2.1

Embalmed cadaveric feet, preserved in situ, were obtained from donors to the Jacques Lisfranc Faculty of Medicine. Specimens with prior surgery, trauma, osteoarthritis, rheumatologic disease, ligament injury, or restricted motion were excluded. The protocol was approved by the Institutional Review Board (IRBN762024/CHUSTE) and followed the Declaration of Helsinki. Embalming was considered valid given evidence that it does not significantly alter ligament or connective tissue biomechanics .

2.2

Cadavers were embalmed using the Graz protocol and stored at 4 °C. Specimens were equilibrated to room temperature two hours before testing , without prior manipulations that could compromise joint integrity. Feet remained attached to preserve proximal muscle–tendon insertions and the native periarticular environment of the ankle and subtalar joints.

2.3

The motion-analysis protocol followed a previously described method . Four custom supports were fixed to the tibia, fibula, talus, and calcaneus with 3 mm bicortical pins, each carrying three retroreflective markers. Triangular bone models were built following the Rizzoli approach and International Society of Biomechanics guidelines ^, by palpating three osseous landmarks per bone. Tibial and fibular landmarks were the tibial spine center, medial malleolus, and lateral malleolus ^, . Talar landmarks were the medial and lateral dome peaks and the intersection of the talar-neck axis with the head articular surface, exposed through an anterior arthrotomy. Calcaneal landmarks included the sustentaculum tali apex, peroneal tubercle peak, and superior posterior tuberosity margin, accessed via a short incision.

CFL and ATFL footprints were identified by an experienced surgeon, with soft tissues preserved. Three-dimensional motion of the four bones was recorded at 100 Hz using eight synchronized Kestrel 2200 cameras (Motion Analysis Corp., Santa Rosa, CA, USA). The system was statically and dynamically calibrated before each test, with residual error < 0.15 mm. Segment kinematics were reconstructed in Cortex 9.5 (Motion Analysis Corp.). Motion of the tibia, fibula, talus, and calcaneus was analyzed, and changes in ATFL and CFL insertion distances quantified ligament strain under varying subtalar conditions.

2.4

Three preliminary varus-valgus and flexion-extension cycles released periarticular adhesions. With the tibia fixed, a single experimented foot and ankle surgeon performed three manual tests: anterior drawer (ADT), combining anterior translation and internal rotation to assess ankle and subtalar motion; varus tilt in neutral (VTTN) to evaluate coronal rotation; and varus tilt in dorsiflexion (VTTF), locking the talus in the mortise to isolate subtalar rotation ^, .

Tests were repeated under four conditions: 1) intact ankle, 2) unstable ankle after ATFL, CFL, ITCL, and CL disinsertion, 3) Broström repair with Gould augmentation (BG), and 4) Broström repair with inferior extensor retinaculum augmentation (IER) after Gould removal ( Fig. 1 ).

Illustration of the experimental protocol. For each ligament condition, each test was repeated three times. Ligament sectioning followed a progressive severity model. At the third stage, an open anatomical repair of the ATFL and CFL was performed and augmented with a Gould procedure, after which the tests were repeated. The Gould augmentation was then removed, and at the fourth stage an IER flap augmentation was performed; the full test protocol was again carried out under this condition. unstable: combined disinsertion of anterior talo-fibular ligament (ATFL), calcaneo fibular ligament (CFL), Interosseus talocalcaneal ligament (ITCL), and cervical ligament (CL); ADT: Anterior drawer test combining anterior and internal rotation test; VTTN: varus test on ankle in neutral flexion; VTTF: varus test on maximal dorsiflexion .

2.5

The joint capsule and inferior extensor retinaculum (IER) were exposed through a skin flap. The ATFL, CFL, CL, and ITCL were disinserted to reproduce severe ankle and subtalar instability. Anatomical reinsertion of ATFL and CFL was performed with two 3.0-mm anchors: the first placed 5 mm above the fibular tip at the common ATFL’s inferior fascicle-CFL footprint, and the second 10 mm above for the ATFL’s superior fascicle ( Fig. 2 ).

Illustration of anatomical open ligament repair procedures., The Brostrom procedure corresponded to the anatomical reinsertion of ATFL (green rectangle) and CFL (yellow trapeze) using one anchor for each ligament. The light pink rectangle corresponds to the IER, and the dark pink rectangle corresponds to the bulkiest part of the IER (frondiforme ligament). The Gould augmentation corresponded to an insertion of the proximal part of the IER to the anterior edge of the fibula (blue arrows) using one anchors. ATFL and CFL insertions are draped by the proximal part of IER. The IER flap augmentation corresponded to an attachment of a threated IER flap (dark pink rectangle) fixed in a fibular tunnel at mid distance between ATFL anchor and common ATFL and CFL anchor.

A Gould augmentation (BG group) was then performed by draping the proximal IER over the reinserted ATFL and CFL, secured with a 3.0-mm anchor while holding the foot in eversion . The ankle was tested, after which the augmentation was released by transecting sutures without damaging reinsertion sites. ( Fig. 2 )

For the IER flap augmentation (IER group), the thickest IER portion (frondiform ligament) was dissected, and a flap of its lateral fascicle was elevated at its reflection over the extensor digitorum longus, preserving calcaneal insertion. A 5-mm fibular tunnel was drilled midway between ATFL and CFL anchors. The flap was threaded into the tunnel and fixed with a 4.75-mm interference screw with the foot in eversion, before retesting . ( Fig. 2 )

2.6

Statistical analyses were performed in SPSS Statistics 28 (IBM, Armonk, NY, USA). Three-dimensional ankle and subtalar kinematics were evaluated with one-way repeated-measures ANOVA, using ligament status as the within-specimen factor (intact, unstable, BG, IER). For the anterior drawer test (ADT), dorsiflexion-plantarflexion (FE positive for dorsiflexion) and internal-external rotation (IR/ER positive for internal) amplitudes were analyzed, while varus-valgus (var/val positive for varus) amplitudes were assessed during varus tilt in neutral ankle position (VTTN) and dorsiflexion (VTTF). Kinematic comparisons involved three bone pairs: calcaneus–tibia (ankle–subtalar complex), talus–tibia (ankle), and calcaneus–talus (subtalar). Rotational amplitudes were used for joint motion, and maximal values for ligament elongation. ATFL and CFL stress was assessed by analyzing changes in insertion distances under the same tests.

Comparisons were made between BG and IER, BG and intact, and IER and intact ankles. Statistical significance was set at p < 0.05.

3.1

3.1.1

Motion between calcaneus and talus

When comparing BG and IER, varus rotations are more restricted between the calcaneus and the talus after IER augmentation when performing a VTTN and a VTTF (respectively −0.48° and −0.54°; p < 0.05). Results are detailed in Table 1 and Fig. 3 .

Table 1

Comparison of the rotation (°) between talus, tibia and calcaneus for different ligament conditions.

Joint assessed	Ligament status				Difference
	NI	Unstable	BG	IER	IER vs BG	IER vs NI	BG vs NI
Calcaneus-Talus
F/E ADT	1.08	1.16	0.82	0.59	-0.22	-0.49	-0.26
IR/ER ADT	0.78	0.84	0.57	0.46	-0.11	-0.32	-0.21
var/val VTTN	6.28	6.31	3.62	3.14	-0.48*	-3.14*	-2.66*
var/val VTTD	2.05	3.79	2.18	1.64	-0.54*	-0.41*	0.13
Calcaneus-Tibia
F/E ADT	5.33	9.09	4.20	3.53	-0.67	-1.81*	-1.14*
IR/ER ADT	2.18	1.89	1.58	1.79	0.21	-0.40*	-0.61*
var/val VTTN	9.43	14.55	4.95	4.18	-0.77*	-5.25*	-4.48*
var/val VTTD	2.53	5.41	2.68	2.10	-0.58*	-0.43	0.15
Tibia-Talus
F/E ADT	6.28	9.50	4.88	4.03	-0.85*	-2.25*	-1.40*
IR/ER ADT	2.87	2.29	1.85	1.91	0.06	-0.96*	-1.02*
var/val VTTN	3.07	8.16	1.56	1.63	0.07	-1.44*	-1.51*
var/val VTTD	0.41	1.42	0.44	0.38	-0.06	-0.03	0.03

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

Accelerated versus standard ponseti method for idiopathic clubfoot: A systematic review and meta-analysis of efficacy and safety Systemic and local risk factors for major amputation following diabetic minor amputation Posterior ankle arthroscopic reduction and fixation for treatment of posterior malleolus fractures with absorbable screws Comparing patient reported outcomes and complications following open versus minimally invasive double and triple arthrodesis for rigid flatfoot deformity: A retrospective analysis The fibular groove deep and its relationship with the superior peroneal retinaculum morphology in peroneal tendon stability: A cadaveric study Talar neck and body fractures: An observational cohort study originating from the Swedish Fracture Register

Stay updated, free articles. Join our Telegram channel

Join