Paprosky IIIA Research Articles

Mid-Term Clinical and Radiographic Results of Complex Hip Revision Arthroplasty Based on 3D Life-Sized Model: A Prospective Case Series.

Background: The pre-operative three-dimensional (3D) assessment of acetabular bone defects may not be evaluated properly with conventional radiographic and computed tomography images. This paper reports mid-term clinical and radiographic outcomes of complex revision total hip arthroplasty (r-THA) based on a 3D life-sized printed model. Methods: Patients who underwent r-THA for septic or aseptic acetabular loosening with acetabular defects Paprosky types IIc, IIIa, and IIIb between 2019 and 2021 were included. The outcomes of the study were to determine clinical and radiographic assessment outcomes at the time of the last follow-up. Results: 25 patients with mean age of 62.9 ± 10.8 (18-83) years old were included. The mean Harris hip score improved from 34.8 ± 8.1 pre-operative to 81.6 ± 10.4 points (p < 0.001). The mean visual analog scale decreased from 6.7 ± 1.4 points pre-operative to 2.4 ± 1.0 points (p < 0.001). The mean limb length discrepancy improved from -2.0 ± 1.2 cm pre-operative to -0.6 ± 0.6 cm (p < 0.001). The mean vertical position of the center of rotation (COR) changed from 3.5 ± 1.7 cm pre-operative to 2.0 ± 0.7 cm (p < 0.05). The mean horizontal COR changed from 3.9 ± 1.5 cm pre-operative to 3.2 ± 0.5 cm (p < 0.05). The mean acetabular component abduction angle changed from 59.7° ± 29.6° pre-operative to 46° ± 3.9 (p < 0.05). Conclusions: A three-dimensional-printed model provides an effective connection between the pre-operative bone defects' evaluation and the intraoperative findings, enabling surgeons to select optimal surgical strategies.

Bispherical metal augment improved biomechanical stability in severe acetabular deficiency reconstruction: a comparative finite element analysis

BackgroundThis study used finite element analysis (FEA) to compare the biomechanical stability of bispherical metal augment (BA) and wedge-shaped trabecular-metal augment (TA) in different acetabular defect reconstruction models, thereby explaining the application value of this novel bispherical augment in complex hip revision.MethodsThree different acetabular defect pelvis models originating from three representative patients with different types of severe acetabular defects (Paprosky IIC, IIIA, and IIIB) were constructed and reconstruction with BA and TA technique was simulated. Based on the FEA models, the displacement of reconstruction implants, relative displacement of bone implants, and hemi-pelvic von Mises stress were investigated under static loads.ResultsBA acquired smaller reconstruction system displacement, less relative displacement of bone implants, and lower pelvic von Mises stress than TA in all Paprosky IIC, IIIA, and IIIB defect reconstructions.ConclusionThe FEA results show that BA could acquire favourable biomechanical stability in severe acetabular defect reconstruction. This technique is a reliable method in complex hip revision.

Acetabular Distraction: Promising 5-Year Outcomes for the Treatment of Chronic Pelvic Discontinuity

BackgroundSevere acetabular bone loss encountered during revision total hip arthroplasty (THA) poses a clinical challenge. In cases involving pelvic discontinuity, where the ilium is separated superiorly from the inferior ischiopubic segment through the acetabulum, acetabular distraction may be used to restore the biomechanics of the hemipelvis. This technique allows for correct sizing of the acetabulum, and the subsequent peripheral distraction and medial compression at the discontinuity provide initial mechanical stability and biological fixation as bone in growth occurs. Accordingly, this study aimed to assess long-term 5-year outcomes following acetabular distraction across 2 institutions. MethodsWe retrospectively identified all patients who underwent revision THA in which the acetabular distraction technique was performed for the treatment of chronic pelvic discontinuity between 2002 and 2018. Demographic, operative, and clinical postoperative data were collected. Clinical endpoints included postoperative radiographic outcomes, complications requiring additional surgery, and reoperation for all causes. Only patients who had a minimum 5-year follow-up were included in this study. ResultsA total of 15 patients (Paprosky IIC: one patient, 6.7%; Paprosky IIIA: 5 patients, 33.3%; Paprosky IIIB: 9 patients, 60%) who had a mean follow-up time of 9 years (range, 5.1 to 13.5) were analyzed. Porous tantalum augments were used in 11 (73.3%) cases to primarily address posteriorsuperior defects (100%). There were 4 (26.7%) patients that required reoperation, only 2 of which were for indications related to the acetabular construct, leading to an overall survivorship of 86.7%. Both patients had a prior revision THA before the implementation of the distraction technique. Evidence of bridging callus formation was reported radiographically for 14 (93.3%) patients at the time of the last clinical follow-up. ConclusionsFor patients who have chronic pelvic discontinuity, acetabular distraction shows promising long-term outcomes. Even so, larger multi-center studies are needed to better support the efficacy of this technique. Level of EvidenceLevel III, retrospective comparative study.

Acetabular Distraction Technique: A Multicenter Study With a Minimum 2-Year Radiographic Follow-Up

BackgroundChronic pelvic discontinuity is a challenge during revision total hip arthroplasty due to the loss of structural continuity of the superior and inferior aspects of the acetabulum from severe acetabular bone loss. Acetabular distraction provides an alternative surgical treatment by stabilizing the acetabular component through elastic recoil of the pelvis, which may be supplemented with modular porous augments for addressing major acetabular defects. This study reports 2-year radiographic findings following acetabular distraction for the treatment of chronic pelvic discontinuity. MethodsPatients undergoing acetabular distraction performed by 5 surgeons from 2002 to 2021 were identified across 5 institutions. Demographic, surgical, and postoperative outcomes, including radiographic component stability, were recorded. There were 53 of 91 (58.2%) patients (5 deceased, 33 lost to follow-up) consisting of 4 Paprosky IIC (7.5%), 8 Paprosky IIIA (15.1%), and 41 Paprosky IIIB (77.4%) defects included, with a mean follow-up time of 4.8 years (range, 2 to 13.5). Modular porous augments were used in 33 (62.3%) cases. Failure was defined as a subsequent revision of the acetabular construct. ResultsAmong the 13 (24.5%) patients who returned to the operating room, 6 (46.2%) had a prior history of revision total hip arthroplasty before undergoing acetabular distraction. Only 5 (9.4%) patients underwent acetabular revision following acetabular distraction, leading to an overall cup survivorship of 90.6%. Of the remaining 48 patients, 46 (95.8%) had evidence of radiographic bridging callus of the chronic pelvic discontinuity at their last clinical follow-up. ConclusionsTo our knowledge, in the largest series to date, acetabular distraction has proven to be a viable treatment for acetabular bone loss with a chronic pelvic discontinuity, with excellent early survivorship and radiographic evidence of bridging callus. Future studies with longer follow-ups are needed to further monitor the efficacy of this technique. Level of EvidenceLevel III, Retrospective Comparative Study.

Cementless Primary Stems in Revision Hip Arthroplasty: A Narrative Review.

Cementless primary stems in revision hip arthroplasties may be conservative options to preserve bone stock and provide adequate reconstruction of the hip biomechanics. However, there is still little evidence about indications, limitations, and outcomes. This narrative review showed that conventional standard stems were adopted in different revision settings, up to Paprosky IIIA grade bone defects. In cases of acceptable metaphyseal bone stock, when a scratch fit of at least 4 cm can be achieved, a conventional cementless stem may be an adequate solution. Mid-term clinical and radiographic outcomes and survival rates were similar to long revision stems, whereas complications, surgical time, and costs were lower among conventional stems. However, unsuitable contexts for conventional stems included canal diameters larger than 18 mm and failed revision stems with cortical weakening. Even short stems can be considered in revisions, in order to preserve bone stock and stay proximal to femoral remodeling zones and bone/cement plugs. Short stems were successfully adopted up to Paprosky IIIA bone defects, achieving mid-term survival rates not inferior to long revision stems. Ageing, osteoporosis, and intraoperative femoral fractures were the main negative prognostic factors. In very select cases, a downsizing technique (from longer to shorter stems) may be adopted to simplify the procedure and reduce complications.

Trabecular titanium cups in hip revision surgery: a systematic review of the literature.

Hip revision surgery in extensive acetabular bone defects represents a complex challenge for hip surgeons. The primary goal is to obtain a stable acetabular component and restore the hip biomechanics. Through the years, different prosthetic implants have been developed to perform acetabular revision depending on bone loss location and extension. This systematic review aims to summarize the clinical outcomes and complications reported with trabecular titanium (TT) cups in hip revision surgery. A literature search of four databases (PubMed, Embase, Scopus and the Cochrane Database of systematic reviews) was performed according to the PRISMA guideline from January 2008 to December 2022. All studies written in English and reporting the clinical outcome of patients undergoing revision total hip arthroplasty using Delta TT cups were included. The initial screening identified 378 studies. Each eligible clinical article was analyzed according to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence (LoE), and the papers' methodological quality was evaluated using The Methodological Index for Non-Randomized Studies Criteria (MINORS) score. Eight clinical studies were included in the analysis. A total of 523 hip revisions were analyzed. Delta TT cups were used in 3.9%, Delta TT one cups in 46.8%, and Delta TT revisions in 49.3%. Paprosky IIIa was the most frequent acetabular bone defect reported in 26.4% of cases. The overall survival rate of TT cups was 93.4%. The dislocation was the most frequent complication in 4.1% of patients, while the prevalence of aseptic loosening was 1.5. Managing severe acetabular bone defects remains a complex challenge for hip surgeons. Since their introduction, TT cups have exhibited good clinical results, with complication rates in line with or lower than those reported by similar implants.

20-year Results of a 3D Titanium Mesh Coating Stability of 31 Artificial Cups.

The aim of this work was to demonstrate the bony bond strength and resilience of a three-dimensional titanium mesh coating of an artificial acetabulum produced using the diffusion bonding technique. Under the extreme conditions ranging from abrasion-related osteolysis to acetabular perforation, the degree of residual bone and the integrity of the coating were determined. The remaining zones of the (still) stable bone connection are inevitably exposed to a greater load of the layer adhesion between the titanium mesh and the core shell. The investigation was intended to provide information about the stages of damage according to Paprosky in which it was still justifiable to leave the implant in place and simply change the inlay from the purely material-technical point of view of a stable coating. The bond between bone and implant was examined with regard to a possible retention of the implant for its adaptive remodeling up to 27 years. In a retrospective study, 31 explanted human acetabular cups of the Harris-Galante II type, with an average lifetime of 19.7 years (11-27 years), were examined by means of digital area measurement to determine both the bone areas remaining on the coating and the damaged areas of the titanium mesh. Periacetabular bone loss was recorded in a modified Paprosky (PAP) damage classification. Full hemispherical sections of 4 acetabular cups with a life time of 16, 20, 22 and 27 years were examined histopathologically using the diamond cut technique. The periacetabular bone loss resulted in damage class PAP I in 8 cases, PAP IIa in 7 cases, PAP IIb in 2 cases, PAP IIc in 9 cases, PAP IIIa in 3 cases and PAP IIIa in 2 cases PAP IIIb. The average amount of bone that was still firmly attached to the coating after explantation was 17% (0-70%) of the total cup surface. Paprosky I accounted for 44.1%, and PAP IIa and IIb stadiums together a total of 17.1%. The average bone fraction of the implants no longer anchored in the host bed at stages IIc, IIIa and IIIb was 2%. The average coating damage was 11% (0-100%) and was exclusively attributable to the unstable implants of stages IIc, IIIa and IIIb. The histopathological findings showed adaptive bone remodeling, that was detectable for up to 27 years through the titanium mesh down to the interface with the solid acetabular core. The titanium wire mesh was mostly surrounded by lamellar, mature bone. The results show that the connection between the Tivanium cup and the previously oldest and unchanged sintered coating - in the form of a three-dimensional titanium mesh applied in point and line contact - is very load-resistant even under the extreme loads of periacetabular osteolysis and cup perforations. Since there was no damage to the coating in periacetabular damage stages Paprosky I, IIa and IIb, it is justifiable in these damage stages to leave the implant in situ and to continue to use it with sole replacement of the inlay, but leaving the socket shell. The third-generation acetabular cup (Trilogy) with unchanged three-dimensional titanium mesh coating has been implanted in over 1.2 million cases for 26 years. After a long service life, an increasing number of wear and tear conditions can be expected in today's mostly elderly and vulnerable patient clientele. In view of the results presented here, the early detection of damage would make it possible to avoid costly and stressful explantation of the entire acetabular cup in favor of replacing the sole inlay in Paprosky stages I, IIa and IIb.

Clinical and Radiographic Outcomes of a Monoblock Fluted Titanium-Tapered Stem for Paprosky IIIa, IIIb, and IV Femoral Bone Defects

BackgroundModern fluted titanium-tapered stems (FTTS) have been increasingly utilized to achieve primary stability in conversion and revision total hip arthroplasty with major femoral bone loss. This study sought to determine the radiographic and clinical outcomes of a monoblock FTTS in patients who had major femoral bone loss. MethodsA multicenter retrospective observational study of all total hip arthroplasty patients who received a monoblock FTTS who had up to 5-year radiographic follow-up was conducted. Only patients with femoral Paprosky classifications of IIIa, IIIb, and IV were included. Eighty-one monoblock FTTS were examined. Median clinical follow-up was 29 months (range, 18 to 58). Stem subsidence and loosening were assessed on most recent radiographs. All-cause revisions and stem survivals were assessed. ResultsMedian subsidence was 1.4 millimeters (mm) (range, 0 to 15.0). Sixteen (23.9%) and 3 (4.5%) stems had subsidence greater than 5 and 10 mm, respectively. All stems not acutely revised appeared stable, without evidence of loosening, at latest follow-up. Ten hips (12.3%) required reoperations. Of these, only 5 (6.2%) stems were removed; 4 due to periprosthetic joint infection and 1 for surgical exposure during acetabular revision. Kaplan–Meier analyses yielded an all-cause stem survivorship of 95.1% at 2-years and 87.1% at 4-years. Stem survivorships excluding septic causes was 98.8% at both 2 and 4 years. ConclusionMonoblock FTTS in complex femoral reconstruction cases showed encouraging clinical and radiographic results in patients who had severe femoral bone loss at median 29 months follow-up.

Shape suitability and mechanical safety of customised hip implants: Three-dimensional printed acetabular cup for hip arthroplasty

BackgroundOwing to an increase in the number of hip arthroplasty surgeries, the number of implant replacement surgeries is increasing rapidly as well. This necessitates the study of hip joint conditions. Therefore, Paprosky defined a classification system to indicate the degree of damage to the hip joint. In this study, a customised hip implant suitable for Paprosky classification Type ⅡC and over was designed. The shape, suitability, and mechanical safety of the worst-case model for the implant were evaluated. Materials and methodsTo identify the implant size depending on states over Type ⅡC acetabulum bone loss, a size range was selected and a customised implant was designed according to the computed tomography data within the size range. The implant was designed for the flange, hook, and flattened model types. The worst-case selection test was conducted using finite element analysis. The von Mises stresses of the flange, hook, and flattened models were found as 76.223, 136.99, and 80.791 MPa, respectively. Therefore, the hook-type model was selected as the worst case for the mechanical performance test. ResultsA bending test was conducted on the hook-type model without fracture and failure at 5344.56 N. The proposed customised implant was found suitable for Type ⅢA acetabulum bone loss, whereas the shape suitability and mechanical safety were verified for the worst case. ConclusionThe shape of a customised implant suitable for Paprosky ⅢA type was designed. The shape suitability and mechanical safety were evaluated using finite element method analysis and bending tests. Clinical validation is required through subsequent clinical evaluation.

Porous tantalum shell and augment for acetabular defect reconstruction in revision total hip arthroplasty: a mid-term follow-up study.

The use of porous tantalum trabecular metal (TM) shell and augment to reconstruct acetabular defects in revision total hip arthroplasty (THA) is a reliable technique. We evaluated the mid-term implant survival, clinical, and radiological outcomes of our first 48 revisions using this technique. A total of 45 patients (48 hips) who had acetabular revision of THA between 2011 and 2017 using TM shell and augment with possible mid-term follow-up were included. Twenty-two patients were men (49%) and 23 were women (51%), mean age was 62.5years (34 to 85) and mean follow-up was 75months (54 to 125). Twenty-four hips (50%) had a Paprosky IIIA defect, 14 (29.2%) had a type IIIB defect, six (12.5%) had a type IIC defect, and four hips (8.3%) had a type IIB defect. None of the patients had pelvic discontinuity (PD). At a mean 6.25years follow-up, all hips remained well-fixed and implant survival of 100% with the need of re-revision as the end point. Screw fixation was used for all shells; augments and the shell-augment interface was cemented. Excellent pain relief (mean WOMAC score pain 90.5, (38.3 to 100)), and functional outcomes (mean WOMAC function 88.3 (31.9 to 100), mean OHS 89.2 (31.8 to 100)) were noted. Patient satisfaction scores were excellent. This study demonstrated satisfactory mid-term clinical and radiological outcomes of using TM shell and augment for reconstructing major acetabular defects without PD in revision THA.

Revision of Total Hip Replacement with Acetabular Deficiency

Background: The paradigm of revision surgery has been evolving constantly. There is a wide range of surgical options for successful reconstruction. Objective: This study aimed to evaluate the results of reconstruction techniques in acetabular deficiency. Patients and methods: A prospective interventional designincluded patients with acetabular deficiency who were admitted to Orthopedic Department at Zagazig University Hospitals. We had 10 patients with acetabular deficiency (Three were classified as Paprosky IIIA; one of them was AAOS IIB and two were AAOS III, Two were classified as Paprosky IIIB and AAOS III, Two were classified as Paprosky IIA and AAOS IIA; one was Paprosoky IIB and AAOS IIB and Two patients were classified as Paprosky IIC; one of them was AAOS IIB and the other was AAOS III). The evaluation and follow up of patients depended mainly on the Harris hip score, which evaluates the patient clinically preoperatively and postoperatively. Results: All the patients reached full weight bearing between 7 and 9 weeks after surgery. Revision total hip replacement (THR) was the treatment of choice for patients with severe groin pain and apparent acetabular deficiency. Restoration of the normal center of rotation was essential for the joint biomechanics and survival of the prosthesis. Conclusion: There was no method of reconstruction of acetabulum superior to another method; each method had specific indication, which differs according to the percentage of acetabular coverage and bone stock. Patients with mild to moderate acetabular deficiency (Paprosky I, IIA and IIB) were managed by using acetabular augmentation graft or small acetabular component with medialization. Keywords:

One-stage exchange should be avoided in periprosthetic joint infection cases with massive femoral bone loss or with history of any failed revision to treat periprosthetic joint infection.

There is a paucity of long-term studies analyzing risk factors for failure after single-stage revision for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). We report the mid- to long-term septic and non-septic failure rate of single-stage revision for PJI after THA. We retrospectively reviewed 88 cases which met the Musculoskeletal Infection Society (MSIS) criteria for PJI. Mean follow-up was seven years (1 to 14). Septic failure was diagnosed with a Delphi-based consensus definition. Any reoperation for mechanical causes in the absence of evidence of infection was considered as non-septic failure. A competing risk regression model was used to evaluate factors associated with septic and non-septic failures. A Kaplan-Meier estimate was used to analyze mortality. The cumulative incidence of septic failure was 8% (95% confidence interval (CI) 3.5 to 15) at one year, 13.8% (95% CI 7.6 to 22) at two years, and 19.7% (95% CI 12 to 28.6) at five and ten years of follow-up. A femoral bone defect worse than Paprosky IIIA (hazard ratio (HR) 13.58 (95% CI 4.86 to 37.93); p < 0.001) and obesity (BMI ≥ 30 kg/m2; HR 3.88 (95% CI 1.49 to 10.09); p = 0.005) were significantly associated with septic failure. Instability and periprosthetic fracture were the most common reasons for mechanical failure (5.7% and 4.5%, respectively). The cumulative incidence of aseptic failure was 2% (95% CI 0.4 to 7) at two years, 9% (95% CI 4 to 17) at five years, and 12% (95% CI 5 to 22) at ten years. A previous revision to treat PJI was significantly associated with non-septic failure (HR 9.93 (95% CI 1.77 to 55.46); p = 0.009). At the five-year timepoint, 93% of the patients were alive (95% CI 84% to 96%), which fell to 86% (95% CI 75% to 92%) at ten-year follow-up. Massive femoral bone loss was associated with greater chances of developing a further septic failure. All septic failures occurred within the first five years following the one-stage exchange. Surgeons should be aware of instability and periprosthetic fracture being potential causes of further aseptic revision surgery. Cite this article: Bone Joint J2021;103-B(7):1247-1253.

Acetabular impaction grafting with mesh for acetabular bone defects: a systematic review.

In conjunction with impaction bone grafting (IBG), metal meshes have been proposed to minimise defects of the medial and superolateral walls in order to convert combined complex uncontained segmental defects into contained cavitary defects to facilitate IBG. The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications from January 1980 to March 2019 utilising keywords pertinent to total hip arthroplasty (THA), acetabular impaction bone grafting, clinical or functional outcomes, revision THA, or postoperative complications. 7 articles were found to be suitable for inclusion in the present study. The mean modified Coleman methodology score for methodological deficiencies of the studies was 45.3 (range 38-59). Severe acetabular bone loss was present in 56% of cases having moderate bone loss in 18%, and mild in 26%. The all-cause reoperation rate was 7.4%, while the all-cause revision rate of the acetabular component was 6.2%. IBG with mesh is effective for selected patients with acetabular bone defects. Most patients with moderate bone loss as well as selected patients with large superolateral defects can be successfully treated with IBG combined with mesh. There is limited data to show that IBG with mesh might be associated with decreased survival rates in patients with severe lateral defects (Paprosky IIIA) combined with ischial or medial wall osteolysis who require combined medial and lateral meshes. In addition, patients with severe superomedial migration of the cup (Paprosky IIIB) should not be treated with IBG and mesh.

Tantalum Augments Combined with Antiprotrusio Cages for Massive Acetabular Defects in Revision Arthroplasty

BackgroundTantalum components have gained popularity for the management of Paprosky type IIIA and IIIB defects during revision total hip arthroplasty. Although the use of antiprotrusio cages solely shows suboptimal results, there are certain defects that still require their use. We hypothesized that combining tantalum augments and an antiprotrusio cage would (1) improve radiographic stability, (2) enhance survivorship, (3) decrease complications, and (4) improve clinical outcomes. MethodsWe retrospectively reviewed 20 patients with Paprosky type IIIA or IIIB defects who underwent revision of the acetabular component with a highly porous tantalum augment and an antiprotrusio cage combination. Preoperative and postoperative radiographs, survivorship free from aseptic component revision, and the Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, and Short Form-36 scores were analyzed. The mean follow-up was 2.8 years. ResultsAt the most recent follow-up, no antiprotrusio cages had migrated and all tantalum augments had radiographic evidence of osseointegration. In addition, only 2 components were revised for aseptic etiologies and only 1 was loose. Both were revised secondary to failures of the inferior flange of the antiprotrusio cage. All clinical outcome scores significantly improved postoperatively. Finally, the risk of major postoperative complications was noted to be 10%. ConclusionsIn summary, a tantalum augment combined with an antiprotrusio cage in Paprosky IIIA and IIIB defects with divergent anatomy not amenable to a hemispherical socket provides a reliable technique to restore the anatomic hip center and prevent superior migration and provides a bony ingrowth surface. Longer term follow-up is required before the technique is widely adapted. Level of EvidenceLevel IV, therapeutic studies.

Effects of 3D Imaging on Surgical Tactics in Primary and Revision Hip Arthroplasty

3D imaging tools significantly expand the ability to assess the bone tissue condition, both in terms of its qualitative properties and in terms of accurate determination of bone defect geometry and volume.The purpose of the study was to determine the 3D imaging potential for the preoperative planning and correction of surgical tactics in hip arthroplasty.Materials and Methods. A retrospective analysis of the preoperative planning of 110 primary and revision hip arthroplasties with 3D imaging was performed. The following specialized software were employed: RadiAnt DICOM Viewer file converter — for 3D models production; 3D/CAD designers — for volumetric models processing and correction; InVesalius 3.0 program — for bone density evaluation by the Hounsfield scale; K-Pacs — for viewing MSCT and X-ray images. All patients underwent pelvic bones radiography in the front and anterior-lateral planes. Post-traumatic acetabular deformity was described in accordance with the X-ray picture in each individual clinical case. For revision arthroplasty, the acetabular defect was determined according to the W.G. Paprosky classification. In 36 patients (32.7%), the acetabulum defect was the result of trauma. In 74 patients (67.3%), the cause of surgery was endoprosthesis components loosening.Results. In 80% of cases (88 patients), the analysis of the 3D model did not change the surgical tactics determined in the preoperative planning using pelvic radiographs; in 20% of cases (22 patients), the use of 3D imaging revealed new circumstances and changed the surgical tactics.Conclusion. In standard cases, it is possible to use the traditional preoperative planning using radiographs in several planes. In primary hip arthroplasty in the patients with post-traumatic deformity, including a false joint of acetabulum bottom or 2 to 3 degree osteopenia, it is advisable to perform 3D imaging. In the case of revision arthroplasty, 3D visualization is indicated in acetabulum Paprosky IIIA, IIIB defects with pelvic discontinuity.

Primary stability of a cementless modular revision hip stem in relation with the femoral defect size: A biomechanical study.

Cementless modular fluted hip stems are commonly used in revision arthroplasty. Nevertheless, there is a wide spectrum of recommendations concerning the minimum bone stock required to enable osseous ingrowth and implant-bone micromotions <100 µm. This experimental study investigated the primary stability of a tapered cementless fluted revision stem depending on different types of bone defects. Implant-bone interface movements with a bimodular stem were examined under cyclic axial and torsional loading using composite femora. In four degrees of freedom, the implant subsidence and micromotions were captured with linear variable differential transformers for the intact femora and seven different defects ranging from Paprosky type I to type IIIB. With a 7-cm length of intact diaphysis proximal to the isthmus (Paprosky IIIA), mean implant-bone micromotions of 66 µm occurred. An implant-bone contact zone of only 5 cm (Paprosky IIIA) resulted in micromotions notably over 100 µm and significantly increased subsidence (p < 0.05). With a Paprosky IIIB defect (3 cm of intact diaphysis) rotational instability occurred in all specimens. Aside from critically increased interfacial micromotions (>100 µm), rotational instability emerged as a mechanism of fixation failure when the implant-bone contact zone was only 5 cm or less. Hence, future studies investigating the implant fixation in the case of femoral bone defects should consider both axial and torsional loading. With regard to the clinical application, our data suggest maintaining 7 cm of diaphyseal implant-bone contact for a safe anchorage of cementless fluted hip revision stems.

Stemmed acetabular cup as a salvage implant for revision total hip arthroplasty with Paprosky type IIIA and IIIB acetabular bone loss

IntroductionCertain cases of repeated acetabular loosening with severe bone loss are hardly amenable to reconstruction using a Kerboull-type plate with allograft. This limitation is more likely when the severe bone loss occurs in older adults with significant comorbidities that may require a faster procedure. In these indications, a stemmed acetabular cup may be an alternative, although the outcomes have not been well defined, especially for a version where the peg is coated with porous material and additional screws can be added. This led us to conduct a retrospective study to determine: (1) whether a stemmed cup anchored in the iliac isthmus is a viable alternative in these situations, (2) the complication rate and (3) the revision rate for any reason. HypothesisA stemmed cup anchored in the iliac isthmus is a viable alternative in cases of repeated revision with severe acetabular bone loss. Materials and methodsWe performed a retrospective single-center study. Sixteen Integra™ cups were implanted in 14 patients (mean age 72.8±10.4 years, minimum–maximum: 58–95) who had aseptic acetabular loosening combined with severe acetabular bone loss graded as Paprosky IIIA in 7 hips and IIIB in 9 hips. The patients had undergone a mean of 2.7±1.8 (minimum–maximum: 1–6) procedures (i.e. primary and/or revision arthroplasty) before this cup was implanted. The cup's survivorship at the time of review and the complication rate were determined. ResultsAt a mean follow-up of 48.8±23.4 months (minimum–maximum: 7–85), two patients had died and two were lost to follow-up. Six hips experienced one or more complications (37.5%): three infections (18.8%), two mechanical failures (12.5%) and one dislocation (6.7%). The cup had to be removed in three patients (18.8%). These complications required reoperation, thus the cumulative incidence of revision for any reason at 5 years was 31% (95% CI: 11–55%). ConclusionDespite the high complication and revision rates, we believe the stemmed acetabular cup is a viable alternative in salvage reconstruction procedures. Level of evidenceIV, Retrospective case study.

Reconstruction for pelvic discontinuity and massive acetabular defects

ObjectiveThe acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive series of cases. Material and methodsRetrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary arthroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect mechanical failures and loosening of the implant. ResultsWith a middle follow-up of 45.06 months (12–73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13.63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d’Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16–55) to 72 (40–90) in the latest follow up. ConclusionThe acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.

Short-term effectiveness of acetabular reconstruction with three-dimensional printed trabecular metal pads in hip revision

To investigate the short-term effectiveness of three-dimensional (3D) printed trabecular metal pads for Paprosky type Ⅲ acetabular defect in hip revision. Between August 2014 and December 2015, the 3D printed trabecular metal pads were used to repair Paprosky type Ⅲ acetabular defects and reconstruct the annular structure of the acetabulums in 5 cases of primary hip revision. There were 3 males and 2 females, aged from 50 to 72 years, with an average age of 66 years. The time from initial replacement to revision was 10 to 18 years, with an average of 14.4 years. The types of prostheses in primary replacement were non-cemented in 3 cases and cemented in 2 cases. The types of acetabular bone defects were Paprosky type ⅢA in 3 cases and Paprosky type ⅢB in 2 cases. The preoperative Harris score was 34.23±11.67. The height of rotation center of affected hip was (38.17±8.87) mm and the horizontal position was (35.62±9.12) mm. The operation time was 120-180 minutes, with an average of 142 minutes. The intraoperative bleeding volume was 800-1 700 mL, with an average of 1 100 mL. Five patients were followed up 18-24 months (mean, 21 months). At last follow-up, the Harris score was 79.82±8.70, which was significantly higher than that before operation (t=16.991, P=0.000). At 1 week after operation, the abduction angle of acetabular cup was 38-42° (mean, 39.4 °) and the anteversion angle was 13-18 ° (mean, 14.6°). The height and horizontal position of rotation center of affected hip were (22.08±8.33) mm and (29.03±6.28) mm, respectively, showing significant differences when compared with those before operation (P<0.05); there was no significant difference when compared with those of healthy hip [(28.62±7.73), (27.29±4.22) mm] (P>0.05). During the follow-up, there was no complication such as prosthesis loosening, dislocation, or periprosthetic fracture. In hip revision, 3D printed trabecular metal pads can repair Paprosky type Ⅲ acetabular defect, reconstruct the structure of acetabulum, provide a stable supporting structure for the acetabular cup, reconstruct the relatively normal rotation center of the hip joint, avoid iatrogenic bone loss, and achieve satisfactory functional recovery of the hip. The long-term effectiveness needs further follow-up.

Reconstrucción acetabular con el sistema Cup-Cage para discontinuidades pélvicas y defectos acetabulares masivos

ObjectiveThe acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive serie of cases. Material and methodsRetrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary artroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect machanical failures and loosening of the implant. ResultsWith a middle follow-up of 45.06 months (12-73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13,63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d’Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16-55) to 72 (40-90) in the latest follow up. ConclusionThe acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.