Faculty Bibliography

While there have been great advancements in total knee arthroplasty (TKA) over the past 50 years, anterior knee pain (AKP) remains the most common concern among patients postoperatively. Despite exhausting evidence supporting no clinical difference in AKP with resurfaced vs. unresurfaced patellae in TKA, 87% of TKAs are resurfaced in the United States, compared with 2% in other countries. These large practice variations underscore a lack of consensus regarding the role of the patella and the approach to the anterior compartment of the knee in TKA. The aim of this review was to go beyond patellar resurfacing and describe the effects that surgical technique and implant design may have on AKP in current TKA.

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/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.

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.

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.

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.

Cementless fixation in total knee arthroplasty (TKA) offers the potential for biologically active osseointegration and the potential for life-long fixation. With early cementless TKA designs, several design issues were identified related to early failure, particularly with the tibial and patellar components. However, in the recent two decades, with improvements upon the early designs, particularly in porous metal technology as well as improved early biomechanical stability, interest was re-established in cementless TKA. The surgical technique for cementless TKA is more exacting than cemented technique, with an important emphasis on indications, accurate resections, and component alignment. Modern cementless TKA designs have demonstrated excellent early- and mid-term survivorship equivalent to cemented TKA. More long-term studies are needed to study this comparison. While implant cost maybe higher with cementless designs, there is emerging evidence that there may be an overall cost saving with the use of cementless components given the shorter operative time and the savings in the cost of supplies associated with the use of cement. As the population undergoing TKA is becoming younger and more active, interest in the use of cementless implants will likely increase.