Introduction: Radial Impaction Grafting (RIG) has been proposed as a method for improving durability and reliability of cementing a collared femoral component in radial compressed bonegraft. In a prospective, baseline-control, multicenter clinical study the clinical and quality of life scores, survival rate, complications and radiographic findings were evaluated. The main objective of this study is to establish and indentify factors that contribute to the fracture rate. We tried to establish a model that represents the simplest combination of factors that predict femur fracture following the RIG technique. Patients and Methods: Eighty-eight patients enrolled the study: 59 women and 29 men with average age of 74 (38–90) years. The average follow-up was 4 years (2–7.2). The results of 81 patients were evaluated. The Endo-classification (EC) was used for the determination of the pre-operative femoral bone loss; type 1 was noticed in 25 cases, type 2 in 44, type 3 in 17 and type 4 in 1 case. At 70 patients the femur was augmented (mesh, cerclage(s) and/or plate). A short stem (115–135mm) was used in 48% and a long stem (165–225mm) in 52% of the cases. Results: The average total HHS increased from a pre-operative score of 44 (median 44) to 91 (median 94) at > 5 years fu and the HHS-pain score from 17 (median 20) respectively to 43 (median 44). The average VAS for pain at > 5 years fu was 2.5 (0–100 scale). Ninety-three percent of the patients were very-extremely satisfied with the result. Postoperative the femoral stem had a varus position (6 –10°) in 4 cases. In 6 cases the stem was in posterior and 3 cases in anterior position. Progressive subsidence was demonstrated in 1 patient increasing to 5 mm at 1 year fu. Three patients showed subsidence of 3 mm at 3 months, but were stable afterwards. Slightly increasing radiolucent lines (> 2 mm) were noticed in 2 patients in subcortical areas, but never any signs of osteolysis. Intra- and postoperative femoral fractures occurred in 12 patients (13,6%). There were 3 dislocations and 1 loosening of a trochanteric osteotomy. Despite the fractures there was no loosening of a stem during follow-up period. After bivariate multilevel analysis, conducted to determine a relationship between the fracture complication and all other variables, a multivariate model was developed of the most significant variables to determine the predictor factors for femoral fracture. Only the Endo-classification and age are predictors for a fracture following a RIG procedure (p-value 0.003). Each higher EC type increases the probability of a fracture after RIG 2.01 times and each added year of life 1.07 times. So the risk of getting a femoral fracture increases exponentially with age from 1.7% at 55 years to 15.5% at 90 years in EC type 1. The fracture risk in EC type 4 increases from 4.7% at 40 years to almost 60% at 90 years

Introduction: Total hip arthroplasty is one of the most frequently performed surgical procedures, with implants usually giving over 90% survival at 10 years. The failure rate is primarily due to aseptic loosening often associated with progressive bone stock loss. Impaction of cancellous morselized allografts with cement can be used for revision total hip arthroplasty in such cases. There is increasing interest in the use of synthetic bone graft substitutes as extenders to allograft due to the shortage and variable quality of allograft. A chemically-pure synthetic calcium phosphate (CaP) allograft extender is compared with allograft alone for acetabular and/or femoral revisions using the Impaction Grafting technique. Methods: 96 hips in 94 patients underwent revision hip arthroplasty using impaction grafting at 4 sites. Hip revision using impaction grafting was carried out using the Exeter X-Change Instrumentation system, using an Exeter Stem and/or a cemented polyethylene cup. Patients were randomized to receive allograft or CaP plus allograft in a 50:50 volume. Clinical and radiographic assessment was conducted pre-operatively and immediately post-operatively and at 6, 12 and 24 months. Clinical assessments included Harris Hip, Oxford and Charnley modified Merle d’Aubigne scores. Clinical complications were also recorded. Radiographs were assessed for the graft quality, radiolucent lines, lyses or migration, and incorporation of graft. The X-rays were also independently reviewed by an experienced author. Results: The mean age was 70.2 years (range 41–89 years) with 58 males and 36 females. A total of 40 femoral revisions and 88 acetabular revisions were conducted. There were 46 patients in the ApaPore group, 49 patients in the allograft group and 1 patient who received CaP/allograft and allograft for an acetabular and femoral revision respectively. No deep infections or adverse events due to the CaP were reported, with no significant difference in complication rates including revision and re-operations. No significant difference in acetabular migration, femoral subsidence, radiolucencies and lyses between the groups was observed. The independent review found no difference between the groups in terms of migration. The bone density was apparently greater for the ApaPore group at 12 months (p=0.001) and 24 months (p=0.012) although the significance of this is unclear. No significant difference in the clinical measures was observed between the groups. Conclusion: CaP is comparable with allograft in terms of performance and safety when used as an allograft extender for total hip revision arthroplasty using impaction grafting

Femoral revision after cemented total hip arthroplasty (THA) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. Bone loss may occur because of implant loosening or polyethylene wear, and should be addressed at time of revision surgery. Stem revision can be performed with modular cementless reconstruction stems involving the diaphysis for fixation, or alternatively with restoration of the bone stock of the proximal femur with the use of allografts.

Impaction bone grafting (IBG) has been widely used in revision surgery for the acetabulum, and subsequently for the femur in Paprosky defects Type 1 or 2. In combination with a regular length cemented stem, impaction grafting allows for restoration of femoral bone stock through incorporation and remodeling of the proximal femur. Cavitary bone defects affecting the metaphysis and partly the diaphysis leading to a wide femoral canal are ideal indications for this technique. In case of combined segmental-cavitary defects a metal mesh is used to contain the defect which is then filled and impacted with bone grafts. Cancellous allograft bone chips of 2 to 4 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a dummy of the dimensions of the definitive cemented stem is inserted and tapped into the femur to ensure that the chips are firmly impacted. Finally, a standard stem is implanted into the newly created medullary canal using bone cement. To date several studies from Europe have shown favorable results with this technique, with some excellent long-term results reported.

Advantages of IBG include the restoration of the bone stock in the proximal femur, the use of standard length cemented stems and preserving the diaphysis for re-revision. As disadvantages of the technique: longer surgical time, increased blood loss and the necessity of a bone bank can be mentioned.

Uncontained acetabular defects with loss of superior iliac and posterior column support (Paprosky 3) represent a reconstructive challenge as the deficient bone will preclude the use of a conventional hemispherical cup. Such defects can be addressed with large metallic constructs like cages with and without allograft, custom tri-flange cups, and more recently with trabecular metal augments. An underutilised alternative is impaction bone grafting, after creating a contained cavitary defect with a reinforcement mesh. This reconstructive option delivers a large volume of bone while using a small-size socket fixed with acrylic cement.

Between 2005 and 2014, 21 patients with a Paprosky 3B acetabular defect were treated with cancellous, fresh frozen impaction grafting supported by a peripheral reinforcement mesh secured to the pelvis with screws. A cemented all-polyethylene cup was used. Pre-operative diagnosis was aseptic loosening (15 cemented and 6 uncemented). The femoral component was revised in 10 patients. Post-operative course consisted of 3 months of protected weight bearing. Patients were followed clinically and radiographically.

One patient had an incomplete post-operative sciatic palsy. After a mean follow up of 47 months (13 to 128) none of the patients required re-revision of the acetabular component. One asymptomatic patient presented with aseptic loosening 9 years post-operatively. Hardware failure was not observed. All patients had radiographic signs of graft incorporation and bone remodeling. There were no dislocations.

The early and mid-term results of revisions of large acetabular defects with this technique are encouraging. Reconstitution of hip center of rotation and bone stock with the use of a small-size implant makes this technique an attractive option for large defects. Longer follow-up is needed to assess survivability.

The technique involves impaction of cancellous bone into a cavitary femur. If segmental defects are present, the defects can be closed with stainless steel mesh. The technique requires retrograde fill of the femoral cavity with cancellous chips of appropriate size to create a new endomedullary canal. By using a set of trial impactors that are slightly larger than the real implants the cancellous bone is impacted into the tube. Subsequent proximal impaction of bone is performed with square tip or half moon impactors. A key part of the technique is to impact the bone tightly into the tube especially around the calcar to provide optimal stability. Finally a polished tapered stem is cemented using almost liquid cement in order to achieve interdigitation of the implant to the cancellous bone.

The technique as described is rarely performed today in many centers around the world. In the US, the technique lost its interest because of the lengthy operative times, unacceptable rate of peri-operative and post-operative fractures and most importantly, owing to the success of tapered fluted modular stems. In centers such as Exeter where the technique was popularised, it is rarely performed today as well, as the primary cemented stems used there, rarely require revision.

There is ample experience from around the globe, however, with the technique. Much has been learned about the best size and choice of cancellous graft, force of impaction, surface finish of the cemented stem, importance of stem length, and the limitations and complications of the technique. There are also good histology data that demonstrate successful vascularization and incorporation of the impacted cancellous bone chips and host bone.

Our experience at the clinic was excellent with the technique as reported in CORR in 2003 by M Cabanela. The results at mid-term demonstrated minimal subsidence and good graft incorporation. Six of 54 hips, however, had a post-operative distal femoral fracture requiring ORIF. The use of longer cemented stems may decrease the risk of distal fracture and was subsequently reported by the author after reviewing a case series from Exeter.

Today, I perform this technique once or twice per year. It is an option in the younger patient, where bone restoration is desired. Usually in a Paprosky Type IV femur, where a closed tube can be recreated and the proximal bone is reasonable. If the proximal bone is of poor quality, then I prefer to perform a transfemoral osteotomy, and perform an allograft prosthetic composite instead of impaction grafting, and wrap the proximal bone around the structural allograft. I prefer this technique as I can maintain the soft tissues over the bone and avoid the stripping that would be required to reinforce the bone with struts or mesh. Another indication for its use in the primary setting is in the patient with fibrous dysplasia.

The principles of acetabular reconstruction include the creation of a stable acetabular bed, secure prosthetic fixation with freedom of orientation, bony reconstitution, and the restoration of a normal hip centre of rotation with acceptable biomechanics.

Acetabular impaction grafting, particularly with cemented implants, has been shown to be a reliable means of acetabular revision. Whilst our practice is heavily weighted towards cementless revision of the acetabulum with impaction grafting, there is a large body of evidence from Tom Slooff and his successors that cemented revision with impaction grafting undertaken with strict attention to technical detail is associated with excellent long terms results in all ages and across a number of underlying pathologies including dysplasia and rheumatoid arthritis.

We use revision to a cementless hemispherical porous-coated acetabular cup for most isolated cavitary or segmental defects and for many combined deficiencies. Morsellised allograft is packed in using chips of varied size and a combination of impaction and reverse reaming is used in order to create a hemisphere. There is increasing evidence for the use of synthetic grafts, usually mixed with allograft, in this setting. The reconstruction relies on the ability to achieve biological fixation of the component to the underlying host bone. This requires intimate host bone contact, and rigid implant stability. It is important to achieve host bone contact in a least part of the dome and posterior column – when this is possible, and particularly when there is a good rim fit, we have not found it absolutely necessary to have contact with host bone over 50% of the surface.

Once the decision to attempt a cementless reconstruction is made, hemispherical reamers are used to prepare the acetabular cavity. Sequentially larger reamers are used until there is three-point contact with the ilium, ischium and pubis. Acetabular reaming should be performed in the desired orientation of the final implant, with approximately 200 of anteversion and 400 of abduction (or lateral opening). Removing residual posterior column bone should be avoided. Reaming to bleeding bone is desirable. Morsellised allograft is inserted and packed and/or reverse reamed into any cavitary defects. This method can also be applied to medial wall uncontained defects by placing the graft onto the medial membrane or obturator internus muscle, and gently packing it down before inserting the cementless acetabular component. Either the reamer heads or trial cups can be used to trial prior to choosing and inserting the definitive implant. The fixation is augmented with screws in all cases. Incorporation of the graft may be helped by the use of autologous bone marrow.

Cementless acetabular components with impaction grafting should not be used when the host biology does not allow for stability or for bone ingrowth. This includes the severely osteopenic pelvis, pelvic osteonecrosis after irradiation, tumours, and metabolic bone disorders. They should also not be used in the presence of pelvic discontinuity unless the structure of the pelvic ring has been restored with a plate, or specialised materials/porous metals are used.

The challenge of reconstituting the acetabulum depends on the degree and type of bone loss. The principles of maximising host bone-implant contact and implant stability have borne fruit in our experience with cementless revision. The advantages of bone grafting in acetabular reconstruction include the ability to restore bone stock, to rebuild a normal hip center and hip biomechanics and to increase bone stock for future revisions.

Introduction: The impaction grafting technique appears to be a very useful method for revising failed THA with extensive cavitary proximal femoral bone loss. However, its use with short, polished stems has been associated with femoral fractures, stem subsidence and instability. This study describes a new surgical impaction grafting technique and reports the results using blasted femoral stems of variable lengths, with variable head-neck offsets and lengths.

Methods – Results: Fifteen revision THA using an impaction grafting technique were performed. Minimum follow-up was five years. Preoperative diagnosis was aseptic loosening of cemented femoral stems in 11 cases, and uncemented stems in four cases. Thirteen of the 15 revision cases with impaction grafting were cemented. Three revision cases were performed using stems less than 150 mm in length, the remainder utilised stems from 165 mm – 315 mm in length. Neck lengths of the revision implants ranged from 40 – 80 mm, including four calcar replacements. Intraoperative fractures occurred in two cases and were successfully treated with cerclage wires. There were two postoperative fractures, both in patients with stems less than 150 mm. Both were successfully treated with plates and onlay allografts. At most recent follow-up, all patients were pain-free. All patients were ambulating unlimited distances. Two patients required canes. All stems were well fixed radiographically with no evidence of progressive radiolucencies or subsidence. The graft appeared to be incorporating. The surgical technique consists of: 1.) removal of previously failed implant and cement; 2.) placement of cerclage wires around femur into which graft will be impacted; 3.) introduction of impacted allograft; 4.) radially impacting with tapered, polished, smooth straight impactors to a distance into femur that permits firm engagement with endosteal cortex for a distance of at least 3 cm; 5.) use of polished, smooth broaches to create final shape of cavity; 6.) trial reduction using polished broaches; and 7.) insertion of implant with or without cement.

Discussion – Conclusions: This report describes a new technique for impaction grafting in revision THA. This study suggests that the use of rough surfaced, long femoral stems with variable head-neck lengths and offsets in conjunction with the impaction grafting technique may reduce the incidence of subsidence, femoral fractures, and dislocations that can occur when this revision technique is used with short, polished stems.

Impaction grafting has been used for both femoral and acetabular defects quite successfully for over 15 years. Sloof, Ling and others have demonstrated consistent remodelling of the morselised allograft in both locations as well as long-term survivorship in a high percentage of difficult revisions. The application of this concept to the knee is somewhat novel, although there have been a few scattered reports, but bone loss in revision knee surgery can also be profound. Like its counterpart in the hip, it relies heavily on meticulous technique for success. Key aspects of the technique: the use of crushed cancellous fresh frozen allograft; tight packing of the graft; containment of the graft with mesh when necessary; and secondary packing with proper instruments to ensure stability of and load bearing on the graft. The need for polished tapered stems remains in question, as RSA techniques in the hip have indicated that motion is less commonly linked with stability. Subsidence, mechanically speaking, will not be tolerated as well at the knee as in the hip and will, in most cases, lead to loosening or gap mismatching with accompanying instability.

Patients with greater than 50% loss of cancellous bone stock volume, tibial height at or below the fibular head, and/or distal femoral loss to or beyond the epicondyle(s) are ideal candidates. Augments usually have difficulty restoring the joint line in these massive loss cases and usually add nothing that can potentially serve as a foundation for new implants should yet another revision be necessary in a patient’s lifetime. Impaction grafting at the knee has the potential to augment the bone stock in such cases substantially.

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodelling of the allograft bone by the host skeleton. Historically it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland. Indications might include all femoral revisions with bone stock loss, while the Endo-Clinic experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient.

Generally, the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Incorporation of these grafts has been described in 89%. Technical steps include: removal of failed stem and all cement, reconstruction of segmental bone defects with metal mesh (if necessary), preparation of fresh frozen femoral head allografts with bone mill, optimal bone chip diameter 2–5 mm, larger chips for the calcar area (6–8 mm), insertion of an intramedullary plug including central wire, 2 cm distal the stem tip, introduction of bone chips from proximal to distal, impaction started by distal impactors over central wire, then progressive larger impactors proximal, insertion of a stem “dummy” as proximal impactor and space filler, removal of central wire, retrograde insertion of low viscosity cement (0.5 Gentamycin) with small nozzle syringe, including pressurization, and insertion of standard cemented stem. The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Post-operative care includes usually touch down weightbearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches.

Relevant complications include mainly femoral fractures due to the hardly impacted allograft bone. Subsidence of tapered polished implants might be related to cold flow within the cement mantle, however, could also be related to micro cement mantle fractures, leading to early failure. Subsidence should be less than 5 mm. Survivorship with a defined endpoint as any femoral revision after 10-year follow up has been reported by the Exeter group being over 90%, while survivorship for revision as aseptic loosening being above 98%. Within the last years various other authors and institutions reported about similar excellent survivorships, above 90%. In addition, a long-term follow up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years.

Impaction grafting might technically be more challenging and more time consuming than cement-free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might especially become important in further revision scenarios in younger patients.

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodeling of the allograft bone by the host skeleton. Historically, it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland.

Indications might include all femoral revisions with bone stock loss, while the ENDO-Klinik experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient.

Generally the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Incorporation of these grafts has been described in 89%.

Technical steps include: removal of failed stem and all cement, reconstruction of segmental bone defects with metal mesh (if necessary), preparation of fresh frozen femoral head allografts with bone mill, optimal bone chip diameter 2 – 5 mm, larger chips for the calcar area (6 – 8 mm), insertion of an intramedullary plug including central wire, 2 cm distal to the stem tip, introduction of bone chips from proximal to distal, impaction started by distal impactors over central wire, then progressively larger impactors proximal, insertion of a stem “dummy” as proximal impactor and space filler, removal of central wire, retrograde insertion of low viscosity cement (0.5 Gentamycin) with small nozzle syringe, including pressurization, insertion of standard cemented stem. The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Originally the technique is described with a polished stem. We use standard brushed stems with comparable results. Postoperative care includes usually touch down weight bearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches.

Survivorship with a defined endpoint as any femoral revision after 10 year follow up has been reported by the Exeter group being over 90%. While survivorship for revision related to aseptic loosening being above 98%. Within the last years various other authors and institutions reported similar excellent survivorships, above 90%. In addition a long term follow up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years.

Impaction grafting might technically be more challenging and more time consuming than cement free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might become important in further revision scenarios in younger patients.

Introduction: Freezing and storage of fresh frozen femoral heads destined for use in revision hip arthroplasty is thought to result in graft cell death. Washing of the graft following the morsellisation process also removes a large proportion of the marrow content of the allograft. However, the immunological load of the impaction allografting process remains unknown. The aim of this study was to investigate the immune response by observing any changes in peripheral blood lymphocyte subsets in response to allografted bone used in revision hip replacement

Methods: 87 patients were entered into this prospective study and grouped according to whether impaction allograft was used or not. Venous blood samples were collected pre-operatively and at set time intervals up to one year post-operatively. Using flow cytometry, analysis of venous blood allowed counts of the following cells: Helper T-lymphocytes, cytotoxic T-lymphocytes, memory T-lymphocytes, naïve T-lymphocytes, Natural Killer cells and B-lymphocytes.

Results: All patients had a successful outcome at one year. 50 patients with radiologically defined host-graft union were compared with 37 patients who did not receive allograft. Pre-operatively, a significant difference (p=0.03) was found between the groups of patients with respect to Natural Killer cells but other subsets showed no significant difference. Post-operatively the significant difference between Natural Killer cells resolved. T-helper lymphocytes, cytotoxic lymphocytes, memory T-lymphocytes and naïve T-lymphocytes in both groups showed decreases in values immediately post surgery, recovering to normal values within 6 weeks post-surgery. The allograft group showed significant increases from baseline in cytotoxic T-lymphocytes at 6 months (p< 0.01) and memory T-lymphocytes one year postoperatively (p=0.04). B-lymphocyte numbers did not alter significantly from baseline.

Conclusion: Cytotoxic T-lymphocytes recognise HLA-class I molecules which are present on all nucleated cells and have been implicated in having a role in osteoclast regulation. Memory T-lymphocytes are produced after a naïve T-lymphocyte is exposed to an antigen. The observed increases of these subsets were not observed in the non-grafting group suggesting the allografted bone had elicited an immunological response. At 12 months all grafts appeared radiologically stable and the immunological response may have been beneficial to the outcome.

Introduction: Impaction allografting is a technique that is used at revision where the bone stock in the femur is poor. Femoral heads are ground to create morsellised bone, which is impacted down the femur prior to the cementing a new stem into the canal. The results of this technique are variable and there is a high incidence of stem migration. This variation in results may be due to the degree of bone loss or the techniques used to impact the graft. The aim of this study was to quantify the forces currently used in revision hip surgery with impaction allografting.

Methods: To enable these measurements the Exeter slap hammer (Stryker Howmedica) was altered to include a load washer. The load washer had a special cable welded to it so that sterilisation could still be conducted in an autoclave. During surgery the end of the load washer cable is passed to the operator, who is able to connect it to a laptop computer. A specially written Labview program is then used to store the data and determine the impaction forces. The load washer is mounted within the hammer at the point of impact between the sliding mass and the hammer, consequently it is reading the force transmitted to the hammer, not that transmitted to the graft chips. Calibration was performed in an in vitro experiment with a second load washer, which found that the force in the hammer is three times that in the impactor. The force is so much less because it is taken up in the hammer’s inertia.

Conclusions: The impaction forces have been measured during eight operations performed by three different surgeons. The study shows variability between surgeons, and variability between patients operated on by the same surgeon. These readings show that the forces travelling through the impactor range between three to eleven time body weight.

Introduction

The reconstructive hip surgeon is commonly faced with complex cases where severe bone loss makes conventional revision techniques difficult or impossible. This problem is likely to increase in future, as there is a good correlation between the degree of bone loss seen and number of previous total hip operations. In such situations, one alternative is the use impaction allografting with cement. This has captured the attention of the orthopaedic community because of its potential for reconstituting femoral bone stock.

There has been an escalation in the number of revision total hip arthroplasty (THA) procedures. In the UK, revision operations now make up 15% of THA surgery. The use of bone graft in revision surgery is a major challenge. Prosthetic stability within the graft is essential for the process of new bone formation.

This presentation discusses the parameters that influence the stability of the composite construct, such as implant design, graft composition and impaction technique.

Introduction:

The reconstructive hip surgeon is commonly faced with complex cases where severe bone loss makes conventional revision techniques difficult or impossible. This problem is likely to increase in future, as there is a good correlation between the degree of bone loss seen and number of previous total hip operations. In such situations, one alternative is the use of impaction allografting with cement.

Introduction

The reconstructive hip surgeon is commonly faced with complex cases where severe bone loss makes conventional revision techniques difficult or impossible. This problem is likely to increase in future, as there is a good correlation between the degree of bone loss seen and number of previous total hip operations. In such situations, one alternative is the use impaction allografting with cement. This has captured the attention of the orthopaedic community because of its potential for reconstituting femoral bone stock.

The reconstructive hip surgeon is commonly faced with complex cases where severe bone loss makes conventional revision techniques difficult or impossible. This problem is likely to increase in future, as there is a good correlation between the degree of bone loss seen and number of previous total hip operations. In such situations, one alternative is the use impaction allografting with cement. This has captured the attention of the orthopaedic community because of its potential for reconstituting femoral bone stock.

The first clinical reports of impaction allografting on the femoral side were in relation to revision with cementless stems. The use of morsellised bone with cement on the femoral side was first reported by the Exeter group. The great enthusiasm with which this technique has been received is related to its biological potential to increase bone stock. The rapid revascularisation, incorporation and remodelling of morsellised compacted cancellous allograft differs dramatically from structural allografting where bone ingrowth usually is limited to 2–3mm. Histological evidence for bony reconstitution has been presented from postmortem retrievals, and from biopsies at the time of trochanteric wire removal.

The size of the bone chips used as morsellised allograft is important. The graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. It is recommended that particles of 3–5mm in diameter make up the bulk of the graft. A bone slurry, such as that produced by blunted bone mills, or by the use of acetabular reamers or high speed burrs would not give satisfactory stability. A wide range of particle sizes is recommended in order to achieve the greatest stability. Future considerations will include the potential for either adding biomaterials to the allograft, or ultimately substituting it completely.

A satisfactory cement mantle is required to ensure the longevity of any cemented stem. The primary determinant of cement mantle thickness is the differential between the graft impactors and the final stem. All femoral impaction systems require careful design to achieve a cement mantle that is uninterrupted in its length and adequate in its thickness.

The technique of impaction allografting on the femoral side was first and most successfully reported using a highly polished stem with a double tapered geometry and no collar. It is thought to be ideal for this technique as it can subside within the cement mantle, thus generating hoop stresses on the cement which creeps, potentially maintaining physiological loads on the supporting bone. The extension of this technique to other stems has led to some controversy. Confounding factors such as surgical technique, the impaction system available, the type and size of allograft bone used, and the extent of the pre-operative bone loss, will undoubtedly continue to influence such comparisons. It appears that the exact stem configuration may not be as critical as its surface finish, the amount of graft impaction possible and the cement mantle produced.

Impaction allografting is the only technique currently available that reverses the loss of bone stock seen in a revision hip arthroplasty. Moreover, this technique does not sacrifice host tissue, and could facilitate further surgery. Impaction allografting, performed with great attention to detail using appropriate equipment, represents an exciting reconstructive solution for contained femoral defects. Its role in larger and combined defects remains open to scrutiny. Careful observation and cautious optimism are necessary as further refinements may well improve the predictability of the clinical results and expand the indications for this important addition to the armamentarium of the revision surgeon.

Purpose:

Tuberosity healing in hemiarthroplasty for proximal humerus fractures remains problematic. Improved implant design and better techniques for tuberosity fixation have not been met with improved clinical results. The etiology for tuberosity failure is multifactorial; however thermal injury to host bone is a known effect of using polymethylmethacrylate for implant fixation. We hypothesized that the effect of thermal injury at the tuberosity shaft junction could be diminished by utilizing an impaction grafting technique for hemiarthroplasty stems.

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: Impaction bone grafting is a very useful technique in the armament of a revision hip surgeon. Traditionally fresh frozen allograft has been used for this technique. However there are concerns about the transmission of viral proteins and prions through this form of allograft.As a result irradiated bone graft has been favoured in some centres. There is no long term series describing the results of impaction bone grafting using irradiated bone

Method: We describe a series of 58 cases of acetabular revision surgery done at the Avon Orthopaedic Centre between 1995 and 2001 and followed up over a period of 48–90 months. The preoperative bone defect was graded by the Paprosky classification. There were 10cases of type 1,15 type 2a, 5 type 2b, 7 type 2c, 14 type 3a and 7 type 3c.50 cases were operated by the two senior surgeons and 8 were senior trainees.All uncontained defects were first contained by using a mesh or cages. The bone graft used was freeze-dried femoral head allograft, which was milled and used without defatting. The cases were followed up clinically and radiologically.Case notes were reviewed to gain information about the primary prosthesis, and operative details as well as the cause of the revision. All the cases were the first revisions.

The radiological picture was evaluated for signs of incorporation, remodelling, loosening and migration of the cemented acetabular component. Clinical evaluation was from the last clinic visit and included the presence of pain, mobility status, range of movement and patient satisfaction. Revision was the end point of the study

Results: There were no cases which underwent loosening and all the cups were stable.1 case had recurrent dislocation and was revised.26 (44.8%) cases showed changes of incorporation, and 4 cases (6%)showed changes of remodelling.23 cases (39.6%) underwent femoral impaction grafting as well. Clinically the results were satisfactory with absence of pain in 38 cases (65%). Trochanteric pain was present in 3 cases.

Conclusion: The results suggested that the results of impaction bone grafting on the acetabular side using irradiated bone graft are comparable to those with fresh frozen allograft and significantly better than those on the femoral side. This could be attributed to the compressive forces acting across the acetabular side as against the predominantly shear forces acting on the femur. The low percentage of remodelling remains a concern and warrants further studies.