Comparison of Fixation Techniques in Oblique and Biplanar Chevron Medial Malleolar Osteotomies; a Finite Element Analysis

This study aimed to evaluate different fixation techniques and implants in oblique and biplanar chevron medial malleolar osteotomies using finite element analysis. Both oblique and biplanar chevron osteotomy models were created, and each osteotomy was fixed with 2 different screws (3.5 mm cortical screw and 4.0 mm malleolar screw) in 2 different configurations; (1) 2 perpendicular screws, and (2) an additional third transverse screw. Nine simulation scenarios were set up, including 8 osteotomy fixations and the intact ankle. A bodyweight of 810.44 N vertical loading was applied to simulate a single leg stand on a fixed ankle. Sliding, separation, frictional stress, contact pressures between the fragments were analyzed. Maximum sliding (58.347µm) was seen in oblique osteotomy fixed with 2 malleolar screws, and the minimum sliding (17.272 µm) was seen in chevron osteotomy fixed with 3 cortical screws. The maximum separation was seen in chevron osteotomy fixed with 2 malleolar screws, and the minimum separation was seen in oblique osteotomy fixed with 3 cortical screws. Maximum contact pressure and the frictional stress at the osteotomy plane were obtained in chevron osteotomy fixed with 3 cortical screws. The closest value to normal tibiotalar contact pressures was obtained in chevron osteotomy fixed with 3 cortical screws. This study revealed that cortical screws provided better stability compared to malleolar screws in each tested osteotomy and fixation configuration. The insertion of the third transverse screw decreased both sliding and separation. Biplanar chevron osteotomy fixed with 3 cortical screws was the most stable model.

Influence of the Medial Malleolus Osteotomy on the Clinical Outcome of M-BMS + I/III Collagen Scaffold in Medial Talar Osteochondral Lesion (German Cartilage Register/Knorpelregister DGOU)

OBJECTIVE

Osteochondral lesions of the talus are common injuries, with one of the leading treatment options being the M-BMS (matrix-augmented bone marrow stimulation) + I/III collagen scaffold. Osteotomy of the medial malleolus is not unusual but presents the risk of malunion or irritation by hardware. The aim of the study was to analyze data from the German Cartilage Society (Knorpelregister DGOU) to evaluate the influence of medial malleolar osteotomy on clinical results of M-BMS + I/III collagen scaffold.

DESIGN

The ankle module of the Cartilage Register includes a total of 718 patients, while 45 patients met the inclusion criteria. Patients were treated with an M-BMS + I/III collagen scaffold of the medial talus, 30 without and 15 with an osteotomy of the medial malleolus. The follow-up evaluations included FAAM (Foot and Ankle Ability Measure), FAOS (Foot and Ankle Outcome Score), and VAS (visual analogue scale).

RESULTS

Forty-five patients (22 male, 23 female) aged between 18 and 69 years (mean: 34 years) were included in this study. Between preoperative and 12 months postoperative, we noted a significant improvement in FAAM-ADL (Activity of Daily Living) (P = 0.004) as well as FAOS-Pain (P = 0.001), FAOS-Stiffness (P = 0.047), FAOS-ADL (P = 0.002), FAOS-Sport (P = 0.001), and FAOS Quality of Life (P = 0.009). There was no significant difference between patients who underwent an osteotomy or not.

CONCLUSION

The results show a significant improvement in patients' outcome scores following a M-BMS + I/III collagen scaffold. No statistical difference was noted among those undergoing medial malleolar osteotomy.

Quantification and Comparison of Talar Exposure Utilizing a Posteromedial Approach and Medial Malleolar Osteotomy

Background:

Fractures of the talus are a rare but challenging injury. This study sought to quantify the area of osseous exposure afforded by a posteromedial approach to the talus and medial malleolar osteotomy.

Methods:

Five fresh-frozen cadaveric lower extremities were dissected using a posteromedial approach and medial malleolar osteotomy respectively. Following exposure, the talar surfaces directedly visualized were marked and captured using a calibrated digital image. The digital images were then analyzed using ImageJ software (National Institutes of Health) to calculate the surface area of the exposure.

Results:

The average square area of talus exposed using the posteromedial approach was 9.70 cm² (SD = 2.20, range 7.20-12.46). The average quantity of talar exposure expressed as a percentage was 9% (SD = 1.58, range 7.03-10.40). The average square area of talus exposed using a medial malleolar osteotomy was 14.32 cm² (SD = 2.00, range 11.26-16.66). The average quantity of talar exposure expressed as a percentage was 12.94% (SD = 1.79, range 9.97-14.73). The posteromedial approach provided superior visualization of the posterior talus, whereas the medial malleolar osteotomy offered greater access to the medial body.

Conclusion:

The posteromedial approach and medial malleolar osteotomy allow for significant exposure of the talus, yielding 9.70 and 14.32 cm², respectively. Given the differing portions of the talus exposed, surgeons may prefer to use the posteromedial approach for operative fixation of posterior process fractures and elect to use a medial malleolar osteotomy in cases requiring more extensive medial and distal exposure for neck or neck/body fractures.

Level of Evidence:

Level IV.

Midterm Results of Fresh-Frozen Osteochondral Allografting for Osteochondral Lesions of the Talus

BACKGROUND

Osteochondral lesions of the talus (OLT) are relatively common. Following the failure of conservative treatment, many operative options have yielded varied results. In this study, midterm outcomes after fresh-frozen osteochondral allograft transplantation for the treatment of OLT were evaluated.

METHODS

Twenty-five patients (12 women and 13 men) with a mean age 40.4 (range 18-70) years between 2009 and 2014 were enrolled. Of 25 ankles, 3, 13, 4, and 4 were involved with the talus at Raikin zone 3, 4, 6, and 7 as well as one coexisted with zone 4 and 6 lesion. The mean OLT area was 1.82 cm² (range, 1.1-3.0). The mean follow-up period was 5.5 years (range, 4-9.3). Outcomes evaluation included the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, visual analog scale score, and 12-item Short Form Health Survey (SF-12).

RESULT

AOFAS ankle-hindfoot score increased from 74 preoperatively to 94 at 2 years postoperatively (P < .001) and the SF-12 physical health component scores increased from 32 to 46 points (P < .001). Incorporation was inspected in all patients in the latest follow-up, and graft subsidence and radiolucency were observed in 2 and 7 cases, respectively, whereas graft collapse and revision OLT graft were not observed. Bone sclerosis was found in 6 of 25 patients.

CONCLUSION

With respect to midterm results, fresh, frozen-stored allograft transplantation might be an option in the management of symptomatic OLT.

LEVEL OF EVIDENCE

Level IV, retrospective case series.