First Detection of Human Coronavirus HKU1 in Greece, in an Immunocompromised Patient With Severe Lower Respiratory Tract Infection

Human coronavirus HKU1 (HCoV-HKU1) is a RNA virus which gets in the human cells by binding to the receptor of N-acetyl-9-O-acetylneuraminic acid. Human Coronaviruses (HCoVs), including HCoV-HKU1, are globally found. HCoV-HKU1 is responsible for upper and lower respiratory tract infections, usually with mild symptoms. In severe cases, HCoV-HKU1 can cause life-threatening respiratory illness especially in vulnerable hosts such as elderly, children and immunocompromised patients. In Greece, Respiratory Syncytial Virus (RSV) and influenza are the most common viruses causing respiratory tract infections. Traditionally, HCoVs are responsible for less than 3% of respiratory infections in Greek population. HCoVs 229E and OC43 have been shown to circulate in Greece. We report the first case of lung infection in an immunocompromised woman due to HCoV-HKU1, that has never been before detected in Greece. HCoV-HKU1 is related to severe disease even in healthy individuals and must be considered in the differential diagnosis of severe respiratory infections.

Evaluation of Immature Platelet Fraction in Lower Respiratory Tract Infections: A Retrospective Study

Introduction

Immature platelet fraction (IPF) is a parameter of an automated hematologic analyzer and is related to platelet size and cytoplasmic RNA content. It reflects thrombopoiesis and is often used as the marker of platelet activity. IPF has been evaluated mostly in hematologic disorders and has also been evaluated in patients with gestational hypertension, sepsis, autoimmune diseases and in hospitalised patients with neutrophilia. Platelets, asides from the maintenance of hemostasis, release inflammatory mediators that can modify leukocyte and endothelial responses to various inflammatory stimuli. Lower respiratory tract infections are the leading cause of death from infections worldwide. The role of platelets in lower respiratory tract infections has been reported in many studies. IPF, which is related to platelet activation, has not been evaluated in patients with lower respiratory tract infections.

Methods

The study involved patients who fulfilled the criteria of community-acquired pneumonia (CAP) and aspiration pneumonia (AP). In addition, age and sex-matched healthy controls were involved. Whole blood samples were collected from healthy controls and from the patients on admission. The mean IPF% and C-reactive protein (CRP) levels were measured in patients with CAP, in patients with AP and in healthy controls. The mean IPF% values in patients with infection were compared to mean IPF% values in healthy controls. The mean IPF% values were compared to mean CRP levels in patients with infection. Additionally, the mean IPF% values in patients that died in the first 14 days were compared to the mean IPF% values in patients that were alive. The statistical analysis of data was performed with the Statistical Package for the Social Sciences (SPSS) for Windows, Version 13.0 (SPSS Inc, Chicago, IL). 

Results

The study population consisted of 45 patients (27 patients with CAP and 18 patients with AP), 27 males and 18 females, with a mean age of 72.11 ± 16.4 years and 39 healthy controls, 22 males and 17 females with a mean age of 64.2 ± 14.8 years. The mean CRP levels in patients with infection were 155.2±119.1 mg/dl. The mean IPF% value of patients with infection was 2.76 ± 2.27 and the mean IPF% value of controls was 1.72 ± 0.77 (p < 0.006). The IPF% value in patients with CAP was 2.55 ± 2.02 and in patients with AP 3.07 ± 2.64 (p = 0.595). The mean IPF% value in patients with infection had no linear correlation with CRP value in these patients (r = 0.076, p = 0.62). The mean IPF% value in all patients that died in the first 14 days was 3.75 ± 2.44 and the mean IPF% value in all patients alive was 2.35 ± 2.11 (p = 0.06). The mean IPF% value in patients with CAP who died in the first 14 days of hospitalisation was 5.54 ± 3.17 and in patients with CAP who were alive was 1.87 ± 0.72 (p = 0.06). The mean IPF% value in patients with AP who died was 2.63 ± 0.85 and in patients with AP who were alive was 3.41 ± 3.51 (p = 0.554).

Conclusions

Mean IPF% value is greater in patients with lower respiratory tract infections, including CAP and AP, compared to healthy controls. There is no linear correlation between IPF values and CRP values in patients with lower respiratory tract infections. In addition, there is a difference in mean IPF% value between patients who died in the first 14 days of hospitalisation compared to those who were alive, but not statistically significant.

Correlation Between Serum Levels of 25-Hydroxyvitamin D and Severity of Community-Acquired Pneumonia in Hospitalized Patients Assessed by Pneumonia Severity Index: An Observational Descriptive Study

Introduction Pneumonia severity index (PSI) is a prognostic index used for estimating the possibility of death due to community-acquired pneumonia. Vitamin D is a fat-soluble vitamin, essential for calcium and phosphate homeostasis. Vitamin D also has antimicrobial properties and according to recent studies, its deficiency may be correlated to an increased frequency of respiratory infections. The serum concentration of 25-hydroxyvitamin D (25(OH)D) is the best vitamin D status index reflecting vitamin D produced in the skin and offered from food and dietary supplements. Methods The study involved patients, who fulfilled the criteria of community-acquired pneumonia. The exclusion criteria were: patients <18 years old, severely immunocompromised patients, patients with tuberculosis, patients with malabsorption disorders, nursing home residents, patients with a history of malignancy, chronic renal or liver disease, patients with congestive health failure or cerebrovascular disease, and patients receiving vitamin D as a supplement. The following parameters, recorded on admission, were evaluated: age, sex, co-morbidity, residence in a nursing home, duration of symptoms, clinical symptoms, confusion, blood gas analysis, chest radiograph (pleural effusion), and laboratory parameters. The patients were classified in risk classes according to the PSI. Blood samples were collected within the first 48 hours of hospitalization. The serum levels of 25-hydroxyvitamin D were determined by electrochemiluminescence binding assay in Roche Cobas 601 immunoassay analyzer and mean serum levels of 25-hydroxyvitamin D in each risk class were calculated. For statistical analysis, the statistical program SPSS for Windows version 17.0 (Statistical Package for the Social Sciences, SPSS Inc., Chicago, IL) was used. Results A total of 46 patients, 28 males and 18 females, with a mean age of 71.5±17.57 years, hospitalized with community-acquired pneumonia, were included. Sixteen patients (35%) had a severe deficiency, with 25(OH)D levels <10 ng/ml, 17 patients (37%) had moderate deficiency with 25(OH)D levels between 10-20 ng/ml, and 13 patients (28%) had insufficiency with 25(OH)D levels between 20-29 ng/ml. According to the PSI, four (8.7%) patients with a mean age of 53.75±15.43 years were classified as risk class I, 10 (21.7%) patients with a mean age of 54.7±14.82 years as class II, 10 (21.7%) patients with a mean age of 68.41±3.96 years as class III, 17 (37%) patients with a mean age of 84.82±9.73 years as class IV, and five (10.9%) patients with a mean age of 80.2±9.41 years as class V. The mean levels of 25(OH)D were 19.11±11.24 ng/ml in class I, 16.81±8.94 ng/ml in class II, 16.65±9.18 ng/ml in class III, 14.76±10.22 ng/ml in class IV, and 7.49±4.41 ng/ml in class V. There was a positive correlation between low levels of 25(OH)D and the pneumonia severity and statistically significant difference between the mean levels of 25(OH)D in class V (7.49±4.41 ng/ml) compared to overall mean levels in classes I, II, III and IV (16.15±9.49 ng/ml), with p<0.05. Conclusions According to our results, there was a positive association between low levels of 25-hydroxyvitamin D and community-acquired pneumonia severity assessed by PSI. The determination of 25-hydroxyvitamin-D status, mostly in patients >60 years old, may prevent severe community-acquired pneumonia.

Metallosis after contemporary metal-on-metal total hip arthroplasty. Five to nine-year follow-up

BACKGROUND

Authors of recent studies have reported early periprosthetic osteolysis in patients who have been treated with a contemporary metal-on-metal total hip arthroplasty and have suggested that metal hypersensitivity associated with an immunologic response to metal may be of etiologic importance. We evaluated the results and histologic findings in patients who had undergone revision of a failed contemporary metal-on-metal total hip arthroplasty.

METHODS

Two hundred and seventeen total hip arthroplasties (SL-Plus stem and Bicon-Plus cup) with a Sikomet metal-on-metal articulation were implanted in 194 consecutive patients, and the results were retrospectively reviewed at a mean of seventy-seven months postoperatively. Clinical follow-up with the Harris hip score and plain radiographic evaluation were performed. Periprosthetic tissues from fourteen hips that had undergone revision arthroplasty were subjected to histologic analysis.

RESULTS

The mean Harris hip score improved from 45 points preoperatively to 88 points at the final evaluation. Fourteen hips (6.5%) were revised: nine because of aseptic loosening, two because of technical failure, and three because of septic failure. Histologic examination of the retrieved periprosthetic tissues from the eleven patients who had undergone revision because of aseptic loosening or technical failure showed metallosis and extensive lymphocytic and plasma-cell infiltration around the metal debris. With removal of the component because of aseptic loosening as the end point, survivorship was 93% for the stem and 98% for the cup.

CONCLUSIONS

Our findings are in agreement with those in recent publications and support the possibility that periprosthetic osteolysis and aseptic loosening in hips with a metal-on-metal articulation are possibly associated with hypersensitivity to metal debris. Prospective, comparative, randomized long-term studies are necessary to determine the cause(s) of loosening of prostheses with this particular articulation.

Anterior surgery with insertion of titanium mesh cage and posterior instrumented fusion performed sequentially on the same day under one anesthesia for septic spondylitis of thoracolumbar spine: is the use of titanium mesh cages safe?

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate the outcome on patients with pyogenic spondylitis of the thoracolumbar spine following combined anterior and posterior surgery.

SUMMARY AND BACKGROUND DATA

Several methods of surgical treatment of pyogenic spondylitis have been reported. These include anterior approach, staged and simultaneous anterior decompression, and posterior stabilization. The use of anterior implants in the presence of an infection presents a challenge for spine surgeons. This study analyzes the clinical and radiologic outcome of surgical intervention on patients with pyogenic spondylitis of the thoracolumbar spine who were treated surgically for intractable pain, instability, and neurologic impairment.

METHODS

Fourteen patients (6 women, 8 men) with thoracolumbar spondylitis were treated with anterior surgery with insertion of titanium mesh cage and posterior instrumented fusion performed sequentially on the same day under one anesthesia. The age (average, SD) of the patients at the time of surgery was 55 +/- 16 years (range, 29-83 years). Most patients had also systemic diseases as lung tuberculosis, hepatic cirrhosis, diabetes mellitus, or chronic renal failure. Patients were evaluated before and after surgery in terms of pain, neurologic level, sagittal spinal balance, and radiologic fusion.

RESULTS

The average duration of the combined surgery was 4.5 hours. All patients were observed up for an average of 45 months (range, 37-116 months). The Visual Analog Scale score (average, range) improved from 7 (range, 4-10) before surgery to 2 (range, 0-5) after surgery. Correction (average, range) of segmental kyphotic deformity was 6 degrees (range, 0 degrees-11 degrees) without loss of correction at the final observation. Neither a postoperative change of the position of mesh cage nor any posterior instrumentation failure was recorded. Patients with incomplete neurologic impairment showed improvement after surgery at an average 1.4 Frankel's grade. There was one complication, an anterior wound abscess culminating in an abdominal hernia.

CONCLUSIONS

This clinical study showed that patients with thoracolumbar osteomyelitis can successfully undergo anterior surgery with insertion of titanium mesh cage and posterior instrumented fusion performed sequentially on the same day under one anesthesia. The presence of the mesh cage anteriorly at the site of spondylitis had no negative influence on the course of infection healing, and additionally it stabilized the affected segment maintaining sufficient sagittal profile.

Combined anterior plus posterior stabilization versus posterior short-segment instrumentation and fusion for mid-lumbar (L2-L4) burst fractures

STUDY DESIGN

Prospective randomized study. OBJECTIVES.: To compare the results of the combined anterior-posterior surgery (Group A) with posterior "short-segment" transpedicular fixation (SSTF) (Group B) in mid-lumbar burst fractures.

SUMMARY OF BACKGROUND DATA

There are no comparative randomized clinical studies on the outcome following operative treatment of mid-lumbar fractures.

METHODS

Forty consecutive patients with L2-L4 fresh single A3-type/AO burst fractures and load sharing score up to 6 were randomly selected to underwent either combined one-stage anterior stabilization with mesh cage and SSTF (Group A) or solely SSTF with intermediate screws in the fractured vertebra (Group B). Kyphotic Gardner angle, anterior and posterior vertebral body height (PVBHr, AVBHr), spinal canal encroachment (SCE), SF-36, VAS, and Frankel classification were used.

RESULTS

The follow-up observation averaged 46 and 48 months for Group A and B, respectively. Operative time, blood loss, and hospital stay were significant more in Group A. More surgical complications were observed in the Group A. After surgery, VAS was reduced to 4.3 and 3.6 for Group A and Group B, respectively. The SF-36 domains Role physical and Bodily pain improved significantly only in Group B (P = 0.05) and (P = 0.06), respectively. Correction of AVBHr, PVBHr, and spinal canal clearance was similar in both groups. Spinal canal clearance did not differ between the two groups, but it was continuous until the last evaluation in Group B. The final Gardner angle loss of correction averaged 2 degrees and 5 degrees for Group A and Group B, respectively. The posttraumatic Gardner deformity did not significantly improve by SSTF at the final evaluation in the spines of Group B. Gardner angle correlated significantly with SCE in Group B and Group A in all three periods and in the last evaluation, respectively. Frankel grade did not correlate with loss of correction of AVBHr and PVBHr in Group A, while it significantly correlated with loss of PVBHr correction and SCE in the patients of Group B. There was no neurologic deterioration after surgery in any patient. VAS and SF-36 scores did not significantly correlate with the loss of kyphotic angle correction and AVBHr, PVBHr at the final observation in any patient of both groups.

CONCLUSIONS

SSTF offered similar significant short-term correction of posttraumatic deformities associated with mid-lumbar A3-burst fractures, but better clinical results as compared to combined surgery. However, SSTF did not significantly maintain the after surgery achieved correction of local posttraumatic kyphosis at the final evaluation. Thus, SSTF is not recommended for operative stabilization of fractures with this severity.

One-stage combined surgery with mesh cages for treatment of septic spondylitis

There is a controversy regarding most effective operative method for treatment of pyogenic spondylitis and whether to use metallic implants on the site of infection. This retrospective study reports on the outcome of 17 patients with persistent cervical and lumbar pyogenic spondylitis who had one-stage combined surgery and fusion with use of a titanium mesh cage for intractable pain, kyphosis, and neurologic impairment. All patients tolerated the combined operation and were followed up on for 45 months. Incomplete neurologic lesions improved postoperatively an average 1.4 Frankel grades. Visual analog pain score (mean) improved from 7 preoperatively to 2 postoperatively. Average correction of local kyphotic deformity was 6 degrees without loss of correction at final observation. There was no expulsion or migration of any titanium mesh cage or loosening of the posterior instrumentation. There was an approach-related abdominal hernia after wound infection. At the final followup, the combined operation in combination with the use of the mesh cage improved sagittal alignment and resulted in eradication of the infection and attainment of solid fusion. The presence of the titanium mesh cage anteriorly at the site of infection had no adverse effect on the course of infection. Patients with cervical and lumbar osteomyelitis can successfully have instrumented-combined, one-stage surgery.

LEVEL OF EVIDENCE

Prognostic study, Level II (retrospective study). Please see the Guidelines for Authors for a complete description of levels of evidence.

Posterior transcanal lumbar interbody fusion for septic vertebral fracture pseudarthrosis and sitting imbalance

STUDY DESIGN

Case report.

OBJECTIVE

To describe a new method to treat septic pseudarthrosis of the lumbar spine via a transcanal approach.

SUMMARY OF BACKGROUND DATA

Septic pseudarthrosis of the spine after multiple unsuccessful anterior and posterior surgeries for vertebral fracture represents a challenge for spine surgeons.

METHODS

Septic pseudarthrosis associated with dorsal fistula developed in a 40-year-old paraplegic man after unsuccessful combined anterior and posterior instrumentation for L3-burst fracture and sagittal sitting imbalance caused by collapsing spine.

RESULTS

The instrumentation was removed together with meticulous pseudarthrosis debridement, fistula excision, and intravenous antibiotics plus continuous irrigation. Three months later, the pseudarthrosis area was approached via a posterior transcanal route because of the preceding multiple anterior transperitoneal and retroperitoneal surgeries. Posterior interbody instrumentation and fusion were performed with titanium mesh cages filled with autologous iliac bone graft. Pedicle screw-rod instrumentation was additionally applied to reinforce the interbody fusion and restore lumbar lordosis. Following this operation, the patient was ambulated with a custom made plastic jacket in his wheelchair. The postoperative course was uneventful, and the patient regained his sitting ability progressively. Four months later, the blood count analysis was within normal limits. Radiologically, there was a complete fusion at the level of instrumentation, while the preoperative lost lumbar lordosis was sufficiently restored. The patient was reemployed 6 months after surgery in his previous work in a sitting position, and, during the last observation 4 years later, he had normal labor analysis and lumbar lordosis.

CONCLUSION

This extremely rare case focuses on the use of the transcanal approach to treat adequately lumbar septic pseudarthrosis and restore lumbar lordosis in definitively paraplegic patients in whom no anterior approach can be used.

Zweymueller with metal-on-metal articulation: clinical, radiological and histological analysis of short-term results

BACKGROUND

This is a prospective study.

METHOD

. A total of 266 consecutive patients, who received 350 third-generation Zweymueller-SL total hip arthroplasties with metal-on-metal articulation for primary or secondary osteoarthritis, was followed and evaluated clinically, radiologically and histologically. The age of the patients at the time of surgery was 55+/-9 years, (range 25-70 years). Seven ( 3%) patients did not return for their last follow-up evaluation for reasons unrelated to their hip operation.

RESULTS

The mean follow-up was 52 months (range 37-92 months). The preoperative Harris hip score was 45+/-19 and increased to 96+/-4 postoperatively. The invalidity of the patients was significantly improved postoperatively ( p<0.001). In all, 97% of the patients were satisfied or very satisfied with the result of the operation. There was no aseptic loosening noted in this series. Revision was done in 6 (1.8%) hips because of septic loosening ( n=5, 1.5%) or technical error ( n=1, 0.3%) during implantation. Dislocation of the prosthesis occurred in the early postoperative period in 2 (0.6%) hips. Periarticular ossification was observed in 30% of the hips (5% Brooker grades III and IV), but without associated disability. During revision surgery, no macroscopic metalosis could be identified in the newly formed hip joint membrane; however microscopic evidence for metalosis (Mirra grades 1 and 2) was seen in all revised hips. The survival for Zweymueller screw socket and stem 7.6 years after implantation was 99.4% and 96.8%, respectively.

CONCLUSIONS

This study showed that the short-term results of Zweymueller total hip arthroplasty with metal-on-metal articulation were just as satisfactory as those of a conventional polyethylene on ceramic articulation, while the metal-on-metal articulation does not seem to give rise to new problems or complications.

Neurological deterioration due to cord and cauda compression at the site of laminar hook insertion : Immediate complication of Texas Scottish Rite Hospital instrumentation for lumbar vertebral fracture

We report an unusual case of a 71-year-old female patient with incomplete paraplegia who experienced neurological deterioration a few hours after the insertion of TSRH (Texas Scottish Hospital Rite) laminar hooks for correction and stabilisation of a fracture of the first lumbar vertebra. Combined CT-myelography revealed significant encroachment of the hooks on the spinal canal, associated with compression of the spinal cord and cauda. The hardware was removed a few hours after the first operation. Two weeks after the revision operation the neurological picture improved. Three months postoperatively the patient died from lung embolism while she was improving neurologically. This case demonstrates that caution should be exercised during the introduction of laminar hooks for thoracolumbar fractures in elderly patients with degeneration of the lumbar spine and stenosis. To avoid such problems careful attention should be paid to appropriate hook selection and safe hook anchorage during fixation and distraction-compression manoeuvres.

Posterior compact Cotrel-Dubousset instrumentation for occipitocervical, cervical and cervicothoracic fusion

The authors report on 32 consecutive patients with instability at the craniocervical, cervical and cervicothoracic regions suffering from various pathologies, who were treated with posterior instrumentation and fusion using the posterior hooks-rods-plate cervical compact Cotrel-Dubousset (CCD) instrumentation alone or, in three patients, in combination with anterior operation. The patients were observed postoperatively for an average of 31 months (range 25-44 months) and evaluated both clinically and radiographically using the following parameters: spine anatomy and reconstruction, sagittal profile, neurologic status, functional level, complications and status of arthrodesis. All patients but one (who died) achieved a solid arthrodesis based on plain and flexion/extension roentgenograms. Cervical lordosis (skull-C7) and cervicothoracic kyphosis (C7-T2) was improved by instrumentation towards a physiological lateral curve by an average of 33% (P<0.05) and 28% (P<0.05) respectively. Anterior vertebral olisthesis was reduced in the craniocervical and cervicothoracic region, by 73% and 90% respectively. At final follow-up there was an improvement of the neurologic Frankel status by an average of 1.2 grades and of myelopathy in 75% of the operated patients. Good to excellent functional results were seen in 77% of the operated patients, while acute and chronic pain was reduced by an average of 2.4 grades, on a scale of 0-3, in operated patients. No neurovascular or pulmonary complications arose from surgery. There was no significant change in lateral spine profile and olisthesis at the latest follow-up evaluation. There were no instrument-related failures. One patient requested hardware removal in the hope of reducing postoperative pain in the cervicothoracic region. The poor and fair results were related to the lack of improvement of neurologic impairment and myelopathy. The results of this study demonstrate that cervical CCD instrumentation applied in the region of the skull to the upper thoracic region for various disorders is a simple and safe instrumentation that restores lateral spine alignment, improves the potential for a solid fusion and offers sufficient functional results in the vast majority of the operated patients. However, the use of hooks in spinal stenosis is contraindicated.

Treatment of dysplastic and congenitally dislocated hips with the Zweymueller total hip prosthesis

Uncemented Zweymueller total hip prostheses were implanted in 35 dysplastic or dislocated hips in 33 patients. Sixteen hips were dislocated and 19 hips were dysplastic; in 12 hips, an intertrochanteric or pelvic osteotomy was performed in early childhood. In all cases, the titanium screw socket was implanted at the level of the original cotyloid cavity. Osteotomy of the greater trochanter, shortening osteotomy, or roof acetabuloplasty were not performed. In cases in which the femoral cavity was too narrow for the Zweymueller stem, an anterolateral longitudinal window-shaped osteotomy was performed. In cases of severe dysplasia, cotyloid cavity bone grafts from the resected femoral head were placed medially to reinforce the acetabular bottom. Clinical and radiographic follow-up ranged from 3-8 years. Average Harris hip score improved from 47 points preoperatively to 86.2 points postoperatively. Complications included two primary anterior dislocations, two temporary femoral nerve pareses, and two deep vein thromboses. At longest follow-up evaluation, no revision was indicated in any of the hips. Satisfactory results in this series were attributed to careful patient selection, precise preoperative radiographic planning, and an operative technique that included implantation of the socket at the primary acetabulum and achievement of primary stability using press-fit fixation.

Prediction of thoracic kyphosis using the Debrunner kyphometer

The Debrunner kyphometer is an accepted tool for detecting and evaluating thoracic kyphosis. This prospective study was conducted to create a mathematical formula that provides, with high approximation, the roentgenographic angle of thoracic kyphosis (T4-T12) using only the kyphometer. Several clinical (kyphometer value, age, and sex) and radiographic (Cobb angle [T4-T12]) parameters from 90 consecutively screened adolescents (44 male and 46 female) were correlated using simple and multiple linear regression analyses. The reliability of measurement using the Debrunner kyphometer was high. The kyphometer value was strongly correlated with the roentgenographically measured thoracic Cobb angle (simple linear regression analysis; probability range, 0.0026 to 0.0002). There was no correlation between age or sex and thoracic kyphosis. The predicted kyphosis angle using the kyphometer and the mathematic formula was 44.66 degrees +/- 2.68 degrees, (range 27 to 62 degrees), and the real roentgenographic kyphosis angle was 47.5 degrees +/- 3.53 degrees, (range, 24 to 70 degrees). The kyphometer and formula were more reliable and accurate when kyphosis less than 50 degrees was measured. In this study, the authors constructed a mathematical formula that accurately provides the roentgenographic T4-T12 kyphosis angle in adolescents using only the Debrunner kyphometer with a deviation of less than 3 degrees. The authors recommend that all physicians engaged in kyphosis screening programs use the kyphometer combined with the recently constructed simple mathematic formula. This method will reduce the cost of school screening programs, overdiagnoses, and unnecessary exposure of adolescents to irradiation.

Mueller roof reinforcement rings. Medium-term results

Short term results of cemented acetabular reconstruction with the use of the Mueller reinforcement ring in 30 hips in 29 patients have been reported previously. The indications for reinforcement were primary and postrevision segmental, cavitary, and combined acetabular deficiencies. The current study reports the medium term clinical and radiologic results of 20 of the 29 patients who were surgically treated (18 primary and eight postrevision hips) and who underwent followup with detailed clinical and radiographic analysis within an average of 9 years (range, 7-12 years). In the latest followup, there has been a statistically insignificant decrease in clinical scores compared with those obtained immediately after surgery; the changes probably are a result of the patients' aging. The radiologic scores at the latest followup were lower, although not statistically significant, than those at the short term followup. The causes of the three ring failures that occurred 5, 8, and 8.5 years after surgery and required revision arthroplasty were either acute trauma or tuberculous arthritis. Three additional hips (two primary and one revision) had evidence of loosening in the ring and socket associated with symptomatology and were considered as hips with impending revision. The rate of success of primary implantation was 94% at 7 years, 86% at 10 years, and 86% at 12 years and was not statistically different from that of revision implantation, which was 86% in all three followup periods. In this small series this surgical technique was successful and effective and followed by good medium term clinical and radiographic results in primary and revision implantation in segmental, cavitary, or complex acetabular deficiencies and in osteoporotic or deficient acetabular bone.