Background. Failed ingrowth and subsequent separation of revision acetabular components from the inferior hemi-pelvis constitutes a primary mode of failure in revision total hip arthroplasty (THA). Few studies have highlighted other techniques than multiple screws and an ischial flange or hook of cages to reinforce the ischiopubic fixation of the acetabular components, nor did any authors report the use of porous metal augments in the ischium and/or pubis to reinforce ischiopubic fixation of the acetabular cup. The aims of this study were to introduce the concept of extended ischiopubic fixation into the ischium and/or pubis during revision total hip arthroplasty [Fig. 2], and to determine the early clinical outcomes and the radiographic outcomes of hips revised with inferior extended fixation. Methods. Patients who underwent revision THA utilizing the surgical technique of extended ischiopubic fixation with porous metal augments secured in the ischium and/or pubis in a single institution from 2014 to 2016 were reviewed. 16 patients were included based on the criteria of minimum 24 months clinical and radiographic follow-up. No patients were lost to follow-up. The median duration of follow-up for the overall population was 37.43 months. The patients' clinical results were assessed using the Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Short form (SF)-12 score and satisfaction level based on a scale with five levels at each office visit. All inpatient and outpatient records were examined for complications, including infection, intraoperative fracture, dislocation, postoperative nerve palsy, hematoma, wound complication and/or any subsequent reoperation(s). The vertical and horizontal distances of the center of rotation to the anatomic femoral head and the inclination and anteversion angle of the cup were measured on the preoperative and postoperative radiographs. All the postoperative plain radiographs were reviewed to assess the stability of the components. Results. At the most recent follow-up, 11 (68.8%) patients rated their satisfaction level as “very satisfied” and 4 (25.0%) were “satisfied.” The median HHS improved significantly and the WOMAC global score decreased significantly at the latest follow-up (? 0.001). No intraoperative or postoperative complications were identified. All constructs were considered to have obtained bone ingrowth fixation. The median vertical distance between the latest postoperative center of rotation to the anatomic center of the femoral head improved from 14.7±10.05 mm preoperatively to 6.77±9.14 mm at final follow-up (p=0.002). The median horizontal distance between the latest postoperative center of rotation to the anatomic center of femoral head improved from 6.3±12.07 mm laterally preoperatively to 2.18±6.98 mm medially at the most recent follow-up (p=0.013) postoperatively. The median acetabular cup abduction angle improved from 55.04°±10.11° preoperatively to 44.43°± 5.73° at the most recent follow-up postoperatively (p=0.001). However, there was no difference in the median cup anteversion angles preoperatively (9.15°±5.36°) to postoperatively (9.66°±3.97°) (P=0.535). Conclusions. Early follow-up of patients reconstructed with the technique of extended ischiopubic fixation with porous metal augments demonstrated satisfactory clinical outcomes, restoration of the center of rotation and adequate biological fixation. For any figures or tables, please contact the authors directly

Impaction grafting is an excellent option for acetabular revision. It is technique specific and very popular in England and the Netherlands and to some degree in other European centers. The long term published results are excellent. It is, however, technique dependent and the best results are for contained cavitary defects. If the defect is segmental and can be contained by a single mesh and impaction grafting, the results are still quite good. If, however, there is a larger segmental defect of greater than 50% of the acetabulum or a pelvic discontinuity, other options should be considered. Segmental defects of 25–50% can be managed by minor column (shelf) or figure of 7 structural allografts with good long term results. Porous metal augments are now a good option with promising early to mid-term results. Segmental defects of greater than 50% require a structural graft or porous augment usually protected by a cage. If there is an associated pelvic discontinuity then a cup cage is a better solution. An important question is does impaction grafting facilitate rerevision surgery? There is no evidence to support this but some histological studies of impacted allograft would suggest that it may. On the other hand there are papers that show that structural allografts do restore bone stock for further revision surgery. Also the results of impaction grafting are best in the hands of surgeons comfortable with using cement on the acetabular side, and one of the reasons why this technique is not as popular in North America

The major causes of revision total knee are associated with some degree of bone loss. The missing bone must be accounted for to insure success of the revision procedure, to achieve flexion extension balance, restore the joint line to within a centimeter of its previous level, and to assure a proper sizing especially the anteroposterior diameter of the femoral component. In recent years, clinical practice has evolved over time with a general move away from a structural graft with an increase in utilisation of metal augments. Alternatives include cement with or without screw fixation, rarely, with the most common option being the use of metal wedges. With the recent availability of highly porous augments, the role of metal augmentation has increased. Bone graft is now predominantly used in particulate form for contained defects with more limited use of structural graft. The role of the allograft-prosthetic composite has become more limited. For the elderly with osteopenia and massive bone loss, complete metal substitution with an oncology prosthesis has become more common. The degree of bone loss is a major determinant of the management strategy. For contained defects less than 5 mm, cement alone, with or without screw supplementation, may be adequate. For greater than 5 mm, morselised graft is frequently used. For uncontained defects of up to 15 mm or more, metal augmentation is the first choice. Bone graft techniques can be utilised in this setting, however, these are more time consuming and technically demanding with little demonstrated advantage. For larger, uncontained defects, newer generation highly porous augments and step wedges are useful. Large contained defects can be dealt with utilising impaction grafting, similar to the hip impaction grafting technique. Massive distal defects are expeditiously managed with oncology defects in the case of periprosthetic fracture and/or massive osteolysis particularly when combined with osteopenia in an elderly, low demand patient. Surgeons must be familiar with an array of techniques in order to effectively deal with the wide spectrum of bone defects encountered during revision total knee arthroplasty

This paper presents an ongoing review of the use of a wedge-shaped porous metal augments in the shoulder to address glenoid retroversion as part of anatomical total shoulder arthroplasty (aTSA). Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42 to 85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients received either a 15º or 30º PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Standardized Shoulder Assessment Form [ASES], visual analogue scale [VAS] pain scores and forward elevation [FE]) preoperatively, at three, six, and 12 months, and yearly thereafter, with similar radiological surveillance. Forty-nine consecutive series shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24–87 months). Median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90º to 140º). Four patients died, but no others were lost to follow-up. Apart from one infection at 18 months postoperatively and one minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency or posterior re-subluxations. Radiographs showed good incorporation of the wedge augment with correction of glenoid retroversion from median 22º (13º to 46º) to 4º. All but four glenoids were corrected to within the target range (less than 10º retroversion). The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure

Aims. Severe, superior acetabular bone defects are one of the most challenging aspects to revision total hip arthroplasty (THA). We propose a new concept of “superior extended fixation” as fixation extending superiorly 2 cm beyond the original acetabulum rim with porous metal augments, which is further classified into intracavitary and extracavitary fixation. We hypothesized that this new concept would improve the radiographic and clinical outcomes in patients with massive superior acetabular bone defects. Patients and Methods. Twenty eight revision THA patients were retrospectively reviewed who underwent reconstruction with the concept of superior extended fixation from 2014 to 2016 in our hospital. Patients were assessed using the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC). In addition, radiographs were assessed and patient reported satisfaction was collected. Results. At an average follow-up of 28 months (range 18 – 52 months), the postoperative HHS and WOMAC scores were significantly improved at the last follow-up (p < 0.001). The postoperative horizontal and vertical locations of the COR from the interteardrop line were significantly improved from the preoperative measurements (p < 0.001). One (3.6 %) patient was dissatisfied due to periprosthetic joint infection. Conclusion. Extracavitray and intracavitary superior extended fixation with porous metal augments and cementless cups are effective in reconstructing severe superior acetabular bone defects, with promising short-term clinical and radiographic outcome

Stems are a crucial part of implant stabilization in revision total knee arthroplasty. In most cases the metaphyseal bone is deficient, and stabilization in the diaphyseal cortical bone is necessary to keep the implant tightly fixed to bone and to prevent tilt and micromotion. While sleeves and cones can be effective in revision total joint arthroplasty, they are technically difficult and may lead to major bone loss in cases of loosening or infection, especially if the stem is cemented past the cone. A much more conservative method is to ream the diaphysis to the least depth possible to achieve tight circumferential fixation, and to apply porous augments to the undersurface of the tibial tray or inner surface of the femoral component to allow them to bottom out against the bone surface and apply compressive load. If a robust, strong taper, stem and component combination is used, rim contact on only one side is necessary to achieve rigid permanent fixation. Porous and non-porous stems are available. The non-porous stems should have a spline surface that engages the diaphyseal bone and achieves rigid initial fixation but does not provide long-term axillary support. In that way the porous rim-engaging surface can bear compressive load and finally unload the stem and taper junction. Correctly designed stems do not stress relieve unless they are porous-coated. In situations where metaphyseal bone is not available, porous-coated stems that link to hinge prostheses are a very important part of the armamentarium in complex revision arthroplasty. Use of stems requires experience and special technique. Slight underreaming and initial scratch fit are necessary techniques. This does not result in tight fixation every time because split of the cortex does occasionally occur. In most cases these splits do not need to be repaired, but when there is a question, an intra-operative x ray should be taken and the surgeon should be prepared to repair the fracture. Stems are an essential part of revision total knee arthroplasty. A tightly fit stem in the diaphysis is necessary for fixation when metaphyseal bone is deficient. No amount of cement pressed into the deficient metaphyseal bone will substitute for rigid stem fixation

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

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

Introduction. Reconstructing acetabular defects in revision hip arthroplasty can be challenging. Small, contained defects can be successfully reconstructed with porous-coated cups without bone grafts. With larger uncontained defects, a cementless cup even with screws, will not engage with sufficient host bone to provide enough stability. Porous titanium augments were originally designed to be used with cementless porous titanium cups, and there is a scarcity of literature on their usage in cemented cups with bone grafting. Methods. We retrospectively reviewed five hips (four patients – 3 women, 1 man; mean age 65 years) in which we reconstructed the acetabulum with a titanium augment (Biomet, IN, USA) as a support for impaction bone grafting and cemented acetabular cups (Figure 1). All defects were classified according to Paprosky classification. Radiographic signs of osseointegration were graded according to Moore grading. Quality of life was measured with the Oxford Hip Score. Results. At a minimum of one year follow-up, none of the patients required any further surgery for aseptic loosening or re-revision. The Oxford Hip Scores generally improved and two of the patients were very satisfied with the overall outcome of the surgery and would have undergone the surgery again for a similar problem. The patient that underwent bilateral acetabular reconstruction during a period one month, scored lowered than the other patients and was less satisfied with the outcome. Radiographs at the latest follow-up revealed incorporation of the augment with mean change in acetabular component inclination of less than 1° and cup migration of less than 5 mm in both horizontal and vertical axes. Discussion. Acetabular reconstruction using porous titanium augments as a support for bone grafting and cemented acetabular cups can be an effective way of managing uncontained structural acetabular defect, with biocompatibility and osteoinducive characteristics. The early results are promising but longer follow-up is required

Pelvic discontinuity is defined as a separation of the ilium superiorly from the ischiopubic segment inferiorly. In 2018, the main management options include the following: 1) hemispheric acetabular component with posterior column plating, 2) cup-cage construct, 3) pelvic distraction, and 4) custom triflange construct. A hemispheric acetabular component with posterior column plating is a good option for acute pelvic discontinuities. However, healing potential is dependent on host's biology and characteristic of the discontinuity. The plate should include 3 screws above and 3 screws below the discontinuity with compression in between. In addition, the hemispherical acetabular component should have at least 50% host bone contact with 3–4 screws superior and 2–3 screws inferior to the discontinuity. On the other hand, a cup-cage construct can be used in any pelvic discontinuity. This includes a highly porous acetabular component placed on remaining host bone. Occasionally, highly porous metal augments are used to fill the remaining bone defects. A supplemental cage is placed over the acetabular component, spanning the discontinuity from the ilium to the ischium. A polyethylene liner is then cemented into place with antibiotic-loaded bone cement. Rarely, pelvic distraction may be needed. With this technique, pelvic stability is obtained via distraction of the discontinuity by elastic recoil of the pelvis and by fixing the superior hemipelvis and inferior hemipelvis to a highly porous metal cup or augment with screws, thereby unitizing the superior and inferior aspects of the pelvis. In essence, the cup acts as a segmental replacement of the acetabulum, with healing occurring to the cup or augment, resulting in a unitised hemipelvis. Frequently, the discontinuity itself does not achieve bony healing. Finally, custom triflange constructs are being utilised with increasing frequency. Triflange cups are custom-designed, porous and/or hydroxyapatite coated, titanium acetabular components with iliac, ischial, and pubic flanges. Rigid fixation promotes healing of the discontinuity and biologic fixation of the implant. It requires a CT scan, dedicated preoperative design, and fabrication costs

Dislocation and instability remain leading cause of failure following THA. We present a single-surgeon 10-year experience with use of Dual Mobility (DM) bearings in Primary and Revision THA using posterior approach. 127 DM bearings were implanted between September 2006 – September 2016; 102 in high-risk primary THA's and 25 revision THA's for either treatment or prevention of instability. Selection for DM bearing followed individual patient risk assessment. Criteria for use of DM bearing were presence of multiple risk factors. Mean age was 72.9 years. 100 Mono-block DM implants, 22 Modular DM implants and 5 custom-made DM devices were implanted. Revision cohort included those used in conjunction with a cage or porous metal augments. 2 dislocations (1.6%) were observed, both in the Revision group, 1 was recurrent requiring revision to constrained liner. Primary group had 2 revisions; 1 peri-prosthetic fracture and 1 deep infection. No DM bearing specific complications were observed. A constructed life table calculated survival function with endpoint set as revision for any reason demonstrated a cumulative survival of 94% at 7.4 years. In high-risk patients, DM bearings are successful at preventing and treating dislocation in THA. Primary cohort in this study all had multiple risk factors for instability but no dislocations or bearing specific complications were observed. Dislocations observed in Revision group were associated with major soft tissue deficiency. This study adds to the promising results already reported with DM THA articulations and should be considered for patients at risk of dislocation or instability. Runner Up – Best Paper Award

Acetabular distraction for the treatment of chronic pelvic discontinuity was first described by Sporer and Paprosky. The authors advocate the posterolateral approach for exposure of the posterior ilium and posterior column, The patient is secured in the lateral decubitus position. Following a systematic approach to surgical exposure, acetabular component removal should be performed with “cup out” osteotomes resulting in minimal iatrogenic bone loss. Following component removal and confirmation of a chronic discontinuity determine the integrity of the remaining AS and PI columns. If porous metal augments are needed for primary stabilization, the augments are placed prior to cup insertion for reconstruction of the AS and/or PI column. Next, Kirschner (K) wires (size 2.4) are placed in the remaining AS and PI bone so that the distractor can be secured in an extra-acetabular position. The distractor is placed over the K-wires allowing for lateral or peripheral acetabular distraction and resultant medial or central compression at the discontinuity. With the distractor in an extra-acetabular position, hemispherical reamers are used until an interference fit is achieved between the native or augmented AS and PI columns. The acetabulum should be reamed on reverse to avoid excessive removal of host bone. When the proper acetabular component size has been reached, the reamer will disengage from the reamer handle and the reamer can be used as a surrogate acetabular shell; when the acetabulum is maximally distracted, the entire construct will move as a unit. Crushed cancellous allograft is used to bone graft the discontinuity and reamed on reverse. A revision tantalum cup is inserted with continual distraction using the distractor. Cement is applied to the augment surface prior to cup insertion in order to utilise the construct. Following cup insertion, the distractor and K-wires are removed. Adjuvant screw fixation is performed, with a minimum of 4 screws, and placing at least one of the screws inferiorly for fixation in the superior public ramus or ischium to prevent abduction failure of the construct. In the setting of severely osteoporotic bone and inadequate screw fixation, an augment placed posterosuperiorly can be used for supplemental fixation. This augment is also unitised to the cup with cement at the same time as the liner is cemented into the cup. Bone wax is placed over the exposed tantalum surface of the posterosuperior augment to minimise soft-tissue ingrowth into the augment

Highly porous metal surfaces have transformed acetabular revision surgery by providing (1) enhanced friction which potentially provides greater primary fixation, (2) enhanced bone ingrowth potential, (3) enhanced screw fixation options. These characteristics have led many surgeons to use these devices routinely in acetabular revision and have led to an expansion of the indications for porous uncemented hemispherical cups in acetabular revision. Mid-term results suggest that the historical indications for hemispherical cups in revision surgery can be moderately expanded with some implants with these characteristics. In a recent study of 3448 revision total hip arthroplasties, we found porous tantalum cups had a statistically lower revision rate than other materials/designs. Highly porous metals also have provided the options of metal augments to fill selected bone defects—which can both enhance cup fixation and manage bone loss simultaneously. A number of different highly porous metals are now available, and how each will perform is not yet known. Highly porous metal shells may be used in combination with highly porous metal augments to make up for segmental bone deficiency. Examples will be shown. Finally, highly porous metal shells may be used as a “cup-cage” combination to provide extra initial cup mechanical stability in extreme cases. Examples will be shown

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty (TKA). Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating pre-operative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System as it provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft. Options for bone defect management are: 1) Fill with cement; 2) Fill with cement supplemented by screws or K-wires; 3) Morselised bone grafting (for smaller, especially contained cavitary defects); 4) Small segment structural bone graft; 5) Impaction grafting; 6) Large prosthetic augments (cones); 7) Massive structural allograft-prosthetic composites (APC); 8) Custom implants. Maximizing support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Pre-operative planning is facilitated by good quality radiographs, supplemented on occasion by additional imaging such as CT. Fluoroscopically controlled x-ray views may assist in diagnosing the loose implant by better revealing the interface between the implant and bone and can facilitate accurate delineation of the extent of bone deficiency present. Part of the pre-operative plan is to ensure adequate range and variety of implant choices and bone graft resources for the planned reconstruction allowing for the potential for unexpected intra-operative findings such as occult fracture through deficient periprosthetic bone. Reconstruction of bone deficiency following removal of the failed implant is largely dictated by the location and extent of bone loss and the quality of bone that remains. While massive bone loss may compromise ligamentous attachment to bone, in the majority of reconstructions the degree of implant constraint needed for proper balancing and restoration of stability is independent of the bone defect. Thus some knees with minimal bone deficiency may require increased constraint due to the status of the soft tissues while others involving very large bone defects especially of the cavitary sort may be well managed with minimal constraint. Highly porous metal augments designed to reestablish metaphyseal support and function in the manner of a prosthetic structural graft have been introduced or are under development by several manufacturers. Published reports of short term experiences have been encouraging for both the tibial side and for femoral augmentation. It remains to be seen whether these implants will provide the desired longer term durability

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