A Biomechanical Comparison of the Effect of Baseplate Design and Bone Marrow Fat Infiltration on Tibial Baseplate Pullout Strength.

BACKGROUND: Early clinical results of a new total knee arthroplasty (TKA) implant design show promise for improved outcomes and patellofemoral function scores. However, reports of early tibial component-cement interface debonding requiring revision have been published. This study investigated the biomechanical properties of three different tibial baseplates to understand potential causes of failure. METHODS: PFC Sigma (control), Attune (1st generation) and Attune S+ (2nd generation) tibial baseplates were implanted into 4th generation sawbone tibia models using a standardized technique. Three of each baseplate were cemented with and without additional bovine bone marrow fat. All models were tested to failure with measured axial distraction force. Implant type, presence or absence of bovine marrow and load to failure were all recorded and compared. Two-way ANOVA followed by post-hoc pairwise comparisons were used to determine statistical significance, which was set to P < .05. RESULTS: The 2nd generation tibial baseplates required significantly more force to failure. The presence of bovine marrow significantly reduced the pullout force of the implant designs overall. No significant difference was detected between the 1st generation and control baseplates. Failure mode for each model was also noted to be different irrespective of the presence or absence of bone marrow fat. CONCLUSION: The 2nd generation baseplates required significantly more force to failure compared with older designs. The presence of bone marrow during cementation of a tibial base plate significantly decreased axial pullout strength of a tibial baseplate in this laboratory model. All 1st generation baseplates exhibited debonding at the cement-implant interface.

Arthroscopic Versus Open Rotator Cuff Repair: Fellowship-Trained Orthopaedic Surgeons Prefer Arthroscopy and Self-Report a Lower Complication Rate.

PURPOSE: To evaluate whether fellowship training had an effect on the practice pattern and complication rates among Part II examinees of the American Board of Orthopaedic Surgery (ABOS) for rotator cuff repair (RCR) from 2007-2017. METHODS: The ABOS database was queried for arthroscopic (Current Procedural Terminology [CPT] code 29827) and open/mini-open (CPT codes: 23410, 23412) RCR performed from 2007-2017. Excluded were procedures that did not included CPT codes 29827, 23410, 23412. A comparison between arthroscopic and open/mini-open use as well as self-reported complications were assessed based on recorded fellowship training. RESULTS: A total of 31,907 RCR were reported over the past 10 years (2007-2017). The percentage of RCR procedures performed using arthroscopic technique vs open/mini-open varied among surgeons who completed one fellowship: Sports Medicine (92.5 % arthroscopy; 7.5 % mini/open), Shoulder & Elbow (91.3 % arthroscopy; 8.7% mini/open), and Hand & Upper Extremity (69.6 % arthroscopy; 30.4 % open). Total complication rates varied among surgeons who completed one fellowship: Sports Medicine (11.5 %), Shoulder & Elbow (13.5 %), and Hand & Upper Extremity (13.4 %). Surgeons completing one fellowship in either Sports Medicine, Shoulder & Elbow, Hand & Upper Extremity all reported significantly lower complication rates using arthroscopic over mini/open technique (P < .001). CONCLUSIONS: Among ABOS Part II examinees completing a Sports Medicine, Shoulder and Elbow or Hand and Upper Extremity fellowship, Sports Medicine trained surgeons had significantly greater rates of performing arthroscopic over open RCR and significantly lower self-reported intraoperative complication rates. CLINICAL RELEVANCE: Understanding the effects of fellowship training may guide mentors and future trainees.

Arthroscopic and Open or Mini-Open Rotator Cuff Repair Trends and Complication Rates Among American Board of Orthopaedic Surgeons Part II Examinees (2007-2017).

PURPOSE: To ascertain trends and reported complication rates of arthroscopic and open or mini-open rotator cuff repairs (RCRs) reported by American Board of Orthopaedic Surgery (ABOS) Part II examinees between 2007-2017. METHODS: The ABOS database was queried for both arthroscopic RCR (International Classification of Diseases code 29827) and open or mini-open RCR (International Classification of Diseases codes 23410 and 23412) performed by Part II examinees from 2007-2017. A comparison between overall procedure rates, as well as reported complications (anesthetic, medical, surgical, reoperations, and readmissions) associated with the respective repair technique, was performed. RESULTS: From 2007-2017, a total of 31,907 RCRs were reported by Part II examinees. Of those, 85.2% (n = 27,189) were arthroscopic whereas 14.8% (n = 4,718) were open or mini-open. The rate of arthroscopic RCR increased from 73% (n = 2,138) in 2007 to 90% (n = 2,031) in 2017, whereas the rate of open or mini-open RCR decreased from 27% (n = 771) to 10% (n = 234) during the same period. Rates of reported annual complications were significantly lower for arthroscopic RCR (7.4%-16.2%) than for open or mini-open RCR (12.9%-30.3%) for each of the past 6 years (2012-2017) (P < .001). Arthroscopic RCR had an overall lower cumulative occurrence of complications than open or mini-open RCR over the past decade (2007-2017) (P < .001). The relative risk of complications for arthroscopic RCR compared with open RCR was 0.71 (95% confidence interval, 0.66-0.77). CONCLUSIONS: ABOS Part II examinees reported an increased practice of arthroscopic RCR in comparison with open or mini-open RCR over the past 10 years. Reported annual complication rates have been significantly lower for arthroscopic RCR over the past 6 years, with an overall lower cumulative rate from 2007-2017. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Capnocytophaga canimorsus Periprosthetic Joint Infection in an Immunocompetent Patient: A Case Report.

INTRODUCTION: A periprosthetic joint infection (PJI) is a potentially devastating complication following an arthroplasty procedure. There are many organisms that commonly cause this complication; in this case report, we will discuss a PJI caused by an unusual bacteria found in the mouths of domestic pets. OBJECTIVE: To present a case report of a patient with a periprosthetic hip infection from Capnocytophaga canimorsus and review the literature. METHODS: We present a case of C canimorsus PJI in an immunocompetent woman who had undergone a total hip arthroplasty. The patient was doing well postoperatively for many years until she was bitten on the foot by a domestic canine. Patient diagnosed using Musculoskeletal Infection Society criteria, then treated with explant of the hip prosthesis, irrigation and debridement, placement of an antibiotic cement spacer, and a 6-week course of intravenous antibiotics. RESULTS: Unfortunately, while awaiting replant, this patient had a massive myocardial infarction and died. DISCUSSION: Current literature suggests treating canine bites with amoxicillinas well as a discussion with patients pre-/postoperatively from a lower extremity arthroplasty specialist. CONCLUSION: Capnocytophaga canimorsus is a rare cause of infection, even more unusual in an immunocompetent patient. This study highlights the importance of considering C canimorsus as a cause of PJI, regardless of the immunologic status of the patient.