Risk of Periprosthetic Joint Infection in Patients With Ipsilateral Infected Arthroplasties.

Background: The risk of periprosthetic joint infection (PJI) subsequently developing at a second site after an initial PJI has been documented to be approximately 18%-20%. To the best of our knowledge, only a single study has evaluated the incidence in ipsilateral joints and if the risk of infection would be different. While this was the only other study to evaluate this specific subfield, we set to re-evaluate and confirm the incidence of developing a second PJI in the setting of an ipsilateral prosthesis and possible associated risk factors. Methods: We retrospectively reviewed all patients treated surgically for lower-extremity PJI at our institution by 5 surgeons from 2015 to 2021. Patients with multiple arthroplasties on the ipsilateral extremity were included. Time between initial and subsequent infection, risk factors for infection, bacterial source, and bacteremia were identified. Results: Of 392 patients treated for PJI, 179 (45.6%) had multiple prosthetic joints. Forty-seven of those 179 patients had ipsilateral extremity prosthesis, which made up our study population. Three patients (6.4%) developed a separate infection at an ipsilateral TJA. In total, 10 patients (21.3%) developed a separate PJI. Patients on immunosuppressants had a higher likelihood of developing second PJI on the ipsilateral extremity (P = .02). Conclusions: Our study identified the risk of developing an ipsilateral PJI to not be any greater than that in patients with contralateral TJAs. It appears that sharing an extremity with an infected TJA does not pose substantially increased risk of subsequent infection of the un-involved prosthesis. Furthermore, immunosuppressant use may increase the risk of a separate ipsilateral PJI.

Impact of State Opioid Regulation on Postoperative Opioid Prescribing Patterns for Total Knee Arthroplasty: A Retrospective Analysis.

BACKGROUND: Limited studies have assessed the impact of state regulations on opioid prescribing patterns for patients undergoing total knee arthroplasty (TKA). This study evaluates how Florida House Bill 21 (FL-HB21) affected postoperative opioid prescribing for patients after TKA. METHODS: Institutional review board approval was obtained to retrospectively review all patients who underwent TKA during 3 months of 2017 (pre-law) and 2018 (post-law) by five arthroplasty surgeons in Florida. Prescribed opioid quantity in morphine milligram equivalents (MME), quantity of refills, and number of prescribers were recorded for each patient's 90-day postsurgical episode. The differences between pre-law and post-law prescription data and short-term postoperative pain levels were compared. RESULTS: The average total MME was notably reduced by over 30% for all time periods for the post-law group. The average MME per patient decreased by 169 MME at the time of discharge, by 245 MME during subsequent postoperative visits, and by 414 MME for the 90-day postsurgical episode ( P < 0.001 for all). The quantity of refills was unchanged (1.6 vs. 1.6, P = 0.885). The total number of prescribers per patient for the 90-day postsurgical episode was unchanged (1.31 vs. 1.24 prescribers/patient, P = 0.16). Postoperative pain levels were similar at discharge (3.6 pre-law vs. 3.3 post-law, P = 0.272). DISCUSSION: Restrictive opioid legislation was associated with notably reduced postoperative opioid (MME) prescribed per patient after TKA at the time of discharge and for the entire 90-day postsurgical episode. There was no increase in the number of prescribers or refills required by patients. LEVEL OF EVIDENCE: Level III retrospective cohort.

Low dislocation rates with the use of patient specific "Safe zones" in total hip arthroplasty.

INTRODUCTION: The purpose of this study was to compare patient-specific acetabular cup target orientation using functional simulation to the Lewinnek Safe Zone (LSZ) and determine associated rates of postoperative dislocation. METHODS: A retrospective review of 1500 consecutive primary THAs was performed. Inclination, anteversion, pelvic tilt, pelvic incidence, lumbar flexion, and dislocation rates were recorded. RESULTS: 56% of dynamically planned cups were within LSZ (p < 0.05). 6/1500 (0.4%) of these cups dislocated at two year follow-up, and all were within LSZ. CONCLUSION: Optimal acetabular cup positioning using dynamic imaging differs significantly from historical target parameters but results in low rates of dislocation. LEVEL OF EVIDENCE: Level III: Retrospective.

Routine Postoperative Complete Blood Counts Are Not Necessary After Most Primary Total Hip and Knee Arthroplasties.

BACKGROUND: Routine postoperative complete blood count tests are commonplace after total joint arthroplasty. The goal of this study was to identify if these result in any clinically meaningful action and if it would be safe to forego this testing in a population without known risk factors for transfusion. METHODS: A retrospective review of 1060 patients undergoing a total knee or total hip arthroplasty at a single institution was performed. Data points including patient demographics, preoperative and postoperative laboratory results, tranexamic acid use, preoperative and postoperative medication for venous thromboembolism prophylaxis and anticoagulation, as well as 90-day readmission related to anemia were collected. RESULTS: The transfusion rate for all patients was 0.66% (7/1060) and there was only one transfusion for a patient with a preoperative hemoglobin (Hb) greater than 12 g/dL (1/976; 0.1%). There was no difference in the change from preoperative to postoperative day 1 Hb levels in patients treated with aspirin compared with those on direct oral anticoagulation (P = .73). There were no 90-day readmissions related to acute blood loss anemia. CONCLUSIONS: This study demonstrates that routine postoperative complete blood count testing is not absolutely necessary and does not provide additional value in the vast majority of patients with preoperative Hb levels equal to or greater than 12 g/dL when tranexamic acid is administered. This could avoid unnecessary testing in patients and increased savings to the health care system. LEVEL OF EVIDENCE: Level 3, retrospective cohort.

Double Oblique Osteotomy: A Technique for Correction of Posttraumatic Deformities of the Distal Femur.

OBJECTIVE: To evaluate the outcomes of a double oblique osteotomy for the management of distal femoral malunions and a combination malunion/nonunion. DESIGN: Case series. SETTING: Level 1/2 hospital. PATIENTS/PARTICIPANTS: Ten patients with a mean age of 50 years (range 30-69 years) with posttraumatic deformities of the distal femur. INTERVENTION: A 2-level, length-sparing osteotomy was performed in accordance with a detailed preoperative plan for correction of the mechanical axis in a distal femoral deformity. MAIN OUTCOME MEASUREMENTS: Radiographic alignment and physical examination. RESULTS: Average length of follow-up was 26 months. The average coronal plane correction was 12 degrees (range 4-20 degrees) for a residual coronal plane deformity average of 0 degrees. The residual flexion deformity was less than 10 degrees in all cases. All rotational deformities were corrected to within 5 degrees of neutral. The average limb length correction was 1.6 cm (range 0.4-2.6 cm). Eight patients recovered without complication. One patient received bone grafting to achieve union, and a prominent angled blade plate was removed in another. An isolated saphenous nerve sensory deficit resolved spontaneously. CONCLUSIONS: The double oblique osteotomy is a reliable technique for the correction of multiplane deformities of the distal femur. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Changing the paradigm for myoglobin: a novel link between lipids and myoglobin.

Myoglobin (Mb) is an oxygen-binding muscular hemeprotein regulated via Ca(2+)-signaling pathways involving calcineurin (CN), with Mb increases attributed to hypoxia, exercise, and nitric oxide. Here, we show a link between lipid supplementation and increased Mb in skeletal muscle. C2C12 cells were cultured in normoxia or hypoxia with glucose or 5% lipid. Mb assays revealed that lipid cohorts had higher Mb than control cohorts in both normoxia and hypoxia, whereas Mb Western blots showed lipid cohorts having higher Mb than control cohorts exclusively under hypoxia. Normoxic cells were compared with soleus tissue from normoxic rats fed high-fat diets; whereas tissue sample cohorts showed no difference in CO-binding Mb, fat-fed rats showed increases in total Mb protein (similar to hypoxic cells), suggesting increases in modified Mb. Moreover, Mb increases did not parallel CN increases but did, however, parallel oxidative stress marker augmentation. Addition of antioxidant prevented Mb increases in lipid-supplemented normoxic cells and mitigated Mb increases in lipid-supplemented hypoxic cells, suggesting a pathway for Mb regulation through redox signaling independent of CN.

Use of jumbo cups for revision of acetabulae with large bony defects.

Several methods of treatment are available for acetabular revision associated with bone loss. Jumbo cups (minimum diameter of 62 mm in women, 66 mm in men, or 10 mm larger than the normal contralateral acetabulum) are often useful for large defects. The purpose of this study is to report a large jumbo cup series with an average 10-year follow-up. A total of 196 jumbo cups in 186 patients with a minimum of 2-year follow-up were available for review. Harris hip score improved from 44 preoperatively to 72 postoperatively. Survivorship was 98% at 4 years and 96% at 16 years. Five revisions and two resection arthroplasties were performed for failure. In conclusion, porous jumbo cup acetabular revision with supplemental screw fixation provides good to excellent intermediate- and long-term outcomes.

In the face of hypoxia: myoglobin increases in response to hypoxic conditions and lipid supplementation in cultured Weddell seal skeletal muscle cells.

A key cellular adaptation to diving in Weddell seals is enhanced myoglobin concentrations in their skeletal muscles, which serve to store oxygen to sustain a lipid-based aerobic metabolism. The aim of this study was to determine whether seal muscle cells are inherently adapted to possess the unique skeletal muscle adaptations to diving seen in the whole animal. We hypothesized that the seal skeletal muscle cells would have enhanced concentrations of myoglobin de novo that would be greater than those from a C(2)C(12) skeletal muscle cell line and reflect the concentrations of myoglobin observed in previous studies. In addition we hypothesized that the seal cells would respond to environmental hypoxia similarly to the C(2)C(12) cells in that citrate synthase activity and myoglobin would remain the same or decrease under hypoxia and lactate dehydrogenase activity would increase under hypoxia as previously reported. We further hypothesized that ß-hydroxyacyl CoA dehydrogenase activity would increase in response to the increasing amounts of lipid supplemented to the culture medium. Our results show that myoglobin significantly increases in response to environmental hypoxia and lipids in the Weddell seal cells, while appearing similar metabolically to the C(2)C(12) cells. The results of this study suggest the regulation of myoglobin expression is fundamentally different in Weddell seal skeletal muscle cells when compared with a terrestrial mammalian cell line in that hypoxia and lipids initially prime the skeletal muscles for enhanced myoglobin expression. However, the cells need a secondary stimulus to further increase myoglobin to levels seen in the whole animal.

Locking plate technology and its role in osteoporotic fractures.

Osteoporosis is a public health issue that leads to increased morbidity and dependency in an increasing population. Fractures in osteoporotic bone have been a contraindication to internal fixation due to their past poor results. Various treatment methods and innovations have been attempted that have met with some success. This paper reviews one such innovation, locking-plate osteosynthesis, looking at its technology and success and its role in osteoporotic patients. As this is an evolving technology, surgeon's experience with these plates and screws are in advance of clinical studies and therefore the surgeons should proceed with caution when choosing locking plate technology in the treatment of osteoporotic fractures.

Salvage of distal tibia metaphyseal nonunions with the 90 degrees cannulated blade plate.

Nonunion of distal tibia metaphyseal fractures after trauma is a major problem. Treating these nonunions is made more challenging by the presence of symptomatic ipsilateral tibiotalar arthrosis. The current study examined the use of the 90 degrees cannulated blade plate as an alternative method of stable internal fixation for 13 distal tibia metaphyseal nonunions and simultaneous fusion of three arthritic tibiotalar joints in 13 patients (seven males and six females) with an average age of 42.4 years (range, 21-73 years). Each patient had an average of three prior procedures (range, 2-6). Patients were followed up for an average of 34.2 months (range, 24-55 months). All 13 patients achieved radiographic and clinical union an average of 15.6 weeks (range, 12-20 weeks) from the date of the definitive procedure. There were two broken screws, but no secondary procedures were required to obtain fusion. All patients were ambulatory without support at the last followup. The implant proved effective for stable internal fixation of distal tibia metaphyseal nonunions alone or with simultaneous fusion of the tibiotalar joint.