Is there adequate provision of venous thromboembolism prophylaxis following hip arthroplasty? An audit and international survey.

INTRODUCTION: The peak incidence of venous thrombo-embolism (VTE) occurs 3 weeks following hip arthroplasty surgery and current guidelines proposing VTE prophylaxis continuing for 4 weeks after surgery. This study first compares the duration of treatment and satisfaction between patients prescribed low molecular weight heparin (LMWH) and rivaroxaban, a new oral Factor Xa inhibitor, following elective hip arthroplasty; and second, surveys the duration of LMWH use in other units. SUBJECTS AND METHODS: An international survey detailing the use of LMWH was performed. A prospective audit was performed of 100 hip replacements, with 50 prescribed 40 mg once daily of subcutaneous enoxaparin and subsequently 50 patients prescribed 10 mg once daily of oral rivaroxaban. The duration of treatment, patient satisfaction and complications for both cohorts was quantified and compared against published evidence-based guidelines. RESULTS: The survey demonstrated that four out of 39 (10.2%) units that routinely prescribe LMWH do so for at least 4 weeks following surgery. The audit demonstrated that rivaroxaban afforded a superior mean duration of postoperative VTE prophylaxis (35 days vs 5.4 days; P < 0.05) and superior patient satisfaction. There was no difference in the incidence of bleeding, wound infection or thrombotic complications. CONCLUSIONS: This study demonstrates that patients are exposed to an increased VTE risk following hip replacement surgery due to the inadequate prescription of LMWH. This is poor clinical practice, contrary to current evidence-based guidelines and has potential medicolegal implications. The prescription of rivaroxaban affords a superior patient compliance compared with subcutaneous LMWH, thus ensuring that patients receive VTE prophylaxis for the current recommend period of time.

Revision total hip arthroplasty using impaction bone grafting with cemented nonpolished stems and charnley cups.

This article reports the results of 181 cemented revision total hip arthroplasties in which impacted morcellized allograft and cement was used for reconstitution of acetabular and femoral bone deficiencies. There were 173 acetabular and 79 femoral reconstructions. The mean follow-up was 4.0 years. The overall survival rate was 97.2%. Evidence of revascularization of the impacted allograft was shown in 29 of 30 (97%) randomly selected bone scintigraphies. Radiographic evidence of allograft incorporation was observed in 128 of 173 (74%) acetabula and 48 of 73 (61%) femora. Stem subsidence occurred in all types of femoral bone deficiencies and was not time dependent (P =.17). The acetabular components showed significant migration with increased bone deficiency (P =.0003). Impaction bone grafting has shown promising results in revision total hip arthroplasty but is not recommended in type 3 acetabular defects.

Impaction bone grafting using freeze-dried allograft in revision hip arthroplasty.

We report on 32 patients undergoing revision hip arthroplasty using cemented components and impaction allografting with processed freeze-dried bone. The survivorship with this type of graft at a mean follow-up of 4 years was 91%. There were no femoral component failures, although revision was required in 3 patients because of failure of the acetabulum. Freeze-dried graft can require prolonged rehydration for satisfactory impaction. The results of impaction bone grafting with freeze-dried bone alone have been satisfactory, although we recommend caution in its use alone in the hostile acetabulum.

Radiographic assessment of the cement mantle thickness of the femoral stem in total hip replacement: a case study of 112 consecutive implants.

The results are reported of a radiographic study of cement mantle thickness in 112 consecutive primary hip replacements. Measurements were made by three observers of the apparent cement thickness medially and laterally using standard anterior-posterior radiographs. The average cement thickness was 3.2 mm, which is 1.2 mm greater than the size difference between the broach and the prosthesis, and was in the range 2-5 mm in 67 per cent of all measurement points. This has significance for the design of instrumentation to prepare the femoral cavity to give a defined cement mantle thickness. There was a greater cement mantle thickness proximally than distally. In 95 cases it was possible to determine the orientation of the stem within the cement mantle, which showed an even distribution between varus and valgus orientation; 49 per cent were within 1 degree of neutral and only one case was more than 5 degrees from neutral.

A lump in the groin: an unusual presentation of loose hip prosthesis.

We describe the loose hip prosthesis presenting as a mass in the groin, with a collection of titanium and polyethylene debris within the ileopsoas bursa. Titanium tissue staining has been noted, at the time of revision of titanium prostheses, but frank ileopsoas bursitis presenting as a groin mass, after hip replacement has not previously been described.

Effect of counterface material on the characteristics of retrieved uncemented cobalt-chromium and titanium alloy total hip replacements.

A number of total hip components explanted at revision with bearing surfaces in either cobalt-chromium-molybdenum alloy or titanium-6% aluminium-4% vanadium alloy were examined and compared to contemporaneously manufactured but unused items; particular attention was paid to the bearing surfaces which were examined visually, by low-power microscopy, scanning electron microscopy (SEM), confocal microscopy, white light interferometry, laser profilometry and conventional stylus profilometry. The cobalt alloy heads maintained their surface finish well over periods up to 12 years. The titanium implants became badly damaged over much shorter periods although even badly scratched heads continued to meet the current standards for titanium alloy heads. Analysis showed that the damage to the titanium alloy heads was not a random but a well-defined process of scarring of a consistent size created by abrasion with small particles of bone. These damaged heads had the potential to wear the matching UHMWPE components rapidly creating large amounts of polymer debris. The finding that measurement of these damaged heads is within current standards raises concerns as to whether current standards incorporate fully the requirements for clinical performance.

Soft-tissue swelling following fractures of the ankle.

One hundred and thirty-six consecutive fractures of the ankle were assessed over a 2-year follow-up period in order to determine the rate at which soft-tissue swelling subsides. The effect of anatomical and non-anatomical reduction by both open and closed methods was compared. The results showed that soft-tissue swelling following external rotation fractures of the lateral malleolus treated by closed methods subsides initially over a 3-month period. Anatomical reduction, whether achieved by open or closed methods, in bi- and trimalleolar fractures results in a rapid resolution of the swelling over 3 months, followed by a slower return to normal over the ensuing 6 months. Persistent soft-tissue swelling remains when these intra-articular fractures are not anatomically reduced. The swelling is more marked and persists for 2 years or more in those fractures treated by open methods with poor anatomical restoration compared with poor reduction achieved by closed methods.

Uncemented acetabular cups in dysplastic and protrusio acetabuli.

Total hip arthroplasties using the Ring uncemented polyethylene to metal system were carried out in 84 hips with either protrusio or dysplasia of the acetabulum. The results of the operation, the stability and function of the acetabular implant, and radiologic changes in the medial wall of the acetabulum in the protrusio hips were assessed over a two- to five-year follow-up period. Annual assessment over the follow-up period showed that an excellent functional result was achieved in all patients. Six of the eight hips with severe protrusio showed an increase in the thickness of the medial acetabular wall one year from the time of operation. Lack of bony cover over the lateral surface of the acetabular cup in the dysplastic hips did not have any adverse effect on the stability and function of these hips.

Stiffness after fractures around the knee in spina bifida.

A study was made of knee stiffness after fractures around the knee in patients with spina bifida. Thirty-one patients with 45 fractures were followed up for 2 to 15 years after the fracture. Knee stiffness was found in 67% of patients; this amounted to loss of up to half the normal range of movement. The stiffness appeared at two months from the time of the fracture and was established by six months. However, in all patients it had resolved by three years, so that their mobility was not affected in the long term. It is concluded that though stiffness is common after fractures in patients with spina bifida, it should be treated expectantly as it will resolve within three years without specific treatment.