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Introduction

The degree of cartilage degeneration assessed intraoperatively may not be sufficient as a criterion for patellar resurfacing in total knee arthroplasty (TKA). However, single-photon emission tomography/computed tomography (SPECT/CT) is useful for detecting osteoarthritic involvement deeper in the subchondral bone. The purpose of the study was to determine whether SPECT/CT reflected the cartilage lesion underneath the patella in patients with end-stage osteoarthritis (OA) and whether clinical outcomes after TKA without patellar resurfacing differed according to the severity of patellofemoral (PF) OA determined by visual assessment and SPECT/CT findings.

Methods

This study included 206 knees which underwent TKA. The degree of cartilage degeneration was graded intraoperatively according to the International Cartilage Repair Society grading system. Subjects were classified into four groups according to the degree of bone tracer uptake (BTU) on SPECT/CT in the PF joint. The Feller's patella score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were assessed preoperatively and postoperative 1 and 2 years.


The Bone & Joint Journal
Vol. 102-B, Issue 7 | Pages 941 - 949
1 Jul 2020
Price AJ Kang S Cook JA Dakin H Blom A Arden N Fitzpatrick R Beard DJ

Aims

To calculate how the likelihood of obtaining measurable benefit from hip or knee arthroplasty varies with preoperative patient-reported scores.

Methods

Existing UK data from 222,933 knee and 209,760 hip arthroplasty patients were used to model an individual’s probability of gaining meaningful improvement after surgery based on their preoperative Oxford Knee or Hip Score (OKS/OHS). A clinically meaningful improvement after arthroplasty was defined as ≥ 8 point improvement in OHS, and ≥ 7 in OKS.


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 44 - 44
1 Apr 2018
Shin J Song M Yoon C Chang M Chang C Kang S
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Background

As the number of primary or revision TKA with stem extension cases are growing simultaneously, the number of periprosthetic fracture in these cases has also increased accordingly. However, there have been few reports on the classification and treatment of periprosthetic fracture following stemmed TKA and lack of information about the treatment outcome. The purposes of this study were 1) to demonstrate classification and management of periprosthetic fractures after stemmed TKA and 2) to report treatment outcome after the periprosthetic fractures.

Materials and Methods

This retrospective study included 17 knees (15 patients) with an average age of 69.7 years. All cases were revision TKA cases, and there were 13 female and 2 male patients. The patients were treated nonoperatively or underwent operation by orthopedic principle. The period of union was evaluated by confirming the formation of callus crossing fragments in radiographs. We reviewed the complications and functional outcomes after treatment of periprosthetic fracture following revision TKA by assessing FF, FC and scoring WOMAC and KSS.


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 45 - 45
1 Apr 2018
Yoon C Chang C Chang M Shin J Song M Kang S
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Background

Joint line, patellar height and posterior condylar offset (PCO) are related to functional outcome such as stability and range of motion after revision total knee arthroplasty (TKA). The purpose of this study was (1) to determine whether revision TKA can restore the joint line, patella height and condylar offset after surgery, and (2) to assess factors associated with failed restoration.

Materials and Methods

We retrospectively reviewed 27 consecutive patients who underwent revision TKA. Among 27 patients, 11 patients had two-stage revision TKA due to periprosthetic joint infection while 14 patients underwent revision TKA due to aseptic loosening. In addition, there were 2 patients who had traumatic event causing a periprosthetic fracture which led to revision TKA. The joint line was measured using the distance from the adductor tubercle of the femur to the most distal portion of the medial femoral component on knee anterior-posterior radiographs. Patella height was assessed using the Caton-Deschamps method. In addition, PCO were measured relative to the tangent of the posterior cortex of the femur using knee lateral radiograph. All parameters were compared between pre- and postoperative radiographs after revision TKA.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 2 - 2
1 Apr 2018
Jo S Lee S Kang S
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Introduction

The correct anteversion of the acetabular cup is critical to achieve optimal outcome after total hip arthroplasty. While number of method has been described to measure the anteversion in plane anteroposterior and lateral radiograph, it is still controversial which method provides best anteversion measurement. While many of the previous studies used CT scan to validate the anteversion measured in plane anteroposterior radiograph, this may cause potential bias as the anteversion measured in CT scan reflects true anteversion while the anteversion measurement methods in plane radiograph are design to measure the planar anteversion. Thus, in the current study, we tried to find the optimal anteversion measurement method free from the previously described bias.

Material and method

Custom made cup model was developed which enables change in anteversion and inclination. Simple radiograph was taken with the cup in 10° to 70° degree of inclination at 10° increments and for each inclination angle, anteversion was corrected from 0° to 30° at 5° increments. The radiograph was taken with the beam directed at the center of the cup (mimicking hip centered anteroposterior radiograph) and at 9cm medial to the cup (mimicking pelvis anteroposterior radiograph). The measurements were done by two orthopaedic surgeons using methods described by 1) Pradhan et al, 2) Lewinak et al, 3) Widmer et al, and 4) Liaw et al. For each measurements, the anteversion were compared with the actual anteversion.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_6 | Pages 33 - 33
1 Apr 2018
Song M Kim Y Yoo S Kang S Kwack C
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Purpose

Unicompartmental Knee Arthroplasty (UKA) has been indicated for inactive elderly patients over 60, but for young and active patients less than 60 years old, it has been regarded as a contraindication. The purpose of this study is to evaluate the usefulness of UKA performed on young Asian patients under 60 years of age by analyzing clinical outcomes, complications and survival rate.

Materials and Methods

The subjects were 82 cases, which were followed up for at least 5 years (from 5 to 12 years). Only Oxford phase III® (Biomet Orthopedics, Inc, Warsaw, USA) prosthesis was used for all cases. The clinical evaluation was done by the range of motion, Knee society score (KSS), WOMAC score. The radiographic evaluation was performed on weight bearing long-leg radiographs, AP and lateral view of the knee and skyline view of the patella. The survival rate was estimated by Kaplan-Meier survival analysis.


The Bone & Joint Journal
Vol. 99-B, Issue 3 | Pages 401 - 408
1 Mar 2017
Kang S Lee JS Park J Park S

Aims

Children treated for osteosarcoma around the knee often have a substantial leg-length discrepancy at skeletal maturity. The aim of this study was to investigate the results of staged skeletal reconstruction after a leg lengthening procedure using an external fixator in these patients.

Patients and Methods

We reviewed 11 patients who underwent staged reconstruction with either an arthroplasty (n = 6) or an arthrodesis (n = 5). A control group of 11 patients who had undergone wide excision and concurrent reconstruction with an arthroplasty were matched for gender, location, and size of tumour. We investigated the change in leg-length discrepancy, function as assessed by the Musculoskeletal Tumor Society Scale (MSTS) score and complications.


The Bone & Joint Journal
Vol. 98-B, Issue 9 | Pages 1270 - 1275
1 Sep 2016
Park S Kang S Kim JY

Aims

Our aim was to investigate the predictive factors for the development of a rebound phenomenon after temporary hemiepiphysiodesis in children with genu valgum.

Patients and Methods

We studied 37 limbs with idiopathic genu valgum who were treated with hemiepiphyseal stapling, and with more than six months remaining growth at removal of the staples. All children were followed until skeletal maturity or for more than two years after removal of the staples.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 74 - 74
1 May 2016
Kang S Chang C Choi I Woo J Woo M Kim S
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Introduction

Deformity of knee joint causes deviation of mechanical axis in the coronal plane, and the mechanical axis deviation also could adversely affect biomechanics of the ankle joint as well as the knee joint. Particularly, most of the patients undergoing total knee arthroplasty (TKA) have significant preoperative varus malalignment which would be corrected after TKA, the patients also may have significant changes of ankle joint characteristics after the surgery. This study aimed 1) to examine the prevalence of coexisting ankle osteoarthritis (OA) in the patients undergoing TKA due to varus knee OA and to determine whether the patients with coexisting ankle OA have more varus malalignment, and 2) to evaluate the changes of radiographic parameters for ankle joint before and 4 years after TKA.

Methods

We evaluated 153 knees in 86 patients with varus knee OA who underwent primary TKA. With use of standing whole-limb anteroposterior radiographs and ankle radiographs before and 4 years after TKRA, we assessed prevalence of coexisting ankle OA in the patients before TKA and analyzed the changes of four radiographic parameters before and after TKA including 1) the mechanical tibiofemoral angle (negative value = varus), 2) the ankle joint orientation relative to the ground (positive value = sloping down laterally), 3) ankle joint space, and 4) medial clear space.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 78 - 78
1 May 2016
Kang S Chang C Woo J Woo M Choi I Kim S
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Introduction

Even a number of studies have reported clinical outcomes after revision total knee arthroplasty (revision TKA), little information is still available on whether outcomes of patients undergoing a revision TKA as a second stage procedure because of infected TKA are poorer than those of the patients undergoing a single-stage revision TKA because of non-infectious causes. In addition, use of various revision prostheses in most previous studies may limit solid interpretation of the outcomes after revision TKA. This study sought to determine whether outcomes in patients undergoing revision TKA due to infected TKA would be different from those in patients undergoing revision TKA due to non-infectious causes.

Materials and Methods

We assessed 71 cases undergoing revision TKAs with use of a same revision system (Scorpio TS®, Stryker, Mahwah, NJ) from October 1999 to February 2012. All patients followed more than two years and mean follow-up period was 67 months (range: 24 – 168 months). Of them, thirty five patients underwent revisions due to infected TKA (group for infected TKA) while 36 patients due to non-infectious causes including loosening, wear, and/or instability (group for non-infected TKA). All patients in the group for infected TKA underwent two-stage revision surgeries while all patients in the group for non-infected TKA single stage revision surgeries. Comparative variables between two groups were preoperative range of motion (ROM) and American knee society (AKS) scores, postoperative ROM and AKS scores assessed at latest follow-up, amount of bone loss and requirement of stem assessed during the surgeries, and survival rate.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 79 - 79
1 May 2016
Kang S Chang C Woo M Woo J Choi I Kim S
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Introduction

Total knee arthroplasty (TKA) is a proven treatment method for advanced knee arthritis in terms of pain relief, function restoration, and quality-of-life improvement. The TKA use has increased significantly over the past decade and the growing rate is more prominent in Asian countries. Thus, the revision TKA may also increase in recent days, which represents a burden to the national health care system. To the best of our knowledge, little information is currently available regarding the incidence and related factors of revision TKA in Asian countries on the basis of nationwide database. This study sought to find the incidence of revision TKA and related factors in South Korea using national database from 2007 to 2012.

Material and Method

Data collected by the Health Insurance Review Agency of Korea, from 260,068 TKA patients between 2007 and 2012, were used to estimate the incidence of revision TKA according to age group, gender and hospital TKA and manufacturer prosthesis volume (i.e., the number of TKA procedures carried out at a given hospital, and the number of procedures performed using a given manufacturer's prosthesis, respectively). Age group and hospital and manufacturer volumes were categorized into three groups and TKA incidence rates were computed for groups stratified according to age, gender and hospital and manufacturer volumes.


The Bone & Joint Journal
Vol. 97-B, Issue 1 | Pages 134 - 140
1 Jan 2015
Kang S Kam M Miraj F Park S

A small proportion of children with Gartland type III supracondylar humeral fracture (SCHF) experience troubling limited or delayed recovery after operative treatment. We hypothesised that the fracture level relative to the isthmus of the humerus would affect the outcome.

We retrospectively reviewed 230 children who underwent closed reduction and percutaneous pinning (CRPP) for their Gartland type III SCHFs between March 2003 and December 2012. There were 144 boys and 86 girls, with the mean age of six years (1.1 to 15.2). The clinico-radiological characteristics and surgical outcomes (recovery of the elbow range of movement, post-operative angulation, and the final Flynn grade) were recorded. Multivariate analysis was employed to identify prognostic factors that influenced outcome, including fracture level. Multivariate analysis revealed that a fracture below the humeral isthmus was significantly associated with poor prognosis in terms of the range of elbow movement (p < 0.001), angulation (p = 0.001) and Flynn grade (p = 0.003). Age over ten years was also a poor prognostic factor for recovery of the range of elbow movement (p = 0.027).

This is the first study demonstrating a subclassification system of Gartland III fractures with prognostic significance. This will guide surgeons in peri-operative planning and counselling as well as directing future research aimed at improving outcomes.

Cite this article: Bone Joint J 2015;97-B:134–40.


The Bone & Joint Journal
Vol. 97-B, Issue 1 | Pages 121 - 128
1 Jan 2015
Kang S Han I Hong SH Cho HS Kim W Kim H

Cancellous allograft bone chips are commonly used in the reconstruction of defects in bone after removal of benign tumours. We investigated the MRI features of grafted bone chips and their change over time, and compared them with those with recurrent tumour. We retrospectively reviewed 66 post-operative MRIs from 34 patients who had undergone curettage and grafting with cancellous bone chips to fill the defect after excision of a tumour. All grafts showed consistent features at least six months after grafting: homogeneous intermediate or low signal intensities with or without scattered hyperintense foci (speckled hyperintensities) on T1 images; high signal intensities with scattered hypointense foci (speckled hypointensities) on T2 images, and peripheral rim enhancement with or without central heterogeneous enhancements on enhanced images. Incorporation of the graft occurred from the periphery to the centre, and was completed within three years. Recurrent lesions consistently showed the same signal intensities as those of pre-operative MRIs of the primary lesions. There were four misdiagnoses, three of which were chondroid tumours.

We identified typical MRI features and clarified the incorporation process of grafted cancellous allograft bone chips. The most important characteristics of recurrent tumours were that they showed the same signal intensities as the primary tumours. It might sometimes be difficult to differentiate grafted cancellous allograft bone chips from a recurrent chondroid tumour.

Cite this article: Bone Joint J 2015;97-B:121–8.


The Bone & Joint Journal
Vol. 95-B, Issue 9 | Pages 1197 - 1200
1 Sep 2013
Zhaoning X Xu Y Shaoqi T Baiqiang H Kang S

A total of 187 patients with primary osteoarthritis (OA) of the knee undergoing total knee replacement (TKR) were randomly divided into two groups, one of which underwent synovectomy. The patients and assessors were blinded to the randomisation both before and after surgery. The duration of surgery, hospitalisation period, concealed bleeding, drainage volume, blood transfusion rate and range of movement of the knee at three days after the operation were analysed. Patients were followed up at four weeks and 12 months after their operation, and a visual analogue score (VAS) for pain, Knee Society score (KSS) and a patellar ballottement test were compared between the groups.

The mean amount of concealed bleeding was higher in the synovectomy group compared with the control group (1.24 l (0.08 to 3.28) vs 1.03 l (0.16 to 2.94); p = 0.042), as was the mean drainage volume (0.90 l (0.35 to 1.81) vs 0.81 (0.25 to 1.65); p = 0.030). The mean operating time was also higher in the synovectomy group compared with the controls (1.50 hours (1.34 to 1.75) vs 1.41 hours (1.21 to 1.79); p = 0.006). There were no significant differences in blood transfusion rate (p = 0.882), hospital stay (p = 0.805) or range of movement of the knee (p = 0.413) between the two groups. At four weeks and 12 months post-operatively there were no statistically significant differences in any of the measured parameters. We concluded that synovectomy confers no clinical advantages in TKR for primary OA while subjecting patients to higher levels of bleeding and longer operating times.

Cite this article: Bone Joint J 2013;95-B:1197–200.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 39 - 39
1 Mar 2013
Chung PH Kang S Kim J Kim YS Lee HM
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A seventy-five-year-old female patient presented with pain and deformity of her left leg of three days duration. Hybrid THRA has been done 11 years ago at her left hip for the treatment of osteoarthritis. Massive osteolysis and pathologic fracture were observed on plain radiograph (Fig. 1). Revision THRA using an allograft prosthesis composite (APC) was planned for solution of extensive bone loss of the proximal femur. Surgical exposure was performed through extended trochanteric osteotomy with the patient supine. Step-cut osteotomy was done at the remained proximal part of host femur to make match with the distal part of APC. Meticulous removal of granulation tissues and remaining cement was done. As Acetabular cup was stable, 60 mm sized high-walled polyethylene liner was exchanged. Calcar reconstruction prosthesis was cemented into a proximal femoral allograft measuring 15 cm and cement at the vicinity of the step-cut osteotomy was removed for later bony union at interface. After solid fixation of APC with cement, the distal half of APC was cemented with the host femur. Step-cut osteotomy was wired and autogenous bone grafts from the greater trochanter were added at the interface. Leg length and stability were rechecked using a standard necked 28 mm metal head and reduction was done stably. Greater trochanter was fixed over the trimmed proximal allograft with multiple wiring and paper-thin host femur was enveloped around the femoral allograft using absorbable sutures. Following insertion of the closed suction drainage drains, closure was done as routine fashion and healing of the wound was uneventful (Fig. 2). An abduction brace was applied post operatively for a period of four weeks. Crutch walking with partial weight bearing was started at four weeks and crutch protection was applied for a period of six months. Incorporation of allograft with the host bone was observed on two-year follow-up radiographs. At seven-year follow-up, the patient walks well with a mild limp, and Harris score is 90. We report on a seven-year follow-up case of revision THRA with APC with references (Fig. 3).