Staged Revision Hip Arthroplasty With Femoral Impaction Bone Grafting for Prosthetic Joint Infections: Radiostereometric Analyses and Clinical Outcomes at Minimum 5-Year Follow-Up.

BACKGROUND: There are ongoing concerns regarding the use of bone graft following prosthetic joint infection and subsequent implant subsidence. The aim of this study was to determine whether the use of a cemented stem combined with femoral impaction bone grafting (FIBG) at second stage revision for infection results in stable femoral stem fixation, determined by accurate methods, and good clinical results. METHODS: A prospective cohort of 29 patients underwent staged revision total hip arthroplasty for infection using an interval prosthesis followed by FIBG at the final reconstruction. The mean follow-up was 89 months (range, 8 to 167 months). Femoral implant subsidence was measured with radiostereometric analysis. Clinical outcomes included the Harris Hip Score, Harris Pain score and Société Internationale de Chirurgie Orthopédique et de Traumatologie activity scores. RESULTS: At 2-years follow-up the median stem subsidence relative to femur was -1.36 mm (range, -0.31 to -4.98), while the cement subsidence relative to femur was -0.05 mm (range, 0.36 to -0.73). At 5-years follow-up, the median stem subsidence relative to femur was -1.89 mm (range, -0.27 to -6.35), while the cement subsidence relative to femur was -0.06 mm (range, 0.44 to -0.55). There were 25 patients who were confirmed infection-free after the second stage revision with FIBG. The median Harris Hip Score improved from 51 pre-operatively to 79 at 5 years (P = .0130), and Harris Pain score from 20 to 40 (P = .0038). CONCLUSIONS: Stable femoral component fixation can be achieved with FIBG when reconstructing the femur after revision for infection without compromising infection cure rates and patient-reported outcomes.

Highly Porous Tantalum Acetabular Components Without Ancillary Screws Have Similar Migration to Porous Titanium Acetabular Components With Screws at 2 Years: A Randomized Controlled Trial.

BACKGROUND: It is proposed that highly porous coatings on acetabular components, such as a porous tantalum coating, provide adequate fixation without ancillary screw fixation in primary total hip arthroplasty (THA). However, tantalum acetabular components have been associated with higher rates of revision than other uncemented components in national registries. The aim of this randomized controlled trial is to determine whether the early migration of a solid-backed tantalum acetabular component was no greater than that of a titanium acetabular component with ancillary screw fixation that has proven good clinical results. METHODS: Sixty-six patients aged 40 to 64 years, with osteoarthritis and Charnley grade A or B activity grade and who underwent primary THA, were recruited into the trial. Patients were randomized intraoperatively to receive either the tantalum or titanium acetabular component. All patients received the same cemented polished tapered femoral stem, 28-mm cobalt-chromium femoral head, and highly cross-linked polyethylene liner. Acetabular component migration was measured using radiostereometric analysis at 4-6 days postoperatively and at 6 weeks, 3 months, 1 and 2 years following THA. RESULTS: The mean proximal migration at 2 years for the tantalum cohort was 0.17 mm (95% confidence interval, 0.09-0.24) which was no greater than that of the titanium cohort which was 0.19 mm (0.07-0.32). Harris hip scores and functional activity scores were similar between groups. CONCLUSION: These results demonstrate that early stability can be achieved without ancillary screw fixation through the use of a highly porous high friction coating on a solid-backed modular acetabular component. LEVEL OF EVIDENCE: Level I.

Vancouver B2 Peri-Prosthetic Fractures in Cemented Femoral Implants can be Treated With Open Reduction and Internal Fixation Alone Without Revision.

BACKGROUND: The aim of this study is to assess the outcomes of 52 consecutive Vancouver B2 peri-prosthetic fractures around cemented polished double-tapered stems treated by open reduction and internal fixation in 2 trauma centers in 2 countries. METHODS: Outcomes included modified Harris Hip Score (mHHS), Harris Pain Score, and return to pre-injury mobility. Fracture healing was assessed; implant subsidence measured and complications including re-operations reported. RESULTS: No patient was lost to follow-up. Median patient age at operation was 82 years (range 43-98); Harris pain scores showed minimal pain (median 42, range 10-44) at latest follow-up. Median total subsidence at 1 year was 1.1 mm (range 0-5.4), the majority of which occurred within the cement mantle. No subsequent femoral stem revision was required (median 2.9 years, 0-10); however, there were 3 re-operations: 1 re-operation for pre-existing recurrent dislocation involving head liner exchange and 2 for repeat fixation due to metal fatigue. Two additional fractures occurred below the new plating, requiring further plating whilst still retaining the original stems. CONCLUSION: Anatomical reduction and open reduction and internal fixation of Vancouver B2 peri-prosthetic fractures should be considered as an appropriate treatment solution for frail elderly patients with a peri-prosthetic fracture around cemented polished double-tapered stems.

Advantages in Using Cemented Polished Tapered Stems When Performing Total Hip Arthroplasty in Very Young Patients.

BACKGROUND: The risk of revision following primary total hip arthroplasty (THA) is increased in young patients who undergo THA for pathologies other than primary osteoarthritis. We report the results of primary THA performed with cemented polished stems in patients aged 40 years and younger for pathologies other than primary osteoarthritis. METHODS: We investigated 52 patients (65 hips) who underwent primary THA for secondary osteoarthritis with a cemented tapered polished stem between 1990 and 2007. Clinical and radiographic outcomes, available in 46 patients (57 hips), included the Harris Hip Scores, Societe Internationale de Chirurgie Orthopedique et de Traumatologie activity, patient satisfaction, stem survival and reoperations, and assessment of prosthesis-cement-bone radiolucencies, osteolysis, and femoral bone deficiencies. RESULTS: Median patient age was 34 years (16-40) and follow-up was 14 years (mean 13, range 5-22). Stem survival to the endpoint revision for loosening was 100% and to the endpoint revision for any reason, excluding infection was 88% (95% confidence interval 78-98) at 16 years. No stem was revised for aseptic loosening. Nine stems were revised for other reasons. Radiographically, one stem was definitely loose at 16 years. The median patient Harris pain score improved from marked pain to no pain at latest follow-up. Patient activity level improved, albeit minimally, for 8 years after surgery. At latest follow-up, 98% of the patients remained satisfied with their surgery. CONCLUSION: Primary THA with a cemented polished stem shows excellent results in young patients with pathology other than primary osteoarthritis. In addition, the stem design facilitates cement within cement exchange and therefore preservation of proximal femoral bone stock at revision surgery.

Does cup-cage reconstruction with oversized cups provide initial stability in THA for osteoporotic acetabular fractures?

BACKGROUND: The incidence of acetabular fractures in osteoporotic patients is increasing. Immediate total hip arthroplasty (THA) has potential advantages, but achieving acetabular component stability is challenging and, at early followup, reported revision rates for loosening are high. QUESTIONS/PURPOSES: This study measured acetabular component stability and the initial surface contact achieved between the acetabular component and unfractured region of the pelvis after THA using an oversized acetabular component and cup-cage reconstruction. METHODS: Between November 2011 and November 2013, we treated 40 acute acetabular fractures in patients older than 70 years of age. Of these, 12 (30%) underwent immediate THA using an oversized acetabular component with screws inserted only into the ilium and a cup-cage construct. Postoperatively all patients were mobilized without weightbearing restrictions. Indications for immediate THA after acetabular fractures were displaced articular comminution deemed unreducible. Eleven of the 12 were prospectively studied to evaluate the initial stability of the reconstructions using radiostereometric analysis. One of the patients died of a pulmonary embolism after surgery, and the remaining 10 (median age, 81 years; range, 72-86 years) were studied. Of these, five were analyzed at 1 year and five were analyzed at 2 years. Acetabular component migration was defined as acceptable if less than the limits for primary THA that predict later loosening (1.76 mm of proximal migration and 2.53° of sagittal rotation). The contact surface between the acetabular component and ilium in direct continuity with the sacroiliac joint, and the ischium and pubis in direct continuity with the symphysis pubis, was measured on postoperative CT scans. RESULTS: At 1 year the median proximal migration was 0.83 mm (range, 0.09-5.13 mm) and sagittal rotation was 1.3° (range, 0.1°-7.4°). Three of the 10 components had migration above the suggested limits for primary THA at 1 year postoperatively. The contact surface achieved at surgery between the acetabular component and pelvis ranged from 11 to 17 cm(2) (15%-27% of each component). CONCLUSIONS: The majority of acetabular components in this cohort were stable despite the small contact surface achieved between the component and pelvic bone. Three of 10 migrated in excess of the limits that predict later loosening in primary THA but it remains to be seen whether these limits apply to this selected group of frail osteoporotic patients. We continue to use this technique routinely to treat patients with the same indications, but since the analysis of these data we have added screw fixation of the acetabular component to the ischial tuberosity and the superior pubic ramus. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Wear of highly crosslinked polyethylene acetabular components.

BACKGROUND AND PURPOSE: Wear rates of highly crosslinked polyethylene (XLPE) acetabular components have varied considerably between different published studies. This variation is in part due to the different techniques used to measure wear and to the errors inherent in measuring the relatively low amounts of wear in XLPE bearings. We undertook a scoping review of studies that have examined the in vivo wear of XLPE acetabular components using the most sensitive method available, radiostereometric analysis (RSA). METHODS: A systematic search of the PubMed, Scopus, and Cochrane databases was performed to identify published studies in which RSA was used to measure wear of XLPE components in primary total hip arthroplasty (THA). RESULTS: 18 publications examined 12 primary THA cohorts, comprising only 260 THAs at 2-10 years of follow-up. The mean or median proximal wear rate reported ranged from 0.00 to 0.06 mm/year. However, differences in the manner in which wear was determined made it difficult to compare some studies. Furthermore, differences in RSA methodology between studies, such as the use of supine or standing radiographs and the use of beaded or unbeaded reference segments, may limit future meta-analyses examining the effect of patient and implant variables on wear rates. INTERPRETATION: This scoping review confirmed the low wear rates of XLPE in THA, as measured by RSA. We make recommendations to enhance the standardization of reporting of RSA wear results, which will facilitate early identification of poorly performing implants and enable a better understanding of the effects of surgical and patient factors on wear.

Altered load transfer in the pelvis in the presence of periprosthetic osteolysis.

Periprosthetic osteolysis in the retroacetabular region with cancellous bone loss is a recognized phenomenon in the long-term follow-up of total hip replacement. The effects on load transfer in the presence of defects are less well known. A validated, patient-specific, 3D finite element (FE) model of the pelvis was used to assess changes in load transfer associated with periprosthetic osteolysis adjacent to a cementless total hip arthroplasty (THA) component. The presence of a cancellous defect significantly increased (p < 0.05) von Mises stress in the cortical bone of the pelvis during walking and a fall onto the side. At loads consistent with single leg stance, this was still less than the predicted yield stress for cortical bone. During higher loads associated with a fall onto the side, highest stress concentrations occurred in the superior and inferior pubic rami and in the anterior column of the acetabulum with larger cancellous defects.

The variability of the volume of os coxae and linear pelvic morphometry. Considerations for total hip arthroplasty.

This study investigated the variability of os coxae's volume and linear morphometry in 50 dry adult bones. There was a wide variability, with coefficients of variation exceeding 30%, of the bones' volumes (mean 142 ml, range 80 to 300 ml) and distances between the acetabular rim and the horizontal plane through the sciatic notch (mean 10.6 mm, range -7 to 19 mm). The smallest width of the ilium ranged between 3 and 9 mm at a level between 1.5 and 4 cm above the acetabulum. The volume of os coxae correlated with the acetabular diameter (r = 0.79), the height of os coxae (r = 0.88) and antero-posterior length of the ilium at mid-acetabular level (r = 0.70). Knowledge of the variability of os coxae may be useful during preoperative planning in primary and revision hip arthroplasty.

Cemented liner exchange with bone grafting halts the progression of periacetabular osteolysis.

The aims of this were to examine the effect of acetabular liner exchange and intra-operative bone grafting surgery on peri-prosthetic osteolysis. Seven patients with well-fixed Harris-Galante-1 acetabular components received cemented exchange liners for worn liners associated with pre-operatively CT-quantified osteolysis. During surgery, accessible osteolytic lesions were debrided and bone-grafted. Except for one patient with recurrent dislocation and acetabular component revision, the other patients had CT scans at a median of 4 months and at approximately 4 years after surgery. None of the pre-operative lesions increased in volume during the post-operative reporting period and no new lesions were detected. These results show that cemented liner exchange surgery can halt the progression of osteolysis and that bone grafting has the potential to restore bone.

Validity and reliability of the Paprosky acetabular defect classification.

BACKGROUND: The Paprosky acetabular defect classification is widely used but has not been appropriately validated. Reliability of the Paprosky system has not been evaluated in combination with standardized techniques of measurement and scoring. QUESTIONS/PURPOSES: This study evaluated the reliability, teachability, and validity of the Paprosky acetabular defect classification. METHODS: Preoperative radiographs from a random sample of 83 patients undergoing 85 acetabular revisions were classified by four observers, and their classifications were compared with quantitative intraoperative measurements. Teachability of the classification scheme was tested by dividing the four observers into two groups. The observers in Group 1 underwent three teaching sessions; those in Group 2 underwent one session and the influence of teaching on the accuracy of their classifications was ascertained. RESULTS: Radiographic evaluation showed statistically significant relationships with intraoperative measurements of anterior, medial, and superior acetabular defect sizes. Interobserver reliability improved substantially after teaching and did not improve without it. The weighted kappa coefficient went from 0.56 at Occasion 1 to 0.79 after three teaching sessions in Group 1 observers, and from 0.49 to 0.65 after one teaching session in Group 2 observers. CONCLUSIONS: The Paprosky system is valid and shows good reliability when combined with standardized definitions of radiographic landmarks and a structured analysis. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Periprosthetic osteolysis after total hip replacement: molecular pathology and clinical management.

Periprosthetic osteolysis is a serious complication of total hip replacement (THR) in the medium to long term. Although often asymptomatic, osteolysis can lead to prosthesis loosening and periprosthetic fracture. These complications cause significant morbidity and require complex revision surgery. Here, we review advances in our understanding of the cell and tissue response to particles produced by wear of the articular and non-articular surfaces of prostheses. We discuss the molecular and cellular regulators of osteoclast formation and bone resorptive activity, a better understanding of which may lead to pharmacological treatments for periprosthetic osteolysis. We describe the development of imaging techniques for the detection and measurement of osteolysis around THR prostheses, which enable improved clinical management of patients, provide a means of evaluating outcomes of non-surgical treatments for periprosthetic osteolysis, and assist in pre-operative planning for revision surgery. Finally, there have been advances in the materials used for bearing surfaces to minimise wear, and we review the literature regarding the performance of these new materials to date.

Piriformis muscle rupture during total hip arthroplasty using a muscle-preserving posterior approach.

Total hip arthroplasty via muscle-sparing approaches is advocated and performed with increasing frequency. However, performing total hip arthroplasty through muscle-sparing approaches may require a more forceful retraction, which in turn may damage the muscles which the less invasive approach intended to preserve. We report on the rupture of the piriformis muscle during primary total hip replacement performed through a posterior approach intended to preserve this muscle. The prevalence and effects of such iatrogenic injuries are currently unknown, although unrecognised muscle damage may be a potential reason why early postoperative gait analyses could not demonstrate the expected benefits of less invasive surgery. Surgeons should be aware of this potential complication when performing total hip arthroplasty through a less invasive posterior approach.

Impaction bone grafting of segmental bone defects in femoral non-unions.

Impaction bone grafting shows encouraging early results as a method of immediately restoring leg length, while allowing weight-bearing as tolerated, in the treatment of large segmental femoral defects after femoral shaft and metaphyseal non-unions. The operative technique followed is described in three consecutive cases and the effectiveness of impaction bone grafting for femoral non-unions with associated large segmental bone defects has been demonstrated. Between 80 and 120 cm3 of coarsely milled irradiated bone allograft was used to reconstruct the defects, which were contained in malleable metal mesh. All three patients were fully weight-bearing by three months postoperatively. At two years follow-up, plain radiographs demonstrated maintenance of reduction and healing in all three cases.

Femoral bone is preserved using cemented polished stems in young patients.

BACKGROUND: Techniques that ensure femoral bone preservation after primary THA are important in younger patients who are likely to undergo revision surgery. QUESTIONS/PURPOSES: We examined femoral stem survival, bone deficiency at revision arthroplasty, and radiographic bone loss in hips implanted with a cemented polished double-taper stem in a cohort of patients younger than 55 years. METHODS: We reviewed 197 hips (median patient age, 47 years; range, 16-54 years) after a minimum followup of 2 years (median, 7 years; range, 2-19 years) since primary THA. Clinically, we determined survival to major and minor stem revision and cases of bone deficiency requiring a long stem or impaction bone grafting or created by the need for femoral osteotomy at revision arthroplasty. Radiographically, we assessed stem loosening, femoral osteolysis, and femoral bone deficiency. RESULTS: Stem survival to major revision for aseptic loosening was 100% at 13 years and for any reason was 97% (95% CI, 93-100%). At revision of seven stems, a long stem was used in one hip, a total femoral replacement in one hip and impaction bone grafting in one hip. No femoral osteotomies were required. Bone was preserved in four hips by cement-within-cement stem exchange. No stems were radiographically loose. Proximal osteolysis was present in 11% of femurs. Femoral bone deficiency was graded as Paprosky Type I (97%) or II (3%) and Endo-Klinik Grade 0 (79%) or I (21%). CONCLUSIONS: Cemented polished taper stems have high survival at 13 years in young patients and enable femoral bone preservation for subsequent revision. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Does bone wax induce a chronic inflammatory articular reaction?

BACKGROUND: Bone wax is used to control femoral neck bleeding during open femoroacetabular impingement (FAI) surgery. Despite its widespread use, only a few case reports and small case series describe side effects after extraarticular use. It is unclear whether intraarticular use of bone wax leads to such complications. However, during revision FAI surgery, we have observed various degrees of articular inflammatory reactions. QUESTIONS/PURPOSES: We therefore investigated whether the bone wax used intraarticularly to control femoral neck bleeding during FAI surgery could be associated with the inflammatory reactions observed at revision surgery. METHODS: We visually inspected the area and analyzed biopsy specimens from all 14 patients undergoing revision surgery from March 2005 to March 2006, 11 of whom had bone wax used at the time of original surgery. The three patients who did not have bone wax were used as controls. RESULTS: Bone wax was identified macroscopically on the femoral neck at the time of the revision surgery in all 11 patients. In all 11 patients, biopsy results indicated a foreign body-type chronic synovial inflammation. Five patients also had an associated synovial lymphoplasmacytic inflammatory reaction. No inflammatory reaction was observed in the biopsy specimens obtained from the three patients in whom bone wax was not originally used. CONCLUSIONS: Our findings suggest a synovial foreign body reaction, with or without an associated lymphoplasmacytic chronic inflammatory reaction, may be associated with intraarticular use of bone wax.

The effect of hip position on the length of trochanteric muscles: potential implications for early postoperative management of hip arthroplasty.

We investigated the effect several lower limb positions have on muscles that are detached to perform hip arthroplasty through posterior and lateral approaches. We used string models and computer navigation to measure the length changes in these muscles throughout hip movements in the anatomical planes and while simulating several sitting and lying postures. Piriformis and the obturators were shortened by sitting and lying postures when the femur was externally rotated and abducted; the clinical implication being that such postures have the potential to best protect their repair after a posterior approach. The anterior part of gluteus medius was lengthened with femoral external rotation. This lengthening was prevented, and therefore, theoretically, the gluteus medius repair protected after a lateral approach, by neutral or internal femoral rotation.

Imaging periprosthetic osteolysis around total knee arthroplasties using a human cadaver model.

We examined the sensitivity and accuracy of measuring osteolysis around total knee arthroplasty (TKA) on radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) in a cadaver model. Fifty-four simulated osteolytic defects ranging from 0.7 to 14 cm(3) were created in 6 cadaver knees implanted with either a cemented or an uncemented TKA. Three blinded investigators assessed the presence, location, and volume of defects on radiographs and CT and MRI scans with metal reduction protocols. Both CT and MRI had significantly higher sensitivities and specificities than did plain radiographs (P < .005). Overall, there was no difference in the accuracy of defect volume measurements between CT and MRI (P = .574). This study demonstrates the limitations of radiographs and the high sensitivity and specificity of both CT and MRI in assessing osteolysis around TKA.

Mentoring in complex surgery: minimising the learning curve complications from peri-acetabular osteotomy.

PURPOSE: The aim of this study was to determine whether a complex surgical procedure such as peri-acetabular osteotomy could be safely learnt by using a programme involving mentoring by a distant expert. To determine this, we examined the incidence of intra-operative complications, the acetabulum correction achieved, the late incidence of re-operation and progressive degenerative arthritis. METHODS: Between 1992 and 2004, peri-acetabular osteotomy was performed in 26 hips in 23 patients. The median follow-up was ten (5-17) years. The median age of the patients at operation was 28 (14-41) years. Clinical outcomes were reported and radiographic results were determined by an independent expert. RESULTS: There were no intra-articular osteotomies, sciatic nerve injuries, hingeing deformities or vascular injuries. There was one ischial nonunion. The lateral centre-edge angle improved from a median 4° pre-operatively to 25°. One revision osteotomy, one osteectomy and three total hip replacements were required, two for progression of osteoarthritis. CONCLUSIONS: The programme of mentoring was successful in that there was a low incidence of the major intra-operative complications that are often reported during the learning curve period and the acetabular corrections achieved were similar to the originators.

A preclinical study of stem subsidence and graft incorporation after femoral impaction grafting using porous hydroxyapatite as a bone graft extender.

This preclinical in vivo screening study compared bone graft incorporation and stem subsidence in cemented hemiarthroplasty after femoral impaction bone grafting with either morselized allograft bone (n = 5, control group) or a 1:1 mix of allograft and porous hydroxyapatite ceramics (HA) granules (n = 5, HA group). At 14 weeks, there was excellent bone graft incorporation by bone, and the stems were well fixed in both groups. The median subsidence at the cement-bone interface, measured using radiostereometric analysis, was 0.14 and 0.93 mm in the control and HA groups, respectively. The comparable histologic results between groups and good stem fixation in this study support the conduct of a larger scale investigation of the use of porous HA in femoral impaction bone grafting at revision hip arthroplasty.

The variation in hip stability measurements between supine and standing radiographs of dysplastic hips.

AIMS: The aims of this study were to compare clinically relevant measurements of hip dysplasia on radiographs taken in the supine and standing position, and to compare Hip2Norm software and Picture Archiving and Communication System (PACS)-derived digital radiological measurements. METHODS: Preoperative supine and standing radiographs of 36 consecutive patients (43 hips) who underwent periacetabular osteotomy surgery were retrospectively analyzed from a single-centre, two-surgeon cohort. Anterior coverage (AC), posterior coverage (PC), lateral centre-edge angle (LCEA), acetabular inclination (AI), sharp angle (SA), pelvic tilt (PT), retroversion index (RI), femoroepiphyseal acetabular roof (FEAR) index, femoroepiphyseal horizontal angle (FEHA), leg length discrepancy (LLD), and pelvic obliquity (PO) were analyzed using both Hip2Norm software and PACS-derived measurements where applicable. RESULTS: Analysis of supine and standing radiographs resulted in significant variation for measurements of PT (p < 0.001) and AC (p = 0.005). The variation in PT correlated with the variation in AC in a limited number of patients (R2 = 0.378; p = 0.012). CONCLUSION: The significant variation in PT and AC between supine and standing radiographs suggests that it may benefit surgeons to have both radiographs when planning surgical correction of hip dysplasia. We also recommend using PACS-derived measurements of AI and SA due to the poor interobserver error on Hip2Norm. Cite this article: Bone Joint J 2021;103-B(11):1662-1668.