Faculty Bibliography

Due to femoral head-neck deformities and hip joint incongruence, patients with Legg-Calvé-Perthes Disease (LCPD) commonly require total hip arthroplasty (THA) in the fifth and sixth decades of life. These patients present additional challenges to arthroplasty surgeons not only because of their complicated hip anatomy but also because patients may have undergone prior operative procedures in childhood and thus present with pre-existing proximal femoral deformities. THA in LCPD patients can be associated with peri-operative complications such as fracture or nerve injury, and the rate of reoperation has been reported to be higher in the LCPD population as compared to the general population undergoing THA. Despite this, multiple case reports and studies have shown the relative long-term success of THA in patients with history of LCPD. In particular, uncemented modular stems are a commonly used implant choice in such cases. This article reviews and discusses the technical considerations for THA in patients with LCPD and highlights three such cases.

Introduction: Bone loss is present in all revision total knee arthroplasties. Metaphyseal cones allow surgeons to negotiate loss of femoral and tibial bone stock while obtaining stable bony fixation. This study examines the mid-term functional and radiographic outcomes in patients undergoing revision total knee arthroplasty (rTKA) utilizing a novel metaphyseal cone system. Methods: This multicenter retrospective study examined all patients who received a porous, titanium tibial or femoral cone at four academic urban tertiary care institutions and presented for a minimum two-year follow-up. Patient demographics, indications for revision surgery, knee range-of-motion (ROM), re-revision rates, radiographic measurements, bone defect per AORI classification, and implant osseointegration were evaluated according to the Knee Society total knee arthroplasty (TKA) radiographic evaluation system. Results: One-hundred and four patients received 128 cone implants (84 tibial, 44 femoral cones; 24 patients with simultaneous ipsilateral tibial and femoral cones; 104 rTKA) with mean follow-up of 32.75 ± 6.54 months. The pre-operative main revision indications were aseptic loosening 36 (34.61 %), periprosthetic infection (PJI) 23 (22.11 %) and instability 18 (17.3 %). Thirteen rTKA underwent re-revision surgery: 3 for acute PJI, 4 for chronic PJI, 5 for instability, and 1 for mechanical failure of a hinged system. At most recent radiographic follow-up available, all unrevised cones had evidence of osteointegration and no visible implant migration. All-cause re-operation free survivorship was 87.5 % (91/104), and all-cause cone implant survivorship was 96.09 % (123/128 cones) at 2-year follow-up. Conclusion: This study demonstrates excellent mid-term outcomes of a novel porous, titanium metaphyseal cone in patients with large bone defects undergoing complex revision TKA. Level of evidence: IV, case series.

INTRODUCTION/UNASSIGNED:Bone loss is present in all revision total knee arthroplasties. Metaphyseal cones allow surgeons to negotiate loss of femoral and tibial bone stock while obtaining stable bony fixation. This study examines the mid-term functional and radiographic outcomes in patients undergoing revision total knee arthroplasty (rTKA) utilizing a novel metaphyseal cone system. METHODS/UNASSIGNED:This multicenter retrospective study examined all patients who received a porous, titanium tibial or femoral cone at four academic urban tertiary care institutions and presented for a minimum two-year follow-up. Patient demographics, indications for revision surgery, knee range-of-motion (ROM), re-revision rates, radiographic measurements, bone defect per AORI classification, and implant osseointegration were evaluated according to the Knee Society total knee arthroplasty (TKA) radiographic evaluation system. RESULTS/UNASSIGNED:One-hundred and four patients received 128 cone implants (84 tibial, 44 femoral cones; 24 patients with simultaneous ipsilateral tibial and femoral cones; 104 rTKA) with mean follow-up of 32.75 ± 6.54 months. The pre-operative main revision indications were aseptic loosening 36 (34.61 %), periprosthetic infection (PJI) 23 (22.11 %) and instability 18 (17.3 %). Thirteen rTKA underwent re-revision surgery: 3 for acute PJI, 4 for chronic PJI, 5 for instability, and 1 for mechanical failure of a hinged system. At most recent radiographic follow-up available, all unrevised cones had evidence of osteointegration and no visible implant migration.All-cause re-operation free survivorship was 87.5 % (91/104), and all-cause cone implant survivorship was 96.09 % (123/128 cones) at 2-year follow-up. CONCLUSION/UNASSIGNED:This study demonstrates excellent mid-term outcomes of a novel porous, titanium metaphyseal cone in patients with large bone defects undergoing complex revision TKA. LEVEL OF EVIDENCE/UNASSIGNED:IV, case series.

INTRODUCTION/BACKGROUND:The purpose of this study was to assess how quality and volume of common orthopaedic care varies across private, municipal, and federal healthcare delivery systems (HDSs). METHODS:Hip and knee arthroplasty, knee and shoulder arthroscopy, and hip fracture repair were audited over a two-year period. Electronic medical records were reviewed for demographics, diagnosis, lengths of stay (LoSs), surgical wait times, inpatient complication, readmission, and revision surgery rates. Multivariate regression controlled for differences in age, sex, diagnosis, and Charlson Comorbidity Index to determine how HDS correlated with surgical wait time, length of stay, complication rates, readmission, and revision surgery. RESULTS:The 5,696 included patients comprise 87.4% private, 8.6% municipal, and 4.0% federal HDSs. Compared with private HDS for arthroplasty, federal surgical wait times were 18 days shorter (95% CI = 9 to 26 days, P < 0.001); federal LoS was 4 days longer (95% CI = 3.6 to 4.3 days, P < 0.001); municipal LoS was 1 day longer (95% CI = 0.8 to 1.4, P < 0.001); municipal 1-year revision surgery odds were increased (odds ratio [OR] = 2.8, 95% CI = 1.3 to 5.4, P = 0.045); and complication odds increased for municipal (OR = 12.2, 95% CI = 5.2 to 27.4, P < 0.001) and federal (OR = 12.0, 95% CI = 4.5 to 30.8, P < 0.001) HDSs. Compared with private HDS for arthroscopy, municipal wait times were 57 days longer (95% CI = 48 to 66 days, P < 0.001) and federal wait times were 34 days longer (95% CI = 21 to 47 days, P < 0.001). Compared with private HDS for fracture repair, municipal wait times were 0.6 days longer (95% CI = 0.2 to 1.0, P = 0.02); federal LoS was 7 days longer (95% CI = 3.6 to 9.4 days, P < 0.001); and municipal LoS was 4 days longer (95% CI = 2.4 to 4.8, P < 0.001). Only private HDS fracture repair patients received bone health consultations. DISCUSSION/CONCLUSIONS:The private HDS provided care for a markedly larger volume of patients seeking orthopaedic care. In addition, private HDS patients experienced reduced surgical wait times, LoSs, and complication odds for inpatient elective cases, with better referral patterns for nonsurgical orthopaedic care after hip fractures within the private HDS. These results may guide improvements for federal and municipal HDSs.

Cam-post dislocations are a unique complication of total knee arthroplasty (TKA) designs that utilize a cam-post mechanism, representing an extreme form of deep flexion instability. They are rare complications and are poorly defined in the existing literature. The purpose of this case study is to present a series of six cam-post dislocation cases to improve understanding of this complication and its mechanism, presentation, and available treatment options. All patients experienced cam-post dislocations after a deep flexion moment that were identified clinically and confirmed radiographically. Affected implants included both primary and revision components and all utilized a cam-post mecha- nism. Three patients underwent revision surgery whereas the remaining three were treated with closed reduction only. Cam-post dislocations are rare complications of posterior- stabilized TKA that should be understood and recognized by adult reconstruction surgeons. Closed reduction may be achieved with hyperflexion and anterior drawer or with hyperextension, but these patients may ultimately require a revision procedure.

Dual mobility designs in total arthroplasty allow for increased range of motion prior to impingement and dislocation. While valuable for reducing dislocation, dual mobility has its own unique complication profile that includes intraprosthetic dislocation, corrosion, and femoral notching. Despite these relatively rare complications, dual mobility articulations are valuable options for patients at higher risk of dislocation-both early and contemporary reports on dual mobility in total hip arthroplasty suggest that it can reduce the risk of dislocation without leading to unacceptable rates of complication or early revision. Cost analyses and longer follow-up studies on newer dual mobility designs will help determine the future of dual mobility in total hip arthroplasty.

Dual-mobility (DM) articulations are increasingly utilized to prevent or manage hip instability after total hip arthroplasty (THA). DM cups offer enhanced stability due to the dual articulation resulting in larger jump distance and greater range of motion before impingement. Improvement in design features and biomaterials has contributed to increased interest in dual-mobility articulations due to lower risk of complications compared to their historic rates. The incidence of implant-specific complications like intra-prosthetic dislocation (IPD) and wear has reduced with newer-generation implants. DM THAs are used in primary THA in patients with high risk for dislocation, e.g. neuromuscular disorder, femoral neck fracture, spinopelvic deformity, etc. They offer an attractive alternative option to constrained liner for treatment of hip instability in revision THA. The medium- to short-term results with DM THA have been encouraging in primary and revision THA. However, there are concerns of fretting, corrosion and long-term survivorship with DM THA. Hence, longer-term studies and surveillance are required for the safe use of DM THA in clinical practice.