Gender and age based differences in behavioural patterns following anterior cruciate ligament injury.

ACL injury can be clinically diagnosed prior to imaging, and therefore understanding any symptomatology differences between age-groups and genders is critical. Data gathered from 341 patients with ACL injuries over six years showed no gender-based difference in ability to continue playing sport post-injury. Fewer males required crutches (37.2% vs. 49.5%, p = 0.04) and more males returned to sports prior to treatment (24.4% vs. 14.1%, p = 0.04). There was no age based difference in play continuation post-injury, however more elderly patients fell post-injury (<30 y: 91.9%, 30 y 83.8%, p = 0.02). Therefore, there are few differences in behavioural patterns following ACL injury based on age or sex.

The diameter of single bundle, hamstring autograft does not significantly influence revision rate or clinical outcomes after anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament (ACL) graft failure is a complication of ACL reconstruction (ALCR). Smaller autograft diameter may be a contributing factor. Our aim was to determine if hamstring autograft diameter influences graft rupture and patient-reported outcome scores. METHODS: This study included 786 consecutive patients undergoing primary, single bundle, autograft hamstring ACLR. The primary outcome was revision ACLR surgery. Secondary outcomes were patient reported International Knee Documentation Committee (IKDC) score, Knee Injury & Osteoarthritis Outcome Score (KOOS) and Tegner Activity score. Multiple logistic regression and Fischer Exact tests were employed for statistical analysis. RESULTS: Increasing autograft diameter did not lead to a reduction in revision ACLR surgery (odds ratio [OR], 1.093; 95% confidence interval [CI], 0.612 to 1.954; P=0.76). Revision ACLR positively correlated with male gender (OR, 3.971; 95% CI 1.109 to 14.214; P=0.03) and negatively correlated with increasing age (OR, 0.919; 95% CI 0.882-0.958, P<0.0001). There was no association between graft rupture rate and dichotomized graft size. At latest follow-up, there was no correlation between graft diameter and IKDC (Pearson's adjusted R2=0.058; P=0.75), Tegner Activity score (Pearson's adjusted R2=0.244; P=0.53), or any component of the KOOS (Pearson's adjusted R2 range: 0.008 to 0.141; P-value range: 0.21 to 0.76). CONCLUSION: Increased hamstring autograft diameter did not significantly reduce revision ACLR surgery or improve clinical outcomes. Other factors such as gender and age do influence the rate of revision ACL surgery. STUDY DESIGN: Level IV, retrospective case series.

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

BACKGROUND: Rotational alignment of prosthetic components in total knee arthroplasty (TKA) is important to successful outcomes. Component malrotation is a known cause of revision and understanding normal rotational alignment may help recreate normal joint kinematics. To date, no large MRI study assessing femorotibial rotational alignment in nonarthritic knees has been undertaken. QUESTIONS/PURPOSES: Is Insall's tibial axis a reliable rotational landmark against common femoral rotational axes in the nonarthritic patient population? METHODS: We reviewed 544 knee MRI scans performed for suspected soft tissue pathology and identified Insall's tibial rotational axis as well as the femoral clinical trans-epicondylar axis (TEAc), femoral surgical trans-epicondylar axis (TEAs), posterior condylar articular axis (PCA), and a modified Eckhoff's cylindrical axis. The perpendiculars of these axes were superimposed on Insall's tibial axis, and the angular differences were measured. RESULTS: Insall's axis was internally rotated to the TEAc by 1.4°, externally rotated to Eckhoff's cylindrical axis by 1.8°, externally rotated to the TEAs by 2.7°, and externally rotated to the PCA by 3.5°. The mean deviation from 0° (optimal alignment for each femoral axis) was significantly greater for the PCA relative to all other femoral axis. CONCLUSION: Insall's axis is a reliable landmark for rotational positioning of the tibial component and may optimize femorotibial kinematics in fixed-bearing TKA.

Erratum to: Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

[This corrects the article DOI: 10.1007/s11420-016-9491-y.].

Comparison of tibial bone coverage of 6 knee prostheses: a magnetic resonance imaging study with controlled rotation.

PURPOSE: To compare the extent of tibial bone covered by the tibial tray in 6 most commonly used total knee arthroplasty designs in order to strike a balance between mediolateral cortical fit and optimal tibial component rotation. METHODS: In 74 men and 27 women aged 17 to 60 (mean, 32) years with suspected soft-tissue injuries, their magnetic resonance images of the knee in full extension were superimposed with scans of the tibial trays of the 6 designs (one asymmetric and 5 symmetric). The tibial coverage by the tray and any posterolateral/posteromedial overhang/underhang were measured. RESULTS: All 6 tray designs achieved tibial bone coverage of over 80%. Only 28% of all trays achieved optimal posterolateral fit, whereas 49% had posterolateral overhang enough to cause popliteal tendon impingement. Although the asymmetric tray provided highest tibial coverage (88%), its rates of relative and absolute posterolateral and posteromedial overhang were also highest (64%). CONCLUSION: The asymmetric tray provided improved tibial coverage at the expense of posterolateral and posteromedial overhang of the tibial tray.

Using magnetic resonance imaging to predict adequate graft diameters for autologous hamstring double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To determine whether the preoperative magnetic resonance imaging (MRI) cross-sectional area (CSA) of the hamstring tendons can predict intraoperative bundle diameters during double-bundle anterior cruciate ligament reconstruction. METHODS: A prospective study of 34 patients undergoing anterior cruciate ligament reconstruction with hamstring autografts was performed. CSAs of independent and combined hamstring tendon diameters were correlated to preoperative magnetic resonance images. RESULTS: Intraoperative tendon diameter measurement positively correlated with preoperative MRI tendon CSA measurement for gracilis (P = .0006), semitendinosus (P = .001), and final graft size (P = .001). Double-stranded gracilis grafts greater than or equal to 5 mm in diameter had a mean preoperative MRI gracilis CSA of 9.98 mm(2) compared with a mean of 7.76 mm(2) for grafts less than 5 mm (P = .002). Double-stranded semitendinosus grafts greater than or equal to 6 mm had a mean preoperative MRI tendon CSA of 17.33 mm(2) compared with 14.80 mm(2) for grafts less than 6 mm (P = .02). Final grafts of diameter greater than or equal to 7 mm had a mean preoperative MRI total tendon CSA of 26.54 mm(2) compared with 22.22 mm(2) for grafts under 7 mm (P = .06). CONCLUSIONS: Preoperative MRI is a clinically useful tool to assess hamstring tendon graft diameter. We recommend preoperative CSA threshold values of 10 mm(2) and 17 mm(2) for the gracilis and semitendinosus tendons, respectively, to reliably predict the potential for a double-bundle anterior cruciate ligament reconstruction. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Mycobacterium fortuitum infection after anterior cruciate ligament reconstruction using a polylactic acid bioabsorbable screw: Case report.

We report a case of pretibial sinus and abscess after anterior cruciate ligament reconstruction using a polylactic acid tricalcium phosphate bioabsorbable screw for tibial fixation. Mycobacterium fortuitum was identified as the pathogen after specific mycobacterial cultures were obtained from operative specimens. M. fortuitum is a known but rare cause of periprosthetic infection. Diagnosis is often delayed as routine microbiological cultures do not utilise specific culture requirements for mycobacterial growth. There have been several reports in the literature of sterile abscesses associated with bioabsorbable screws. To our knowledge, this is the first case report of a non-tuberculous mycobacterial infection associated with a bioabsorbable implant. This case illustrates that post-operative Mycobacterium infection can occur as a complication of ACL reconstruction with bioabsorbable screw fixation and should be considered in the differential diagnosis of post-operative periprosthetic infection.