Measured distance from posterior tibia to popliteal artery increases with flexion and subluxation of the knee.

Purpose: Popliteal artery laceration is a devastating complication in total knee arthroplasty (TKA). Its anatomic position relative to the tibia has been studied using ultrasound or magnetic resonance imaging. This is the first study performed in a laboratory using radiographic measurements to determine if increased flexion and subluxation of the knee increase the distance between the tibia and popliteal artery. Methods: The femoral artery was infused with radiopaque dye in six cadavers. The knee was placed in two different degrees of flexion and three of subluxation. The radiographic distance between standardized markers in the posterior tibia and popliteal artery was measured. Results: The average distance from the tibial peg to the popliteal artery at 90° of flexion increased from 0% to 50% to 100% subluxation. The increase was statistically significant (Friedman test p = 0.016). The contrast between neutral and 100% subluxation was statistically significant (Sign test p = 0.031). At 115° flexion, average distance from the peg to popliteal artery significantly increased as subluxation increased (Friedman test p = 0.05). In three specimens, at 115° of flexion and 100% subluxation, a line perpendicular to the axis of the tibia, failed to intersect the popliteal artery. The measured distance increased from 90° to 115° of flexion at a given degree of subluxation, but this difference did not reach statistical significance. Conclusions: Increasing flexion and subluxation of the tibia results in increasing distance between the cut plane of the tibial plateau and popliteal artery and decreases risk of laceration. Level of Evidence: Not applicable.

Late Atraumatic Ceramic Head Fracture in Total Hip Arthroplasty: A Case Report.

Introduction: Atraumatic ceramic femoral head fracture is an uncommon but overwhelming complication of total hip arthroplasty (THA). The complication rate is low, with few reports in the literature. It is critical to continue researching late fracture risk to mitigate these instances. Case Report: A 68-year-old Caucasian female presented with an atraumatic ceramic femoral head fracture in the setting of a ceramic-on-ceramic THA 17 years after primary surgery. The patient was successfully revised to a dual-mobility construct with a ceramic femoral head and a highly cross-linked polyethylene liner. The patient returned to normal function without pain. Conclusion: The complication rate for fracture of the ceramic femoral head is as low as 0.001% for fourth-generation aluminum matrix composite designs, while the complication rate of late atraumatic ceramic fracture is largely unknown. We present this case to add to the current literature.

Liposomal Bupivacaine vs Ropivacaine for Adductor Canal Blocks in Total Knee Arthroplasty: A Prospective Randomized Trial.

BACKGROUND: The purpose of this study is to determine the benefit of the analgesic liposomal bupivacaine compared to ropivacaine, by assessing pain and joint stiffness, and total oral opioid consumption by milligram morphine equivalent (MME) after total knee arthroplasty. METHODS: Patients were randomized to receive either the study drug (liposomal bupivacaine admixed with bupivacaine) or the control drug (ropivacaine) in an adductor canal block. Only the anesthesiologist performing the block was aware of which arm of the study the patient was randomized to. MME, pain, Knee injury and Osteoarthritis Outcome Score Joint Replacement, and overall benefit of analgesia scores were recorded 24, 48, and 72 hours post-surgery either face-to-face or via telephone depending on patient discharge status. RESULTS: One hundred patients were enrolled into the study and analyzed: 54 in the control group and 46 in the experimental group. Primary outcomes measured were pain as a numerical rating scale, MME, and length of stay in hours. Secondary outcomes were joint pain and stiffness recorded as Knee injury and Osteoarthritis Outcome Score Joint Replacement outcome and overall benefit of analgesia score. No statistically significant between-group differences were observed for any measured outcome. CONCLUSION: We did not find any supporting evidence that liposomal bupivacaine yields increased pain relief following total knee arthroplasty compared to the control drug, ropivacaine.

No Increase in Instability with Obturator Externus Release in Direct Anterior Approach.

Use of the direct anterior approach in total hip arthroplasty is becoming increasingly common. Complications associated with this approach pertain to proximal femoral exposure. Selective capsular and tendinous releases improve exposure intraoperatively. Release of obturator externus has been avoided to prevent postoperative instability. A retrospective case-control review of consecutive patients who underwent direct anterior approach was performed. Demographic information, sequence of releases performed, dislocations that occurred postoperatively, and revision total hip arthroplasties (THAs) were recorded. Overall dislocation rate was 0.6% (2/340). Obturator externus release was performed in 169 cases (49.7%). Both groups with and without release experienced a single dislocation event (p = 1.0). Overall revision rate was also 0.6% (2/340). One dislocation underwent revision for instability. Selective release of obturator externus after other releases have failed to improve proximal femoral exposure does not result in an increased rate of postoperative hip instability in direct anterior approach THA. (Journal of Surgical Orthopaedic Advances 30(2):082-084, 2021).