Acetabular diameter measurement determines proper prosthetic head size in hemiarthroplasty for femoral head osteonecrosis

In hemiarthroplasty for femoral head osteonecrosis, collapse and deformity may make femoral head measurement difficult, thus, precluding the selection of an appropriate prosthetic head. We describe a method for measuring the acetabular diameter using acetabular sizing gauges to estimate the prosthetic head size. We evaluated the precision of this method and found it to be highly accurate and reliable.     

Femoral head blood flow in femoral neck fractures. An analysis using intra-osseous pressure measurement

We studied 50 patients with fractures of the femoral neck, 33 intracapsular and 17 extracapsular. Intraosseous pressure was measured by a transducer within the bone to quantify blood flow, and intracapsular pressure by a needle introduced into the joint space. The mean intracapsular pressure was lower in the extracapsular fractures. In these, the mean intraosseous pressure in the femoral head was unchanged by aspiration of the joint. However in the intracapsular fractures aspiration produced a significant decrease in intra-osseous pressure and an increase in pulse pressure within the femoral head. The results suggest that aspiration of intracapsular haematoma produced an increase in femoral head blood flow by relieving tamponade.     

Mammography: interobserver variability in breast density assessment

Our objective was to determine the interobserver variability of breast density assessment according to the Breast Imaging Reporting and Data System (BI-RADS) and to examine potential associations between breast density and risk factors for breast cancer. Four experienced breast radiologists received instructions regarding the use of BI-RADS and they assessed 57 mammograms into BI-RADS density categories of 1-4. The weighted kappa values for breast density between pairs of observers were 0.84 (A, B) (almost perfect agreement); 0.75 (A, C), 0.74 (A, D), 0.71 (B, C), 0.77 (B, D), 0.65 (C, D) (substantial agreement). The weighted overall kappa, measured by the intraclass correlation coefficient (ICC), was 0.77 (95% CI: 0.69-0.85). Body mass index was inversely associated with high breast density. In conclusion, overall interobserver agreement in mammographic interpretation of breast density is substantial and therefore, the BI-RADS classification for breast density is useful for standardization in a multicentre study.     

Clinical results of hemiarthroplasty using new bipolar cups for stage 3 or lower osteonecrosis of the femoral head: a retrospective study

Purpose

The aim of this study was to evaluate clinical and radiographic findings of stage 3 or lower osteonecrosis of the femoral head (ONFH) with intact acetabular cartilage in patients treated with bipolar hemiarthroplasty (BHA).

Methods

A total of 79 hips that underwent BHA for ONFH were included in this study. The average observation period was 7.6 years. Clinical results were evaluated using the Harris hip score. We performed radiographic analysis to assess the migration of the outer cup, the permanent image around the outer cup, and loosening of the stem.

Results

The total Harris hip score improved from 50 points before surgery to 92 points at final follow-up, while pain improved from 14 points to 36 points. Flexion improved from 94° to 120° and abduction from 27° to 37°. One patient on dialysis showed progress in terms of inward migration, and revision surgery was performed on the patient 14 years after the original surgery.

Conclusions

Midterm performance of BHA for stage 3 or lower ONFH at our hospital was good.

     

Shoulder hemiarthroplasty in the management of humeral head fractures

The results of hemiarthroplasty for shoulder fracture were evaluated in 26 patients, 20 women and 6 men with a mean age of 64.7 +/- 8.2 years. The follow-up period was 2 to 7 years. Cofield prostheses were used for the first 10 patients and subsequently 9 Global and 7 Aequalis prostheses were implanted, all cemented. The clinical outcome was assessed using the Constant-Murley scale. The mean score, at the last follow-up, was 70.4 +/- 16.4 (39-96). Mean forward elevation of the arm was 150 degrees (300-175 degrees), mean abduction was 145 degrees (30 degrees -170 degrees), and mean external rotation was 30 degrees (10 degrees-45 degrees). In most of the cases internal rotation corresponded with a position of the dorsum of the hand at the L3 vertebrae. The patients in our series achieved their optimal clinical result within the first 6 months after operation. Shoulder hemiarthroplasty is a worthwhile procedure, giving predictable results provided the patients have been carefully selected, the individual anatomy of the shoulder is restored and an aggressive rehabilitation program is implemented during the first six months after surgery.     

Determination of the anaerobic threshold in the pre-operative assessment clinic: inter-observer measurement error

The variability between observers in the interpretation of cardiopulmonary exercise tests may impact upon clinical decision making and affect the risk stratification and peri-operative management of a patient. The purpose of this study was to quantify the inter-reader variability in the determination of the anaerobic threshold (V-slope method). A series of 21 cardiopulmonary exercise tests from patients attending a surgical pre-operative assessment clinic were read independently by nine experienced clinicians regularly involved in clinical decision making. The grand mean for the anaerobic threshold was 10.5 ml O₂.kg body mass⁻¹.min⁻¹. The technical error of measurement was 8.1% (circa 0.9 ml.kg⁻¹.min⁻¹; 90% confidence interval, 7.4–8.9%). The mean absolute difference between readers was 4.5% with a typical random error of 6.5% (6.0–7.2%). We conclude that the inter-observer variability for experienced clinicians determining the anaerobic threshold from cardiopulmonary exercise tests is acceptable.     

Femoral cement pressurization in hip arthroplasty: a comparison of 3 systems

Cement pressurization is critical to achieving optimal results in cemented arthroplasty of the hip. An in vitro experiment using plastic femoral models (10 per group) was undertaken to measure the pressures developed by 3 cementing systems: the Howmedica Mark 1 (Stryker Howmedica, Limerick, Ireland) and DePuy Cemvac retrograde cementation systems (DePuy CMW, Blackpool, UK), and a novel antegrade system consisting of a 60-mL catheter-tipped syringe and a Miller proximal femoral seal (Zimmer Ltd, Swindon, UK). The mean pressure was higher for the syringe system (161.45 +/- 28.9 kPa) than the Mark 1 (103.51 +/- 22.0 kPa) or Cemvac (92.65 +/- 30.7 kPa) systems (P = .0001). In addition, fewer cement mantle defects were seen with the syringe system (1, interquartile range [IQR] 1-2) than the Mark 1 (3, IQR 2-4) or Cemvac (3, IQR 1-3) systems (P = .0256).     

Femoral head resurfacing in the treatment of osteonecrosis: 3 to 5-year follow-up

We reviewed the clinical and radiological results of 32-cemented femoral head resurfacing arthroplasty, performed by a single surgeon in 25 patients with femoral head osteonecrosis at a mean age of 36.2 years. All patients received a cemented conserve (Wright Medical Technology Inc., Arlington, TN, USA) femoral hemiresurfacing arthroplasty. Data were complete on 16 patients with 21 hips at a mean follow-up period of 50.8 months. Five patients had bilateral procedures. The Harris hip score, and the Merle d’Aubigné score improved significantly from 54.7 to 72.3 (P = 0.0001), and from 12.1 to 13.9 (P = 0.01), respectively. Seven hips had undergone revision to total hip arthroplasty at the time of follow-up while one hip is scheduled for revision surgery, representing a 38% failure rate. When clinical failure is defined as a Harris Hip Score of less than 70 at follow-up, clinical failure was 81% at 4.25 years.     

Observer error in the assessment of nodal disease in head and neck cancer

BACKGROUND: There is no previously published information on clinicians' abilities to accurately differentiate between different stages of node positive disease in head and neck cancer. METHODS: Forty-two surgeons examined standardized nodes in a model neck and estimated nodal size. Each recorded their confidence in their ability to perform the task using a visual analogue scale. Reference nodes of known size were provided for comparison during a second examination of each node. The study was repeated after 1 month. RESULTS: Accuracy was poor and was not dependent on experience or confidence. There was a tendency to underestimate the size of smaller nodes. Estimates were strongly influenced by volume independent of largest diameter (p <.001). Reference nodes aided accuracy (p =.031). Subjects were not consistent on repeated testing (p <.001). CONCLUSIONS: Both trainees and specialists are poor at accurately staging nodal disease using palpation alone.     

Measurement of vertebral rotation in idiopathic scoliosis using the Perdriolle torsionmeter: a clinical study on intraobserver and interobserver error

Summary This study was designed to determine the reliability and accuracy of the Perdriolle torsionmeter. Fifty-four observers were divided into three groups according to their previous experience in the field of orthopaedics and the treatment of scoliosis. Each observer, on two separate occasions, measured the apical vertebral rotation on preoperative and postoperative roentgenograms of three idiopathic thoracic scoliotic curves using the torsionmeter. For all groups, there was no statistically significant difference (P>0.05) between the average of the first and the average of the second measurements of vertebral rotation of any of the curves. In the curve with the highest frontal Cobb angle and vertebral rotation of more than 30°, there was a statistically significant difference (P=0.03) between the average measurements of the three groups of observers. We concluded that, as both intraobserver and interobserver error risks were insignificant, the torsionmeter can be accurately used by everyone in the fields of orthopaedics provided the vertebral rotation is not greater than 30° and the curve is mild or moderate. The reliability and accuracy of the torsionmeter was found to be questionable at more than 30° of vertebral rotation because of increased risk of interobserver error.This study was presented as a free paper at the SICOT Regional and 14th National Turkish Congress of Orthopaedic Surgery and Traumatology, 29 September–4 October 1995, Izmir     

The interobserver reliability of classification systems for radial head fractures: the Hotchkiss modification of the Mason classification and the AO classification systems

Background

Radial head fractures are common injuries, and there is little information on the reliability of classification systems for such injuries. The purpose of our study was to report the interobserver reliability of 2 commonly used classification systems: the Hotchkiss modification of the Mason classification and the AO classification systems.

Methods

We compiled the radiographs from a cohort series of 43 patients with radial head fractures, and 5 observers classified the radiographs according to both classification systems. Additionally, we collapsed the systems, with types II and III combined for the Hotchkiss classification and the final digit dropped for the AO classification. We calculated percent agreement, the κ statistic and the associated 95% confidence intervals (CIs).

Results

The mean percent agreement was 72.3% (95% CI 65.8%–78.9%) for the Hotchkiss classification and 37.7% (95% CI 30.5%–44.9%) for the AO classification. The κ statistic was 0.585 (0.541–0.661) for the Hotchkiss classification and 0.261 (0.240–0.350) for the AO classification. The mean percent agreement was 89.3% (86.6%–92.0%) for the consolidated Hotchkiss classification and 67.4% (54.6%–80.3%) for the consolidated AO classification. The κ statistic was 0.760 (0.691–0.805) for the consolidated Hotchkiss classification and 0.455 (0.372–0.521) for the consolidated AO classification.

Conclusion

The interobserver reliability for the Hotchkiss modification of the Mason classification was moderate, and that for the AO classification was fair according to the criteria of Landis and Koch. Collapsing the Hotchkiss classification improved the reliability to substantial, and collapsing the AO system improved reliability to the lower end of moderate.     

Outcome of cemented Neer II hemiarthroplasty in displaced humeral head fractures

The functional and radiological outcome of cemented Neer II hemiarthroplasty performed within six weeks after a fracture-dislocation or a three/four-part humeral head fracture was evaluated in 48 patients with an average age of 73 years (range: 45 to 89), with an average follow-up period of 44 months (range: 6 to 106). Thirty-two (67%) patients were satisfied or very satisfied. Twenty-nine (61%) patients had no or mild pain, 17 (35%) had moderate pain and two (4%) had severe pain. Constant Score averaged 49 (range: 8 to 71) compared to 78 (range: 40 to 100) for the nonoperated shoulder (p < 0.001). The 26 (57%) patients with abnormal radiographs (malpositioning or loosening of the prosthesis, non-union of tuberosities, heterotopic ossification, and/or glenoid erosion) had a significantly lower Constant Score (45 [range: 8 to 69] versus 55 [range: 31 to 71], p = 0.013). The functional outcome is disappointing and related to the radiographic status. The patients however seem to be satisfied despite a rather stiff shoulder and in our opinion a non-acceptable pain relief.     

A radiological assessment of interprosthetic movement in the Charnley-Hastings hemiarthroplasty

Forty-six patients with acute displaced subcapital fractures of the femur were treated between December 1982 and December 1984 with Charnley-Hastings bipolar prostheses. The interprosthetic movement in 23 patients was assessed radiologically at least 1 year after surgery. Four patients (17.4 per cent) had no interprosthetic movement in abduction but the remainder (82.6 per cent) had some movement, although only 3 patients (13 per cent) had more than 5 degrees of abduction within the prosthesis.     

A radiographic evaluation of birotational head motion in the bipolar shoulder hemiarthroplasty

The concept of bipolar hemiarthroplasty has been described in the hip for more than 20 years, its role being to decrease acetabular wear. Shoulder bipolar hemiarthroplasty was described shortly afterward. The purpose of this study was to determine if the prosthesis acted as a bipolar device moving primarily at the inner metal on polyethylene bearing as intended, or as a unipolar hemiarthroplasty moving at the outer metal on glenoid surface articulation. Eleven bipolar shoulder hemiarthroplasties, with a minimum follow-up of 22 months, were examined fluoroscopically. The proportion of arm abduction occurring at the scapulothoracic articulation and between the two components of the bipolar hemiarthroplasty was assessed and compared with that of normal patients and those with total shoulder replacements previously reported in the literature. The results of this study show that most of the movement in active arm abduction occurred at the scapulothoracic articulation and that the bipolar hemiarthroplasty acted predominantly as a unipolar device.