Noise characteristics in ceramic-on-ceramic vs. metal-on-polyethylene total hip arthroplasty: a comparative study.

INTRODUCTION: A comparison of noise in ceramic-on-ceramic (CoC) bearings and metal-on-polyethylene (MoP) bearings after total hip arthroplasty (THA) was undertaken. Noise associated with MoP implants is rarely reported and has not been linked to squeaking. METHODS: A noise characterising hip questionnaire and Oxford Hip Score (OHS) was sent to 1,000 THA patients; there were 509 respondents 282 CoC and 227 MoP; mean age 63.7 years (range 45-92 years), mean follow up 33 months (range 6-156 months). RESULTS: Of 282 repsondents 47 (17%) of the CoC patients reported noise compared to 19 (8%) of the MoP patients (p = 0.048); 9 CoC patients and 4 MoP patients reported squeaking. Overall, 27% patients with noise reported avoiding recreational activities because of it and patients with noisy hips scored on average 5 points less on the OHS (CoC: p = 0.04 and MoP: p = 0.007). DISCUSSION: This is the first study to report squeaking from MoP THAs. The squeaking hip phenomenon is not exclusive to CoC THAs. Noisy hip implants may have social implications, and patients should be aware of this. We have shown a relationship between noise and a lower OHS. However, longer follow-up is needed to link noise to a poorly functioning implant.

Outcome after femoral revision using the restoration cone/conical femoral revision stem.

Despite improvements in implant technology and surgical technique, failure of total hip arthroplasty (THA) remains a persistent problem. This article reports clinical outcomes at a mean follow-up of 42 months using the Restoration cone/conical modular femoral revision stem (Stryker, Newbury, United Kingdom). A prospective cohort study was performed of 46 consecutive patients who underwent revision THA between January 2004 and June 2007. Patients were reviewed pre- and postoperatively at regular intervals for clinical and radiological assessment. Forty-six patients (17 men, 29 women) with a mean age of 72 years (range, 44-93 years) were observed for a mean of 42 months (range, 28-66 months). Indications for surgery included aseptic loosening/osteolysis (38/46 [83%]), periprosthetic fracture (4/46 [9%]), and infection (4/46 [8%]). Median time from index procedure was 16 years (range, 1-26 years). No patient was lost to follow-up. Two patients (4%) with well-fixed asymptomatic stems died during follow-up. Three patients (7%) sustained an early postoperative dislocation. One patient sustained a periprosthetic fracture after a fall. This was treated by osteosynthesis, and stem revision was not required. Mean Oxford Hip Score improved from 42 points (range, 24-57 points) to 28 points (range, 18-51 points) at 3-month follow-up (P=.003). Median stem subsidence was 1.0 mm (standard error of the mean, ±1.7 mm; range, 0-7mm) at last follow-up. No patient developed loosening or osteolysis around the stem. The Restoration femoral revision system has favorable clinical and radiological outcomes at a mean follow-up of 42 months.

A deep breath bronchoconstricts obese asthmatics.

BACKGROUND: Asthma is characterized by the loss of a deep breath (DB)-induced bronchodilation and bronchoprotection. Obesity causes lung restriction and increases airway resistance, which may further worsen the capacity of a DB to induce bronchodilation; however, whether increasing BMI impairs the bronchodilatory response to a DB in asthmatics is unknown. METHODS: The population consisted of 99 subjects, 87 with moderate to severe persistent asthma and 12 obese control subjects. Using transfer impedance we derived airway resistance (Raw). Participants breathed for 1 minute and took a slow DB followed by passive exhalation to functional residual capacity (FRC) and tidal breathing for another minute. RESULTS: After a DB, obese asthmatics had the largest percent increase in Raw (median 9.8% interquartile range [IQR] 3.1-15.1), compared with overweight (6.5% IQR -1.3, 12.1) and lean (0.7% IQR -3, 7.9) asthmatics and obese controls (2.5% IQR -.6, 11) (p for trend = 0.008). The association between the percent increase in Raw after a DB and BMI as a continuous variable was significant (p = 0.02). CONCLUSIONS: In obese, moderate to severe and poorly controlled asthmatics, a DB results in increased Raw. This phenomenon was not observed in leaner asthmatics of similar severity or in obese control subjects.

A prospective comparison of two treatment options for tuberosity fractures of the proximal fifth metatarsal.

BACKGROUND: Tuberosity 'avulsion' fractures of the proximal fifth metatarsal are common injuries, but with few comparisons of conservative treatment options. OBJECTIVE: This study prospectively compared two commonly used conservative treatment methods. METHODS: 37 patients were allocated to treatment in either a plaster slipper (n=20) or tubi-grip support (n=17) for a period of 6 weeks. Patients were assessed at 2, 6 and 12 weeks after injury using a modified foot score which measured the level of pain and dysfunction. A radiograph was taken at 12 weeks. A Mann-Whitney U test compared median foot scores between the treatment groups at each review (p-value of 0.05 or less was deemed significant). RESULTS: A significantly (p=0.02) better foot score was measured in the plaster group at 2 weeks after injury (median score 68 (plaster group) compared to 57 (tubi-grip group)). However by the 6- and 12-week stages, the scores were comparable. Radiographs indicated two patients in each group with no clear evidence of union after 12 weeks. One patient remained symptomatic and required surgical treatment. CONCLUSIONS: The eventual clinical and radiological outcomes were comparable. During the initial 2 weeks, patients treated in plaster had a better-combined level of pain and function.

Deep breath reversal and exponential return of methacholine-induced obstruction in asthmatic and nonasthmatic subjects.

A deep breath (DB) during induced obstruction results in a transient reversal with a return to pre-DB levels in both asthmatic and nonasthmatic subjects. The time course of this transient recovery has been reported to be exponential by one group but linear by another group. In the present study, we estimated airway resistance (Raw) from measurements of respiratory system transfer impedance before and after a DB. Nine healthy subjects and nine asthmatic subjects were studied at their maximum response during a methacholine challenge. In all subjects, the DB resulted in a rapid decrease in Raw, which then returned to pre-DB levels. This recovery was well fit with a monoexponential function in both groups, and the time constant was significantly smaller in the asthmatic than the nonasthmatic subjects (11.6 +/- 5.0 and 35.1 +/- 15.9 s, respectively). Obstruction was completely reversed in the nonasthmatic subjects (pre- and postchallenge mean Raw immediately after the DB were 2.03 +/- 0.66 and 2.06 +/- 0.68 cmH2O.l-1.s, respectively), whereas in the asthmatic subjects complete reversal did not occur (2.29 +/- 0.78 and 4.84 +/- 2.64 cmH2O.l-1.s, respectively). Raw after the DB returned to postchallenge, pre-DB values in the nonasthmatic subjects (3.78 +/- 1.56 and 3.97 +/- 1.63 cmH2O.l-1.s, respectively), whereas in the asthmatic subjects it was higher but not significantly so (9.19 +/- 4.95 and 7.14 +/- 3.56 cmH2O.l-1.s, respectively). The monoexponential recovery suggests a first-order process such as airway wall-parenchymal tissue interdependence or renewed constriction of airway smooth muscle.

Evaluation of the Hemocue portable hemoglobinometer after major joint arthroplasty.

We evaluated the potential use of the Hemocue (Hemocue AB, Sweden) portable hemoglobinometer on the 1st postoperative evening after major joint arthroplasty. We compared hemoglobinometer values with conventional Coulter counter laboratory analysis in a population of 67 patients. The hemoglobinometer proved practical, economical, and accurate in general, although 2 outlying values were severe enough as potentially to influence clinical decision making. Potential causes and solutions are discussed.