Background: The second generation of a custom total knee arthroplasty (TKA) implant cast from a 3D-printed mold was introduced into the market in 2012. The purpose of this retrospective study was to investigate short- to mid-term survivorship and complication rates of this novel implant. Methods: This study is a retrospective analysis of 314 TKA procedures (264 patients) performed by a single surgeon using a customized TKA from September 2012 to November 2015. Patient demographics, rate of implant revision, rate of reoperation for any reason, and rate of postoperative complications were recorded. Results: At the time of index surgery, the mean patient age was 64.7 years, and the mean follow-up duration was 3 years. At the final follow-up, implant survivorship free from revision was 98.1%, and survivorship free from reoperation for any reason was 92.4%. Conclusions: Our analysis revealed favorable short- to mid-term survivorship for a customized TKA implant. While the short- to mid-term outcomes for this implant are promising, future studies are required to assess long-term outcomes and durability.

BACKGROUND:Spino-pelvic orientation may affect dislocation risk following total hip arthroplasty (THA). It can be measured on lateral lumbo-pelvic radiographs. The sacro-femoro-pubic (SFP) angle, measured on an antero-posterior (AP) pelvis radiograph, is a reliable proxy for pelvic tilt, a measurement of spino-pelvic orientation measured on a lateral lumbo-pelvic radiograph. The purpose of this study was to investigate the relationship between SFP angle and dislocation following THA.METHODS:An Institutional Review Board-approved retrospective case-control study was conducted at a single academic center. We matched 71 dislocators (cases) to 71 nondislocators (controls) following THA performed by 1 of 10 surgeons between September 2001 and December 2010. Two authors (readers) independently calculated SFP angle from single preoperative AP pelvis radiographs. Readers were blinded to cases and controls. Conditional logistic regressions were used to identify factors differentiating cases and controls.RESULTS:The data did not show a clinically relevant or statistically significant difference in SFP angles after adjusting for gender, American Society of Anesthesiologists classification, prosthetic head size, age at time of THA, measurement laterality, and surgeon.CONCLUSION:We did not find an association between preoperative SFP angle and dislocation following THA in our cohort. Based on our data, SFP angle as measured on a single AP pelvis radiograph should not be used to assess dislocation risk prior to THA.

BACKGROUND:The sacro-femoro-pubic (SFP) angle is a surrogate measurement for pelvic tilt obtained on anteroposterior (AP) pelvis radiographs. It is unknown whether the SFP angle can be measured reliably by senior surgeons and trainees alike.METHODS:We conducted an intrareader and interreader reliability study using preoperative AP pelvis radiographs. Using our hospital electronic database, we randomly selected 31 subjects undergoing primary total hip arthroplasty. An attending orthopedic surgeon and two orthopedic surgery residents performed two separate SFP angle measurements for each subject. Intrareader and interreader agreement were measured using intraclass correlation coefficients (ICC).RESULTS:Pairwise intrareader and interreader ICCs ranged from 0.91 to 0.99. Overall ICC was 0.94. Interreader ICCs between the attending surgeon and each orthopedic resident were 0.93 and 0.98, and the ICC between orthopedic residents was 0.91. Interreader mean differences for SFP angle measurements were 2.32 degrees or less: -2.03 (standard deviation: 2.23) and 0.29 (1.64) between the attending surgeon and each orthopedic resident, and 2.32 (2.44) between orthopedic residents.CONCLUSION:SFP angle may be measured reliably on AP pelvis radiographs by senior clinicians and trainees. SFP angle measurement may prove helpful as an alternative to pelvic tilt measurements when lateral pelvic radiographs are not available.