The increasing number of total hip arthroplasty (THA) used in young patients will inevitably lead to more revision procedures at younger ages, especially since the outcome of primary THA in young patients is already inferior compared to older patients. However, these data are lacking in literature. The aim of this study was to determine the survival of both acetabular and femoral components placed during primary and revision hip arthroplasty in patients under 55 years using Dutch Arthroplasty Register (LROI) data.

All primary THA registered in the LROI between 2007–2018 in patients under 55 years were selected (n=25,682). Subsequent cup- and stem revision procedures were included. Kaplan-Meier survival analyses were used to estimate the survival probability of primary and revised cup- and stem components.

Mean follow-up of primary cups and stems was 5.8 years (SD 3.2) and 5.9 years (SD 3.2), respectively. In total, 659 cup revision procedures and 532 stem revision procedures were registered. Most common reason for cup revision was acetabular loosening (n=163), most common reason for stem revision was femoral loosening (n=202). Primary cup survival for any reason at 10 years follow-up was 96.1% (95%CI: 95.7–96.4). For primary stems, 10 year survival for any reason was 97.1% (95%CI: 96.7–97.3). Mean follow-up of all revision procedures was 4.1 years (SD 2.9). Out of 659 cup revisions, 113 cup re-revisions were registered. Survival of revised cups, with end-point cup re-revision for any reason was 82.2% (95%CI: 78.8–85.1) at 5 years follow-up. Out of 532 stem revisions, 89 stem re-revisions were registered. For revised stems, survival at 5 year follow-up, with endpoint stem re-revision for any reason was 82.0% (95%CI: 78.2–85.2).

The outcome of revised acetabular and femoral components is worrisome, with a survival of 82% at 5 years follow-up. This information is valuable to provide realistic expectations for these young patients at time of primary THA.

Total hip arthroplasty (THA) in patients under 30 years remains a challenge. The long-term survival data are often disappointing. In our institution, we have always used cemented components in all patients under 30 years, combined with acetabular impaction bone grafting (IBG), if necessary.

We reviewed 139 consecutive patients (180 hips) treated between 1986 to 2014. Mean age at time of surgery was 24 (13–30.0) years. Acetabular IBG was applied in 127 (71%) cases. AAOS cavitary defect was seen in 26 (14%) cases, a AAOS segmental defect in 51 (28%) and a combination in 17 (9%).

The mean preoperative HHS improved from 47 (20–81) to 87 (28–100) at review. During follow-up 26 hips have been revised (23 cups and 11 stems). Indications for revision were aseptic loosening (n=15), septic loosening (n=5), recurrent dislocation (n=3), wear (n=1), and stem fracture (n=1).

The 10-year Kaplan-Meier survival of any component with endpoint revision for any reason was 87% (95% CI 79%–92%) and for aseptic loosening 92% (84%–96%). The 15-year survival of any component with revision for any reason as the endpoint was 77% (65%–86%) and for aseptic loosening 84% (71%–92%).

Cemented THA and, if needed with impaction bone grafting, in patients under 30 years provides satisfying long-term results up to 15 years after surgery. Probably this biological approach with IBG may facilitate the inevitable revisions in the future in these young patients because of more bone stock.

Background

Fretting at modular junctions is thought to be a ‘mechanically assisted’ corrosion phenomenon, initiated by mechanical factors that lead to increased contact stresses and micromotions at the taper interface. We adopted a finite element approach to model the head-taper junction, to analyse the contact mechanics at the taper interface. We investigated the effect of assembly force and angle on contact pressures and micromotions, during loads commonly used to test hip implants, to demonstrate the importance of a good assembly during surgery.

Introduction

Fretting corrosion of the modular taper junction in total hip arthroplasty has been studied in several finite element (FE) investigations. In FE analyses, different parameters can be varied to study micromotions and contact pressures at the taper interface. However, to truly study taper wear, the simulation of micromotions and contact pressures in non-adaptive FE models is insufficient, as over time these can change due to interfacial changes caused by the wear process.

In this study we developed an FE approach in which material removal during the wear process was simulated by adaptations to the taper geometry. The removal of material was validated against experiments simulating the clinical fretting wear process.

Introduction

Fretting corrosion at the taper interface has been implicated as a possible cause of implant failure. Using in-vitro testing, fretting wear observed at tapers of retrieved implants may be reproduced (Marriott, EORS-2014). In order to reduce time and cost associated with experimental testing, a validated finite element method (FE) can be employed to study the mechanics at the taper. In this study we compared experimental and representative FE simulations of an accelerated fretting test set-up. Comparison was made by between the FE wear score and volumetric material loss from the testing.

Prosthetic joint infection (PJI) is a severe complication of prosthetic joint implantation, with an estimated incidence of 2.18%. Most frequently used treatment strategy for PJI is a two-stage revision procedure. However there are specific patients with a new or persisting infection after primary or revision surgery where further surgical treatment is not attractive. This may be because of medical or local surgical conditions, or patient's refusal to undergo (further) surgical therapy. For these patients suppressive antibiotic therapy (SAT) may be an alternative treatment.

The aim of this study is to describe the clinical and radiological outcome of patients with a PJI of a hip arthroplasty, treated with SAT.

Twenty-four patients with a hip arthroplasty treated with suppressive antibiotic therapy for PJI between January 1, 2008 and December 31, 2013 were included. All patients had a proven prosthetic joint infection, either by ≥2 intraoperative cultures or joint aspiration. SAT was defined as treatment with antibiotic therapy for more than three months. Most used antibiotics were doxycycline in 15 patients and cotrimoxazole in six patients.

Patients were supposed to have a successful outcome when their prosthesis remained in situ and they had no relapse or new infection.

Suppressive antibiotic therapy was considered successful in 15 (62.5%) patients with a mean follow-up of 20.6 months. Two patients (8.3%) had to stop the antibiotic therapy due to adverse effects.

The mean duration of the SAT was 20.4 months (range 0.92–92.65 months).

Mean modified Oxford hip score of the successfully treated patients at the latest follow up was 35 (range 16–49) and mean Harris hip score 71 (range 40–93). The mean visual analogue scale (VAS) was 16 (range 0–70) in rest, 32 (range 0–85) during exercise and 65 (range 10–100) for satisfaction.

Of the 9 patients with an unsuccessful outcome, there was a radiological loosening of the cup in 4 patients. In the group of 15 patients that were considered successful, 2 patients had a radiological loosening of the cup and one patient loosening of the stem.

Suppressive antibiotic therapy can be an attractive alternative treatment in selected patients with a prosthetic joint infection of a hip arthroplasty who cannot or will not undergo (further) surgical therapy.

Further research with a larger number of patients is required. Also the optimal dosage and duration of suppressive antibiotic therapy and possible resistance to the antibiotic therapy is unknown.

Surgical site infections after total hip arthroplasty result in decreased quality of life, increased morbidity and increased health care cost. We hypothesized that the implementation of a bundle of care for total hip arthroplasty decreases the amount of surgical site infections.

In this retrospective cohort study we investigated the implementation of this bundle in a University Medical Centre and its effect on perioperative surgical site infections after total hip arthroplasty and on incidence of hypothermia.

In 2009 the bundle of care consisting of four elements was implemented in total hip arthroplasty in our hospital; (I) perioperative normothermia, (II) hair removal before surgery, (III) the use of preoperative antibiotic prophylaxis and (IV) discipline on the operation room measured by door movements. For this study we used data from January 2010 – October 2013. We measured all parameters prospectively including surgical site infections within 6 weeks postoperatively.

In the study period a total of 585 patients received a primary total hip arthroplasty. Bundle compliance improved significantly in 3.5 years from 71.7% in 2010 to 91.6% in 2013. Postoperative hypothermia decreased from 10.5% to 8.4% (non-significant) and SSI rate from 0.9% to 0.0% (non-significant).

Implementation of this bundle of care is possible in an academic tertiary referral center. A relatively cheap solution can increase patient safety in a surgical environment. Introduction of a bundle of care resulted in a non-significant reduction of hypothermia and rate of surgical site infections in total hip arthroplasty.

Local infiltration analgesia (LIA) is promoted as an effective treatment modality for pain control after total knee arthroplasty (TKA) (1). A mixture of drugs is used to provide a multimodal analgesic effect. Previous studies reported that the use of these drugs is safe. After we carefully implemented a LIA study protocol in our practice, concerns raised about patient safety with probably higher infection rates. This forced us to perform an interim analysis after the first 58 cases.

58 patients underwent a unilateral TKA with a standardised LIA protocol (2), which consisted of a mixture of ropivacaine, epinephrine, and triamcinolone acetonide. Complications, knee function and patient satisfaction scores were prospectively recorded during regular outpatient control.

Four patients (6.9%) presented with signs of periprosthetic joint infection (PJI) within two months after surgery. Baseline characteristics were similar between the infected and non infected group. All infections were treated with debridement and retention, and antimicrobial treatment was started. One patient who suffered an infection died during followup. At two years followup all implants could be retained. Knee function and KSS score were acceptable for the patients who suffered PJI.

There is no consensus on the combination of drugs used for LIA. The application of corticosteroids in LIA is reported to be safe (3), but arguable results about the injection of local corticosteroids around knee arthroplasty surgery in the past have raised suspicion in literature (4). Combined with our unacceptable high rate of PJI, we believe that the current body of evidence, with small heterogeneous series, does not support the safe use of corticosteroids in LIA.

This retrospective study evaluates the outcome of patients with a late infection of a cemented total hip arthroplasty (THA) treated with two-stage revision with retention of the original well-fixed femoral cement mantle.

Operation reports of all two stage revision performed in our clinic between 2009 and 2013 were reviewed (249 patients). Patients in which femoral cement mantle was retained during surgery were included (10 patients). The average age at the first stage revision procedure was 61.5 years (range 38–80). The mean follow-up period was 26 months (range 5 to 54 months). Clinical, laboratory, and radiological outcomes were evaluated.

Successful treatment of periprosthetic joint infection (PJI) was achieved in six out of 10 patients; four patients showed no signs of infection during follow-up. Two of these patients received three months of antibiotic treatment after second stage, because of positive cultures at second stage. The other two successfully treated patients showed recurrence of PJI one week after second stage. Debridement with retention of prosthesis (DAIR) was performed. Newly cultured microorganisms were successfully treated with 3 months of antibiotics.

The other four patients were considered to be failures; in three patients, the femoral cement mantle was removed after the first stage due to recurrent infection. The other failure showed a recurrent PJI after second stage. Despite DAIR and three months of antibiotic treatment, this patient is treated with suppressive antibiotics until latest follow-up.

Based on this study, results in managing an infected THA with cement-within-cement revision are disappointing. Therefore, more research is required to determine which patients are appropriate for cement-within-cement revision.

Introduction

The Kaplan Meier estimator is widely used in orthopedics. In situations where another event prevents the occurrence of the event of interest, the Kaplan Meier estimator is not appropriate and a competing risks model has to be applied. We questioned how much bias is introduced by erroneous use of the Kaplan Meier estimator instead of a competing risks model in a hip revision surgery cohort.

Introduction

The different types of treatment for osteonecrosis of the femoral head have not led to a consensus about which treatment is best for the different stages. Particularly in the later stages of osteonecrosis, the disease still progresses to destruction of the femoral dome. The purpose of our study was to check the outcome of bone impaction grafting used for the head-preserving treatment of severe femoral head osteonecrosis. In order to preserve the femoral head, the sphericity and mechanical properties of the femoral dome must be contained and further collapse prevented.

Bone impaction grafting (BIG) is a surgical technique for the restoration of bone stock loss with impaction of autograft or allograft bone particles (BoP). The goal of a series in-vitro and in-vivo experiments was to assess the suitability of deformable pure Ti (titanium) particles (TiP, FONDEL MEDICAL BV, Rotterdam, The Netherlands) for application as a full bone graft substitute in cemented revision total hip arthroplasty. TiP are highly porous (interconnective porosity before impaction 85 to 90%). In-vitro acetabular reconstructions were made in Sawbones (SAWBONES EUROPE, Malmö, Sweden) to evaluate migration by roentgen stereo photogrammetric analysis and shear force resistance by a lever out experiment. In-vitro femoral TiP reconstructions (SAWBONES, Malmö, Sweden) were used to evaluate micro-particle release and subsidence. Mature Dutch milk goats were used for two in-vivo experiments.

A non-loaded femoral defect model was used to compare osteoconduction of bioceramic coated TiP with BoP and ceramic particles (CeP).

Blood samples were taken for toxicological analysis.

In-vitro: TiP were as deformable as BoP and created an entangled graft layer (porosity after impaction 70 to 75%). Acetabular TiP reconstructions were more stable and resistant to subsidence and shear force than BoP reconstructions (lever-out moment 56 ± 12 Nm respectively 12 ± 4 Nm, p < 0.001). After initial setting, femoral subsidence rates were smaller than seen in femoral bone impaction grafting (0.45 ± 0.04 mm after 300 000 loading cycles). Impaction generated 1.3 mg particles/g TiP (particle Ø 0.7–2 000 μm, tri-modal size distribution). In-vivo: Bioceramic coated (10 −40 μm) TiP showed bone ingrowth rates comparable to BoP and CeP. Reconstructed acetabular defects showed rapid bone ingrowth into the layer of TiP. Serum titanium concentrations slowly increased from 0.60 ± 0.28 parts per billion (ppb) preoperatively to 1.06 ± 0.70 ppb at fifteen weeks postoperatively (p = 0.04).

Mechanical studies showed very good initial mechanical properties of TiP reconstructed defects. The in-vitro study showed micro-particle generation, but in the short-term goat studies, histology showed very few particles and no negative biological effects were found. The in-vivo acetabular study showed very favorable bone ingrowth characteristics into the TiP layer and a much thinner interface with the cement layer compared to similar defects reconstructed with BoP or mixtures of BoP with CeP. Further analysis in a human pilot study should proof that TiP is an attractive and safe alternative for allograft bone in impaction grafting revision arthroplasty.

The clinical application of bone morphogenetic proteins (BMPs) offers solutions to many challenging problems in orthopaedics. However, a practical clinical problem is to obtain a controlled release of the BMPs. The attachment of heparin to biomaterials may result in an appropriate matrix for the binding, and sustained release of BMPs. Binding of growth factors to heparin stabilizes these growth factors, protects them from proteolytic degradation, and prolongs the half-life of BMPs in culture media 20-fold. We created a carrier based delivery system with a localized sustained release by loading a tricalciumphosphate/hydroxyapatite (TCP/HA) bone substitute coated with cross-linked collagen and heparin, with BMP-7.

TCP/HA granules (BoneSave^™, Stryker Orthopaedics) were coated with collagen, and subsequently the collagen was cross-linked in the presence (TCP/HA-Col-Hep) and absence (TCP/HA-Col) of heparin. BMP-7 was loaded onto the coated TCP/HA granules. Morphology of the coated collagen with and without heparin, and release kinetics of BMP-7 from the granules were analyzed. TCP/HA granules without coating were used as controls.

Analysis showed a highly porous collagen network on both TCP/HA-Col and TCP/HA-Col-Hep granules. Immersion of the granules in BMP-7 solution, resulted in the binding of 54±3% (62.9±5.4 ng BMP-7/mg granule) to the TCP/HA granules, 64±8% (69.0±9.6 ng BMP-7/mg granule) to the TCP/HA-Col granules, and 78±1% (92.9±4.8 ng BMP-7/mg granule) to the TCP/HA-Col-Hep granules. TCP/HA granules showed a burst release of BMP-7 within the first 4 h. TCP/HA-Col granules showed an initial burst release, followed by a more gradual release. In contrast, BMP-7 release from the TCP/HA-Col-Hep granules was sustained up to 21 days.

The sustained delivery system for BMP-7 developed in this study may provide a powerful tool for bone regeneration. This system could probably also be applied to deliver multiple growth factors that have affinities for heparin, which could for instance synergistically enhance osteogenesis by increasing vascularity.

Introduction: Results of primary total hip arthoplasty (THA) for osteonecrosis of the femoral head are improving with newer cementation techniques and components. However not much is known about results of THA after an initial femoral head preserving procedure. The purpose of this study is to compare the complications and the clinical and radiological outcome of THA after failed transtrochanteric rotational osteotomy (Sugioka technique) (THA after TRO) and THA after failed bone impaction grafting (THA after BIG) for osteonecrosis of the femoral head.

Methods: In this retrospective comparative study, sixteen cemented THA after TRO and seventeen cemented THA after BIG were performed from 1994 to 2004. These groups were compared at a minimum follow-up time of two years. The average age at time of THA was 35 years in the THA after TRO group and 39 in the THA after BIG group.

Results: In THA after TRO, perioperative blood loss was significantly increased, operation time was significantly longer, and hospital admission was significantly longer compared with THA after BIG. In THA after TRO, 4 patients required re-operations because of infection (2) and dislocations (2) compared to one re-operation in THA after BIG (revision of acetabular cup). A radiolucency of the cup without re-operation was observed in one patient in the THA after TRO group. The average Harris Hip Score (HHS) in THA after TRO improved from 52 points prior to THA to 89 points at time of review and in the THA after BIG group from 42 to 91 points with a higher rise of HHS per year of follow-up.

Discussion: We conclude that a THA after TRO was technically more demanding with a higher rate of complications and re-operations compared to THA after BIG. However, because of the small groups, no significant difference in outcome was demonstrated.

Introduction: Osteonecrosis of the distal femur produces a segment of dead bone in the weight-bearing portion of the femoral condyle, frequently associated with subchondral fracture and collapse, and eventually resulting in secondary osteoarthritis.

Materials and Methods: We developed a new surgical technique; the osteonecrotic lesion was removed and impacted bone grafts were used to regain sphericity and prevent collapse. In this prospective one surgeon study, we included 9 consecutive knees (6 patients) with extensive steroid-associated osteonecrotic lesions of the femoral condyles. A new staging system was developed that includes location and quantification of the osteonecrotic lesion.

Results: Six knees showed a preoperative collapse. The mean age of the patients was 31 years (range, 16–47 years). At a mean follow up of 51 months (range, 29–93 months), no conversion to total knee arthroplasty was performed. The objective Knee Society Score improved from 63 to 89 points. The functional Knee Society Score improved from 19 to 81 points. At follow up, there was no progression of collapse observed and only 3 knees showed slight signs of osteoarthritis. The clinical success rate was 75%, and 78% were radiologically successful.

Discussion: This method is attractive as a salvage procedure, is relatively simple and quick and does not interfere with an eventual future total knee arthroplasty.

Introduction The results of THA in patients with post-traumatic arthritis are inferior to those in nontraumatic arthritis, both after cemented and noncemented THA. This increased failure rate is caused by the bone stock loss and the abnormal anatomy. We studied the outcome of acetabular bone impaction grafting and a cemented cup in 20 cases at 3 to 18 years follow-up.

Materials and Methods Between January 1984 and January 2000 in 20 consecutive patients bone impaction grafting was used for arthritis after previous acetabular fracture, grafting was done in all for bone stock loss. There were 14 men and 6 women. The average age at THA was 53.3 years (range, 35 to 75 years). Defects were classified according to the AAOS acetabular defect classification (3 type I defects, 10 type II defects, 5 type III defects and 2 type V). Metal meshes were used in 6 medial wall and in 3 peripheral wall defects. In 15 cases autograft bone chips were used, in 5 both auto- and allograft was used. Grafts were impacted using impactors and a hammer and a PE cup was cemented. At review in January 2003 no patient was lost.

Results Two patients died during follow up after 3 and 4 years respectively, deaths were not related to surgery and data are included. The mean follow up was 9.5 years (range, 3 to 18 years). The pre-operative Harris hip score was 44 (32–61). During follow up a cup revision was performed in two cases; one for a culture proven septic loosening 14.5 years after surgery and the other for aseptic loosening at 15.3 years after surgery. Both revised cups were radiologically loose at revision. At review the 16 surviving hips had an aver. Harris hip score of 93 points (range, 62 to 100 points). Fourteen hips were free of pain, one patient had slight and one had mild pain.

Radiologically, none of these 16 cups was loose. However, two of the cups migrated more than 5 mm (e.g. 6 and 8 mm) relative to the initial post-operative X-ray. At review, both patients were symptom free.

The Kaplan-Meier survival rate of the cup with endpoint revision for any reason was 100% at ten years and 80% (95% CI, 62–98%) after 15 years; with endpoint cup revision for aseptic loosening the survival was 100% both at 10 and 15 years.

Conclusion The acetabular bone impaction grafting technique with a cemented cup is a biologically attractive technique to reconstruct the bone stock loss after posttraumatic arthritis with good long-term survival, even after long follow-up.

Introduction: The transtrochanteric rotational osteotomy according to Sugioka is used to preserve the femoral head and to prevent secondary osteoarthritis in young patients with osteonecrosis of the femoral head. Several Japanese studies showed favorable results, but European and American studies were disappointing. However, many factors could be responsible for this outcome including race dependent differences and the followed post-operative rehabilitation program. The purpose of our study was to investigate this transtrochanteric rotational osteotomy in Caucasian patients with osteonecrosis in which we followed the original method of Sugioka as close as possible including a 6 months period of non-weightbearing.

Methods: In a single surgeon prospective study we included 26 hips in 22 consecutive patients who were followed for 8.7 years (range, 6.6–10 years) after surgery. The average age at time of surgery was thirty-two years (range, 22–49 years). No patient was lost to follow up. According the ARCO classification, 7 hips were in stage 2, 2 hips in stage 3 early and 17 hips in stage 3 late.

Results: At review 17 hips had been converted to total hip arthroplasty; 2 for infection, 3 for failed osteosyntheses or non-healing of the osteotomy, 12 for progressive osteoarthritis. Taking conversion to total hip arthroplasty for any reason or Harris Hip Score below 70 as endpoint, the clinical survival rate using the Kaplan-Meier analysis was 56 per cent after 7 years (95% C.I. 36–76%). Patients with a higher age at time of surgery had a tendency to a lower clinical survival rate. Taking conversion to total hip arthroplasty, progression of collapse of the femoral head or progression of osteoarthritis of the femoral head as endpoint, the radiological survival rate using the Kaplan-Meier analysis was 89 per cent after 1 year (95% C.I. 68–100%) for patients without pre-operative collapse of the femoral head. For patients with a pre-operative collapse of the femoral head, this survival rate was 35 per cent after 1 year (95% C.I. 13–58%).

Conclusion: Even after excluding the failures due to problems with osteosynthesis the results were not satisfying and the osteoarthritic process was not delayed in an effective way. Based on our results we cannot recommend this technique as an alternative for total hip arthroplasty in Caucasians.

Introduction: The purpose of this study was to evaluate the long-term clinical and radiological outcome of instrumented femoral revisions after failed total hip arthroplasties using the impaction bone grafting technique with morsellized bone chips in combination with a cemented polished stem.

Methods: Thirty-three consecutive femoral reconstructions were performed between November 1991 and February 1996 using the X-Change femoral impaction system with fresh frozen morsellized bone grafts and a cemented polished Exeter stem. All patients were prospectively followed. The learning curve with this new technique is included in this report. This technique was used in twenty-four women and nine men; the average age at surgery was sixty-three years (range 33–82). Femoral bone stock defects were classified according to the Endoklinik classification as grade 1 in three hips, grade 2 in fourteen hips, grade 3 in twelve hips and grade 4 in four hips. At a minimal eight years follow-up no patient was lost to follow-up, but eight patients died (at 0.5, 3.5, 3.5, 7.0, 7.0, 7.5 and 9.0 after reconstruction). All were followed until death, none of these deaths was related to the surgery, and none had a re-revision

Results: No femoral reconstruction was re-rerevised at a mean follow-up of 10.4 years (range 8 to 13 years). However, there were three femoral fractures during follow-up (at 3, 6 and 22 months), all at the level of tip of the prostheses. All healed after plating, all femoral implants were left in situ. The average Harris hip score improved from 49 prior to surgery to 85 at review (68–100). The average migration of the stem within the cement mantle was three mm (0–14 mm), most migration was seen in the first year. Radiologically, there were no failures. With an endpoint of femoral revision for any reason, with endpoint aseptic loosening or with endpoint radiological loosening the survival rate using the Kaplan-Meier analysis was hundred per cent in all situations (one-sided 95% C.I. 100–91.3 %)

Conclusions Femoral revision using bone impaction grafting with fresh frozen bone grafts and a cemented polished stem showed an excellent survival at eight to thirteen years follow-up.

Aims: To reconstruct acetabular bone stock loss in revision hip surgery, from 1979 on we have used a biologic reconstruction method with tightly impacted cancellous allografts in combination with a cemented polyethylene cup. Methods: This studies presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients at a mean of 16.5 years (15–20 years) followup. The Kaplan-Meier survivorship for the cup with end-point revisions for any reason was 79% at fifteen years followup (95% C.I.: 67–91%). Results: Excluding two revisions for septic loosening at 3 and 6 years, the survivorship with end point aseptic loosening was 84% at fifteen years years (95% C.I.: 73–95%). At review there were no additional radiological loosenings, although 7 acetabular reconstructions showed radiolucent lines in one or two zones. Conslusions: This acetabular bone impaction technique using large morselized bone chips (range 0.7–1.0 cm) and a cemented cup is a reliable reconstruction technique, even after a 15–20 years followup.

Bone impaction grafting of the femur is associated with more complications when segmental defects are present. The effect of segmental defect repair on initial stem stability was studied in an in vitro study with fresh frozen goat femora. A standardized medial segmental defect was reconstructed using a cortical strut or a metal mesh. As controls we used intact femora and femora with a non-reconstructed defect. In all four groups impacted bone grafting was performed in combination with a cemented Exeter stem. Each group contained five femora. Reconstructions were dynamically loaded up to 1500N. Migration was measured with Roentgen Stereo-photogrammetric Analysis. All cases with a non-reconstructed segmental defect failed into excessive varus rotation. None of the femora with a reconstructed defect failed. Cortical struts and metal meshes were equally effective in creating a stable stem construction (varus rotation 2.89±2.27 and 2.27±0.57, respectively). Reconstructions with a metal mesh were more reproducible, although the obtained stability was significantly lower (p< 0.01) when compared to impaction grafting in an intact femur (varus rotation 0.58±0.36).

Besides, structural grafts may negatively influence the revascularization of the underlying impacted grafts in contrast to an open wire mesh. So, an in vivo study of 12 goats was done. A standardized medial wall defect was reconstructed with a strut or a mesh in six goats per group. In all femora impaction grafting was performed in combination with a cemented Exeter stem. After six weeks the femora were harvested. A high rate of peri-prosthetic fractures was found (43% and 29% for the strut and mesh groups, respectively). Histological and micro-radiological examination showed different revascularization patterns for both reconstruction techniques. In the strut group revascularized graft was found at the edges of the defect. In the mesh group fibrous tissue and blood vessels penetrated through the mesh and a superficial zone of revascularized grafts was found. Segmental defect reconstruction with a strut reduced the amount of revascularized grafts medially behind the strut (p=0.004). This may interfere with the stability of the stem in the first period after surgery and the incorporation of the impacted grafts on the long-term.

We would recommend segmental defect reconstruction with a mesh. A regime of unloading and long-stem prostheses should be used, irrespective of the reconstruction technique