Reconstructing severe acetabular defects in revision total hip arthroplasty remains a challenge. When bulk allografts are used alone to support components, high failure rates are reported within five years. But satisfying results are obtained in most cases when a reinforcement cage and cement are used in combination with bulk allograft. This video demonstrates a technique used at Anderson Orthopaedic Institute that employs an anti-protrusio acetabular support ring with particulate allograft. Considered a salvage procedure, the approach provides an option when a hemispheric acetabular component cannot be adequately placed or properly positioned on host bone. It is recommended for low-demand, elderly patients or those with multiple failures in which no other reconstruction alternative is viable. The partial-pelvic reconstruction ring used in this case has a caudal flange. It comes in multiple sizes and also has flexible flanges that can be contoured to the ilium. The caudal flange secures fixation to the ischium. The acetabular cage enables re-creation of a normal hip center and, thus, improved hip joint stability. Disadvantages are the extensive exposure required and lack of opportunity to trial reduce components. As shown in the video, unique aspects of the surgical exposure are: sciatic nerve exposure to prevent injury during surgery; a trochanteric osteotomy to mobilise abductors and allow exposure and fixation of the cage to the ilium; extensive mobilisation of the femur to visualise acetabular defects; and exposure of the ischium for inferior fixation of the cage

Acetabular components of total hip joint replacement (THJR) in previously irradiated pelvis show high rates of failure. We present a literature review and a retrospective series evaluating the survival of acetabular cages in this difficult situation. Our hypothesis was that cage reinforcement of the acetabulum after previous pelvic irradiation would lead to early failure. A cohort of 11 patients (12 hips) was identified, who had undergone THJR utilising an acetabular cage, after previous pelvic irradiation for malignant tumours. All operations were performed by a single surgeon in Waikato over the period of 1997–2007. Six patients (six hips) died within one year of their operation, the further five patients (six hips) were analysed for survival and radiograpical loosening of the acetabular component. Complications attributed to previous irradiation are also reported. There is a paucity of literature of THJR survivorship after pelvic irradiation. The first series from the 1970’s showed 50% acetabular loosening at 5 years in cemented cups. Two conflicting series are published with 44% vs. 0% failure of uncemented cups. Only one previous series (22 hips) reports the use of acetabular reinforcement rings, and showed a 20% loosening and 10% deep infection rate at 4 years. In our cohort of 12 hips in 11 patients, only five patients survived greater than one year after joint replacement. The average follow up of the remaining six hips is five years (two to ten years). Two out of six of the acetabular cages have catastrophically failed. Of the remaining four cages, one is probably, and three are possibly radiologically loose. Two out of six have raised concerns in regards to deep infection that were not proven microbiologically. Overall of the patients who survived greater than one year after their THJR for pelvic irradiation, only four out of six of the acetabular cages remained insitu, and all had concerns raised in regards to radiographical loosening. We report a high rate of clinical and radiographic failure of cage reconstruction of the acetabulum after previous pelvic irradiation. A superior method of acetabular reconstruction in this difficult situation is yet to emerge. Alternative methods of reconstruction continue to develop, with trabecular metal options a possible consideration

Pathologic fractures about the hip are an uncommon, but increasingly prevalent, clinical scenario encountered by orthopaedic surgeons. These fractures about the hip usually necessitate operative management. Life expectancy must be taken into account in management, but if survivorship is greater than 1 month, operative intervention is indicated. Determination must be made prior to operative management if the lesion is a solitary or metastatic lesion. Imaging of the entire femur is necessary to determine if there are other lesions present. Bone lesions that have a large size, permeative appearance, soft tissue mass, and rapid growth are all characteristics that suggest an aggressive lesion. Biopsy of the lesion in coordination with the operative surgeon should be conducted if the primary tumor is unknown. Metastatic disease is much more common than primary tumors in the adult population. Many metastatic fractures in the intertrochanteric region, and all fractures in the femoral neck and head are an indication for hemiarthroplasty or total hip arthroplasty. Cemented femoral implants are generally indicated. This allows immediate weight bearing in a bone with compromised bone stock, thus reducing the risk of peri-operative fractures. Additionally, patients are often treated with radiation and/or chemotherapy, which may prevent proper osseointegration of an ingrowth femoral component. Highly porous ingrowth shells have been shown to provide reliable and durable fixation even in these situations. Management of a periacetabular pathologic fracture, particularly resulting in a pelvic discontinuity is a particularly challenging situation. Use of a highly porous acetabular component combined with an acetabular cage, a custom acetabular component, a cemented Harrington technique, or a primary acetabular reconstruction cage may be utilised. Patients with neoplastic disease are often at risk for infection and thromboembolic disease both from the disease and treatment. Pre-operative evaluation of nutrition status by measuring albumin and pre-albumin will give the surgeon insight. Additionally, dehydration is commonly seen in cancer patients, and adequate pre-operative optimization of fluids and electrolytes may reduce peri-operative complications from other organ systems

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs:. (A). Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important. (B). Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage. (C). Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs –. Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important. Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage. Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs –. (A). Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture, This reconstruction is used in young patients where restoration of bone stock is important. (B). Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage. (C). Cup-Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup-cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity. Acetabular bone loss and presence of pelvic discontinuity were assessed according to the Gross classification. Sixty-seven cup-cage procedures with an average follow-up of 74 months (range, 24–135 months; SD, 34.3) months were identified; 26 of 67 (39%) were Gross Type IV and 41 of 67 (61%) were Gross Type V (pelvic discontinuity). Failure was defined as revision surgery for any cause, including infection. The 5-year Kaplan-Meier survival rate with revision for any cause representing failure was 93% (95% confidence interval, 83.1–97.4), and the 10-year survival rate was 85% (95% CI, 67.2–93.8). The Merle d'Aubigné-Postel score improved significantly from a mean of 6 pre-operatively to 13 post-operatively (p < 0.001). Four cup-cage constructs had non-progressive radiological migration of the ischial flange and they remain stable

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs –. (A) Conventional cage ± structural or morsellised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important. (B) Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage. (C) Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs –. (A) Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important. (B) Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage. (C) Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity. Acetabular bone loss and presence of pelvic discontinuity were assessed according to the Gross classification. Sixty-seven cup-cage procedures with an average follow-up of 74 months (range, 24–135 months; SD, 34.3) months were identified; 26 of 67 (39%) were Gross Type IV and 41 of 67 (61%) were Gross Type V (pelvic discontinuity). Failure was defined as revision surgery for any cause, including infection. The 5-year Kaplan-Meier survival rate with revision for any cause representing failure was 93% (95% confidence interval, 83.1–97.4), and the 10-year survival rate was 85% (95% CI, 67.2–93.8). The Merle d'Aubigné-Postel score improved significantly from a mean of 6 pre-operatively to 13 post-operatively (p < 0.001). Four cup-cage constructs had non-progressive radiological migration of the ischial flange and they remain stable

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique. At our center we use three types of cage constructs: (A) Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important; (B) Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage; (C) Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used. In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity

Introduction. Patients with osteonecrosis of the femoral head are typically younger, more active, and often require high rates of revision following primary total hip arthroplasty. However, outcomes of revision hip arthroplasty in this patient population have been rarely reported in the literature. The purpose of this study was to report the intermediate-term clinical and radiographic outcomes of revision hip arthroplasty in patients with osteonecrosis of the femoral head. Materials & Methods. Between November 1994 and December 2009, 187 revision hip arthoplasty were performed in 137 patients who had a diagnosis of osteonecrosis of the femoral head. Exclusion criteria included infection, recurrent instability, isolated polyethylene liner exchange, and inadequate follow-up (less than 3 years). The final study cohort of this retrospective review consisted of 72 patients (75 hips) with a mean age of 53.3 years (range, 34 to 76). Components used for the acetabular revision included a cementless porous-coated cup in 58 hips and an acetabular cage in 2 hips. Components used for the femoral revision included a fully grit-blasted tapered stem in 30 hips and a proximally porous-coated modular stem in 9 hips. The mean duration of follow-up was 7 years (range, 3 to 17). Results. Mean Harris hip score improved 49 points preoperatively to 90 points. At the time of final follow-up, 11 hips (14.7%) patients required additional reoperation procedure. Of these, six for aseptic loosening of acetabular cup and/or femoral stem, two for deep infection, one for recurrent dislocation, one for periprosthetic femoral fracture, and one for ceramic head fracture. Kaplan-Meier survivorship with an end point for cup revision for aseptic loosening was 98.4% at 5 years, 93.4% at 10 years, and with an end point for stem revision for aseptic loosening was 100% at 5 years, 97.4% at 10 years (Fig. 1). Conclusions. Unlike the previous report, our study showed lower failure rate of femoral stem after revision hip arthroplasty using modern cementless femoral components in patients with osteonecrosis of the femoral head. Aseptic cup loosening or osteolysis is the most common mechanism of failure at the medium-term follow-up following revision hip arthroplasty in these patients group

Aims

Pelvic discontinuity is a rare but increasingly common complication of total hip arthroplasty (THA). This single-centre study evaluated the performance of custom-made triflange acetabular components in acetabular reconstruction with pelvic discontinuity by determining: 1) revision and overall implant survival rates; 2) discontinuity healing rate; and 3) Harris Hip Score (HHS).

Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented highly porous ingrowth acetabular components can be used for the reconstruction of the vast majority of revision cases, especially where small to mid-sized segmental or cavitary defects are present which do not compromise stable mechanical support by the host bone for the cup after bone preparation is complete. A mechanically stable and near motionless interface between the host bone and the implant is required over the initial weeks post-surgery for bone ingrowth to occur, regardless of the type of porous surface employed. As bone deficiency increases, the challenge of achieving rigid cup fixation also increases, especially if the quality of the remaining host bone is compromised. A stepwise approach to enhanced fixation of the highly porous revision acetabular component is possible as follows:. Maximise Screw Fixation. Use of a limited number of screws in the dome only (as routinely occurs with a cluster hole design) is inadequate, except for primary arthroplasty cases or very routine revision cases with little or no bone loss and good bone quality. Otherwise an array of screws across the acetabular dome and continuing around the posterior column to base of the ischium is strongly recommended. This can help prevent early rocking of the cup into a more vertical position due to pivoting on dome screws used alone, via cup separation inferiorly in zone 3. A minimum of 3 or 4 screws in a wide array are suggested and use of 6 or more screws is not uncommon if bone quality is poor or defects are large. Cement the Acetabular Liner into the Shell. This creates a locking screw effect, which fixes the screw heads in position and prevents any screws from pivoting or backing out. Acetabular Augments (vs Structural Allograft). When critical segmental defects are present which by their location or size preclude stable support of the cup used alone, either a structural allograft or highly porous metal augment can provide critical focal support and enhance fixation. Highly porous metal augments were initially developed as a prosthetic allograft substitute in order to avoid the occasional graft resorption and loss of fixation sometimes seen with acetabular allograft use. Cup-Cage Construct. If one or more of the above strategies are used and fixation is deemed inadequate, it is possible to add a ½ or full acetabular cage “over the top” of the acetabular component before cementing a polyethylene liner in place. The full cup cage construct can be used for maximal fixation in cases of pelvic dissociation, alone or in combination with the distraction method as described by Paprosky. Use of a ½ cage is technically simpler and requires less exposure than a full cage, but still greatly enhances rigidity of fixation when transverse screws into the ilium are combined with standard screws in the cup including vertically into the dome. These techniques used in combination with highly porous tantalum implants have allowed durable fixation for the full range of reconstructive challenges and bone defects encountered. Newer 3-D printed titanium highly porous materials have recently been introduced by multiple manufacturers as a potential alternative that may be more cost effective, but these implants and materials will require clinical validation over the years ahead

Stabilisation of a pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity. We describe the technique of acetabular distraction with porous tantalum components and evaluate its survival, function and complication rate in patients undergoing revision surgery for chronic pelvic discontinuity. Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five patients were lost to follow-up before two years. The remaining twenty patients were followed semiannually for a minimum of two years (average, 4.5 years; range, 2–7 years) with clinical pain and walking scores as well as radiographic evaluation for loosening, migration or failure. In the remaining twenty patients available for follow-up, one patient did require re-revision for aseptic loosening. Fifteen patients remained radiographically stable at last follow-up. Four patients had early migration of their acetabular component but thereafter remained radiographically stable and clinically asymptomatic. The average improvement using the modified Merle d'Aubigne – Postel pain and ambulation score was 6.6 (range, 3.3–9.6). There were no postoperative dislocations; however, we did encounter one infection, one vascular injury and one bowel injury. In this series, the use of acetabular distraction with porous tantalum components provides a biologic alternative to cage constructs with more predictable clinical results (average follow-up 4.5 years) for reconstruction of severe acetabular defects with associated pelvic discontinuity

Stabilisation of a chronic pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. We believe that these chronic discontinuities are really chronic fracture non-unions incapable of healing. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity. We describe the technique of acetabular distraction with porous tantalum components and evaluate its survival, function and complication rate in patients undergoing revision surgery for chronic pelvic discontinuity. Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five patients were lost to follow up before two years. The remaining twenty patients were followed semiannually for a minimum of two years (average, 5.5 years; range, 2–9 years) with clinical pain and walking scores as well as radiographic evaluation for loosening, migration or failure. In the remaining twenty patients available for follow up, one patient did require re-revision for aseptic loosening. Fifteen patients remained radiographically stable at last follow up. Four patients had early migration of their acetabular component but thereafter remained radiographically stable and clinically asymptomatic. The average improvement using the modified Merle d'Aubigne – Postel pain and ambulation score was 6.6 (range, 3.3–9.6). There were no post-operative dislocations; however, we did encounter one infection, one vascular injury and one bowel injury. In this series, the use of acetabular distraction with porous tantalum components provides a biologic alternative to cage constructs with more predictable clinical results (average follow up 5.5 years) for reconstruction of severe acetabular defects with associated pelvic discontinuity

Introduction: The management of periprosthetic osteolysis is a challenging problem in revision hip arthroplasty. Filling acetabular bone defects with structural allografts resulted in early failure due to resorption of the graft. The application in combination with reinforcement rings should promote bone incorporation as a result of reduced mechanical stresses. This study evaluates the long-term results in the treatment of acetabular deficiencies using bulk allografts supported with a Burch-Schneider Anti-Protrusio Cage (APC). Materials and Methods: From January 1992 to December 1995, 69 consecutive patients underwent revision surgery following periprosthetic osteolysis and aseptic loosening of the cup. Acetabular bone loss included IIIA and IIIB types according to Paproski classification. 12 patients died for unrelated causes with a well-functioning total hip arthroplasty in situ. 3 cases were lost at follow-up. The study group consisted of 56 hips in 54 patients. There were 11 males and 43 females, aged from 33 to 84 years (medium 65). Average follow-up was 11.7 years, ranging from 10 to 14.4. Surgical procedure included filling acetabular bone defects with bulk allografts supported with a Burch-Schneider APC which was fixed with screws to the iliac bone. A poly-ethylene cup was finally cemented into the metal cage. Deambulation was allowed one week after surgery, but weightbearing was delayed two months. Clinical evaluation was determined using Harris hip score (HHS). The stability of the acetabular implant was assessed according to Gill criteria. The progression of the bone graft was evaluated using Gross grading. Results: 2 patients developed deep infection that was treated by resection-arthroplasty. Aseptic loosening of acetabular cage following an extensive resorption of bone graft was observed in 6 cases and 3 of them underwent rerevision. X-ray signs of graft incorporation occurred in 48 hips. Average HHS values of 30 (range, 11 to 81) and 75 (range, 28 to 100) points were assessed respectively in the preoperative time and at follow-up. Discussion and Conclusions: In severe acetabular bone deficiencies the application of reinforcement rings in combination with massive allografts has been advocated in order to prevent bone graft resorption and cup loosening. Burch-Schneider Anti-Protrusio Cage is able to protect the graft spanning bone defects and promoting augmentation of periprosthetic bone stock. With an aseptic failure rate of 8.9% and a total survival rate of 85.7% at an average of 11.7 years, the use of APC and structural allograft proved out to be an effective procedure in the long-term reconstructive treatment of extensive loss of acetabular bone stock