Lateral unicondylar knee arthroplasty can help patients return to sport

One prospective study covers patients that undergo unicompartmental arthroplasty from 2000-2005 : nineteen patients underwent lateral unicompartmental (uni) knee replacements, with an average age of 68 years for the lateral unicompartmental group.

Assessments included preoperative and postoperative range of motion, subjective testing, radiographic evaluation and MRI.

Only one patient was converted to a total knee arthroplasty, and none were lost to follow-up.

Successful outcomes are reported in the majority of cases over an average follow-up of 33 months…

Physical examination and subjective questioning along with MRI correlation would help  predict successful outcomes.

Overall, patients reported a return to skiing in 5 months, tennis in 4 months and walking and jogging within 1 to 2 months.

He also reports that long-term results have to be followed and adds that the procedure has shown it is worth consideration.

“You can preserve bone stock, you can get near-normal kinematics, you have low cost and blood loss during surgery is less,” he says.

Reference

Plancher KD, Bishai SK, Ibrahim T. Patients undergoing lateral unicondylar knee arthroplasty: Can we guarantee success and return to sport? Paper SS-38. Presented at the 2010 Annual Meeting of the Arthroscopy Association of North America. May 20-23, 2010. Hollywood, Fla.

Patients with mucoid ACL hypertrophy show a narrower notch, a steeper notch angle, and a smaller notch area

The intercondylar notch width, notch index (width of intercondylar notch/width of femoral condyle), transverse notch angle (TNA), sagittal notch angle (SNA), and notch area are recorded on axial and sagittal MR images at the midpoint of Blumensaat’s line which is identified on sagittal images.

The diameter of the ACL is recorded on coronal MR images at the posterior end of Blumensaat’s line.

The mean values of the intercondylar notch width, notch index, TNA, SNA, notch area, and ACL diameter are

16.0 mm/0.2/50.3 degrees /36.5 degrees /249.0 mm(2)/7.7 mm (group 1);

19.3 mm/0.3/52.9 degrees /40.2 degrees /323.4 mm(2)/4.8 mm (group 2); and

20.3 mm/0.3/51.4 degrees /39.1 degrees /350.8 mm(2)/4.5 mm (group 3).

The intercondylar notch width, notch index, SNA, and notch area is smaller, and ACL diameter is thicker in group 1 compared with the other groups (p < 0.05).

Athletes with smaller ACLs may be more susceptible to injury

People with torn ACLs are more likely to have a smaller ligament than similarly-sized people who have never injured a knee.

The smaller the intercondylar notch the smaller the cross-sectional area of the ACL midsubstance. In addition to the impingement of the ACL at the anterior and posterior roof of the notch, a biomechanically weaker ACL may be the reason for disposition to an ACL rupture in patients with a small intercondylar notch.

High resolution MR imaging performed on a 1.5 T magnet using a dedicated extremity-coil shows women to have a thinner ACL midsubstance than men of the same height which may be one of the critical etiologic factors that predispose women to an ACL rupture.

We are already to confirm(performing hundreds of reconstruction) that there is a statistical difference in femoral notch and anterior cruciate ligament volumes between men and women, which, in turn, is related to differences in height and weight.

Use of oblique coronal MRI of the knee improves both the diagnostic accuracy and confidence for grading ACL graft injury

Images from the article (full text).