Periarticular Injection and Peripheral Nerve Blocks With Standard Agents.

The block of sensory nerves in the ipsilateral limb or locally is an integral part of the multimodal pain management protocol after primary total knee arthroplasty. The 2022 clinical practice guidelines published by the American Association of Hip and Knee Surgeons, the American Society of Regional Anesthesia and Pain Medicine, and the American Academy of Orthopaedic Surgeons describe various strengths of recommendations concerning the use of nerve blocks and periarticular injection. There is also experimental and clinical evidence to support a technique for the surgeon to perform both the periarticular injection and an intra-articular saphenous nerve block. High-dose bupivacaine injection has been shown to be effective and safe. The value of adductor canal block is currently uncertain. Future studies are needed concerning longer-lasting local anesthetic agents and techniques.

Surgical Treatment of Severe Heterotopic Ossification After Total Hip Arthroplasty Over the Last 25 Years: A Systematic Review of the Literature and a New Case Series.

BACKGROUND: Severe heterotopic ossification (HO) (grades III and IV) after total hip arthroplasty (THA) over the last 25 years requiring excision is very uncommon. We performed a systematic review of the literature and reported a new case series with operative treatment after primary uncemented THA. METHODS: A systematic review identified papers describing patients who had excision of HO after THA performed after 1988. Concepts of hip arthroplasty, HO, and surgical excision were searched in MEDLINE, Embase, and Scopus from database inception to November 2022. The inclusion criteria were articles that included specific patient data on the grade of HO, operative procedure, and prophylaxis. Studies were screened for inclusion by 2 independent reviewers. The extracted data included demographic data, the interval from index surgery to excision, clinical results, and complications. There was one surgeon who performed reoperation for ankylosis of primary THA in 3 men who had severe pain and hip deformity. RESULTS: Data from 7 studies were included. There were 41 patients who had grade III or IV HO who had excision, and in 5 patients, revision of a component was also performed. Perioperative prophylaxis was irradiation alone in 10 patients, irradiation and indomethacin in 10 patients, and indomethacin alone in 21 patients. At a mean follow-up time of 14.8 months, the definition of the results was not uniform, and range of motion was improved, but relief of pain was inconsistent. There was one dislocation after resection without revision, one gastrointestinal complication, and 2 recurrences. Treatment of the 3 new patients, with wide excision of periarticular bone, selective exchange of components, and perioperative irradiation prophylaxis, was successful in improving pain, motion, and deformity. CONCLUSIONS: There is insufficient good-quality data on the operative treatment of severe symptomatic HO after THA performed over the last 25 years. Prophylaxis with low-dose irradiation prevented a recurrence. Multicenter studies are needed to determine the optimum timing and prognosis for treatment.

Intraosseous Vancomycin May Not Be Helpful in Aseptic Revision Knee Arthroplasty: A Single-Surgeon Consecutive Case Series.

BACKGROUND: Infection after aseptic revision total knee arthroplasty (TKA) has been reported from 9% to 14%. Intraosseous (IO) vancomycin infusion has decreased the risk of infection after primary TKA. The results of this additional prophylaxis were evaluated in aseptic revision TKA. METHODS: In this prospective, single-surgeon study of 20 consecutive patients having aseptic revision TKA, 500 milligrams of vancomycin in 120 mL of saline were infused into the tibia prior to incision, in addition to intravenous (IV) cefazolin. There were 18 men and 2 women who had a mean age of 67 years (range, 47-79), and mean body mass index of 34.4 (range, 25.9-51.2). The knees were aspirated in the operating room prior to IV and IO antibiotics. The outcomes were infections at 90 days requiring reoperation and complications from the infusion. RESULTS: Three of the 20 aseptic revisions had early prosthetic joint infection, 2 with gram-negative organisms and one with coagulase-negative Staphylococcus. All had debridement, liner exchange and IV antibiotic treatment, but 1 patient eventually had an above knee amputation. No patient had total body "erythema syndrome", but 1 patient had transient facial flushing. Six patients had a transient elevation of serum creatinine including 3 with an abnormal preoperative serum creatinine. CONCLUSION: In this small series of aseptic revision TKA, there was no added benefit of IO vancomycin infusion, but there were no infections with methicillin-resistant Staphylococcus aureus. Additional studies are needed before this technique should be routinely recommended.

Early Infection After Aseptic Revision Knee Arthroplasty: Prevalence and Predisposing Risk Factors.

BACKGROUND: Although patient factors have been associated with prosthetic joint infection (PJI) after primary total knee arthroplasty, there are insufficient data on the relationship of patient and technical factors with early PJI after aseptic revision. METHODS: This is a retrospective study of 157 aseptic revisions performed by 2 surgeons at 1 academic center. A negative intraoperative culture during revision surgery was required for inclusion. Mean follow-up time was 3.8 years (standard deviation 2.8). PJI was defined by positive aspiration or draining wound, and an additional operation within 1 year of aseptic revision. Patient demographics, medical comorbidities, and technical factors were reviewed. Data points were evaluated with univariate and adjusted multivariate regression analyses. RESULTS: The prevalence of PJI after aseptic revision was 9% (14/157). The most common organism was Staphylococcus aureus. Initial treatment included debridement and liner exchange (11) and antibiotic spacer (3). Two patients ultimately had an above-knee amputation. Univariate analysis showed a significant difference in preoperative anemia (P < .01), transfusion (P < .01), and diabetes (P = .05) between cohorts. There was no association among the length of surgery, use of a metaphyseal cone, or the number of components revised and PJI. Adjusted logistic regression demonstrated that preoperative anemia (P < .01) was a significant risk factor for PJI. CONCLUSION: The prevalence of early PJI was similar to other studies in the literature. Anemia was an independent predictor of PJI, while technical factors did not have an association. Medical optimization of patients should be considered prior to revision surgery.

Current Trends in Revision Hip Arthroplasty: Indications and Types of Components Revised.

BACKGROUND: The materials and techniques for both primary and revision total hip arthroplasty (THA) have changed over time. This study evaluated if the indications for revision THA, rates of components utilized (femoral or acetabulum, both, or head/liner exchange), length of stay (LOS), and payments to surgeons and facilities have also changed. METHODS: A retrospective study, utilizing the PearlDiver database, of 38,377 revision THA patients from January 2010 through December 2018 was performed. Data included the indication for revision, components revised (femoral or acetabulum, both, or head/liner exchange), LOS, and payments. Indications and components were analyzed by logistic regression (Dunnett's post hoc test). Revision totals were analyzed with a linear regression model. Analysis of variance assessed changes in LOS and payments. RESULTS: Patients' median age was 67 years (Q1-Q3: 59-74), and 58.7% were female. Revisions for dislocation decreased between 2010 and 2018 (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.68-0.98). Revisions for component loosening increased (OR 1.54, 95% CI 1.25-1.91). Dislocation remained the most common indication (19.3%), followed by PJI (17.3%) and loosening (17.1%). Both-component (OR:1.45; 95% CI:1.25-1.67) and femoral component only revisions increased; acetabular component only and head/liner exchanges decreased. Acetabular (OR 0.57, 95% CI 0.47-0.70) and head/liner exchange (OR 0.29, 95% CI 0.20-0.43) revisions decreased, while both component exchange (OR 1.45, 95% CI 1.25-1.67) and femoral revisions (OR 1.17, 95% CI 0.99-1.37) increased. Average LOS (-0.68 days; P < .001) and surgeon payments decreased (-$261.8; P < .001) while facility payments increased ($4,211; P < .001). CONCLUSION: Indications for revision THA in this database study changed over time, with revision for dislocation decreasing and revision for loosening increasing over time. Both component and femoral revisions increased, and acetabular component and head/liner exchanges decreased. It is possible that these associations could be attributed to a number of details, the method of femoral fixation, surgical approach, and cementing, all of which require additional study.

Knee or Spine Surgery First? A Survey of Treatment Order for Patients With Concurrent Degenerative Knee and Lumbar Spinal Disorders.

BACKGROUND: Total knee arthroplasty (TKA) and lumbar spine surgery have been reported to affect the outcomes of each other. There is insufficient evidence to guide the choice of treatment order for patients with both disorders that are equally symptomatic. METHODS: Five clinical scenarios of concurrent, advanced, degenerative knee and lumbar spinal disorders were designed to survey surgeons' choices of treatment order and rationale. The spinal disorder was consistently degenerative lumbar spinal stenosis, but the knee conditions varied to include (1) osteoarthritis (OA) with varus deformity, (2) OA with valgus deformity, (3) rheumatoid arthritis with a severe flexion contracture, (4) OA without deformity, and (5) bilateral OA with windswept deformities. The survey was distributed to selected clinical members of the Knee Society and Scoliosis Research Society in North America. The surgeons' choices were compared among the 5 scenarios, and their comments were analyzed using text-mining. RESULTS: Responses were received from 42 of 74 (57%) knee arthroplasty surgeons and 55 of 100 (55%) spine surgeons. The percentages of knee arthroplasty surgeons recommending "TKA first" differed significantly among scenarios: 29%, 79%, 55%, 7%, and 81% for scenarios 1 through 5, respectively (P < .001). A similar pattern was noted for the spine surgeons. CONCLUSION: For patients with concurrent degenerative knee and lumbar spinal disorders, the severity and type of knee deformity influenced the preference of treatment order in both specialties. Severe valgus deformity and windswept deformities of the knee would drive the decision toward "TKA first."

Surgeon-Performed High-Dose Bupivacaine Periarticular Injection With Intra-Articular Saphenous Nerve Block Is Not Inferior to Adductor Canal Block in Total Knee Arthroplasty.

BACKGROUND: Periarticular injection or anesthesiologist-performed adductor canal block are commonly used for pain management after total knee arthroplasty. A surgeon-performed, intra-articular saphenous nerve block has been recently described. There is insufficient data comparing the efficacy and safety of these methods. METHODS: This is a retrospective two-surgeon cohort study comparing short-term perioperative outcomes after primary total knee arthroplasty, in 50 consecutive patients with surgeon-performed high-dose periarticular injection and intra-articular saphenous nerve block (60 mL 0.5% bupivacaine, 30 mL saline, 30mg ketorolac) and 50 consecutive patients with anesthesiologist-performed adductor canal catheter (0.25% bupivacaine 6 mL/h infusion pump placed postoperatively with ultrasound guidance). Chart review assessed pain scores through POD #1, opioid use, length of stay, and short-term complications, including local anesthetic systemic toxicity. Statistical analysis was performed with two-tailed Student's T-test. RESULTS: The high-dose periarticular injection cohort had significantly lower pain scores in the postanesthesia care unit (mean difference 1.4, P = .035), on arrival to the inpatient ward (mean difference 1.7, P = .013), and required less IV narcotics on the day of surgery (mean difference 6.5 MME, P = .0004). There was no significant difference in pain scores on POD #1, total opioid use, day of discharge, or short-term complications. There were no adverse events related to the high dose of bupivacaine. CONCLUSION: Compared with postoperative adductor canal block catheter, an intraoperative high-dose periarticular block demonstrated lower pain scores and less IV narcotic use on the day of surgery. No difference was noted in pain scores on POD #1, time to discharge, or complications. There were no cardiovascular complications (local anesthetic systemic toxicity) despite the high dose of bupivacaine injected. LEVEL OF EVIDENCE: III.

HTX-011 Reduced Pain and Opioid Use After Primary Total Knee Arthroplasty: Results of a Randomized Phase 2b Trial.

BACKGROUND: HTX-011 is an extended-release, dual-acting local anesthetic consisting of bupivacaine and low-dose meloxicam in a novel polymer that is administered by needle-free application during surgery. The active ingredients are released from the polymer by controlled diffusion over 72 hours. METHODS: This phase 2b, double-blind, placebo-controlled and active-controlled trial enrolled patients undergoing primary unilateral total knee arthroplasty under general anesthesia. Two hundred thirty-two patients were randomized into 4 groups: HTX-011 400 mg bupivacaine/12 mg meloxicam, applied without a needle into the surgical site, the same dose of HTX-011 with a separate 50 mg ropivacaine injection into the posterior capsule, bupivacaine hydrochloride (HCl) 125 mg injection, and saline placebo injection. Only opioids were permitted for postoperative pain rescue. Primary and key secondary endpoints were mean area under the curve of pain intensity scores over 48 hours and 72 hours, respectively, for HTX-011 groups vs placebo. RESULTS: Both HTX-011 groups had significantly reduced mean pain intensity vs placebo through 48 and 72 hours (both P < .001). Ropivacaine added a small initial benefit in the first 12 hours. Both HTX-011 groups also had decreased mean pain intensity vs bupivacaine HCl alone through 48 and 72 hours (P < .05). The HTX-011 groups had significantly earlier discharge readiness along with lower opioid consumption through 72 hours. HTX-011 alone or with ropivacaine was well-tolerated with a safety profile similar to controls. CONCLUSION: Needle-free application of HTX-011 400 mg bupivacaine/12 mg meloxicam provided superior pain reduction through 72 hours after total knee arthroplasty compared with placebo and bupivacaine HCl alone.

Recurrent Dislocation After Total Hip Arthroplasty: Controversies and Solutions.

Instability remains one of the most common complications after total hip arthroplasty and a notable cause of patient morbidity as well as patient and surgeon dissatisfaction. Isolated dislocations can often be managed successfully with closed reduction; however, recurrent instability poses a substantial diagnostic and therapeutic challenge. The causes are varied and may be related to patient, surgical, and implant factors. A thorough evaluation is important in determining the cause of instability and effectively managing this difficult problem. Management options include component revision for malposition, modular exchange, or revision to specialized components, such as larger femoral heads, constrained liners, or dual-mobility articulations.

Changing Patterns of Anticoagulation After Total Hip Arthroplasty in the United States: Frequency of Deep Vein Thrombosis, Pulmonary Embolism, and Complications With Rivaroxaban and Warfarin.

BACKGROUND: This study evaluated the trends in anticoagulation use after total hip arthroplasty (THA), and the effectiveness and safety of rivaroxaban compared to warfarin. METHODS: This retrospective database analysis used healthcare claims from the Truven Health MarketScan database (2010-2015). Patients undergoing elective THA were followed for use of anticoagulants after surgery. Logistic regression models were used to compare differences in deep vein thrombosis (DVT), pulmonary embolism (PE), and adverse events, within 90 days after THA, among warfarin and rivaroxaban users. Inverse probability treatment weighting was used to account for selection bias. RESULTS: There were 12,876 users of warfarin and 10,892 users of rivaroxaban in commercially insured (CI) patients, and 7416 warfarin users and 4739 rivaroxaban users in Medicare supplement (MS) patients. Warfarin use decreased over time in both insurance cohorts, whereas rivaroxaban use increased from 2011 to 2015. Warfarin users were significantly more likely to experience both DVT (CI: odds ratio [OR] 2.63, 95% confidence interval 1.97-3.50; MS: OR 1.78, 95% confidence interval 1.38-2.29) and PE (CI: OR 2.60, 95% confidence interval 2.04-3.31; MS: OR 2.09, 95% confidence interval 1.66-2.65). There was no significant difference in rates of bleeding between the 2 agents, but warfarin users had higher odds of periprosthetic joint infection in both cohorts (CI: OR 1.57, 95% confidence interval 1.16-2.13; MS: OR 1.79, 95% confidence interval 1.14-2.81). CONCLUSION: There has been an increase in prophylaxis with rivaroxaban, and a decrease in warfarin use after elective THA over 4 years. Warfarin users were more likely to experience DVT and PE than rivaroxaban, and bleeding risks were similar.

Tantalum Components in Difficult Acetabular Revisions Have Good Survival at 5 to 10 Years: Longer Term Followup of a Previous Report.

BACKGROUND: The best method for acetabular revisions in patients with severe bone loss remains controversial; typical approaches include jumbo cups, cages, cup-cages, and custom components. Tantalum (TM) components have good results at midterm followup, but the longer term survival and complications are not available. We previously reported on a series of such reconstructions; here we provide additional followup on that group along with a larger study cohort. QUESTIONS/PURPOSES: (1) What is the survival at a minimum followup of 5 years of these components implanted in difficult revisions and what is the mechanism of failure? (2) What is the most common complication of these reconstructions, and what hip scores did these patients achieve? METHODS: Between 2001 and 2010, one surgeon performed 150 acetabular revisions, of which 74 (49%) were done using TM components. The general indication for use of these devices was the surgeon's perception that there was sufficient bone loss to place the reconstruction at a high risk of mechanical failure (generally Paprosky Type 3 or 4 or lower Paprosky type with < 50% host bone coverage or morbid obesity). No cages were used during this time. Fifteen patients died and 11 were lost or did not return, leaving 48 hips (46 patients) with a mean followup of 8 years (range, 5-14 years). Of these, 39 were reported on in our previous series, and nine are new in the present series; the overall group here has an additional median of 5 years followup (range, 3-7 years). Five hips had six augments placed to obtain stability. Patients were evaluated by the Harris hip score and standard radiographs; survivorship was estimated using the cumulative incidence competing risks survival analysis. The primary outcome was fixation and survival of the TM component and the secondary outcome was complications. RESULTS: Cumulative incidence competing risks estimate survival free from aseptic loosening was 92% at 10 years (95% confidence interval [CI], 0.81-0.98). Dislocation, the most common complication, occurred in seven of 48 (15%) patients, and five of 48 (10%) had a reoperation for it. Survival free from any reoperation was 84% at 10 years (95% CI, 0.72-0.92). The Harris hip score improved from a mean of 50 points (SD 17) before surgery to 85 points (SD 10; p < 0.001) at latest followup. CONCLUSIONS: Given the findings of this study, TM components appear to provide durable fixation at midterm followup in complex acetabular revisions. Steps to minimize dislocation, the most frequent complication of these revisions, may include the routine use of larger femoral heads. Future studies likely will need to be multisurgeon or multicenter and should evaluate different techniques and components for long-term fixation and the prevention of dislocation. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Saphenous Nerve Block From Within the Knee Is Feasible for TKA: MRI and Cadaveric Study.

BACKGROUND: Surgeon-performed periarticular injections and anesthesiologist-performed femoral nerve or adductor canal blocks with local anesthetic are in common use as part of multimodal pain management regimens for patients undergoing TKA. However, femoral nerve blocks risk causing quadriceps weakness and falls, and anesthesiologist-performed adductor canal blocks are costly in time and resources and may be unreliable. We investigated the feasibility of a surgeon-performed saphenous nerve ("adductor canal") block from within the knee at the time of TKA. QUESTIONS/PURPOSES: (1) Can the saphenous nerve consistently be identified distally on MRI studies, and is there a consistent relationship between the width of the femoral transepicondylar axis (TEA) and the proximal (cephalad) location where the saphenous nerve emerges from the adductor canal? With these MRI data, we asked the second question: (2) Can we utilize this anatomic relationship to simulate a surgeon-performed intraoperative block of the distal saphenous nerve from within the knee with injections of dyes after implantation of trial TKA components in cadaveric lower extremity specimens? METHODS: A retrospective analysis of 94 thigh-knee MRI studies was performed to determine the relationship between the width of the distal femur at the epicondylar axis and the proximal location of the saphenous nerve after its exit from the adductor canal and separation from the superficial femoral artery. These studies, obtained from one hospital's MRI library, had to depict the saphenous nerve in the distal thigh and the femoral epicondyles and excluded patients younger than 18 years of age or with metal implants. These studies were performed to evaluate thigh and knee trauma or unexplained pain, and 55 had some degree of osteoarthritis. After obtaining these data, TKA resections and trial component implantation were performed, using a medial parapatellar approach, in 11 fresh cadaveric lower extremity specimens. There were six male and five female limbs from cadavers with a mean age of 70 years (range, 57-80 years) and mean body mass index of 20 kg/m (range, 15-26 kg/m) without known knee arthritis. Using a blunt-tipped 1.5-cm needle, we injected 10 mL each of two different colored solutions from inside the knee at two different locations and, after 30 minutes, dissected the femoral and saphenous nerves and femoral artery from the hip to the knee. Our endpoints were whether the saphenous nerve was bathed in dye and if the dye or needle was located in the femoral artery or vein. RESULTS: Based on the MRI analysis, the mean ± SD TEA was 75 ± 4 mm in females and 87 ± 4 mm in males. The saphenous nerve exited the adductor canal and was located at a mean of 1.5 ± 0.16 times the TEA width in females and a mean of 1.3 ± 0.13 times the TEA width in males proximal to the medial epicondyle. After placement of TKA trial components and injection, the proximal injection site solution bathed the saphenous nerve in eight of 11 specimens. In two cachectic female cadaver limbs, the dye was located posteriorly to the nerve in hamstring muscle. The proximal blunt needle and colored solution were directly adjacent to but did not penetrate the femoral artery in only one specimen. CONCLUSIONS: This study indicates, based on MRI measurements, cadaveric injections, and dissections, that a surgeon-performed injection of the saphenous nerve from within the knee after it exits from the adductor canal seems to be a feasible procedure. CLINICAL RELEVANCE: This technique may be a useful alternative to an ultrasound-guided block. A trial comparing surgeon- and anesthesiologist-performed nerve block should be considered to determine the clinical efficacy of this procedure.

Large Metal Heads and Highly Cross-Linked Polyethylene Provide Low Wear and Complications at 5-13 Years.

BACKGROUND: Highly cross-linked polyethylene (XLPE) is reported to have low rates of linear and volumetric wear at 10-14 years. In a prior study, larger (36 and 40 mm) femoral heads were associated with more volumetric wear, but there were only 12 hips with these heads. METHODS: We evaluated 107 hips (93 patients, with a mean age of 76 years) with one design of uncemented acetabular component, a 36 (90 hips) or 40 mm (17 hips) metal femoral head, and one electron beam 100 kGy irradiated and remelted XLPE at a mean follow-up of 8 years (range 5-13 years). Selection of these femoral heads was based on several factors, including the perceived risk of dislocation, the outer diameter size of the acetabular component, and liner availability. Measurements of linear and volumetric wear were performed in one experienced laboratory by the Martell method and analyzed using the first-to-last method. Standard radiographs, with additional Judet views, were used to detect periprosthetic osteolysis. Clinical records were used to determine the complications of dislocation, liner fracture, and painful trunnion corrosion. RESULTS: For the entire cohort, the median linear wear rate was 0.041 mm/y (95% confidence interval, 0.031-0.057) and the median volumetric wear rate was 34.6 mm3/y (95% confidence interval, 31.4-53.5). With the numbers available, there was no difference in linear or volumetric wear between the 36 and 40 mm head sizes. Small, asymptomatic osteolytic lesions were noted in 3 hips (2%). There were 3 patients (3%) with dislocation (2 early and 1 late), but these have not had a revision. There were no revisions for loosening, no liner fracture, and no patient with symptomatic trunnion corrosion. CONCLUSION: This acetabular component and XLPE with large metal heads had low rates of linear and volumetric wear. Large metal femoral heads did not lead to liner fracture, loosening, or symptomatic trunnion corrosion in this patient population. However, we recommend longer clinical follow-up studies and caution in the routine use of larger metal femoral heads in other, younger patient populations.

Outcomes of Modular Dual Mobility Acetabular Components in Revision Total Hip Arthroplasty.

BACKGROUND: There is a high rate of dislocation after revision total hip arthroplasty. This study evaluated the outcomes of 1 modular dual mobility component in revision total hip arthroplasty in patients at high risk of dislocation. METHODS: We reviewed 64 revisions performed in 27 (42%) patients for recurrent dislocation, 16 (25%) for adverse local tissue reaction, 11 (17%) for reimplantation infection, and 10 (16%) for aseptic loosening, malposition, or fracture. Complications, reoperations, and survivorship were evaluated. RESULTS: Three-year survival was 98% with failure defined as aseptic loosening and 91% with failure as cup removal for any reason. With mean follow-up time of 38 months, there were 14 complications, including 2 dislocations treated with closed reduction, 9 infections, and 12 reoperations. All complications occurred in patients revised for instability, adverse local tissue reaction, or infection. CONCLUSION: The early results of this component are promising, with good overall survival and low rate of dislocation.

Is There a Benefit to Highly Crosslinked Polyethylene in Posterior-stabilized Total Knee Arthroplasty? A Randomized Trial.

BACKGROUND: Polyethylene wear and osteolysis remain a concern with the use of modular, fixed-bearing total knee arthroplasty (TKA). A variety of highly crosslinked polyethylenes (XLPs) have been introduced to address this problem, but there are few data on the results and complications of this polyethylene in posterior-stabilized knee prostheses. QUESTIONS/PURPOSES: In a randomized prospective study design comparing standard polyethylene (SP) tibial inserts with XLP inserts, we asked the following questions: (1) Are there any differences in the clinical results (as measured by the classic Knee Society scoring system) and radiographic results (as measured by an evaluation for radiolucencies and osteolysis) between these groups? (2) What is the frequency of reoperation in these two groups? (3) Are there any specific complications related to XLP liners? METHODS: These are preliminary data from a single surgeon of a planned interim analysis of a prospective randomized study of one modular posterior-stabilized TKA. One hundred ninety-two patients (236 knees) were randomized to receive a SP compression-molded liner or a XLP (6.5 CGy electron beam-irradiated and remelted) polyethylene liner. There was no difference in the number of knees who were lost or refused followup (14 knees [13%] with XLP and 21 knees [17%] with SP). Patients were evaluated clinically using the original Knee Society scores, Lower Extremity Activity Score (LEAS), presence of knee effusion, and by standard radiographs for radiolucent lines and osteolytic lesions. This analysis was performed at a mean followup of 4.5 years (range, 2-8 years). RESULTS: There were no clinical differences between 99 knees with SP and 94 knees with XLP in original Knee Society total score (SP mean 95, SD 5; XLP mean 94, SD 7 [p = 0.16]); change in total score (SP mean 41, 95% confidence interval [CI], 39-41; XLP mean 43, 95% CI, 39-48 [p = 0.56]); knee function score (SP mean 64 [SD 25]; XLP mean 64 [SD 24] p = 0.98; change in function score (SP mean 22, 95% CI, 17-27; XLP mean 21, 95% CI, 17-27 [p = 0.79]); LEAS score (both SP and XLP 9 [SD 2]; p = 0.88); and change in LEAS (both SP and XLP mean 1, 95% CI, 1-2 [p = 0.0.38]). There were no differences, with the numbers available, in the presence of effusion (two of 94 XLP and five of 99 SP) with 2 years minimum followup. There were no differences in the frequency of radiolucent lines (13 knees with SP and 15 with XLP) or of osteolysis (two knees with SP and none with XLP). There was no difference in frequency of reoperation between the two groups (three infections in 110 knees allocated to the XLP group and five (two infections, one femoral loosening, one instability, one fracture plating) in 122 knees allocated to the standard group. There were no complications related to the XLP liner. CONCLUSIONS: In this interim analysis, with the numbers available, there were no complications, but no advantages, related to the use of this XLP tibial liner. Additional enrollment has continued, and longer followup of these patients will be necessary to determine whether long-term wear characteristics differ between the groups. LEVEL OF EVIDENCE: Level I, therapeutic study.

Wear and Osteolysis of Highly Crosslinked Polyethylene at 10 to 14 Years: The Effect of Femoral Head Size.

BACKGROUND: Highly crosslinked polyethylene (XLPE) was introduced to decrease periprosthetic osteolysis related to polyethylene wear, a major reason for revision of total hip arthroplasty. However, there are few reports of wear and osteolysis at 10 years postoperatively. QUESTIONS/PURPOSES: (1) What are the linear and volumetric wear rates of XLPE at 10 to 14 years? (2) What is the relationship among linear wear, volumetric wear, and femoral head size? (3) What proportion of hips developed osteolysis and was there a relationship between osteolysis and femoral head size or polyethylene wear? METHODS: We evaluated a previously reported cohort of 84 hips (72 patients) with one design of an uncemented acetabular component and one electron beam 10-kGy irradiated and remelted XLPE at a mean followup of 11 years (range, 10-14 years). The choice of femoral head size was based on several factors, including the outer diameter size of the acetabular component implanted, the perceived risk of dislocation (including the history of alcohol abuse and patient age), and liner availability from the manufacturer. The femoral head sizes used were 26 mm in 10 hips (12%), 28 mm in 31 hips (37%), 32 mm in 31 hips (37%), 36 mm in eight hips (10%), and 40 mm in four hips (5%). Measurements of linear and volumetric wear were performed in one experienced laboratory by the Martell method and analyzed using the first-to-last method. Standard radiographs, with additional Judet views, were used to detect periprosthetic osteolysis. Statistical analysis of wear and osteolysis compared with head size was performed. RESULTS: For the entire cohort, the median linear wear rate as 0.024 mm/year (95% confidence interval [CI], 0.016-0.030) and the median volumetric wear rate was 12.19 mm(3)/year (95% CI, 6.6-15.7). With the numbers available, we found no association between femoral head size and linear wear rate. However, larger femoral heads were associated with more volumetric wear; 36/40-mm femoral heads had higher volumetric wear (median 26.1; 95% CI, 11.3-47.1) than did 26-mm heads (median 3.1; 95% CI, 0.7-12.3), 28-mm heads (median 12.3; 95% CI, 3.0-19.3), and 32-mm heads (median 12.9; 95% CI, 6.6-16.8; p = 0.02). Small osteolytic lesions were noted in 12 hips (14%), but with the numbers available, there was no association with head size or volumetric wear rates. CONCLUSIONS: This uncemented acetabular component and this particular XLPE had low rates of linear and volumetric wear. Small osteolytic lesions were noted at 10 to 14 years but were not related to femoral head size or linear or volumetric wear rates. We recommend additional longer-term clinical followup studies and perhaps alternative imaging studies of patients with XLPE and osteolysis. LEVEL OF EVIDENCE: Level III, therapeutic study.

Complications Are Not Increased With Acetabular Revision of Metal-on-metal Total Hip Arthroplasty.

BACKGROUND: Isolated revision of the acetabular component in the setting of total hip arthroplasty has an increased risk of dislocation. With local soft tissue destruction frequently associated with failed metal-on-metal (MoM) bearings, it is presumed that acetabular revision of these hips will have even greater risk of complications. However, no study directly compares the complications of MoM with metal-on-polyethylene (MoP) acetabular revisions. QUESTIONS/PURPOSES: In the context of a large database analysis, we asked the following questions: (1) Are there differences in early medical or wound complications after isolated acetabular revision of MoM and MoP bearing surfaces? (2) Are there differences in the frequency of dislocation, deep infection, and rerevision based on the bearing surface of the original implant? METHODS: A review of the 100% Medicare database from 2005 to 2012 was performed using International Classification of Diseases, 9th Revision and Current Procedural Terminology codes. We identified 451 patients with a MoM bearing and 628 patients with a MoP bearing who had an isolated acetabular revision and a minimum followup of 2 years. The incidence, odds ratios, and 95% confidence intervals for early medical or wound complications were calculated using a univariate analysis at 30 days with patient sex and age group-adjusted analysis for blood transfusion. The incidence, odds ratio, and 95% confidence intervals for dislocation, deep infection, and rerevision were calculated using a univariate analysis at 30 day, 90 days, 1 year, and 2 years using a subgroup analysis with the Cochran-Mantel-Haenszel test to adjust for patient gender and age groups. RESULTS: There were no differences between the MoM and MoP isolated acetabular revisions in the incidence of 30-day local complications. There was a greater risk of transfusion in the MoP group than the MoM group (134 of 451 [30%] versus 230 of 628 [37%]; odds ratio [OR], 0.731; 95% confidence interval [CI], 0.565-0.948; p = 0.018). There were no differences at 2 years between the MoM and MoP acetabular revisions in the incidence of dislocation, infection, or rerevision. When analyzed by patient sex and age group, there were more infections in the age 70 to 79 years MoP group compared with MoM (10 of 451 [5%] versus 29 of 628 [10%]; OR, 4.47; CI, 1.699-11.761; p = 0.001). CONCLUSIONS: There were high rates of dislocation, infection, and rerevision in both revision cohorts. The rate of dislocation was not greater after acetabular revision of MoM bearings at 2 years. Based on these findings, clinicians should counsel these patients preoperatively about the risks of these complications. Dual-mobility and constrained components have specific advantages and disadvantages in these settings and should be further studied. LEVEL OF EVIDENCE: Level III, therapeutic study.

Highly Cross-linked Polyethylene Provides Decreased Osteolysis and Reoperation at Minimum 10-Year Follow-Up.

BACKGROUND: Highly cross-linked polyethylene was introduced to decrease periprosthetic osteolysis and reoperation, but this has not been conclusively proven. METHODS: One surgeon performed 513 consecutive primary total hip arthroplasties (450 patients) using 1 modern, cementless, titanium-mesh acetabular component with screw fixation. This study analyzed the differences in the rate of reoperation and incidence of osteolysis between 133 hips with standard and 112 hips with highly cross-linked polyethylene at minimum 10-year follow-up time. RESULTS: Of the entire cohort of 513 hips, no acetabular component was removed or revised for aseptic loosening. There were significantly more reoperations in the cohort with standard polyethylene (11 of 133, 8%) than highly cross-linked polyethylene (1 of 112, 1%; P = .03). Osteolysis was seen in 24% (32 of 133 hips) with standard polyethylene, compared with 13% (15 of 112 hips) with highly cross-linked polyethylene (P = .02). These differences occurred despite the presence of patients with greater BMI and higher activity in the cohort with highly cross-linked polyethylene. CONCLUSION: We continue to use this acetabular component with highly cross-linked polyethylene. Longer follow-up is required to determine the progression of osteolysis.

Effectiveness of Intermittent Pneumatic Compression Devices for Venous Thromboembolism Prophylaxis in High-Risk Surgical Patients: A Systematic Review.

BACKGROUND: Thromboprophylaxis regimens include pharmacologic and mechanical options such as intermittent pneumatic compression devices (IPCDs). There are a wide variety of IPCDs available, but it is uncertain if they vary in effectiveness or ease of use. This is a systematic review of the comparative effectiveness of IPCDs for selected outcomes (mortality, venous thromboembolism [VTE], symptomatic or asymptomatic deep vein thrombosis, major bleeding, ease of use, and adherence) in postoperative surgical patients. METHODS: We searched MEDLINE (via PubMed), Embase, CINAHL, and Cochrane CENTRAL from January 1, 1995, to October 30, 2014, for randomized controlled trials, as well as relevant observational studies on ease of use and adherence. RESULTS: We identified 14 eligible randomized controlled trials (2633 subjects) and 3 eligible observational studies (1724 subjects); most were conducted in joint arthroplasty patients. Intermittent pneumatic compression devices were comparable to anticoagulation for major clinical outcomes (VTE: risk ratio, 1.39; 95% confidence interval, 0.73-2.64). Limited data suggest that concurrent use of anticoagulation with IPCD may lower VTE risk compared with anticoagulation alone, and that IPCD compared with anticoagulation may lower major bleeding risk. Subgroup analyses did not show significant differences by device location, mode of inflation, or risk of bias elements. There were no consistent associations between IPCDs and ease of use or adherence. CONCLUSIONS: Intermittent pneumatic compression devices are appropriate for VTE thromboprophylaxis when used in accordance with current clinical guidelines. The current evidence base to guide selection of a specific device or type of device is limited.