We have evaluated the function of a trabecular metal augmentation patella to restore knee kinetics and kinematics after revision total knee arthroplasty. An “Oxford type” rig was used with fresh frozen cadaveric knees, for an active model that maximally retained the soft tissue envelope. Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella. Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella. The purpose of this study is to evaluate the kinetic and kinematic function of a new trabecular metal augmentation patella. Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella. Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella. This study demonstrates that the augmentation patella restorers the abnormal tracking and higher extensor mechanism forces seen after patelloplasty in revision TKA to those normal after a TKA. The mean, maximum extensor mechanism force in extension for the TKA group as compared to the patelloplasty group (p=0.0000032), reduced to near normal with the augmentation patella (p=0.198). The mean, maximum patella maltracking in extension for the TKA group as compared to the patelloplasty group (p=0.025), reduced to near normal with the augmentation patella (p=0.301). Eight frozen human cadaveric knees (mean age sixty-eight years) were prepared for an “Oxford type” knee rig. Alignment ands offset were addressed and the soft tissue envelope kept as intact as possible. A load cell was introduced into the extensor mechanism. Femoral, patella and tibial motion were assessed using the Optotrak system. Patella bone loss at revision TKA remains an unsolved problem, with the patella often too thin to accept a new prosthesis. Leaving the patella shell to articulate against the femoral component can lead to disappointing results. Funding - Zimmer

We have evaluated the function of a trabecular metal augmentation patella to restore knee kinetics and kinematics after revision total knee arthroplasty. An “Oxford type” rig was used with fresh frozen cadaveric knees, for an active model that maximally retained the soft tissue envelope. Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella. Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella. The purpose of this study is to evaluate the kinetic and kinematic function of a new trabecular metal augmentation patella. Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella. Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella. This study demonstrates that the augmentation patella restorers the abnormal tracking and higher extensor mechanism forces seen after patelloplasty in revision TKA to those normal after a TKA. The mean, maximum extensor mechanism force in extension for the TKA group as compared to the patelloplasty group (p=0.0000032), reduced to near normal with the augmentation patella (p=0.198). The mean, maximum patella maltracking in extension for the TKA group as compared to the patelloplasty group (p=0.025), reduced to near normal with the augmentation patella (p=0.301). Eight frozen human cadaveric knees (mean age sixty-eight years) were prepared for an “Oxford type” knee rig. Alignment ands offset were addressed and the soft tissue envelope kept as intact as possible. A load cell was introduced into the extensor mechanism. Femoral, patella and tibial motion were assessed using the Optotrak system. Patella bone loss at revision TKA remains an unsolved problem, with the patella often too thin to accept a new prosthesis. Leaving the patella shell to articulate against the femoral component can lead to disappointing results. Funding - Zimmer

Purpose To evaluate the kinetic and kinematic function of a new trabecular metal augmentation patella. Method Eight frozen human cadaveric knees (mean age 68 years) were prepared for an “Oxford type” knee rig. Alignment ands offset were addressed and the soft tissue envelope kept as intact as possible. A load cell was introduced into the extensor mechanism. Femoral, patella and tibial motion were assessed using the Optotrak system. Summary of Results The mean, maximum extensor mechanism force in extension for the TKA group as compared to the patelloplasty group (p=0.0000032), reduced to near normal with the augmentation patella (p=0.198). The mean, maximum patella maltracking in extension for the TKA group as compared to the patelloplasty group (p=0.025), reduced to near normal with the augmentation patella (p=0.301). Conclusion Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella. Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella

Introduction. Revision total knee arthroplasy (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone resorption beneath metal block augmentation has been still reported and little information about the reasons of the occurrence of bone resorption is available. The aim of the current study is to identify a possibility of the potential occurrence of bone resorption beneath metal block augmentation, through evaluation of strain distribution beneath metal block augmentation in revision TKA with metal block augmentation, during high deep flexion. Materials and Method. LOSPA, revision TKA with a metal block augmentation (Baseplate size #5, Spacer size #5, Stem size Φ9, L30, Augment #5 T5) was considered in this study. For the test, the tibia component of LOSPA was implanted to the tibia sawbone (left, #3401, Sawbones EuropeAB, Malmö, Sweden), which was corresponded to a traditional TKR surgical guideline. The femoral component of LOSPA was mounted to a customized jig attached to the Instron 8872 (Instron, Norwood, MA, USA), which was designed specially to represent the angles ranged from 0° to 140° with consideration of a rollback of knee joint (Figure. 1). Here, a compressive load of 1,600N (10N/s) was applied for each angle. Strain distribution was then measured from rossete strain gauge (Half Bridge type, CAS, Seoul, Korea) together (Figure 1). Results and Discussions. The strain distribution on the cortical bone of the tibia was shown in Figure 2. The results showed that the strains on the posterior region were gradually increased from extension to high deep of the knee joint and generally larger than the other regions. In contrast to the results on the posterior region, the strains on the medial region were gradually decreased after 60° or 90° flexion position and relatively lower than the other regions. Particularly, the strains on the medial region were generally lower than 50–100 µstrain, which is known as critical value range able to inducing bone resorption, during high deep flexion. This fact indicate that a possibility of the potential bone resorption occurrence in revision TKA used with a metal block augmentation may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. This study may be valuable by identifying for the first time a possibility of the potential bone resorption occurrence through evaluation of the strain distribution beneath metal block augmentation in revision TKA used with a metal block augmentation during high deep flexion. Conclusion. A possibility of the potential bone resorption occurrence in revision TKA used with a metal block augmentation may be dependent on loading patterns applied on the knee joint related to personal lifestyle history. Particularly, it may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. Acknowledgements. This study was supported by a grant from the New Technology Product Evaluation Technical Research project, Ministry of Food and Drug Safety (MFDS), Republic of Korea

Introduction. Revision total knee arthroplasty (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone defects are frequently detected in revision TKA used with metal block augmentation. This study focused on identification of a potential possibility of the bone defect occurrence through the evaluation of the strain distribution on the cortical bone of the tibia implanted revision TKA with metal block augmentation, during high deep flexion. Materials and Methods. Composite tibia finite element (FE) model was developed and revision TKA FE model with a metal block augmentation (Baseplate size #5 44AP/67ML, Spacer size #5 44AP/67ML, Stem size Φ9, L30, Augment #5 44AP/67ML thickness 5mm) was integrated with the composite tibia FE model. 0°, 30° 60°, 90°, 120° and 140° flexion positions were then considered with femoral rollback phenomenon [Fig 1.A]. A compressive load of 1,600N through the femoral component was applied to the composite tibia FE model integrated with the tibia component, sharing by the medial and lateral condyles, simulating a stance phase before toe-off [Fig 1.B]. Results and Discussions. The strain distribution on the cortical bone of the tibia was shown in [Fig 2]. The results showed that the strains on the posterior region were gradually increased from extension to high deep of the knee joint and generally larger than the other regions. This fact was favorably corresponded to the femoral rollback phenomenon in the knee joint, showing a good accuracy of our FE model. In contrast to the results on the posterior region, the strains on the medial region were gradually decreased after 60° or 90° flexion position and relatively lower than the other regions. Particularly, the strains on the medial region were generally lower than 50–100 µstrain, which is known as critical value range able to inducing bone loss, during high deep flexion. This fact indicate that a potential possibility of bone defect occurrence in revision TKA used with a metal block augmentation may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. This study may be valuable by identifying for the first time a potential possibility of the bone defect occurrence through evaluation of the strain distribution beneath metal block augmentation in revision TKA used with a metal block augmentation during high deep flexion. Conclusions. A potential possibility of bone defect occurrence in revision TKA used with a metal block augmentation may be dependent on loading patterns applied on the knee joint related to personal lifestyle history. Particularly, it may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. Acknowledgements. This study was supported by a grant from the New Technology Product Evaluation Technical Research project, Ministry of Food and Drug Safety (MFDS), Republic of Korea

Introduction. The purpose of this study was to evaluate the mid-term clinical and radiological results in patients who were managed by double metal augmentations in proximal tibial uncontained bony defects undergoing primary or revision total knee arthroplasty. Materials and Methods. We performed double metal augmentations in proximal tibial uncontained bony defects undergoing total knee arthroplasty. Out of total 14 patients, 8 patients (4 priamry arthroplasty, 4 revision arthroplasty), mean 61.3 (50–80) years, were available for review at least 5 years follow up. The average follow up period was 86.3(60–99) months. Range of motion, American Knee Society Score were evaluated pre- and postoperatively as a clinical values. Another clinical assessments undertaken at the final reviews, Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Oxford knee score (OKS), Short Form-36 (SF-36), Lower extremity functional scale (LEFS), and Lower extremity activity scale (LEAS) were checked. Radiological results, involving presence of radiolucent lines (RLLs) > 1mm in width, and osteolysis at the block-cement-bone interface were taken under fluoroscopic images at postoperatively and annually thereafter. Results. At the final follow-up, range of motion was increased from 97.5° to 121.3° and American Knee society score was significantly improved from 30.4 to 92.6 (p=0.03) and functional score from 43.1 to 86.9 (p=0.03). At the final follow-up, average WOMAC score was 10(2–20), OKS was 40.5(33–47), LEFS was 55.8(34–75), and LEAS was 10.9(7–15). There was no broken or deterioration sign at between first and second metal block at radiographically. RLLs at the block-cement-bone interfaces under fluoroscopic images were examined in 3 knees, but didn't cause any failure sign such as osteolysis, or collapse, or instability at final reviews. Conclusions. The clinical and radiological evaluations showed that the double metal augmentations is a favorable and useful way to manage severe uncontained proximal tibial bony defects at least 5 years mid-term follow up period. Preoperative standing anteroposterior (AP) radiograph (Fig 1) shows severe uncontained proximal tibial bone defects, approximately 23 mm compared with unaffected lateral tibial condyle. AP view of fluoroscopy with medial double metal blocks (10 mm block + down sized 10 mm block) combined intramedullary stem at 60-month follow-up after primary total knee arthroplasty, demonstrating radiolucent line (white arrow) of 2.5 mm width bottom the block (Fig 2). AP view at 92-month follow-up indicating non-progressive stable radiolucent lines (white arrow) at same area without any radiographic failure signs and broken sign between first and second metal block (Fig 3)

Uncontained peripheral bone defect in posteromedial tibial plateau is not an infrequent problem even in primary total knee arthroplasty, especially in Korean patients some of those have large angular deformities preoperatively. We reviewed the clinical and radiological results of primary total knee replacements of 33 osteoarthritic knees in 28 patients with the use of metal block augmentation for uncontained peripheral tibial bone defects more than 5 millimeters in depth and more than a quarter of medial tibial plateau in width. Those defects were encountered in 75 knees (9.6%) during 779 primary total knee arthroplasties performed by single surgeon between January 2002 and December 2004 at our institution. Modular metal block augmentation was reserved for 42 knees, while the other knees were managed with bone-grafting or cement-filling techniques. Clinical and radiological follow-up more than 12 months were available from 33(78.6%) of 42 knees. At a mean of 32.2 months (range:12~75 months), 31 knees (93.9%) except two cases of failure were evaluated as good or excellent. The average pre-operative American Knee Society Knee and Function scores were 32.5 and 38.6 respectively, which increased to 82.9 and 79.8 respectively at the latest follow-up. There were no radiolucent lines (RLLs) beneath the metallic block or tibial tray, which were progressive or more than 2 millimeters on radiographs, in those knees. Revisions were required for one delayed infection and another aseptic loosening of tibial component. Non-progressive RLLs less than 2 millimeters at the cement-bone interface beneath the metallic block were noted in 10 (32.3%) of 31 knees. The RLLs appeared in 5 (41.7%) of 12 knees with metallic block augmentation alone and 5 (26.3%) of 19 knees which had been treated with the use of additional intramedullary stem augmentation, although this difference was not statistically significant. Since these radiolucent lines were not progressive or symptomatic at all, their clinical meanings or long-term consequences are not determined yet. All knees managed with the additional intramedullary stem augmentation revealed to have radiopaque lines adjacent to the stem on follow-up radiographs. The sclerotic halo around the tip of stem could be interpreted as evidence of the stem’s function in load sharing and might reflect secure fixation of tibial tray to bony interface. We concluded that the use of modular metal block augmentation devices for peripheral tibial defects measuring more than 5 millimeters could provide a simple, rapid and dependable technique that provides predictable results. The observation that all knees managed with additional intramedullary stem augmentation would have sclerotic halo adjacent to the stem on follow-up radiographs may reflect an intramedullary stem is an important adjunct to bone defect management

Introduction. Various methods to manage medial tibial defects in primary total knee arthroplasty (TKA) have been described. According to Vail TP, metal augmentation is usually indicated for defect depth of >10 mm of the medial tibial plateau. The outcomes of metal augmentation have been described as excellent. Nevertheless, we believe that it is mandatory to preserve as much of the bone as possible for future revision surgeries. Therefore, we performed autologous impaction bone grafting even for large bone defects (defect depth of ≥10 mm) in primary TKA. The objectives of this study are to describe our bone grafting technique in detail and to assess the radiological outcomes of the grafted bone. Methods. Between 2003 and 2011, 26 TKAs with autologous impaction bone grafting for ≥10 mm medial tibial defects were performed. The preoperative diagnoses were osteoarthritis in 17 knees, rheumatoid arthritis in 2 knees, osteonecrosis of the medial tibial condyle in 6 knees, and Charcot's joint in 1 knee. The average mediolateral width and depth of the medial tibial defects, measured after the horizontal osteotomy of the tibial articular surface, were 17.8 mm (range, 10–25 mm) and 12.0 mm (range, 10–23 mm), respectively. The average patient age at surgery was 73.2 years (range, 56–85 years). The patients were followed up for an average of 55 months (range 27–109 months). Bone grafting technique: Multiple drill holes (white arrow) were made on the floor of the defect (A) and a morselized cancellous bone was impacted using the grip end of a metal hammer (white asterisk) and firm manual pressure to fill the defect. Thus, the firm impaction prevented bone cement from entering the space between the graft and the tibial host bed. An assistant's index finger (black asterisk) was used as a bank (B). The tibial component was fixed on the grafted bone (white asterisk) with bone cement (C). Internal fixation devices were not required, and stem extension was used in only Charcot's joint (defect depth=23 mm). Aftertreatment was the same as that for the usual TKAs without bone defects. Results. In terms of clinical outcomes, no patient showed disturbances in walking ability at final follow-up. The average knee flexion angle was 114° (range, 95°–130°). The grafted bone was kept at the grafted area on the radiograms throughout the follow-up period. No absorption or collapse of the grafted bone was observed on the radiograms at the final follow-up. Usually, the grafted bone showed osteosclerotic changes around 2–3 months after TKA. Then, the osteosclerosis became weakened and the bony trabeculae could be detected in the grafted area. Finally, the grafted bone completely incorporated into the host bone in all knees with evidence of bony trabeculae crossing the interface by up to 1 year after surgery. The margin of the grafted area resembled bony cortex in 19 TKAs (73.1%). Conclusions. Our technique is easy, economic, and reproducible. It is an acceptable alternative to metal augmentation for large medial tibial defects in primary TKA

Bone loss can be treated in one of two general ways. Missing bone can be replaced either with bone graft applied to the host bone or augmentations attached to the revision implants. The ideal treatment of bone defects during revision TKR surgery: 1) makes immediate full weight bearing possible; 2) provides longterm support for the implants; 3) Restores original bone stock. Bone grafts achieve these goals when the defects are CAVITARY. Therefore, bone grafts rather than metal augmentation devices are the surgical treatment of choice when these types of defects are encountered during revision TKR surgery. Although bone grafts may achieve these goals when the defects are SEGMENTAL, the results are uncertain and more difficult to achieve. Metal augmentations make possible immediate full weight bearing and provide reliable long-term support for revision TKR implants. When these augments are made of Tantalulm, a metal with 80% porosity, the restoration of bone stock is also possible. There are advantages and drawbacks to each approach. The advantages of bone grafts are that they: 1) restore bone stock; 2) are relatively inexpensive (especially if autogenous graft is used); 3) can be applied with relatively simple instrumentation; and 4) allow defects of a wide variety of sizes and shapes to be treated. The disadvantages of bone grafts are that they: 1) have limited application in large, segmental defects where structural support is necessary; 2) do not always unite predictably, particularly when the host bone is osteopenic or when angular deformities exist; 3) are shaped and inserted without the benefit of precise instrumentation; and 4) may require limited weight bearing or restricted activity for a period of time following surgery. The advantages of augmentation devices are that they: 1) can be manufactured in a wide variety of shapes and sizes; 2) provide immediate stable fixation; and 3) can be inserted using precise cutting instruments. Therefore, the indications for metal augmentation devices are: 1) uncontained defects (segmental) that require structural support for the knee implant; 2) knees with osteopenic bone or large angular defects; and 3) older patients in whom the importance of immediate mobilization and unrestricted weight-bearing is more important than the restoration of bone stock

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

Severe glenoid bone loss in patients with osteoarthritis with intact rotator cuff is associated with posterior glenoid bone loss and posterior humeral subluxation. Management of severe glenoid bone loss during shoulder arthroplasty is controversial and technically challenging and options range from humeral hemiarthroplasty, anatomic shoulder replacement with glenoid bone grafting or augmented glenoid component implantation, to reverse replacement with reaming to correct version or structural bone grafting or metallic augmentation of the bone deficiency. Shoulder replacement with severe glenoid bone loss is technically challenging and characterised by higher rates of complications and revisions. Hemiarthroplasty has limited benefit for pain relief and function especially if eccentric glenoid wear exists. Bone loss with >15 degrees of retroversion likely requires version correction include bone-grafting, augmented glenoid components, or reverse total shoulder replacement. Asymmetric reaming may improve version but is limited to 15 degrees of version correction in order to preserve subchondral bone and glenoid bone vault depth. Bone-grafting of glenoid wear and defects has had mixed results with graft-related complications, periprosthetic radiolucent lines, and glenoid component failure of fixation. Implantation of an augmented wedge or step polyethylene glenoid component improves joint version while preserving subchondral bone, but is technically demanding and with minimal short term clinical follow-up. A Mayo study demonstrated roughly 50% of patients with posteriorly augmented polyethylene had radiolucent lines and 1/3 had posterior subluxation. Another wedge polyethylene design had 66% with bone ingrowth around polyethylene fins at 3 years. Long term outcomes are unknown for these new wedge augmented glenoid components. Reverse shoulder arthroplasty avoids many risks of anatomic replacement glenoid component fixation and stability but is associated with a high complication rate (15%) including neurologic and baseplate loosening and often requires structural bone grafting behind the baseplate with suboptimal outcomes or metallic augmented baseplates with limited evidence and short term outcomes. Reverse replacement with baseplate bone grafting or metal augmentation is technically challenging due to limited native glenoid bone stock available for baseplate component ingrowth and long term fixation. Failure to correct glenoid superior inclination and restore neutral version within 10 degrees increases the risks of reverse baseplate failure of fixation, pull out, and failure of reverse replacement. Reverse baseplate failure rates in patients with severe glenoid bone loss and concomitant glenoid bone grafting range from 5–11%. The minimum native glenoid bony contact with the baseplate is unknown but likely is approximately 1cm of native bone contacting a central ingrowth post and a minority (∼15–25%) of native glenoid contacting the backside of the baseplate. Failure to correct posterior bone loss can lead to retroversion of the baseplate, reduced external rotation, posterior scapular notching, and posteromedial polyethylene wear. In summary, shoulder replacement with severe glenoid bone loss is technically challenging and characterised by higher rates of complication and revision

Purpose. Most of revision TKA needs bone reconstruction. The success of revision TKA depends on how well the bone reconstruction can be done. The method of reconstruction includes bone cementing, metal augmentation, allogenic bone graft, APC and tumor prosthesis, etc. In moderate to severe bone defect, allograft is needed. However, allogenic bone graft is surgically demanding and needs long operation time, which is very risky to the elderly patients. The authors revised an alternative method of bone defect reconstruction using cementing method with multiple screws augmentation. Methods. There were 12 cases of patients with large defect which could not be reconstructed with metal augment from April 2012 to April 2014. The authors performed 3 to 5 screws fixation on the defect site. Sclerotic bone is prepared with burring for better cementing. 3 ∼ 5 screws according to the size of defect. The length of screw fixation was determined as deep to the bone until stable fixation just beneath the implant. When drilling for the screw insertion, intramedullary guide is put into the medullary canal so as not to interfere with implant insertion. The defect is filled with cement during prosthesis fixation. Weight bearing was permitted on postoperative 3rd day, as usual manner of primary TKA. Results. According to the AORI classification, there were 10 cases of 2A and 2 cases of 2B. Mean follow up period was average 15 months. The number of screw insertion was 4.3 ea (2∼8). Average operation time was 1 hour and 57 minutes. Mean ROM was 107.9. HSS score, KSS score ad WOMAC score were 86.3, 92.8 and 11, respectively. There were no case of infection and loosening at the last follow-up. Conclusion. Cementing with multiple screws augmentation technique is a good alternative of bone reconstruction

Introduction. The optimal management of severe tibial and/or femoral bone loss in a revision total knee arthroplasty (TKA) has not been established. Reconstructive methods include structural or bulk allografts, impaction bone-grafting with or without mesh augmentation, custum prosthetic components, modular metal augmentations of prosthesis and tumor prosthesis. Recently metaphyseal fixation using porous tantalum cones (Zimmer, Warsaw, IN) has been proposed as alternative strategy for severe bone loss. Objectives. The purposes of this study were to determine the clinical and radiographic outcomes in patients who underwent revision knee arthroplasty with tantalum cones with a minimum of 5-year follow-up. Methods. From November 2005 to August 2008 a total of 26 porous tantalum metaphyseal cones were used to reconstruct severe tibial and/or femoral bone loss in 18 patients during revision TKA at a single institution. There were 12 females and 6 males with an average age of 73 years (range 55–84) at the time of revision. The mean clinical and radiographic follow-up was 6.3 years (range, 5–8). The reasons for revision were aseptic loosening (5 cases) and deep infection (13 cases). A Two stage procedure was used in all septic cases. According to the Anderson Orthopaedic Reseach Institute (AORI) bone defects classification all femoral and tibial defects were rated 2B and 3 (3 T2b, 9 T3, 3 F2b and 10 F3). A femoral cone was inserted in 6 patients, a tibial cone was inserted in 5, a double cone in 6 (femoral and tibial), and a triple cone in 1 (1 femoral and 2 tibial). A constrained condylar implant (LCCK, Zimmer, Warsaw) was inserted in 6 patients and a rotating hinge knee implants (RHK, Zimmer, Warsaw, IN) in 12 pateints. All patients were prospectively followed for clinical and radiographic evaluation preoperatively and postoperatively at 1, 3, 6 months, one year and yearly thereafter. Results. Knee Society knee scores improved from a mean of 31.3 points before surgery to 76.7 points at latest followup (p < 0.001). Knee Society function scores improved from a mean of 21.7 points before surgery to 65.4 points at latest followup (p < 0.001). The average flexion contracture was 6° and the average flection was 88°. At the time of the latest follow-up the average flexion contraction was 3° and the average flexion was 105°. No radiolucent lines were seen between the cones and the adjacent tibial and femoral bone at the latest follow-up. There was no evidence of loosening or migration of any implant at the time of the final follow-up. There have been two reoperations for recurrent infection (11%). Conclusions. Our experience demonstrates excellent clinical and radiographic mid-term outcomes and confirms that metaphyseal fixation with porous tantalum cones can be achieved. Long-term follow up and comparative studies are necessary

Pelvic discontinuity remains one of the most difficult reconstructive challenges during acetabular revision. Bony defects are extremely variable and remaining bone quality may be extremely poor. Careful pre-operative imaging with plain radiographs, oblique views, and CT scanning is recommended to improve understanding of the remaining bone stock. It is wise to have several options available intra-operatively including metal augments, jumbo cups, and cages. Various treatment options have been used with variable success. The principles of management include restoration of acetabular stability by “connecting” the ilium to the ischium, and by (hopefully) allowing some bony ingrowth into a porous surface to allow longer-term construct stability. Posterior column plates can be useful to stabilise the pelvis, and can supplement a trabecular metal uncemented acetabular component. Screws into the dome and into the ischium are used to span the discontinuity. More severe defects may require so-called “cup-cage” constructs or trabecular metal augmentation distraction techniques. The most severe defects typically necessitate custom triflange components. Triflange constructs allow broad based contact with remaining bone stock, and can span surprisingly large defects. Recent cost analyses have shown that custom triflange constructs are comparable to cup-cage-augment reconstructions. The results of these various solutions to manage pelvic discontinuity is extremely variable, however, it is fair to conclude that constructs that allow some bony ingrowth have demonstrated improved survivorship when compared to historical treatments such as bulk allografts protected by cages. The author prefers a posterior column plate and a trabecular metal cup for simple discontinuities, a cup-cage for larger defects, and a custom triflange for the most severe defects. Pre-operative imaging is critical to guide this decision-making, and careful attention to detail is important to obtain a stable, durable construct

Introduction: With the growing number of primary knee arthroplasties, the number of revision operations is also increasing. The large number of unicondylar replacements carried out in the 1980’s, due to lack of modern total condylar implants, grant the revision techniques an outstanding significance in Hungary. One of the main issues of modern revision techniques is the management of bone defects, which can be solved by different methods documented in literature. Aim of study: The aim of our study was to investigate the success and feasibility of the various defect management techniques by evaluating the results of revision knee prosthetic surgeries carried out at our clinic. Patients and methods: Femoral and tibial bone defects had to be solved with revision surgeries in 35 cases, all performed due to aseptic loosening of uni- and total condylar prostheses implanted earlier. For filling of bone defects, metal augmentation of the prostheses was applied in 9 cases, allografts from bone bank were used in 11 cases, own cancellous bone was applied in 20 cases. Results were prospectively analysed with the help of the knee society rating system, with an average follow-up of two and a half years. Results: Revision interventions were successful in 34 cases, detailed results are revealed in the presentation, complemented with case presentations. In a single case, repeated intervention surgery is indicated due to disorganisation of the structural allograft and the resulting loosening of the tibial component. Conclusion: The success of the various bone replacement techniques, completed with adequate indication could be proven in all cases. The unsuccessful case proved that allograft incorporation should be supported by appropriate stem augmentation of the tibial component. In order to perform successful revision knee arthroplasty, we consider it fundamentally important to have a wide variety of allografts from bone bank and a modern knee prostheses system application already during primary implantations

This study was conducted to investigate the cases which were obliged to receive revision surgery within the first 5 years after primary Total Knee Arthroplasty (TKA). The subjects of this study were 15 patients (5 males & 10 females, mean age at revision 72 years) who had undertaken revision surgery within 5 years since 1996. Intervals between primary and revision TKA averaged 29.8 months. Prosthesis used for primary TKA was as follows; 11 Zimmer NexGen LPS-flex fixed bearing, 2 mobile bearing, 2 CR type. Revised components, cause of revision, JOA score as clinical results and FTA as radiographic evaluation were examined. Revised parts were as follows;. All components: 2,. Both Femoral and Tibial components: 4,. only Femoral component: 2,. only Tibial component: 5,. only patella component: 1,. only articular surface: 1. Stemmed Femoral components were used in 6 out of 8 knees, stemmed Tibial components in 9 out of 11 knees. The causes of revision were as follows;. infection: 1,. loosening: 7,. inadequate component position: 4,. instability: 2,. pain: 1. JOA scores improved from 45 points to 78 points, and FTA proved to be 176 deg., postoperatively. Primary TKA remains one of the most successful orthopedic procedures. Survivorship was generally reported over 15 years in the previous article. However, there are some cases in which revision TKA is necessary by some causes. There seems to be various types of causes for revisions, such as loosening, inadequate position, abrasion of components and others. Though loosening of components due to traumatic cause was inevitable, other causes, such as inadequate position of component, imbalanced soft tissues and infection, which depend on our technique, should be cared during and after surgery. From our study, except for 7 (2 trauma, 5 unknown) out of 15 knees, almost half of revision TKA (8 knees) might be due to technical demand. As for surgical techniques, in the case of poor bony quality, we routinely use stemmed components and should try not to impact strongly on setting component to prevent from sinking. In the case of non-traumatic cause, 3 out of 12, though the position of tibial component was acceptable, tibial component sunk because of bony weakness and/or imbalanced soft tissues resulting pain. Adequate position and balance of components should be achieved during primary TKA. In our department, we are trying to revise and routinely use stemmed components as soon as possible, when loosening of component is confirmed. Metal augmentation, if necessary, is mainly used for bone defect to do early rehabilitation. We concluded that adequate position of components and soft tissue balance was very important at the time of primary TKA. Clinical results of revision TKA were almost equal to those of primary TKA, however, long term follow-up will be needed

The patho-anatomy of a valgus knee could be divide into two categories as bony hypolasia and/or deficiency and soft tissue imbalance. The soft tissue in the lateral side of the knee (Including illio-tial band, lateral collateral ligament, poplitious tendon, posterior-lateral ligament, and hamstrings etc) is contracted with or without medial soft tissue attenuation. There are many reasons explain why dealing with a valgus knee is much more difficult than dealing with a varus knee. The most important three factors are:. There is much less room or space to release a LCL,. The MCL could be attenuated,. A fixed valgus deformity is always associated with bone deficiency or hypoplasia. However, it is arbitrary, and in many times, it is wrong to take it for granted that a valgus knee is always associated with a tight LCL. In this article, the author mainly introduce the rationale and clinical application of a LCL tension based classification and treatment algorithm of a valgus knee. The details of how to judge if the LCL is tight, loose or normally tensioned; Is the valgus knee purely or associated with an extra-articular deformity will also be discussed. JST Classification of a Valgus Knee. Femoral deformity. Type F1 Valgus in Extension only. F1a Intra-articular deformity, LCL is loose when the knee extends, while LCL maintains normal tension when the knee flexes. F1b Extra-articular deformity which is close to knee joint(supra-condylar deformity), LCL remains normal length and tension through all the range of motion. Type F2 Valgus in both extension and flexion. Intra-articular deformity, LCL is tight through all the range of motion, hypoplasia or bone deficiency in both distal and posterior lateral femoral condyle. Tibial deformity. Type T1 Intra-articular deformity, lateral tibial plateau deficiency. Type T2 Extra-articular deformity, tibial metaphyseal orshaft deformity. Treatment algorithm of a valgus knee. Type F1a. This type valgus knee is the easiest to deal with. The LCL length is well maintained, and LCL is loose when knee extends. What is tight and restrains the deformity as a fixed valgus one is: ITB and posterior-lateral capsule instead of LCL and poplitous tendon. The deformity is corrected simply by releasing ITB & posterior-lateral capsule and bony graft or using a metal block to augment the deficient or hypoplastic lateral distal femoral condyle. At the same time, the loose LCL is properly tensioned by bone graft of metal augmentation. Since both ITB & posterior capsule are secondary stabilizers, the LCL and poplitous tendon is properly tensioned, the knee is pretty stable. Type F1b. This type of valgus deformity actually comes from juxta supera-condylar area, the deformity is very close to the joint, or in other words, close to the collateral ligament frame, this type deformity is also regard as a type of valgus knee. According to severity of the deformity, patient’s age, and surgeon’s preference, the following methods are commonly used. Method A: lateral condyle distal sliding osteotomy The essence of a sliding osteotomy is converting a F1b deformity into a F1a deformity. By distally sliding osteotomy, the LCL becomes loose when the knee extends, and the valgus deformity is shifted into the collateral ligament frame. Method B: Soft tissue releasing + constrained total knee The LCL of a F1b valgus knee is normal tensioned with normal length, over releasing lateral soft tissue will lead to imbalanced flexion gap, in this meaning, it may not possible to balance a F1b valgus knee properly in both flexion and extension. In such a knee, if the patient is old and is not going to lead an active life, a constrained prosthesis such as CCK or TC III can be used. Method C: One stage or two stage supera-condylar osteotomy+TKA. Since a F1b valgus knee is actually a normal knee combined with a supera-condylar deformity, it is understandable to correct deformity by an supera-condylar osteotomy. The osteotomy can be done in one stage or two stage style. Theoretically, a supera-condylar osteotomy is done in the most deformed region, and is done within cancellous bone, bone union can be predictably expected. But if a total knee and osteotomy is performed in one stage, the operator could encounter the following difficulties:. Conventional instruments can not guarantee correct bone cut because a supera-condylar deformity deviates intramedullary guiding rod;. the canal in distal femoral metaphyseal part is quite expended, it is difficult to achieve solid fixation either by a stem extension or retrograde intramedullary nailing. Total knee replacement, supera-condylar osteotomy and intramedullary could severely damage blood supply to osteotomy line leading to nonunion. The author prefer a two stage TKA and osteotomy for a F1b valgus knee. In one stage TKA and osteotomy, the author will use frontal epicondyle axis instead of intra-medullary rod to guide distal femoral cut. TypeF2. This type knee is consistently valgus no matter the knee extends of flexes, indicating both distal distal and posterior part of lateral femoral condyle is deficient of dysplastic and LCL is contracted. Lateral soft tissue, including LCL and some times popolitous tendon, is inevitable in managing type F2 valgus knee. If soft tissue releasing alone can’t balance medial and lateral part of the knee, a bidirectional sliding osteotomy can be done to shift proximal insertion of LCL both distally and posteriorly, releasing the LCL. Type T deformity. Type T deformity is sparse, Type T1 is typically seen in a rheumatoid arthritis, and Type T2 is usually iatrogenic(over corrected high tibia osteotomy) or after malunion of a tibia metapyseal or proximal shaft fracture. It is possible try to augament the lateral tibial plateau deficiency and release the lateral soft tissue for a Type T1 valgus knee. But for a Type T2 knee, a correctional osteotomy concomitant to a total knee is usually needed

Background: Unicondylar knee arthroplasty (UKA) are being expanded to include younger patients with more active lifestyles because of its minimally invasive nature. Prior to expanding this role, it is important to examine mode of failure and implication of conversion to TKA in the low demand elderly patients. Aim: To ascertain the modes of early failure of unicondylar knee Arthroplasty and assess whether the conversion to TKA improved the functional scores, range of motion, pain, and patient satisfaction. Method: A retrospective study to evaluate the results of 14 revision procedures after failed unicompartmental knee arthroplasty (UKA). Patients’ operative charts were reviewed. Details of modes of failure, technical difficulty of revision including exposure, component removal, and management of bone loss were noted. Post operative functional outcome was assessed using WOMAC osteoarthritis index and SF-36. Result: Total of 106 primary unicondylar knee arthroplasty procedures was performed between 2003 and 2007 in our institution. Oxford unicondylar implant was used in all patients. 13.21% of these were revised to total knee replacement. Revisions were performed 4 months to 36 months after the primary procedure; 86% of these were required within the first 12 months. The average time to failure was 15.6 months. The modes of failure were aseptic loosening (4), progression of osteoarthritis (2), instability (3), infection (2), dislocated insert (1) and persistent pain after UKA (2). Tibia insert exchange was done in one patient and the rest were converted to primary Scorpio and PFC components. Three of the patients had significant defect in femoral condyle. Fourteen percent of cases required femoral stem extension or metal wedge augmentation. Nine of the 14 knees (64%) were followed up for an average of 15 months. The mean WOMAC and SF-36 scores at latest follow up were 33.33 and 63.79 respectively. Conclusion: Despite the advantage of minimally invasive UKA, early failure can occur in the face of good surgical technique. The higher long-term success rate claimed by implant manufacturer is challengeable and patient should be informed during consent