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Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 16 - 16
1 Feb 2020
Song S Kang S Park C
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Background

As life expectancy increases, the number of octogenarians requiring primary and revision total knee arthroplasty (TKA) is increasing. Recently, primary TKA has become a common treatment option in octogenarians. However, surgeons are still hesitant about performing revision TKA on octogenarians because of concerning about risk- and cost-benefit. The purpose of this study was to investigate postoperative complications and mid-term survival in octogenarians following primary and revision total knee arthroplasty (TKA).

Methods

We retrospectively reviewed 231 primary TKAs and 41 revision TKAs performed on octogenarians between 2000 and 2016. The mean age was 81.9 for primary TKA and 82.3 for revision TKA (p=0.310). The American Society of Anesthesiologists (ASA) score was not different, but the age-adjusted Charlson comorbidity index was higher in revision TKA (4.4 vs. 4.8, p=0.003). The mean follow-up period did not differ (3.8 vs. 3.5 years, p=0.451). The WOMAC scores and range of motion (ROM) were evaluated. The incidence of postoperative complication and survival rate (end point; death determined by telephone or mail communication with patient or family) were investigated.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 21 - 21
1 Feb 2020
Park C Kang S Song S
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Purpose

The purpose of the present study was to evaluate the intercompartmental loads with a sensor placed on implants after conventional gap balancing during total knee arthroplasty (TKA) with a tensiometer.

Methods

Fifty sensor-assisted TKA procedures were performed prospectively between August and September 2018 with a cruciate-retaining prosthesis. After applying a modified measured technique, conventional balancing between the resected surfaces was achieved. The equal and rectangular flexion–extension gaps were confirmed using a tensiometer. Then, the load distribution was evaluated with a sensor.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 15 - 15
1 Feb 2020
Song S Kang S Park C
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Purpose

Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics.

Methods

Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in preoperative demographics. The mean follow-up period was 10.7 ±5.7 years for HTO and 12.0 ±7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan–Meier survival analysis was performed (failure: revision to TKA), and the failure modes were investigated.


Purpose

The purpose of this study was to compare intercompartmental loads and the proportion of knees with unbalanced loads after tensiometer-assisted balancing (TAB) between cruciate retaining (CR) and posterior stabilized (PS) total knee arthroplasty (TKA).

Materials and Methods

Forty-five CR and 45 PS TKAs using a single prosthesis were prospectively evaluated. The intercompartmental loads in 10°, 45°, and 90° of knee flexion after TAB were evaluated; the proportions of load imbalance (medial load – lateral load >15 lbs) in each flexion angle after TAB were investigated. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TAB were calculated, with the sensor-balanced loads considered the reference standard.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 98 - 98
1 Apr 2018
Song S Park C Liang H Kang S Bae D
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Objective

The purpose of the present study was to compare the clinical and radiographic results after TKA using a patellofemoral design modified prosthesis and its predecessor. The other purpose was to investigate whether the use of the recent prosthesis increase the risk of posterior tibial cortex injury or patellar fracture.

Materials and Methods

The clinical and radiographic results of 300 knees which underwent TKA using the Attune®prosthesis (group A) were compared with those in a paired match-control group who underwent TKA using the P.F.C. Sigma® prosthesis (group B). The preoperative demographic data between the 2 groups did not differ significantly. The WOMAC, Feller and Kujala scores, and range of motion (ROM) were compared. The minimal distance between the tibial component stem to posterior tibial cortex, and the remnant patella thickness were compared.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 97 - 97
1 Apr 2018
Song S Liang H Bae D Yoo M Kim K Park C
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Introduction

Although total knee arthroplasty (TKA) in end-stage hemophilic arthropathy can reduce the severe joint pain and improve the functional disability, it is technically demanding. In addition, it has generally reported a high rate of complication including periprosthetic joint infection (PJI) and component loosening up to 20%. Although the Knee Society classification system of TKA complication was introduced, the complications of TKA in hemophilic arthropathy has not stratified using this classification system in previous articles to the best of our knowledge.

The purpose of this study was to evaluate the mid-term outcomes and complications of TKA in hemophilic arthropathy.

Methods

The study retrospectively reviewed 131 consecutive primary TKAs (102 patients) in single institute. The mean patient age was 41.0 years and mean follow-up time was 6.4 years. The clinical and radiographic results were evaluated. The complications were categorized according to the classification system of the Knee Society for TKA complications.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 99 - 99
1 Apr 2018
Song S Park C Liang H Bae D
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Background

The knowledge about the common mode of failure and each period in primary and revision TKAs offers useful information to prevent those kinds of failure in each surgery. However, there has been limited report that simultaneously compared the mode of failure between primary and revision TKAs using single prosthesis.

We compared the survival rate, mode of failure, and periods of each mode of failure between primary and revision TKAs.

Methods

A consecutive cohort of 1606 knees (1174 patients) of primary TKA and 258 knees (224 patients) of revision TKA using P.F.C® prosthesis was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 10.2 and 10.8 years, respectively. We compared the above variables between primary and revision TKAs.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_28 | Pages 52 - 52
1 Aug 2013
Ren H Liu W Song S
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Surgical navigation systems enable surgeons to carry out surgical interventions more accurately and less invasively, by tracking the surgical instruments inside human body with respect to the target anatomy. Currently, optical tracking (OPT) is the gold standard in surgical instrument tracking because of its sub-millimeter accuracy, but is constrained by direct line of sight (LOS) between camera sensors and active or passive markers. Electromagnetic tracking (EMT) is an alternative without the requirement of LOS, but subject to environmental ferromagnetic distortion. An intuitive idea is to integrate respective strengths of them to overcome respective weakness and we aim to develop a tightly-coupled method emphasising the interactive coupled sensor fusion from magnetic and optical tracking data. In order to get real-time position and orientation of surgical instruments in the surgical field, we developed a new tracking system, which is aiming to overcome the constraints of line-of-sight and paired-point interference in surgical environment. The primary contribution of this study is that the LOS and point correspondence problems can be mitigated using the initial measurements of EMT, and in turn the OPT result can provide initial value for non-linear iterative solver of EMT sensing module.

We developed an integrated optical and electromagnetic tracker comprised of custom multiple infrared cameras, optical marker, field generator and sensing coils, because the current commercial optical or magnetic tracker typically consists of unchangeable lower level proprietary hardware and firmware. For the instrument-affixed markers, the relative pose between passive optical markers and magnetic coils is calibrated. The pose of magnetic sensing coils calculated by electromagnetic sensing module, can speed up the extraction of fiducial points and the point correspondences due to the reduced search space. Moreover, the magnetic tracking can compensate the missing information when the optical markers are temporarily occluded. For magnetic sensing subsystem comprised of 3-axis transmitters and 3-axis receiving coils, the objective function for nonlinear pose estimator is given by the summation of the square difference between the measured sensing data and theoretical data from the dipole model. Non-linear optimisation is computational intensive and requires initial pose estimation value. Traditionally, the initial value is calculated by equation-based algorithm, which is sensitive to noise. Instead, we get the initial value from the measurement of optical tracking subsystem. The real-time integrated tracking system was validated to have tracking errors about 0.87mm. The proposed interactive and tightly coupled sensor-fusion of magnetic-optical tracking method is efficient and applicable for both general surgeries as well as intracorporeal surgeries.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 8 | Pages 1071 - 1076
1 Aug 2012
Lim H Bae J Song S Kim S

Medium-term survivorship of the Oxford phase 3 unicompartmental knee replacement (UKR) has not yet been established in an Asian population. We prospectively evaluated the outcome of 400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at the time of operation of 69 years (48 to 82). The mean follow-up was 5.2 years (1 to 10). Clinical and radiological assessment was carried out pre- and post-operatively. At five years, the mean Knee Society knee and functional scores had increased significantly from 56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively. The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival rate was 94% (95% confidence interval 90.1 to 98.0). A total of 14 UKRs (3.5%) required revision. The most common reason for revision was dislocation of the bearing in 12 (3%). Conversion to a total knee replacement was required in two patients who developed osteoarthritis of the lateral compartment.

This is the largest published series of UKR in Korean patients. It shows that the mid-term results after a minimally invasive Oxford phase 3 UKR can yield satisfactory clinical and functional results in this group of patients.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 1 | Pages 128 - 133
1 Jan 2012
Kim S Agashe MV Song S Choi H Lee H Song H

Lengthening of the humerus is now an established technique. We compared the complications of humeral lengthening with those of femoral lengthening and investigated whether or not the callus formation in the humerus proceeds at a higher rate than that in the femur. A total of 24 humeral and 24 femoral lengthenings were performed on 12 patients with achondroplasia. We measured the pixel value ratio (PVR) of the lengthened area on radiographs and each radiograph was analysed for the shape, type and density of the callus. The quality of life (QOL) of the patients after humeral lengthening was compared with that prior to surgery. The complication rate per segment of humerus and femur was 0.87% and 1.37%, respectively. In the humerus the PVR was significantly higher than that of the femur. Lower limbs were associated with an increased incidence of concave, lateral and central callus shapes. Humeral lengthening had a lower complication rate than lower-limb lengthening, and QOL increased significantly after humeral lengthening. Callus formation in the humerus during the distraction period proceeded at a significantly higher rate than that in the femur.

These findings indicate that humeral lengthening has an important role in the management of patients with achondroplasia.


The Journal of Bone & Joint Surgery British Volume
Vol. 93-B, Issue 6 | Pages 782 - 787
1 Jun 2011
Sun X Easwar TR Manesh S Ryu J Song S Kim S Song H

We compared the complications and outcome of tibial lengthening using the Ilizarov method with and without the use of a supplementary intramedullary nail. In a retrospective case-matched series assembled from 176 patients with tibial lengthening, we matched 52 patients (26 pairs, group A with nail and group B without) according to the following criteria in order of importance: 1) difference in amount of lengthening (± 2 cm); 2) percentage difference in lengthening (± 5%); 3) difference in patient’s age (± seven years); 4) aetiology of the shortening, and 5) level of difficulty in obtaining the correction. The outcome was evaluated using the external fixator index, the healing index and an outcome score according to the criteria of Paley. It was found that some complications were specific to group A or B respectively, but others were common to both groups.

The outcome was generally better in lengthenings with a nail, although there was a higher incidence of rectifiable equinus deformity in these patients.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 91 - 91
1 Mar 2010
BAE D Song S Cho H
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We analysed the clinical and radiographic results after total knee arthroplasty in the valgus knee. Thirty six knees in 27 patients with a valgus alignment of more than 10 degrees of femorotibial angle underwent TKA. The average followup period was 7 years(range 1 to 14 years). Eighteen knees were implanted with a cruciate retaining prosthesis, 17 knees with a posterior stabilized prosthesis, and one knee with a constrained condylar prosthesis. In knees with a preoperative 15 degrees or greater femorotibial angle, the posterior stabilized prosthesis were necessary in 85%.

Medial parapatellar approach was used in 27 knees with a preoperative valgus 20 degrees or lesser femorotibial angle. With 20 to 29 degrees valgus, medial parapatellar approach was used in 5 knees and lateral parapatellar approach in 2 knees. With 30 degrees or greater valgus, lateral parapatellar approach was used in 2 knees.

The mean postoperative Hospital for Special Surgery knee scores were 89.5 points. Postoperative range of motion averaged 114.4 degrees. Postoperative alignment averaged 6.5 degree valgus. Radiolucent line or loosening was not seen in any knee. There were two deep infections in patients whose preoperative femorotibial angle was greater than valgus 20 degrees using lateral parapatellar approach.

Clinical and functional results after TKA in the valgus knee were similar to those in varus knee. But, prevention of deep infection in patients with marked valgus angle was important, especially using lateral parapatellar approach. A more constrained prosthesis was frequently used in more significant valgus deformity. In patients with severe valgus deformity needing lateral capsular release frequently, lateral parapatellar capsular approach was more reasonable than medial parapatellar approach to avoid medial and lateral capsular release simultaneously.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 117 - 117
1 Mar 2010
Lim H Bae J Cho J Lee J Song S
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Spontaneous osteonecrosis of the knee (SONK) is a distinct clinical condition occurring in patients without any associated risk factors. There is controversy as to the best method of treatment, and the available literature would suggest that patients with SONK have a worse outcome. We evaluated the clinical and radiographic outcomes of unicompartmental knee arthroplasty using Oxford prosthesis in patients with spontaneous osteonecrosis

Between September 2002 and March 2008, 20 knees (18 patients) with SONK were treated with Oxford unicompartmental knee arthroplasty. There were fifteen women and three men with a mean age of 61.1 years old. The mean follow up was 37 months. The clinical assessment was performed using the American knee society score rating system. The preoperative radiography and MRI were analyzed according to size and stage of the osteonecrotic lesion and the osteoarthritic changes. Postoperatively, new osteonecrotic lesion, loosening of implant, subsidence, arthritic changes of other compartment were recorded.

The mean preoperative knee score and the knee function score were 52.5 and 56.0 points, respectively. The knee score was improved to 89.2 points (p < 0.05) and the knee function score was also improved to 85.2 points (p < 0.05) at last follow up. There were no implant failures. There was no new necrotic lesion in the lateral compartment, loosening, subsidence and arthritic change.

The Oxford Unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee provided satisfactory clinical and radiological results in a short to medium term. However, a longer term follow up will be needed.