Prevalence and natural course of pseudotumours after small-head metal-on-metal total hip arthroplasty: a minimum 18-year follow-up study of a previous report

AIMS

The present study investigated the five-year interval changes in pseudotumours and measured serum metal ions at long-term follow-up of a previous report of 28 mm diameter metal-on-metal (MoM) total hip arthroplasty (THA).

PATIENTS AND METHODS

A total of 72 patients (mean age 46.6 years (37 to 55); 43 men, 29 women; 91 hips) who underwent cementless primary MoM THA with a 28 mm modular head were included. The mean follow-up duration was 20.3 years (18 to 24). All patients had CT scans at a mean 15.1 years (13 to 19) after the index operation and subsequent follow-up at a mean of 20.2 years (18 to 24). Pseudotumour volume, type of mass, and new-onset pseudotumours were evaluated using CT scanning. Clinical outcomes were assessed by Harris Hip Score (HHS) and the presence of groin pain. Serum metal ion (cobalt (Co) and chromium (Cr)) levels were measured at the latest follow-up.

RESULTS

At final follow-up, pseudotumours were observed in 26/91 hips (28.6%). There was an increase in volume of the pseudotumour in four hips (15.4%), no change in volume in 21 hips (80.8%), and a decrease in volume in one hip (3.8%). There were no new-onset pseudotumours. There was no significant difference in HHS between patients with and without pseudotumours. At final follow-up, mean serum Co ion levels and median Co:Cr ratios were significantly greater in patients with pseudotumours, but the serum Cr ion levels were not significantly different.

CONCLUSION

At a mean 20 years of follow-up, pseudotumours were observed in 26/91 hips (28.6%) with no new-onset pseudotumours during subsequent follow-up. Most pseudotumours in small-head MoM THA were static in volume and asymptomatic with normal serum metal ion levels. Cite this article: Bone Joint J 2019;101-B:317-324.

Factors affecting peri-implant fracture following locking plate for osteoporotic distal femur fractures

INTRODUCTION

The purpose of this study is to evaluate the outcomes and to analyze the risk factors for the occurrence of peri-implant fracture after treatment of osteoporotic distal femoral fractures using a locking plate.

HYPOTHESIS

Risk factors affecting peri-implant fracture exist after locking plate fixation in osteoporotic distal femur fracture.

MATERIALS AND METHODS

Eighty-nine cases (88 patients) with osteoporotic distal femoral fractures were evaluated between January 2006 and January 2014. The cohort included 13 men and 76 women with a mean age of 70.4 (50-91). Mean duration of follow-up was 47.9 months (12 to 106). All patients with distal femoral fracture were treated with a locking compression plate. Bone mineralized densitometry measurement was obtained from all patients. Risk factors including sex, age, rheumatoid arthritis (RA), taking of bisphosphonate, primary or periprosthetic fracture after total knee arthroplasty (TKA), open or closed fracture, types of the most proximal screw (locking/cortical), and number of proximal screws were analyzed. Complication, union, time to union, and range of motion of knee were also evaluated.

RESULTS

All patients had osteoporosis with the mean BMD of -3.16 (-2.5∼-5.4). The mean range of motion of knee was 126 degrees (90-145). Eighty-four cases (94.4%) showed union, the mean time to union was 14 weeks (10-42). Peri-implant fractures occurred in four patients (4.5%) after bone union at mean 37.5 months (14-62) postoperatively. Eight patients had angular deformities of over 5 degrees. Nonunion was observed in 5 cases and superficial wound infection in 2 cases. There were eight patients with RA, two of whom had suffered a peri-implant fracture. In statistical analysis, rheumatoid arthritis or periprosthetic fracture in TKA patients was a risk factor for peri-implant fracture (P=0.039, 0.019, respectively), and other factors showed no statistical differences.

CONCLUSIONS

Treatment using a locking plate showed favorable outcomes in osteoporotic distal femoral fractures. However, peri-implant fracture could occur in patients with RA or periprosthetic fracture after TKA. Therefore, cautious consideration is required for management of osteoporotic distal femur fracture in patients with RA or periprosthetic fracture after TKA. Analysis of more cases will be needed in order to achieve conclusive results.

LEVEL OF EVIDENCE

Therapeutic study, level IV (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

What is the ideal interval between dressing changes during negative pressure wound therapy for open traumatic fractures?

OBJECTIVE

Negative pressure wound therapy (NPWT) is effective in infection control during treatment of severe open fractures. However frequent dressing changes during NPWT are costly and cause patient discomfort. If the interval between dressing changes could be extended, these problems would be reduced. In this article we compare the outcomes of open IIIB fractures with 3-day versus 7-day intervals between dressing changes.

METHOD

Patients who sustained Gustilo IIIB open fractures were included. All underwent conventional orthopaedic fixation with delayed latissimus dorsi flap coverage. Group 1 had 3-day intervals between dressing changes and group 2 had 7-day intervals. The final outcomes in the two groups were analysed.

RESULTS

There were 38 patients in group 1 and 34 patients in group 2. Although the period between admission and final operation was similar in the two groups, the mean number of NPWT changes was 4.54 in 3 day in group 1 and 1.95 in group 2 (p<0.001). This led to a difference in NPWT-related costs; $341.26 in group 1 and $237.49 in group 2 (p<0.001). There was no difference in the frequency of complications such as infection or non-union of fractures.

CONCLUSION

NPWT is useful treatment option for open fractures, to bridge between initial debridement and final microsurgical tissue transfer. Considering patient comfort, the costs related to the NPWT, and the final flap results, a 7-day interval between changes of the NPWT is acceptable.

Prevalence of a soft-tissue lesion after small head metal-on-metal total hip replacement: 13- to 19-year follow-up study

We investigated the incidence of soft-tissue lesions after small head metal-on-metal total hip replacement (MoM THR). Between December 1993 and May 1999, 149 patients (195 hips) underwent primary cementless MoM THR. During the follow-up period, three patients (five THRs) died and eight patients (14 THRs) were lost to follow-up. We requested that all patients undergo CT evaluation. After exclusion of five patients (six THRs) who had undergone a revision procedure, and 22 (28 THRs) who were unwilling to take part in this study, 111 patients (142 THRs) were evaluated. There were 63 men (88 THRs) and 48 women (54 THRs) with a mean age of 45.7 years (37 to 56) at the time of surgery. The mean follow-up was 15.4 years (13 to 19). A soft-tissue lesion was defined as an abnormal peri-prosthetic collection of fluid, solid lesion or asymmetrical soft-tissue mass. At final follow-up, soft-tissue lesions were found in relation to 28 THRs (19.7%), including 25 solid and three cystic lesions. They were found in 20 men and eight women; 26 lesions were asymptomatic and two were symptomatic. The mean maximal diameter of the soft-tissue lesion was 42.3 mm (17 to 135). The relatively high rate of soft-tissue lesions observed with small head MoM THR remains a concern.

Combined endovenous laser treatment and ambulatory phlebectomy for the treatment of saphenous vein incompetence

Objectives

The aim of this retrospective study is to assess the safety and effectiveness of endovenous laser treatment (EVLT) combined with ambulatory phlebectomy (AP) as a single procedure for treating saphenous vein incompetence.

Methods

The study enrolled 148 patients with saphenofemoral or saphenopopliteal junction reflux associated with saphenous vein incompetence and enlarged branch veins. Patients were treated with EVLT (135 great saphenous veins, 41 small saphenous veins) concomitantly with AP as a single procedure. All patients were followed up by clinical assessment and duplex ultrasound at one week and 12 weeks after the procedure.

Results

No postprocedural deep vein thrombosis and pulmonary embolism occurred. Saphenous vein recanalization rate at three months was 5.7%. Residual varicosities were found in 11.4% of the patients at three months after procedure, but only 2.3% of those required subsequent interventions.

Conclusion

Combined EVLT and AP could be a safe and effective treatment modality for the saphenous vein incompetence.