Jun Gyu Moon

Pelvic osteolysis relationship to radiographs and polyethylene wear.

The relationship of radiographic pelvic osteolysis to computed tomographic (CT) volume and polyethylene wear remains controversial. We evaluated the sensitivity and specificity of radiographs in detecting osteolysis considering CT scan as the true value, in 118 hips with cementless cups. Correlation between osteolysis volume in CT, area of osteolysis in radiograph, and linear wear of polyethylene was assessed. The sensitivity and specificity of anteroposterior radiographs for detection of osteolysis was 57.6% and 92.9%, respectively. Addition of oblique radiographs increased the sensitivity to 64.4% without changing the specificity. The sensitivity increased to 92.8% for lesion more than 1000 mm(3). There was good correlation between 2-dimensional (2D) osteolytic area in radiograph and 3-dimensional (3D) volume (r = 0.74) in CT scan and linear wear of polyethylene showed good correlation with 3D CT volume (r = 0.62) and 2D area in radiograph (r = 0.60). Thus radiographs are useful to screen clinically significant osteolysis.

Can pelvic tilting be ignored in total hip arthroplasty

INTRODUCTION The orientation of acetabular component is influenced by pelvic tilt, body position and individual variation in pelvic parameters. Most post-operative adverse events may be attributed to malposition of the component in the functional position. There is evidence that orientation of the pelvis changes from the supine to standing position. Authors report a case of recurrent dislocation after total hip arthroplasty due to excessive pelvic tilting. PRESENTATION OF CASE A 69-year old female with coxarthrosis had undergone total hip replacement with recurrent dislocation of the hip on bearing weight in spite of using constrained acetabular component. DISCUSSION Our case report substantiates the influence of pelvic tilt, incurred by a sagittal deformity of spine, on dynamic orientation of the acetabular cup which was positioned in accordance with the anatomic landmarks alone. If the reference is only bony architecture and dynamic positions of the pelvis are not taken into account, improper functional orientation of the acetabular cup can result in sitting and standing positions. These can induce instability even in anatomically appropriately oriented acetabular component. CONCLUSION The sagittal position of pelvis is a key factor in impingement and dislocation after total hip arthroplasty. Pelvic tilting affects the position of acetabular component in the sagittal plane of the body as compared with its anatomic position in the pelvis. We suggest a preoperative lateral view of spine-pelvis, in upright and supine position for evaluation of a corrective adaptation of the acetabular cup accordingly with pelvic balance.

Non surgically managed anteromedial coronoid fractures in posteromedial rotatory instability: three cases with 2 years follow-up

Varus posteromedial rotatory instability refers to one of the complex elbow fracture-dislocation caused by anteromedial coronoid fracture with disruption of lateral collateral ligament (LCL). Recent clinical and biomechanical studies have demonstrated that this unstable complex injury resulted in incongruence of joint, which could lead to early posttraumatic arthritis. With reports of poor result after conservative treatment, surgical treatment including anteromedial fixation and LCL repair has been strongly recommended to achieve stable joint. This case series describes three patients with anteromedial coronoid fracture who were managed conservatively with excellent outcomes. This report suggests that anteromedial coronoid fracture associated with posteromedial rotatory instability might be treated using conservative treatment in selective cases when anteromedial coronoid fracture is minimally displaced and there is no evidence of elbow subluxation.

Minimally invasive plate osteosynthesis using a helical plate for metadiaphyseal complex fractures of the proximal humerus

Minimally invasive plate osteosynthesis (MIPO) has been used for humeral shaft fractures, but concerns exist about soft tissue injuries. The purpose of this study was to report the surgical technique and clinical outcomes of MIPO using a helical plate for metadiaphyseal complex humeral shaft fractures. Twelve patients with acute displacement involving proximal and middle third humeral shaft fractures (AO type C) were treated using the MIPO technique with a helical plate. Fracture union, complications, and functional outcomes were evaluated using the Constant-Murley score and Mayo Elbow Performance Score (MEPS) at final follow-up. All fractures united at an average of 17.9 weeks. No major complications, such as neurovascular injury, infection, and nonunion, were observed. Mean Constant-Murley and MEPS scores at final follow-up were 88.6 and 97.9, respectively. A MIPO technique using a helical plate can be a useful surgical option for metadiaphyseal complex fractures of the humeral shaft.

Is two-stage reimplantation effective for virulent pathogenic infection in a periprosthetic hip? A retrospective analysis.

AIM To investigate the effectiveness of two-stage reimplantation using antibiotic-loaded bone cement (ALBC) and the risk factors associated with failure to control periprosthetic joint infection (PJI). METHODS We retrospectively reviewed 38 consecutive hips managed using two-stage reimplantation with ALBC. The mean follow-up period was 5.4 years (range: 2.5-9 years). RESULTS The causative pathogens were isolated from 29 patients (76%), 26 of whom were infected with highly virulent organisms. Sixteen patients (42%) underwent at least two first-stage debridements. An increased debridement frequency correlated significantly with high comorbidity (P < 0.001), a lower preoperative Harris hip score (HHS; P < 0.001), antimicrobial resistance, and gram-negative and polymicrobial infection (P = 0.002). Of the 35 patients who underwent two-stage reimplantation, 34 showed no signs of recurrence of infection. The mean HHS improved from 46 ± 12.64 to 78 ± 10.55 points, with 7 (20%), 12 (34%), 11 (32%) and 5 (14%) patients receiving excellent, good, fair and poor ratings, respectively. CONCLUSION The current study demonstrated that two-stage reimplantation could successfully treat PJI after hip arthroplasty. However, the ability of ALBC to eradicate infection was limited because frequent debridement was required in high-risk patients (i.e., patients who are either in poor general health due to associated comorbidities or harbor infections due to highly virulent, difficult-to-treat organisms). LEVEL OF EVIDENCE Level IV.

Can Ulnar Variance Be Used to Detect Overstuffing After Radial Head Arthroplasty

BackgroundOverstuffing of the radiocapitellar joint during metallic radial head arthroplasty has been reported to cause loss of elbow flexion, capitellar erosion, and early-onset osteoarthritis. Although this is known, there is no agreed-on measurement approach to determine whether overstuffing has occurred.Questions/purposesWe therefore hypothesized that overlengthening the radial head during radial head arthroplasty changes the ulnar variance in the wrist.MethodsSeven cadaveric radii were implanted with radial head prostheses of increasing thickness. Each specimen was implanted successively with increasingly thick radial head prostheses measuring 2, 4, and 6 mm thicker than the native radial head, and radiographs were taken after implantation of each prosthesis. The ulnar variance with each prosthesis was measured using the method of perpendiculars.ResultsThe ulnar variance of the native and 2-mm (p = 0.04), 4-mm (p = 0.008), and 6-mm (p = 0.008) overly thick radial head prosthesis-implanted states decreased significantly with each incremental increase in prosthetic head thickness.ConclusionsImplantation of thicker radial head prostheses decreased the ulnar variance. Our results indicate ulnar variance could be used to detect overstuffing of radial head prostheses.Clinical RelevanceThe simplicity and reliability of ulnar variance make it a potentially useful indicator of overlengthening after radial head arthroplasty.

Healing process of osteonecrotic lesions of the femoral head following transtrochanteric rotational osteotomy: A computed tomography-based study

Background Transtrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT). Methods Among 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans. Results Plain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p = 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p = 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area. Conclusions The majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.