Patellar tilt does not affect patient reported outcomes after modern total knee arthroplasty.

BACKGROUND: The focus of patella maltracking after total knee arthroplasty (TKA) has traditionally been on patella polyethylene damage and failure mechanisms rather than functional outcomes. The purpose of this study was to evaluate the effect of patellar tilt on patient reported outcomes (PROMS) after primary TKA performed with patellar resurfacing. METHODS: A retrospective review using a single implant design was performed. Patella tilt was radiographically measured according to a standardized protocol. PROMS related to pain, function, and satisfaction were evaluated preoperatively and at minimum 1-year follow-up. RESULTS: A total of 468 TKAs were included for analysis. Mean age and BMI were 64 years and 35 kg/m2; respectively while 63% of patients were female. The median follow-up period was 12.7 months. Overall, patellar tilt was corrected from a median of 5.0 degrees preoperatively to a median of 3.0 degrees postoperatively. Preoperative, postoperative, and the change in patellar tilt had no significant effects on PROMS at minimum 1-year follow-up (p ≥ 0.092). Satisfaction in knee function while getting out of bed was higher for patients with approximately the same patellar tilt before and after TKA compared to patients with an increase in lateral patellar tilt (95% vs 80%, p = 0.025). CONCLUSIONS: The range of patellar tilt studied in this cohort had little to no effect on PROMS. However, suboptimal patellar tracking may potentiate edge loading of the polyethylene and contribute to implant damage in the long-term. These results are helpful to focus efforts on the tibiofemoral articulation as the predominant determinant of patient outcomes.

Idiopathic Charcot Arthropathy of the Knee Presenting as a Bicondylar Tibial Plateau Fracture.

Charcot arthropathy is an infrequent condition that primarily involves the foot and ankle; rarely, it has been reported to affect the knee. Risk factors for Charcot arthropathy are well described with diabetes being the most common cause. Idiopathic Charcot arthropathy without a secondary etiology is extremely rare, with only a few cases described involving the foot and shoulder. Clinically, idiopathic Charcot arthropathy presents a notable challenge because delayed diagnosis can lead to surgical complications and advancement of joint destruction. We report idiopathic Charcot arthropathy of the knee presenting as a bicondylar tibial plateau fracture successfully managed with total knee arthroplasty after failed open reduction internal fixation. We diagnosed the patient when the clinical/surgical presentation was indicative of Charcot arthropathy and after excluding all other diagnoses. This previously unreported case describes the complexity of idiopathic Charcot arthropathy with subsequent fractures and highlights the importance of patient history, presentation, and surgical intervention.

Non-invasive repair of an iatrogenic tibial artery branch pseudoaneurysm after intramedullary nailing.

Tibial fractures are a commonly seen injury in orthopedic surgery. Intramedullary nailing is considered the standard of care, as complications are rare. Those of a vascular nature, including iatrogenically induced pseudoaneurysms of the tibial artery have been previously described in the literature, however each reported case has required surgical repair. In the current case, we describe a repair of a tibial artery branch pseudoaneurysm, after direct contact with an interlocking screw from tibial intramedullary nailing, via ultrasound-guided thrombin injection. To the authors' knowledge, this is the first reported case of a tibial artery pseudoaneurysm repaired non-surgically. This adds support to the promising literature on non-invasive repair of orthopedically related pseudoaneurysms.

Thermal Energy Produced by Medium Velocity Pistol Projectiles and the Effects on Peripheral Nerve Tissue.

CONTEXT: Sidearm pistols are more frequently involved in violent crimes due to their relatively small size and ability to be concealed. The extent to which the thermal energy released from such medium velocity pistol projectiles contributes to peripheral nerve injury requires further testing. The purpose of this paper is to describe a method to quantify how much thermal energy is released during impact of medium velocity pistol projectiles and report how thermal energy contributes to peripheral nerve injury. METHODS: Eleven seven-centimeter segments of radial, median, and ulnar nerves were dissected from a thawed fresh frozen cadaver. The nerve segments were placed in a 10% ballistics gel block, one centimeter from the end of the block nearest the shooter. A series of 115-grain 9 mm. NATO-classified ammunitions were fired through the nerve and ballistics gel construct with a pistol. The impacts were recorded with a high-speed infrared camera and nerve samples were sent for histologic analysis by two board-certified pathologists. RESULTS: The average velocity of the projectiles were 391m/s, 95% CI [387-395 m/s], with an average kinetic energy of 572.0 J, 95% CI [560.0-583.0J]. The average observable temperature of the ballistics gel/nerve prior to impact was 28.8°C±0.6ºC, 95% CI [26.4-30.3°C]. Average observable temperature of the surrounding ballistics gel/nerve during projectile impact was 55.1°C±2.4ºC, 95% CI [51.3- 62.1°C], yielding an average observable increase of 26.4°C±3.2ºC, 95% CI [20.2- 35.4°C]. An adjusted temperature increase was also surprisingly high 63.4°C ± 3.2, 95% CI [57.2 - 72.4ºC]. Histology reports of the impacted nerve tissue failed to show any sign of thermal or even crush injury. CONCLUSIONS: Medium velocity handgun projectiles release a significant amount of heat energy when impacting a substance similar to human tissue. The authors' temperature data points were greater than those previously reported to cause thermal injury to peripheral nerves. The authors' findings suggest that nerve injury after collision with pistol projectiles may be secondary to thermal injury in addition to the classic model of concussion and penetration given our documented levels of heat generated during impact.