Osseointegration reduces aseptic loosening of primary distal femoral implants in pediatric and adolescent osteosarcoma patients: a retrospective clinical and radiographic study.

AIM: The challenge of distal femoral replacement (DFR) longevity remains a priority for orthopaedic oncologists as the overall survival and activity level of young patients with osteosarcoma continues to improve. This study hypothesized that increased extracortical osseointegration at the bone-implant shoulder (i.e., where the metal implant shaft abuts the femur) will improve stress transfer adjacent to the implant, as evidenced by reduced cortical bone loss, radiolucent line progression and implant failure in young patients (< 20 years) following DFR surgery. METHODS: Twenty-nine patients of mean age 13.09 ± 0.56 years received a primary DFR. The clinical outcome of 11 CPS®, 10 GMRS®, 5 Stanmore® and 3 Repiphysis® implants was evaluated over a mean follow-up period of 4.25 ± 0.55 years. The osseous response to a bone-implant shoulder composed of either a hydroxyapatite-coated grooved ingrowth collar (Stanmore®), a porous metal coating (GMRS®) or a polished metal surface (Repiphysis®) was quantified radiographically. RESULTS: All (100.0%) of the Stanmore® implants, 90.0% of GMRS®, 81.8% of CPS® and 33.3% of the Repiphysis® implants survived. Significantly increased extracortical bone and osseointegration were measured adjacent to the Stanmore® bone-implant shoulder when compared with the GMRS® and Repiphysis® implants (p < 0.0001 in both cases). Significantly decreased cortical loss was identified in the Stanmore® group (p = 0.005, GMRS® and p < 0.0001, Repiphysis®) and at 3 years, the progression of radiolucent lines adjacent to the intramedullarly stem was reduced when compared with the GMRS® and Repiphysis® implants (p = 0.012 and 0.026, respectively). CONCLUSIONS: Implants designed to augment osseointegration at the bone-implant shoulder may be critical in reducing short- (≤ 2 years) to mid- (≤ 5 years) term aseptic loosening in this vulnerable DFR patient group. Further longer-term studies are required to confirm these preliminary findings.

Mechanism of Knee Injuries in the National Basketball Association: A Video-Based Analysis.

Background: To characterize the mechanism of knee injuries among NBA players during the 2010-2020 seasons using video-based analysis. Methods: An injury database of NBA players was queried for knee injuries from the 2006-07 to 2020-21 seasons and cross-referenced with NBA injury reports. Youtube.com was searched to identify available injury footage. The mechanism of knee injury during play was analyzed by three independent reviewers. Non-mechanistic data related to the injury was gathered from news reports and official NBA websites. Results: A total of 2,868 knee injuries occurred in NBA players from 2010 to 2020 seasons; 121 had high quality videos for analysis. The most common mechanism of injury was knee flexion in valgus with internal rotation (27.3%, p < 0.001), which was associated with injury to the ACL (55.2%, p=0.0001). Injuries occurred most often with control of the ball (62.8%, p=0.0064), while on offense (73.6%, p=0.0001), and without contact (71.1%, p=0.0001). A 28.1% incidence of re-injury was observed in the first 3-year period, and 43.8% of knee injuries required surgery. The average number of games missed due to injury requiring surgery was 55.1 games compared to 8.5 games in those treated nonoperatively (p < 0.0001). Conclusion: Understanding mechanisms of knee injury may guide preventative strategies and injury management programs in NBA players. Video-based analysis reveals the situational characteristics and mechanisms of knee injuries, but further studies are needed to develop injury prevention programs, efficacy of prevention strategies, and rehabilitation to minimize games missed from these injuries.