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

BACKGROUND: Chronic 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. METHODS: Patients 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. RESULTS: Among 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. CONCLUSIONS: To 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 EVIDENCE: Level III, Retrospective Comparative Study.

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

BACKGROUND: Severe 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. METHODS: We 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. RESULTS: A 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. CONCLUSIONS: For 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 EVIDENCE: Level III, retrospective comparative study.

Management of Severe Acetabular Bone Loss With Chronic Pelvic Discontinuity in Revision Total Hip Arthroplasty.

Acetabular bone loss continues to be a challenging clinical problem faced by the revision total hip arthroplasty surgeons. The presence of a chronic pelvic discontinuity further complicates this clinical entity. Several surgical techniques have been described for the management of severe acetabular bone loss with an associated chronic pelvic discontinuity, with increasing enthusiasm for noncemented reconstruction. The focus is on noncemented reconstruction of Paprosky type IIIB acetabular defects with a chronic pelvic discontinuity.

Acetabular Distraction Technique for Severe Acetabular Bone Loss and Chronic Pelvic Discontinuity: An Advanced Course.

Acetabular bone loss, and specifically when it is associated with a chronic pelvic discontinuity, presents a difficult clinical challenge at the time of revision total hip arthroplasty. Most centers have advocated the use of noncemented constructs in an effort to achieve biologic fixation. The authors prefer noncemented fixation with use of the acetabular distraction technique in conjunction with modular porous metal augments for the treatment of severe acetabular bone loss and an associated chronic pelvic discontinuity.

Outcomes of Isolated Head and Liner Exchange Using Large Femoral Heads and Modern Liners in Revision Total Hip Arthroplasty.

BACKGROUND: Previous reports on the outcomes of isolated head and liner exchange in revision total hip arthroplasty have found high rates of instability after these surgeries. Most reports have studied constructs using ≤28 mm femoral heads. The purpose of this study was to determine if modern techniques with the use of larger head sizes can improve the rate of instability after head and liner exchange. METHODS: We identified 138 hips in 132 patients who underwent isolated head and liner exchange for polyethylene wear/osteolysis (57%), acute infection (27%), metallosis (13%), or other (2%). All patients underwent revision with either 32 (23%), 36 (62%), or 40 (15%) mm diameter heads. Cross-linked polyethylene was used in all revisions. Lipped and/or offset liners were used in 104 (75%) hips. Average follow-up was 3.5 (1.0-9.1) years. Statistical analyses were performed with significance set at P < .05. RESULTS: Revision-free survivorship for any cause was 94.6% and for aseptic causes was 98.2% at 5 years. 11 (8%) hips experienced a complication with 7 (5%) hips requiring additional revision surgery. After revision, 4 (3%) hips experienced dislocation, 5 (4%) hips experienced infection, and 1 (1%) hip was revised for trunnionosis. No demographic or surgical factors significantly affected outcomes. CONCLUSION: Our study shows that isolated head and liner exchange using large femoral heads and modern liners provides for better stability than previous reports. The most common complication was infection. We did not identify specific patient, surgical, or implant factors that reduced the risk of instability or other complication.

Adverse Local Tissue Reaction due to Mechanically Assisted Crevice Corrosion Presenting as Late Instability Following Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: Mechanically assisted crevice corrosion (MACC) at modular junctions can cause a spectrum of adverse local tissue reactions (ALTRs) in patients who have undergone total hip arthroplasty (THA). The purpose of this study is to describe the presentation, treatments, and related complications of a cohort of patients presenting with late instability following metal-on-polyethylene THA due to underlying MACC and ALTR. METHODS: This multicenter retrospective case series presents 17 patients (12 women, mean age 62.6, range 42-73) presenting with late instability secondary to ALTR and MACC. All patients had a metal (Cobalt Chrome)-on-polyethylene bearing surface. Patients experienced a mean 2.7 dislocations (range 1-6) at mean 4.3 years (range 0.4-17.0) following their index surgery. Serum metal levels (n = 12) demonstrated a greater elevation of cobalt (mean 6.9, range 0.13-20.88 ng/mL) than chromium (mean 1.9, range 0.13-3.23 ng/mL). RESULTS: Patients were revised for instability at a mean of 6.8 years (range 2.1-19.4) following their index surgery. ALTR was encountered in every case and the modular head-neck junction demonstrated visible corrosion. An exchange of the CoCr head to a ceramic head with a titanium sleeve and placement of a constrained liner was performed for a majority of patients (n = 15, 88.2%). Five patients (29.4%) had complications postoperatively including peroneal palsy (n = 2), periprosthetic joint infection (n = 2), and ALTR recurrence (n = 1). CONCLUSION: Recurrent instability in the setting of otherwise well-positioned THA components and without another obvious cause should raise concern for ALTR as a potential underlying etiology.

Painful Hip Arthroplasty: What Should We Find? Diagnostic Approach and Results.

INTRODUCTION: Identifying the source of pain is paramount for determining appropriate treatment and ensuring successful outcome in terms of management and relief of pain. The difficulty is that each surgeon has his or her own way of seeing the problem, and there is no consensus for the evaluation of these patients. The study hypothesis was that it is possible to find the cause of the pain in most cases. PATIENTS AND METHODS: All patients consulting for unexplained painful hip arthroplasty were included and followed a decision tree to assess the cause of the pain. The primary endpoint was the final diagnosis. Secondary endpoints were subgroup comparison between main causes and assessment of risk factors. RESULTS: Two hundred one hips of 194 patients were included as unexplained painful hip arthroplasty 6 months postoperatively. Final diagnoses comprised periarticular pain in 53 cases (26.4%): 40 cases of trochanteric bursitis, 5 of iliopsoas tendinitis, 5 of abductor deficiency, 1 of ischial tuberosity tendinitis, and 2 of heterotopic ossification; projected pain in 49 (24.4%): 45 cases of back pain with or without neuropathy, 3 of knee osteoarthritis, and 1 of metabolic neuropathy; wear in 40 (19.9%), in the polyethylene liner; loosening in 20 (10.0%): loosening of the femoral component in 8 and that of the cup in 12; material problems in 17 (8.5%): trunnionosis in 13 and metallosis in metal-on-metal implants in 4; no diagnosis in 7 hips (3.5%); infection in 6 (3.0%), all chronic; instability without real dislocation in 3 (1.5%); misplacement in 3 (1.5%), all for leg-length discrepancy; fracture in 2 (1.0%): 1 of greater trochanter and 1 of ilio-ischiopubic ramus; complex regional pain syndrome in 1 (0.5%). DISCUSSION: To our knowledge, this is the first study on the causes of painful hip arthroplasty in clinical practice, whether leading to revision or not. A systematic approach, including physical examination, radiographic assessment and laboratory studies, is needed to find the cause of the pain. It is important to understand the pain so that it can be treated appropriately. Revision surgery can sometimes help-but the worst thing is to make the patient worse. LEVEL OF EVIDENCE: level 4, retrospective study.

Management of Acetabular Bone Loss in Revision Total Hip Arthroplasty.

Revision total hip arthroplasty in patients with acetabular bone loss is a challenge and should only be performed by experienced surgeons. Correct classification of the acetabular bone loss pattern allows for the formulation and execution of a detailed treatment plan. However, reclassification of the bone loss pattern is essential if additional bone loss is discovered intraoperatively so that the patient is appropriately treated. Modular, uncemented, porous metal augments and a jumbo acetabular cup should be used to treat patients with severe acetabular bone loss (Paprosky type IIIA and type IIIB acetabular defects).

Management of Chronic Pelvic Discontinuity in Revision Total Hip Arthroplasty.

Acetabular bone loss is commonly encountered in patients who undergo revision total hip arthroplasty. Severe bony defects may be associated with chronic pelvic discontinuity, which makes acetabular reconstruction considerably more difficult. Surgeons must understand the current treatment options for patients with severe acetabular bone loss and chronic pelvic discontinuity. Surgeons also should understand how to perform acetabular distraction with the use of a porous acetabular shell and porous, modular metal augments.

High Rate of Failure After Revision of a Constrained Liner.

BACKGROUND: The purpose of this study was to examine the outcomes of repeat revision after failure of a constrained liner. METHODS: We reviewed 1212 consecutive revisions and identified 74 (6%) revisions of a failed constrained liner in 46 patients with a mean age of 65 years. The most common reasons for revision of a constrained liner were recurrent instability (64.9%) and infection (25.7%). RESULTS: At a mean of 35 months, 42 of the 74 hips (57%) required repeat revision. Kaplan-Meier revision-free survival was 24% at 10 years. Thirty-two of the 74 revisions (43%) had a dislocation event after the index revision. Kaplan-Meier dislocation-free survival was 43% at 10 years. There was a higher failure rate among the 34 patients with abductor deficiency (hazard ratio 1.90, 95% confidence interval, 1.06-3.43; P = .032). CONCLUSION: Patients undergoing revision of a failed constrained liner have a high likelihood of recurrent dislocation and repeat revision surgery. LEVEL OF EVIDENCE: Level IV.

Do Porous Tantalum Metaphyseal Cones Improve Outcomes in Revision Total Knee Arthroplasty?

BACKGROUND: Some authors have advocated for use of porous tantalum metaphyseal cones to manage bone defects during revision total knee arthroplasty (TKA). The purpose of this study is to compare results with porous metaphyseal cones to results with traditional hybrid stem fixation in revision TKA. METHODS: Forty-nine patients undergoing revision TKA with femoral and/or tibial metaphyseal cones (39 tibial only, 3 femoral only, 7 both) were matched by surgical indication to 49 patients undergoing revision TKA with a traditional hybrid stem (non-cone) technique. Clinical and radiographic outcomes were compared at a minimum of two-year follow-up (mean 3.5 years) with adjustment for baseline characteristics. RESULTS: Pre-revision bone defects and most baseline demographics were similar between the cone and non-cone cohorts suggesting appropriate matching. Patients in the non-cone cohort had greater pre- to post-operative increases in Knee Society Score (37.2 ± 18.6 vs 28.4 ± 17.8, P = .010) and Knee Society Functional Score (30.4 ± 24.3 vs 13.1 ± 27.6, P = .003). The cohorts did not differ with respect to complications, subsequent reoperation, subsequent revision, patient satisfaction, tibial overhang, the presence of radio-sclerotic lines, cortical hypertrophy around the stems, or tibial subsidence. CONCLUSION: In this series, metaphyseal cones were not associated with superior outcomes at short-term follow-up. Given the increased cost associated with use of cones compared to traditional techniques, this study cannot support the routine use of metaphyseal cones in revision TKA. Longer-term follow-up will be necessary to determine if construct durability differs over the long term.

Prevention and Diagnosis of Periprosthetic Knee Infection.

Total knee arthroplasty (TKA) has become an increasingly common treatment option for patients who have debilitating knee arthritis. TKA is a relatively safe and efficient procedure that results in promising outcomes and has a positive effect on a patient's quality of life. More TKAs are being performed annually because the procedure substantially reduces pain and improves functionality; however, as the number of TKAs continues to rise, there is concern for potential complications that may result in prosthetic joint failure. Primary TKA failure may result in revision procedures that have high costs and an increased risk for additional complications. Infection is the second most common cause of primary TKA failure and the single most common cause of revision TKA failure. Surgeons who have a better understanding of the epidemiology, risk factors, and diagnostic modalities associated with periprosthetic knee infection will be able to implement preventive measures and treat patients in whom such a complication occurs.

Single-Stage Revision Total Knee Arthroplasty in the Setting of Periprosthetic Knee Infection: Indications, Contraindications, and Postoperative Outcomes.

Single-stage revision total knee arthroplasty has become an increasingly common treatment option for patients with failed knee prostheses. Periprosthetic knee infection is the leading and most devastating cause of revision total knee arthroplasty. Although periprosthetic knee infection has been extensively studied in the orthopaedic literature, the role of single-stage revision total knee arthroplasty for the treatment of periprosthetic knee infection warrants further research. As healthcare reform shifts from a volume-based to a value-based system, it is imperative that orthopaedic surgeons understand the procedural indications, risks, and benefits of single-stage revision total knee arthroplasty.

Two-Stage Revision Total Knee Arthroplasty in the Setting of Periprosthetic Knee Infection.

Two-stage revision total knee arthroplasty (TKA) is the standard of care for patients who require a revision procedure for the mangement of a late or chronic periprosthetic knee infection. A careful examination of two-stage revision TKA is warranted as the number of patients who require revision TKA in the United States continues to rise. Surgeons should understand the intricacies involved in two-stage revision TKA, including the indications, procedural variations, and current deliberations on two-stage revision TKA in the literature. Surgeons also should understand the alternative treatments for periprosthetic knee infections.

Quantifying Pelvic Motion During Total Hip Arthroplasty Using a New Surgical Navigation Device.

BACKGROUND: Accurate cup positioning is one of the most challenging aspects of total hip arthroplasty (THA). Undetected movement of the patient during THA surgery can lead to inaccuracies in cup anteversion and inclination, increasing the potential for dislocation and revision surgery. Investigations into the magnitude of patient motion during THA are not well represented in the literature. METHODS: We analyzed intraoperative pelvic motion using a novel navigation device used to assist surgeons with cup position, leg length, and offset during THA. This device uses an integrated accelerometer to measure motion in 2 orthogonal degrees of freedom. We reviewed the data from 99 cases completed between February and September 2016. RESULTS: The mean amount of pitch recorded per patient was 2.7° (standard deviation, 2.2; range, 0.1°-9.9°), whereas mean roll per patient was 7.3° (standard deviation, 5.5; range, 0.3°-31.3°). Twenty-one percent (21 of 99) of patients demonstrated pitch of >4°. Sixty-nine percent (68 of 99) of patients demonstrated >4° of roll, and 25% (25 of 99) of patients demonstrated roll of ≥10°. CONCLUSION: Our findings indicate that while the majority of intraoperative motion is <4°, many patients experience significant roll, with a large proportion rolling >10°. This degree of movement has implications for acetabular cup position, as failure to compensate for this motion can result in placement of the cup outside the planned safe zone, thus, increasing the potential for dislocation. Further study is warranted to determine the effect of this motion on cup position, leg length, and offset.

Are Revision Hip Arthroplasty Patients at Higher Risk for Venous Thromboembolic Events Than Primary Hip Arthroplasty Patients?

BACKGROUND: The purpose of this study is to determine whether revision total hip arthroplasty (THA) is associated with increased rates of deep vein thrombosis (DVT) and pulmonary embolism (PE) when compared to primary THA. METHODS: We queried the American College of Surgeons National Surgical Quality Improvement Program database for all primary and revision THA cases from 2011 to 2014. Demographic data, medical comorbidities, and venous thromboembolic rates within 30 days of surgery were compared between the primary and revision THA groups. RESULTS: Revision THA had a higher rate of DVT than the primary THA (0.6% vs 0.4%, P = .016), but there was no difference in the rate of PE (0.3% vs 0.2%, P = .116). When controlling for confounding variables, revision surgery alone was not a risk factor for DVT (odds ratio 0.833, 95% confidence interval 0.564-1.232) or PE (odds ratio 1.009, 95% confidence interval 0.630-1.616). Independent risk factors for DVT include age >70 years, malnutrition, infection, operating time >3 hours, general anesthesia, American Society of Anesthesiologists classification 4 or greater, and kidney disease (all P < .05). Probability of DVT ranged from 0.2% with zero risk factors to 10% with all risk factors. Independent risk factors for PE included age >70 years, African American ethnicity, and operating time >3 hours (all P < .05) with probabilities of PE postoperatively ranging from 0.2% to 1.1% with all risk factors. CONCLUSION: Revision surgery alone is not a risk factor for venous thromboembolism after hip arthroplasty. Surgeons should weigh the risks and benefits of more aggressive anticoagulation in certain high-risk patients.

The Use of Structural Distal Femoral Allograft for Acetabular Reconstruction of Paprosky Type IIIA Defects at a Mean 21 Years of Follow-Up.

BACKGROUND: Revision total hip arthroplasty in patients with a nonsupportive superior acetabulum often requires secondary augmentation beyond a hemispherical cup to achieve reliable fixation. Treatment options include using a higher hip center, jumbo cup, custom triflange implant, cages, or filling the superior defect with a bilobed implant, structural allograft, or metal augments. We previously reported a cohort of 31 patients treated with porous-coated hemispherical cups and distal femoral allograft for Paprosky type IIIA acetabular defects. METHODS: The original cohort of 31 hips was retrospectively reviewed. Fourteen patients died with <15 years of follow-up, and 2 were lost to follow-up. This left 15 patients for evaluation including 5 males and 10 females, with an average age of 61 years (range: 37-74 years) at the time of surgery. Acetabular revision was performed with the use of a porous-coated hemispherical cup along with structural distal femoral allograft, cut to resemble the number 7, and secured with 6.5-mm cancellous screws with washers. RESULTS: Overall, 7 hips failed, resulting in a Kaplan-Meier survivorship of 72% at 25 years of follow-up. In surviving patients, radiographs demonstrated components to be well fixed, and average Merle d'Aubigné score increased from 5 to 10 points. There were a subset of patients that failed early (median: 6.2 years), but the remaining patients demonstrated excellent clinical and radiographic results. CONCLUSIONS: The use of distal femoral allograft can be considered in young patients with type IIIA acetabular defects that could benefit from restoration of bone stock.

Dual-Mobility Articulations for Patients at High Risk for Dislocation.

BACKGROUND: The purpose of this study was to evaluate the performance of dual-mobility articulations in patients at high risk for dislocation after revision total hip arthroplasty. METHODS: We reviewed the results of 36 consecutive revision total hip arthroplasties performed on patients considered high risk for instability. Indications for inclusion included abductor insufficiency, recurrent instability, failure of constrained liner, or inadequate intraoperative stability when trialing. RESULTS: At a minimum of 2 years, there were 4 (11.1%) repeat revisions including both dual-mobility liners that were cemented into an acetabular shell and 2 for deep infection treated with a 2-stage exchange. There was one dislocation that was successfully closed reduced but no revisions for recurrent instability. The mean Harris hip score improved from 45 to 90 points (P < .001). CONCLUSION: Dual-mobility articulations are associated with a low rate of failure with no revisions for instability in this challenging group of patients.

Diagnosis and Management of Adverse Local Tissue Reactions Secondary to Corrosion at the Head-Neck Junction in Patients With Metal on Polyethylene Bearings.

We reviewed 27 patients who underwent revision for an adverse local tissue reaction (ALTR) secondary to corrosion at the head-neck junction with MoP bearings. Serum cobalt and chromium levels were elevated in all cases, with a mean cobalt of 11.2 ppb and chromium of 2.2 ppb. Patients underwent modular bearing exchange, including a ceramic head with a titanium sleeve in 23 of 27 cases with only one recurrence of ALTR in one of the four patients not treated with a ceramic head. The diagnosis of ALTR secondary to corrosion is associated with cobalt levels of >1 ppb with cobalt levels elevated above chromium. Retention of a well-fixed stem and modular exchange to a ceramic head leads to resolution of symptoms and decreases in metal levels.