89.0degrees+/-1.1 (range 86degrees-96.6degrees). The proportion of excellent, good, and poor alignments was 90.6% (231 cases), 8.6% (22 cases), and 0.8% (2 cases), respectively. The intraclass correlation coefficient between the two observers for the frontal femoral component angle was 0.972 which showed high concordance. CONCLUSION: Our results indicate that the extramedullary technique assisted by our new Mechanical Axis Marker can easily identify the center of femoral head and improve the accuracy of frontal femoral component alignment with the proper mechanical axis.

Short Term Results of Cruciate Retaining TypeMobile Bearing Total Knee Arthroplasty: Using a Navigation System

PURPOSE: We wanted to report the minimum 3 year follow-up clinical results of the patients who underwent navigation guided cruciate retaining mobile bearing total knee arthroplasty and to evaluate the radiological results for a consecutive series of patients. MATERIALS AND METHODS: Cruciate retaining mobile bearing total knee arthroplasties with using a navigation system were performed for 54 knees. The mean patient age was 65 years old (range: 51~76 years). The mean follow up period was 44 months (range: 36~61 months). The Knee Society Score (KSS) and range of motion (ROM) were evaluated for the preoperative and postoperative clinical assessments. We evaluated the alignment and the position of the implants by using plane radiographs for the radiological assessment, and we investigated the wear and loosening of implants in the same manner at the last follow-up exam. RESULTS: The knee score improved from 38 to 91 (p=0.001) and the functional score improved from 46 to 92 (p=0.001). The mean range of motion was also improved postoperatively. The radiological results of the coronal axis alignment of the lower extremity and the implant position were satisfactory in 98% of the cases. Periprostheic osteolysis occurred in 4 cases, but there were no clinically significant osteolysis seen on the follow-up radiographs. CONCLUSION: Soft tissue balancing and the accuracy of implantation are necessary when performing cruciate retaining mobile bearing total knee arthroplasty. For this type of implant, navigation is useful tool to perform total knee arthorplasty for insuring the accuracy of the surgical procedure.