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Patient Characteristics Affect the Anatomic Locations of Nearby Neurovascular
Structures in Medial and Lateral Meniscus Repair
Jonathan Yin1, Vincent Michael Moretti, M.D.2, Mark R. Hutchinson, M.D.1.
1
University of Illinois, Chicago, IL, USA, 2University of Illinois, Berwyn, IL, USA.
Disclosures:
J. Yin: None. V.M. Moretti: None. M.R. Hutchinson: None.
Introduction: Arthroscopic inside-out repair of meniscus tears remains popular due to its lower cost and greater strength of
suture material. Complication rates of up to 38% for the saphenous nerve and up to 2.5% for serious peroneal nerve injury have
been reported in previous studies. Case reports also exist for popliteal artery injury during meniscal sutures. A study of the
peroneal nerve in 35 cadavera found significant variability in the branching patterns of the nerve. There remains a paucity of
large sample data on the anatomic course of these neurovascular structures especially as it pertains to patient characteristics.
We use magnetic resonance imaging (MRI) to define the location and variability of the saphenous, peroneal and popliteal
neurovascular structures in medial and lateral menisci repairs and to establish potential patient risk factors.
Methods: Axial MRIs of the knee were retrospectively reviewed for 100 consecutive adult patients in IRB-approved study. To
simulate virtual needle tracks, three lines were drawn along the lateral (L), medial (M) and midline (C) of the patellar tendon at
the joint line. The tracks were converged on the posterior horns of both the medial and lateral menisci at approximately 10mm
from the meniscal roots before continuing to the posterior knee (see Fig 1). Vector distances from each of the needle tracks
were measured to the peroneal and popliteal structures for the lateral meniscus, and measured to the saphenous nerve for the
medial meniscus. Images with gross knee pathology or prior reconstruction were excluded. Patient age, gender, race/ethnicity,
height and weight were also obtained and analyzed. Descriptive statistics were calculated using Student’s t-test, ANOVA and
multivariate regression on Stata/IC 12.0.
Results: Mean patient age was 45.6 years (range 20-75) and 57% of patients were female. Mean height and weight were 1.69m
(±0.10) and 85.7kg (±18.6), respectively. 50% of patients were black, 26% non-Hispanic white, 19% Hispanic and 5% Asian. For
the medial meniscus, the vector distance of the saphenous nerve to the M, C, and L tracks were 12.2mm (±4.8), 8.4mm (±4.8)
and 5.0mm (±4.2), respectively. The saphenous nerve was directly on the L track in 23% of patients and on the C track in 6%. For
the lateral meniscus, the vector distance of the peroneal nerve to the M, C, and L tracks were 8.1mm (±4.5), 12.9mm (±4.9) and
16.6mm (±5.2), respectively. In 5% of patients, we found aberrant division of the common peroneal nerve into the superficial
and deep branches proximal to the joint line with the superficial branch in direct path of the needle tracks. The vector distance
of the popliteal artery to the M, C and L tracks were 12.9mm (±3.5), 10.8mm (±3.5) and 8.3mm (±3.4), respectively.
BMI under 30.0 kg/m2 and weight under 90.0kg were statistically significant (p < 0.0001) for increased proximity of needle tracks
to the common peroneal nerve in all three approaches toward the lateral meniscus (see Table 1). BMI under 30.0 was also
significant (p < 0.03) for increased proximity to popliteal neurovascular bundle. Height under 1.70m was statistically significant
(p < 0.002) for increased proximity in all three needle tracks to the popliteal neurovascular bundle. Patient’s age, race and
gender were not significant for changes in vector distances after controlling for height and weight in multivariate regression.
Discussion: The course of the peroneal nerve varies greatly depending on patient weight, independent of race and gender. Extra
precautions such as posterior incision with dissection should be taken when conducting inside-out lateral meniscal repairs on
non-obese patients and to avoid injuring an aberrant branch of the peroneal nerve. For medial meniscus repairs, the saphenous
nerve is very proximal to our needle tracks consistent with the high complication rates reported in previous meta-analyses
studies. The large variability of the saphenous nerve location, however, was not explained by the patient characteristics
investigated in this study.
Significance: The proximity of the peroneal nerve to potential suture tracks during lateral meniscus repair is highly predicted by
BMI. A posterior incision should be taken when conducting inside-out lateral meniscus repairs on non-obese patients.
Acknowledgments: None
References: Deutsch et al. Evaluation of the anatomy of the common peroneal nerve. American Journal of Sports Medicine,
27(1): 11-
15.
ORS 2014 Annual Meeting
Poster No: 1715