Mode of Fixation and Survivorship in Primary Total Knee Arthroplasty in the American Joint Replacement Registry.

BACKGROUND: A recent rapid increase in cementless total knee arthroplasty (TKA) has been noted in the American Joint Replacement Registry (AJRR). The purpose of our study was to compare TKA survivorship based on the mode of fixation reported to the AJRR in the Medicare population. METHODS: Primary TKAs from Medicare patients submitted to AJRR from 2012 to 2022 were analyzed. The Medicare and AJRR databases were merged. Cox regression stratified by sex compared revision outcomes (all-cause, infection, mechanical loosening, and fracture) for cemented, cementless, and hybrid fixation, controlling for age and the Charlson comorbidity index (CCI). RESULTS: A total of 634,470 primary TKAs were analyzed. Cementless TKAs were younger (71.8 versus 73.1 years, P < .001) than cemented TKAs and more frequently utilized in men (8.2 versus 5.8% women, P < .001). Regional differences were noted, with cementless fixation more common in the Northeast (10.5%) and South (9.2%) compared to the West (4.4%) and Midwest (4.3%) (P < .001). No significant differences were identified in all-cause revision rates in men or women ≥ 65 for cemented, cementless, or hybrid TKA after adjusting for age and CCI. Significantly lower revision for fracture was identified for cemented compared to cementless and hybrid fixation in women ≥ 65 after adjusting for age and CCI (P = .0169). CONCLUSIONS: No survivorship advantage for all-cause revision was noted based on the mode of fixation in men or women ≥ 65 after adjusting for age and CCI. A significantly lower revision rate for fractures was noted in women ≥ 65 utilizing cemented fixation. Cementless fixation in primary TKA should be used with caution in elderly women.

Assessment of the added value of intravenous gadolinium for knee osteosarcoma resection planning in pediatric and young adult patients.

BACKGROUND AND OBJECTIVES: To assess the impact of Gadolinium-enhanced magnetic resonance imaging (MRI) sequences on Preoperative imaging evaluation and surgical planning parameters for osteosarcoma (OS) of the knee in pediatric and young adult patients. METHODS: Thirty MRI scans of patients with OS about the knee were reviewed by five orthopedic oncologists. Key preoperative parameters (neurovascular bundle involvement, intra-articular tumor extension, extent of intramedullary extension) and surgical plans were evaluated based on non-contrast versus Gd contrast enhanced sequences. Assessment agreement, inter-rater agreement, and intrarater agreement between pre and postcontrast images were evaluated via Kappa statistics. RESULTS: Moderate agreement was seen between non and contrast-enhanced assessment of neurovascular involvement and intra-articular tumor extension. Intrarater reproducibility was substantial for neurovascular bundle involvement (precontrast Kappa: 0.63, postcontrast Kappa: 0.69). Intrarater reproducibility was also substantial for precontrast (Kappa: 0.70) and moderate for postcontrast (Kappa: 0.50) assessment of intra-articular tumor extension. Planned resection length and choice of surgical approach were similar between sequences. The addition of Gd-enhanced sequences improved the inter-rater agreement across collected parameters. CONCLUSIONS: While some findings suggest that contrast enhanced sequences may not significantly alter the assessment of key preoperative planning parameters by orthopedic oncologists, they may help reduce variability among providers with differing experience levels.

Analysis of the OITE Oncology Section: An Updated Review of Years 2013 to 2019.

OBJECTIVES: The importance of the Orthopaedic In-Training Examination (OITE) is well documented. The purpose of this study is to provide an updated analysis of the oncology section compared to the review by Frassica et al. from 2002 to 2006, as a means to provide insight into more focused resident study. DESIGN: This study is a retrospective database review using published OITE exams from years 2013 to 2019. Methods were based off a previous review by Frassica et al. where oncology-related questions were analyzed for underlying diagnosis, benign versus malignant condition, imaging and histology provided, and genes/translocations tested. Questions were classified by category and taxonomy. RESULTS: Oncology-related questions per exam ranged from 19 (7%) to 23 (8.4%) of total questions, which is fewer than years 2002 to 2006. Twenty malignant and 27 benign entities were tested with malignant conditions tested at a higher rate of 1.3:1 versus benign. Eighteen combinations of imaging modalities were provided for analysis versus 11 from 2002 to 2006. With regard to taxonomy, the average number of questions per classification ranged from 2.4 to 5.4. The least common classification tested was treatment modality and the most commonly tested classification was treatment from diagnosis (taxonomy 3). Previously, tumor knowledge (taxonomy 1) was most tested with an average of 8.8 questions per exam. 12 questions were directly related to genes and translocations across all years. CONCLUSIONS: Oncology questions made up a smaller percentage of the OITE exam than previous years, although more conditions were tested using more imaging combinations, necessitating a wider range of knowledge. However, malignant conditions continue to be tested more commonly. There has been a shift toward Taxonomy 3 level questions, indicating a higher level of thought processing required from residents as opposed to recall. Additionally, genes and translocations became more commonly tested throughout the most recent analysis, indicating a focus for future years of study.

Factors Considered in Ranking Hip and Knee Arthroplasty Fellowship Applicants: A Survey of Program Directors.

BACKGROUND: Variables considered by hip and knee arthroplasty fellowship program directors (PDs) to select fellowship candidates are not well known. METHODS: A web-based questionnaire containing 5 questions was developed and sent to all 92 adult reconstruction fellowship PDs via email. Three questions collected program information including the number of positions available, the number of candidates interviewed, and ranked annually. PDs were then given a list of 12 factors and asked to rank them in the order of importance. A weighted score for each factor was calculated using the following scale: 5 points each time a factor was ranked 1st, 4 points each time a factor was ranked 2nd, 3 points for each 3rd place rank, 2 points for each 4th place rank, and 1 point for each 5th place rank. PDs were also allowed to write in other factors they considered important when ranking fellowship candidates. RESULTS: The overall response rate was 34.8% (32/92). Seventy-five percent of responding programs indicated that they interview between 21 and 40 applicants per year for their fellowship position(s). The interview was ranked as the most important variable in selecting applicants by 53.1% of responding PDs, followed by letters of recommendation (ranked first by 25% of PDs) and personal connections to the applicant and/or letter writer(s) (ranked first by 9% of PDs). A positive correlation was identified between the program size and an applicant's geographical ties to the city/town of the fellowship program (r s  = 0.472; P = .006). CONCLUSIONS: According to hip and knee arthroplasty fellowship PDs, the interview, letters of recommendation, and personal connections to the applicant and/or letter writers are the most important factors considered in selecting arthroplasty fellowship candidates.

Endoprosthetic Reconstruction of the Upper Extremity in Oncologic Surgery.

In 1943, Austin Moore successfully reconstructed a proximal femur using a Vitallium endoprosthesis. This marked the first successful alternative to amputation in oncologic surgery. However, it was not until the introduction of high-resolution axial imaging and improved chemotherapeutics that the feasibility of limb salvage began to improve. Today, limb salvage surgery can be used to treat most oncologic conditions of the extremities, the most popular reconstruction option being endoprostheses. Megaprostheses use has expanded to nononcologic indications with severe bone loss, including infections, revision arthroplasty, and severe periarticular trauma and its sequelae. The proximal humerus and scapula are challenging for reconstruction, given the complex anatomy of the brachial plexus, the accompanying vascular structures, and the dynamic stabilizers of the relatively nonstable glenohumeral joint. The midhumerus is difficult because of the close location of the radial nerve, whereas the distal humerus is challenging because of the proximity of the brachial artery and its bifurcation, radial, ulnar, and median nerves, and lack of soft-tissue coverage. Despite these challenges, this review demonstrates that many series show excellent mid- to long-term results for pain relief and function restoration after megaprosthetic reconstruction of the scapula and humerus after bone resections for oncologic and nononcologic reasons.

In Vivo analysis of spinopelvic kinematics and peak head-cup contact in total hip arthroplasty patients with lumbar degenerative disc disease.

Anterior instability after total hip arthroplasty (THA) has been described in patients with thoracolumbar kyphotic deformity. Although compensatory posterior pelvic tilt with subsequent increased functional anteversion has been described as the mechanism, there is a paucity of in vivo data. The purpose of our study was to compare pelvic tilt, anteversion, inclination, and position of head-cup contact points in patients with lumbar degenerative disc disease (DDD) and a matched patient cohort without DDD. A total of 50 THA, 18 hips with lumbar DDD and 32 hips without DDD, underwent CT imaging for 3D hip reconstruction. Component orientations and in vivo hip gait kinematics was quantified using a validated dual fluoroscopic imaging system. Hip kinematics and head-cup contact points were compared. Patients with lumbar DDD demonstrated decreased maximum (5.9° ± 4.2° vs. 9.3° ± 5.4°, p = 0.02) and minimum (2.4° ± 4.1° vs. 6.2° ± 5.6°, p = 0.01) anterior pelvic tilt, and increased maximum cup anteversion (29.3° ± 8.7° vs. 25.1° ± 8.1°, p = 0.05). The peak head-cup contact points were shifted closer to the anterior edge of the polyethylene (7.8 ± 1.7 mm vs. 9.6 ± 2.2 mm, p = 0.02). Patients with lumbar degenerative disc disease demonstrated increased posterior pelvic tilt, functional acetabular anteversion, inclination as well as shifting of the peak head-cup contact pattern significantly closer to an anterior edge, suggesting sagittal spinopelvic deformity may predispose to anterior instability in THA patients during upright activities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Durability of a cruciate-retaining TKA with modular tibial trays at 20 years.

BACKGROUND: Modular tibial trays have been utilized in TKA for more than 20 years. However, concerns have been raised about modular implants and it is unclear whether these devices are durable in the long term. QUESTIONS/PURPOSES: We determined (1) survival, (2) relationship of age and polyethylene thickness with revision, (3) function, and (4) radiographic lucencies and osteolysis in patients having a single TKA implant at 20-year followup. METHODS: We prospectively followed 75 patients implanted with 101 Press-Fit Condylar(®) (Johnson and Johnson Professional, Inc, Raynham, MA, USA) posterior cruciate-retaining TKAs (with modular tibial trays) between 1988 and 1991. At 20 years, 59 patients were deceased. We clinically evaluated the living 16 patients (22 knees) and contacted the relatives of all deceased patients to confirm implant status. We clinically assessed 14 of the 16 patients with the Knee Society score, WOMAC, and UCLA and Tegner activity level scores. Radiographically, we determined lucencies, component migration, and osteolysis. We performed survival analysis including all original patients. Minimum followup was 20 years (mean, 20.6 years; range, 20-21.8 years). RESULTS: Six reoperations were performed in five patients (6% rate of revision) over the 20-year followup. All revisions were related to polyethylene wear and occurred at least 10 years after the primary procedure. Survivorship with revision for any reason as the end point was 91% (95% CI, 0.83-0.97) at 20 years. Average Knee Society clinical and functional scores were 90 (range, 60-100) and 59 (range, 30-87), respectively. CONCLUSIONS: Our data demonstrate the durability of this posterior cruciate-retaining TKA design. The data provide a standard for newer designs and newer bearing surface materials at comparable followup.

Four- to six-year follow-up of primary THA using contemporary titanium tapered stems.

Tapered cementless femoral components have been used in total hip arthroplasty constructs for more than 20 years. In the past 5 to 10 years, these stems have gained popularity in the United States. The purpose of this study was to evaluate the results of the authors' initial experience using a contemporary tapered, proximally porous-coated, titanium femoral component at 4 to 6 years of follow-up. Eighty-eight patients underwent 100 total hip arthroplasties using the Summit stem (DePuy, Warsaw, Indiana) and a cementless acetabular component. Average age at the time of surgery was 61.6 years. Patients were prospectively followed for 4 to 6 years or until death. Patients were evaluated clinically using Harris Hip Scores and the need for revision. Radiographs were evaluated for femoral loosening and osteolysis. At final follow-up, no hips had been revised for femoral or acetabular loosening. Two hips required revision for dislocation and 1 for early femoral fracture. Bony ingrowth was seen in all but 2 femoral components. There was 1 instance of proximal femoral osteolysis and none distally on radiographs (cross-linked polyethylene was used in 73% of cases). There were 2 cases of severe stress shielding. One percent of cases had an early fracture (too tight) and 1% subsided without ingrowth (too loose). One patient reported significant thigh pain that did not limit activity. At final follow-up, the Summit femoral component demonstrated durable results at 4 to 6 years. Stability of the implant without femoral fracture is paramount.

Cementing acetabular liners into secure cementless shells for polyethylene wear provides durable mid-term fixation.

BACKGROUND: In a previous experiment studying cementation of liners into cementless acetabular shells, placing grooves in the liner in a spider-web configuration created the greatest construct strength. Scoring shells without screw holes or other texturing helped prevent failure at the shell-cement interface. However, it was unclear whether these practices caused durable constructs in patients. QUESTIONS/PURPOSES: We therefore determined (1) rerevision rates; (2) functional scores (Harris hip scores, WOMAC, and SF-36); (3) acetabular loosening rates; and (4) acetabular osteolysis rates in patients in whom we cemented nonconstrained liners into well-fixed and well-positioned acetabular shells. METHODS: We prospectively followed 30 patients with 31 total hip arthroplasties in which a worn acetabular liner was revised by cementing a new liner into the existing shell that was stable and well positioned. Acetabular liners were prepared as determined by our previous study. Twenty-seven of the 30 patients (28 hips) were evaluated clinically. We recorded revisions and determined radiographic loosening and osteolysis. The minimum clinical followup was 2 years (mean, 5.3 years; range, 2-10 years). Twenty-six hips (87%) had minimum 2-year radiographic followup with an average length of 4.8 years. RESULTS: No hip required rerevision during the followup interval. Two hips (6%) dislocated once, both treated nonoperatively. Harris hip scores, WOMAC, and SF-36 scores increased over preoperatively at last followup. All acetabular shells and liners were radiographically stable without evidence of loosening or progressive acetabular osteolysis. CONCLUSIONS: Cementation of a liner into a well-fixed cementless shell after scoring in a spider-web configuration provided secure fixation with no failures of the construct at average 5.3 years followup. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Durability of second-generation extensively porous-coated stems in patients age 50 and younger.

UNLABELLED: Early versions of uncemented femoral total hip stems were often associated with thigh pain thought to be due to micromotion between the implant and bone in the distal uncoated regions. An extensively coated stem was introduced in 1992 to reduce that risk. We therefore asked whether second-generation extensively porous-coated cementless femoral stems in patients younger than 50 years of age would (1) be durable in terms of revisions; (2) provide high functional scores and reduce thigh pain; and (3) show radiographic signs of durability, including a reduction in stress shielding. We prospectively followed all 100 patients (115 hips) age 50 and younger treated with primary cementless total hip arthroplasties using a second-generation extensively porous-coated femoral stem between June 1994 and December 1999. The average age was 39.6 years (range, 17-50 years). The stems were mated to cementless acetabular components. Ninety patients were followed for a minimum of 5 years (mean, 8.6 years; range, 5-10 years). One stem was revised after a periprosthetic fracture. None were revised for loosening and all stems demonstrated bony ingrowth at last followup. No acetabular shell was revised for loosening and none was radiographically loose. Six acetabular liners were revised for wear (three each were 22-mm and 26-mm heads). This second-generation extensively porous-coated stem was durable at 5- to 10-year followup in this young active population. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Second-generation extensively porous-coated THA stems at minimum 10-year followup.

The relatively high prevalence of thigh pain and stress shielding associated with the AML porous-coated cementless femoral component led to the development of the Prodigy, a femoral component with more extensive porous-coating and a distal polished bullet tip with medial diaphyseal relief to potentially decrease the flexural rigidity. We prospectively evaluated a cohort of 100 consecutive cementless total hip arthroplasties performed using this device. The minimum followup was 10 years (mean, 11.4 years; range, 10-12 years). At 10-year followup, 69 of the 86 patients (82 hips) were living, 14 patients with 15 hips were deceased, and three patients with three hips were lost to followup. No hips required a stem revision. Two patients (two hips) complained of thigh pain. All hips were bone ingrown. Distal tip radiolucencies and osteolysis occurred in 13 hips (17%) and none, respectively. Twenty-one hips (28%) demonstrated moderate or severe stress shielding. Only further followup will determine if this could be a clinical problem or one with revision surgery. These results encourage the authors to continue using second-generation extensively coated stems in their primary total hip arthroplasty constructs.