The Watson Extraction System for removal of well-fixed femoral stems: A retrospective review of 10 cases.

Background: Revision of well-fixed cementless femoral stems is a challenging and time-consuming aspect of revision hip arthroplasty. The Watson Extraction System (WES) is a novel, size-specific 3-D fabricated instrument that mimics the outer geometry of the implanted femoral stem. The device acts to cut circumferentially around the stem as it is impacted into place, effectively disrupting the bone-implant interface. Methods: This is a retrospective review assessing the experience of 3 fellowship-trained adult reconstruction surgeons who used the WES to extract 10 well-fixed femoral stems during rTHA between 11/7/2020 and 11/7/2022. Outcomes and measures included: ability to remove the stem without a femoral osteotomy, femoral stem extraction time, incidence of femoral fracture, stem type used for reconstruction, blood loss, total surgical time, post-operative complications. Results: No femoral osteotomies were required. The mean time for stem extraction was 7 min (range, 2-13), and there were 2 (20%) intra-operative femoral fractures. The stem type utilized for reconstruction included: 4 (40%) modular, tapered style stems, 3 (30%) antibiotic spacers, 2 (20%) primary style stems, and 1 (10%) ream and broach proximally porous stem. The mean blood loss was 425 ml (range, 200-800), total surgical time was 160 min (range, 107-232), and duration of follow-up was 7 months (range, 2-22 months). Conclusion: The WES may mitigate the need for femoral osteotomy, reduce femoral stem extraction and overall intraoperative time, and decrease blood loss in rTHA. Further, reduced bone loss with use of this device may permit final reconstruction with a primary style stem.

Case Report of Successful Bilateral Total Knee Arthroplasty: 46 Years and Still Going.

CASE: A 63-year-old woman with 46-year-old bilateral cemented total knee arthroplasty (TKA) presented to our clinic for routine evaluation. She was diagnosed with idiopathic juvenile arthritis at the age of 17. Radiographically she had well-fixed implants bilaterally without bone-cement lucency. She is ambulating without a limp, pain, or an assistance aid. CONCLUSION: We report TKA implants that lasted for 46 years. Literature suggests that most TKAs can last up to 20 to 25 years, but there are few reports that document implant survivorship longer than that. Our report demonstrates the possibility of long survivorship in TKA implants.

The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Total Hip Arthroplasty With Subtrochanteric Osteotomy for Developmental Hip Dysplasia: A Long-term Follow-up Study.

Background: Total hip arthroplasty (THA) for developmental hip dysplasia (DDH) often requires a subtrochanteric shortening derotational osteotomy (SDO) to limit leg lengthening, mitigate risk of peripheral nerve palsy, and reduce excessive femoral anteversion. Few studies exist detailing long-term clinical outcomes and survivorship. The aim of this study is to analyze the long-term outcomes and survivorship of an SDO-THA cohort. Methods: We retrospectively reviewed all patients who underwent cementless THA with femoral osteotomy due to Crowe I-IV DDH between 1991 and 2001. Primary outcome measures included revision surgery for any reason and functional outcome measures using modified Harris Hip scores. Secondary outcome measures included mode of implant failure and radiographic assessment for osteotomy union, polyethylene wear, osteolysis, and implant loosening. Results: Our review resulted in 24 SDO-THA cases in 20 patients with a mean follow-up of 19 years (range, 8-27 years). Overall survivorship was 67%. All 8 failures were treated with acetabular revision at a mean time to revision of 11 years (range, 1-25 years). Of the failures, there were 5 cases due to polyethylene wear (62.5%), 2 cases due to acetabular loosening (25%), and 1 case due to recurrent instability (12.5%). The mean postoperative modified Harris Hip score was 76 (range, 52-91) with long-term improvement of 43 points maintained (P < .001). Conclusions: THA with SDO can produce durable long-term outcomes for the patient with DDH. It is important to consider some common reasons for revision, namely polyethylene wear and osteolysis, acetabular loosening, and recurrent acetabular dislocations.

An Enhanced Understanding of Culture-Negative Periprosthetic Joint Infection with Next-Generation Sequencing: A Multicenter Study.

BACKGROUND: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI. METHODS: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis. RESULTS: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections. CONCLUSIONS: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Efficacy and Durability of Opioid Restrictive State Legislation Two Years After Implementation for Total Knee Arthroplasty.

BACKGROUND: To curtail the U.S. opioid crisis, many states have instituted regulations that mandate time and/or dosage limits for opioid prescriptions. This study evaluates the impact of one such law, Florida House Bill 21, on postoperative opioid prescribing patterns for patients undergoing total knee arthroplasty (TKA) and the durability of the law's impact over time. METHODS: All patients who underwent TKA at a single institution during the same three-month period in 2017 (pre-law), 2018 (post-law), and 2020 (2 years post-law) were identified. Outcomes and measures included: prescribed morphine milligram equivalents (MME) at discharge and for the 90-day surgical episode, refill quantity with associated MME, and quantity of opioid prescribers. Patients with established chronic pain or those who underwent contralateral TKA during the 90-day window were excluded. Data was compared using a one-way analysis of variance. Significance was set at alpha <0.05. RESULTS: The average MME of filled opioid prescriptions per patient during the 90-day post-surgical episode decreased from 1310 MME in 2017 to 891 MME in 2018 (P < .001). The average MME in 2020 was 814 MME, which was significantly lower than the average in 2017 (P < .001), and statistically stable compared to the average in 2018 (P = .215). CONCLUSION: Restrictive opioid state policy implementation was associated with reduced overall MME prescription to patients undergoing TKA at discharge and for the 90-day surgical episode. There was no increase in the number of opioid refills or opioid prescribers. Durable change and continued improvement were observed 2 years after implementation of law.

The Double-Cup Construct: A Novel Treatment Strategy for the Management of Paprosky IIIA and IIIB Acetabular Defects.

BACKGROUND: Treatment of massive acetabular bone loss in revision total hip arthroplasty is complex, and various treatment strategies have been described. We describe a novel technique of using a Trabecular Metal Revision Shell as a buttress augment creating a "double-cup" construct rather than the use of custom triflanges or cup-cage constructs for Paprosky types IIIA and IIIB acetabular defects. METHODS: We retrospectively reviewed 20 double-cup cases at a mean of 2.4 years follow-up at a single institution between 2005 and 2014. We evaluated postoperative radiographic evidence of acetabular loosening and complication rates, restoration of hip center of rotation, preoperative and postoperative modified Harris Hip Score, and Merle d'Aubigne-Postel pain and walking scores. RESULTS: There were no revisions for acetabular loosening and no cases of aseptic loosening. We observed a 25% dislocation rate, which was the most common complication. Most dislocations occurred within the first year after surgery and most were acetabulum only revisions. Hip center of rotation was restored to an average of 22.5 mm within the interteardrop line. Average Harris Hip Score improved from 28.2 to 68.7 (P < .001) and Merle d'Aubigne-Postel pain and walking scores improved from 2.7 to 5.1 and 2.4 to 4, respectively (P < .001). CONCLUSION: The double-cup construct is a reliable option for reconstruction of Paprosky type IIIA and IIIB acetabular defects with no cases of acetabular loosening both clinically and radiographically at a mean of 2 years follow-up. The most common complication was dislocation in the acetabulum-only revisions, and clinical outcome measures were reliably improved in surviving cases.

Computer navigation and distal femoral reconstruction in the oncologic patient.

OBJECTIVES: As adjuvant treatments for musculoskeletal malignancies improve expectations of preserved function increase. We questioned whether computer navigation for distal femoral reconstruction would improve outcomes. METHODS: Twenty oncology patients were reviewed after distal femoral reconstruction using navigation. Outcomes included local recurrence, implant revision, patient function, patellofemoral complications and leg-length inequality. RESULTS: Implant survivorship was 85% at 26 months. There were no local recurrences and 3 failures for aseptic loosening. Good functional outcomes were observed in remaining cases. CONCLUSION: Computer navigation for distal femoral reconstruction resulted in acceptable functional outcomes and implant survivorship. Reduced local recurrence were observed at intermediate follow-up. Level of Evidence: Level IV.

Biomechanical analysis of impending femoral neck fractures: the role of percutaneous cement augmentation for osteolytic lesions.

BACKGROUND: Management of impending pathologic femoral neck fractures includes internal fixation, arthroplasty and megaprostheses. The study aim was to determine the augmentative effect of cement injection for minimally invasive treatment of femoral neck lesions. METHODS: Twenty-seven cadaveric femora received a simulated osteolytic lesion previously shown to decrease the femur's failure load by 50%. Specimens were allocated to three groups of nine and loaded to failure in simulated single-leg stance: (1) percutaneous cementation + internal fixation (PCIF); (2) percutaneous cementation (PC); and (3) internal fixation (IF). Lesion-only and augmented finite element models were virtually loaded and stresses were queried adjacent to the lesion. FINDINGS: PCIF resulted in the largest failure load though the increase was not significantly greater than the PC or IF groups. Inspection of the PC and PCIF specimens indicated that the generation of a cement column that spanned the superior and inferior cortices of the femoral neck increased failure loads significantly. Finite element analysis indicated that IF and PCIF constructs decreased the stress adjacent to the lesion to intact femur levels. Cementation without superior-to-inferior femoral neck cortical contact did not restore proximal femoral stress toward the intact condition. INTERPRETATION: Internal fixation alone and internal fixation with or without cementation produce similar levels of mechanical augmentation in femora containing a high-risk lesion of impending fracture. A cement injection technique that produces a cement column contacting the superior and inferior femoral neck cortices confers the highest degree of biomechanical stability, should percutaneous cementation alone be performed.

Diagnosis and indications for treatment of unicompartmental arthritis.

Unicompartmental knee arthroplasty (UKA) is a reliable operation for isolated unicompartmental arthritis. A comprehensive understanding of the limitations of UKA is crucial for success in the young patient. Obesity may impact implant longevity; however, acceptable results can be achieved with precise component implantation and careful patient selection. UKA for degenerative medial compartment arthritis with attritional anterior cruciate ligament (ACL) rupture is generally contraindicated. However, concomitant ACL/UKA reconstruction is a dependable treatment for early posterior-medial compartment arthritis caused by an acute ACL rupture. Regardless of its limitations, the functional benefits and limited morbidity of UKA make it an appealing treatment option for unicompartmental disease.

Hip resurfacing arthroplasty in severely obese patients.

We conducted a study of outcomes of modern hip resurfacing arthroplasty (HRA) in severely obese patients. Patients who had undergone HRA and been followed for a minimum of 2 years were divided into 2 groups, those with body mass index under 35 (control, 366 hips) and those with body mass index of 35 or above (study, 63 hips). At mean follow-up of 41 months, there was no significant difference between the groups with respect to postoperative Harris Hip Scores, complication rates, and need for revision. Six revision surgeries were required in the control group (98.4% survival), and 2 were required in the study group (96.8% survival). These results suggest that severely obese patients should be considered candidates for HRA.

Biomechanical model of a high risk impending pathologic fracture of the femur: lesion creation based on clinically implemented scoring systems.

BACKGROUND: Multiple classifications combine objective and subjective measures to predict fracture risk through a metastatic lesion. In our literature review, no studies have attempted to validate this predicted fracture risk from a biomechanical perspective. The study goal was to evaluate proximal femur strength after creating osteolytic defects. We report a standardized technique to re-create a metastatic lesion. METHODS: Eight femoral matched pairs were procured and a standardized technique was used to create an osteolytic femoral neck defect in one femur with the contralateral specimen serving as the control. Femurs were loaded to failure in a material testing machine at 2 mm/s. Failure load (N) and location of failure were documented. 3D finite element (FE) femur models with and without the lesions were developed to predict von Mises stresses in the femoral neck and compare between the two models. FINDINGS: Femurs containing the osteolytic defect failed at significantly lower loads than the intact specimens in a reproducible manner (intact: 10.69 kN (3.09 SD); lesion: 5.56 kN (2.03 SD), p<0.001). The average reduction in failure load was 48%, and the fracture pattern was consistent in all specimens. FE model comparison similarly predicted significantly higher von Mises stress at the lesion. INTERPRETATION: Our methods and pathologic fracture model represent the clinical parameters of metastatic bone disease and suggest a significant reduction in structural integrity of the lesion-containing femur. Prophylactic surgical fixation may be warranted clinically to reduce the risk of pathologic fracture. Our model technique is reproducible and may be used in future studies.

Results of revision total hip arthroplasty with modular, titanium-tapered femoral stems in severe proximal metaphyseal and diaphyseal bone loss.

Evidence supporting modular, tapered stems for severe proximal metaphyseal and diaphyseal bone loss is limited. We report our clinical experience with its use for severely deficient femurs. Of 211 revision total hip arthroplasties (THAs), 18 tapered, modular titanium stems were implanted in Paprosky type III and IV femurs. Clinical data were reviewed for function, stability, structural failure and revision surgery at a mean follow-up of 4.5years. The overall survival rate was 94%. One required revision due to infection and subsidence. The mean subsidence was 3.5mm and the mean pre- and post-operative Harris Hip score was 56 and 79, respectively. In surviving cases, patients achieved satisfactory function and there were no mechanical failures. Modular, tapered stems demonstrated acceptable outcomes for management of severe proximal metaphyseal and diaphyseal defects.

Advances in segmental endoprosthetic reconstruction for extremity tumors: a review of contemporary designs and techniques.

BACKGROUND: Improved understanding and advances in treatment regimens have led to increased longevity among patients diagnosed with extremity soft tissue sarcomas. Limb salvage techniques and implants have improved and continue to evolve to accommodate the increasing demands and survival of these patients. METHODS: The current report is a review of the literature for recent advancements in techniques, implant design, and outcomes in the field of limb salvage therapy using segmental megaprostheses for the treatment of extremity sarcomas. We report on our experience in this field utilizing a classification system of failure mechanisms to outline to discuss current controversies in management. RESULTS: Five mechanisms of failure have been identified: soft-tissue failure, aseptic loosening, structural failure, infection, and tumor progression. Infection was the most common mode of failure in our series, accounting for 34% of cases. Soft-tissue failure occurred most commonly in the joints that depend heavily on periarticular muscles and ligaments for stability due to their high degree of functional range of motion. We observed a 28% soft-tissue failure rate about the shoulder and hip, aseptic loosening accounted for 19% of implant failures, and structural failure was seen in 17% of cases. Seventeen percent of cases failed due to tumor progression, an etiology that is defined by biological factors, surgical technique, and adjuvant therapies. CONCLUSIONS: Surgical techniques and megaprosthesis designs are constantly changing in order to meet the challenge of increasing functional demands and longevity in this unique patient population. A classification system defined by treatment failure etiologies provides the framework for discussion of current controversies in limb salvage therapy as well as a guide for advancement and potential solutions in this challenging arena.

Initial experience of the Journey-Deuce bicompartmental knee prosthesis: a review of 36 cases.

We evaluated the effectiveness of a novel bicompartmental knee arthroplasty prosthesis for the treatment of degenerative disease affecting the medial and patellofemoral compartments. The study included 36 knees in 32 patients with a mean follow-up of 21 months. The mean Knee Society functional survey and Western Ontario McMaster Osteoarthritic Index Survey scores were 65.4 and 75.8, respectively. Thirty-one percent of patients were unsatisfied with the surgery, and 53% stated that they would not repeat the surgery. We report an overall survival rate of 86% with one catastrophically failed tibial baseplate. We conclude that this prosthesis provides inconsistent pain relief and unacceptable functional results for bicompartmental arthritis. Short-term survival of this prosthesis was unacceptably low, and therefore, we no longer implant it at our institution.

Femoral component incarceration at the distal slot.

Femoral components with distal coronal slots were introduced to decrease the stiffness mismatch of the femoral diaphysis and stem. We present 2 cases in which the stem of an S-ROM (DePuy, Warsaw, Ind) endoprosthesis was incarcerated in the diaphysis of the femur by bone growth through the distal slot. In both cases, this finding was discovered intraoperatively, following multiple unsuccessful attempts at stem extraction. We recommend performing a trans femoral cortical window at the distal slot, which provides adequate visualization of the stem and allows for resection of the anterior tine and osseous bar. Early recognition of this potential pitfall may decrease the risk for iatrogenic femur fracture, prolonged operative time, extended anesthetic exposure, and greater blood loss.

Biology, classification, and management of recurrent myxofibrosarcoma 21 years after resection.

Soft-tissue sarcomas (STSs) are a heterogenous group of rare malignancies that have significant lifelong implications. Accepted management options include limb-sparing surgical resection and adjuvant radiation therapy. Here we present the case of a myxoid malignant fibrous histiocytoma, now termed a myxofibrosarcoma, which recurred 21 years after primary surgical resection. To our knowledge, this is the longest documented interval between initial management and recurrence of an STS. Significant changes have been made in classification guidelines and diagnostic methods over this 2-decade period. The pathogenesis of remote recurrence of STSs remains controversial and is discussed in this report.

Purse-string capsule repair to reduce proximal femoral arthroplasty dislocation for tumor--a novel technique with results.

Hip joint dislocation is the most common complication after proximal femoral arthroplasty with a large endoprosthesis. Average dislocation rates are around 15%. In an attempt to decrease dislocations after proximal femoral arthroplasty for tumor resections, we devised a novel closure of the hip capsule. This technique uses a 3-mm cottony Dacron suture placed about the hip capsule in a circumferential, purse-string manner. Thirty-nine patients received hip hemiarthroplasty with purse-string capsular closure. Seven patients were lost to follow-up, leaving 36 patients available for analysis. One patient dislocated (2.8%). We believe this technique is useful in preventing dislocation in patients undergoing proximal femoral arthroplasty for oncologic disease.

Use of extendable prostheses: a limb-salvaging alternative for patients with malignant bone tumors.

Children with primary bone tumors require radical surgical procedures and complex reconstructions. In addition to adequate disease control, the surgeon has to address the injured growth plate and consequent limb length inequality. Extendable prostheses constitute an alternative to other limb-salvaging techniques. Since the first description of the device three decades ago, several changes in materials, design and indications have been a matter of constant debate. The indications and results of this prosthesis will be reviewed and an expert commentary regarding the current and future trends of the device will be presented.