Objectives

Wound complications are reported in up to 10% hip and knee arthroplasties and there is a proven association between wound complications and deep prosthetic infections. In this randomised controlled trial (RCT) we explore the potential benefits of a portable, single use, incisional negative pressure wound therapy dressing (iNPWTd) on wound exudate, length of stay (LOS), wound complications, dressing changes and cost-effectiveness following total hip and knee arthroplasties.

Aim: To investigate whether cement mantle thickness influence early migration of the stem after impaction grafting.

Methods: Twelve artificial femora were prepared to mimic cavitary defects. After compacting morselized bone into the cavities, Exeter stems were cemented in place. By using all combinations of three sizes tamps and stems (0, 1 and 2), we created cement mantles of 0, 1, 2, 3 and 4 mm thickness. Bones with stems were placed in a testing machine and loaded cyclically to 2,500 N while measuring stem migration. Statistical analysis was by regression analysis. Outcomes were stem subsidence and retroversion, predictors were mantle thickness, tamp size and stem size.

Results: Average stem subsidence after 2500 cycles when using size 1 tamp and stem (2 mm mantle) was 0.94 mm. For a 0 mm mantle, subsidence was 0.59 mm and for a 4 mm mantle it was 2.54 mm. Cement mantle thickness significantly influenced stem subsidence (r=0.68, p=0.015). Cement mantle thickness also significantly influenced stem retroversion (r=0.62, p=0.031). Cement mantle thickness was a better predictor of stem stability than tamp or stem size.

Discussion: Concern exists that inadequate cement mantles may affect stability of impaction-grafted stems. In our study, larger difference between tamps and stems gave substantially more subsidence and rotation, whereas a smaller difference reduced them. Concerns over thin mantles may have been premature.

Introduction: Early non progressive horizontal RLLs (< 2mm) under the tibial component following cemented TKR have been noted to be due to poor cement injection into cancellous bone. They may facilitate the entry of joint fluid and wear debris into the interface, which may proceed to ballooning osteolysis. At present, there is no consensus on the preferred cementing technique (single mix versus dual mix cementation) in TKR.

Purposes of the study: To assess RLLs in immediate postoperative radiographs in cemented TKRs at the cement-bone and cement-implant interface.

To compare the RLLs following single mix and dual mix cementation techniques.

Study Design: Prospective, consecutive radiographic analysis.

Material and Methods: 53 consecutive cemented TKRs in 39 patients (12: 27, F: M) with mean age of 72.5 years (range 50–90 y) who were operated on between 2001 to 2004 by the senior author (NMG). 27 had single mix and 26 had double mix cementation. Immediate postoperative radiographic assessment (AP and LAT standing view) was blinded for single mix versus dual mix cementation. All the radiographs were independently assessed by two of the authors for the presence of RLLs using the zonal pattern of the Knee Society scoring system. We have evaluated the RLLs in the cement-implant interface in a similar manner as described for the bone-cement interface.

Results: Most common TKR used was the Maxim (31) followed by the PFC (9). 29(54.7%) TKRs had RLLs (11in single mix : 18 in dual mix). There were more RLLs at the Cement-implant interface (29), than the bone-cement interface (10). In AP view, Zones 1(medial) and 4 (lateral) were the common sites for RLLs in both groups (< 2mm). In Lateral view, Zone 1 (Anterior) followed by Zone 2 (Posterior) were the common sites of RLLs (< 2mm). In AP view, there was no significant difference in the number of RLLs (Zone 4) between the two groups. The total number of RLLs in all zones (Zone 1–4) was significantly low in the single mix group (p< 0.05). There was no difference between the two groups in the lateral view.

Conclusions: Single mix cementation technique reduces the incidence of RLLs in the immediate postoperative radiographs following cemented TKRs.

In Sheffield the senior author has a long experience in the use of massive circumferential proximal femoral allografts in complex revision hip arthroplasty. Sheffield has a well established bone harvesting and banking service, essential for this type of work.

We wish to present the early experience with this technique in the UK.

Between April 1992 and November 1998 a total of 33 circumferential proximal femoral allografts were used by one senior surgeon. They were all fresh frozen, cadaveric grafts. This time period was selected to allow a reasonable minimum follow-up period. Seven patients had died and two were lost to follow up, leaving a total of 24 patients to review.

A step cut osteotomy was utilised and augmented with a cerclage wire and strut allograft where deemed necessary. The proximal femur was retained where possible. The component was cemented into the allograft only, in the majority of the cases. A cemented, collared prosthesis was used in over 85% of cases.

Average follow up was 53 months. By the time of review 2 had undergone further revision, one for sepsis, one for aseptic loosening. A further patient had had revision of the acetabular component in isolation. One patient had recurrent sepsis but is currently being managed non–operatively. One patient required secondary surgery with plate and graft for symptomatic junctional non-union.

Other complications included wound drainage, delaying discharge, in three patients and one chronic sciatic nerve palsy.

The trochanter was considered radiologically united in 18 patients. Junctional union was considered to have occurred in 17 patients. Allograft resorption of 100% cortical thickness was seen in only 9 patients and in only one zone in 6 of these.

Oxford hip scores were collected at follow-up.

We recommend this technique in cases where bone loss is catastrophic and in specialist hands only.