New evaluation indices for rotational knee angles in standing anteroposterior knee radiographs

BACKGROUND: Identifying the time course of rotational knee alignment is crucial for elucidating the etiology in knee osteoarthritis. OBJECTIVE: The aim of this study was to propose new rotational indices for calculating the change in relative rotational angles between the femur and tibia in standing anteroposterior (AP) radiographs. METHODS: Forty healthy elderly volunteers (20 women and 20 men; mean age, 70 ± 6 years) were assessed. The evaluation parameters were as follows: (1) femoral rotational index: the distance between the sphere center of the medial posterior femoral condyle and the lateral edge of the patella, and (2) tibial rotational index: the distance between the medial eminence of the tibia and the lateral edge of the fibula head. The indices were standardized by the diameter of the sphere of the medial posterior femoral condyle. This study (1) identified the relationship between changes in rotational indices and the simulated rotational knee angles in the standing position, (2) proposed a regression equation for the change in relative rotational angles between the femur and tibia in standing AP radiographs, and (3) verified the accuracy of the regression equation. RESULTS: The rotational indices increased in direct proportion to simulated rotational knee angles (femoral index: r > 0.9,p < 0.0001; tibial index: r > 0.9, p < 0.0001). Based on the results, the regression equation with the accuracy of 0.45 ± 0.26° was determined. CONCLUSIONS: The proposed regression equations can potentially predict the change in relative rotational angles between the femur and tibia in a pair of standing AP radiographs taken at different dates in longitudinal studies.

Structures at Risk During Percutaneous Extra-Articular Chevron Osteotomy of the Distal First Metatarsal

Background. Minimally invasive surgery of the forefoot has regained popularity as an alternative to traditional open procedures. Minimally invasive hallux valgus surgery has been shown to be effective and reproducible for the treatment of mild to moderate hallux valgus. The aim of this study is to identify vital structures that are at risk for iatrogenic damage while performing a minimally invasive distal chevron osteotomy due to limited direct visualization. Methods. Ten fresh-frozen below knee cadavers were used for this study. A minimally invasive distal chevron osteotomy and medial eminence resection with a 2.2 mm × 22 mm Shannon burr was performed on each cadaver. Each specimen was dissected to expose the potential structures at risk for injury during the procedure. Structures evaluated included the medial neurovascular bundle, first metatarsophalangeal joint capsule, extensor hallucis longus tendon, flexor hallucis longus tendon, abductor hallucis tendon, and the sesamoid apparatus. Results. Ten specimens were evaluated. The dorsal medial cutaneous nerve was directly injured in 5 of the 10 cadaver specimens and intact/uninjured in the remaining 5 specimens. The flexor hallucis longus, extensor hallucis longus, adductor tendon, sesamoid apparatus, and first metatarsophalangeal joint capsule were uninjured in all specimens. Conclusion. Minimally invasive chevron distal osteotomy and medial eminence resection has a high learning curve. The resection of the medial eminence may iatrogenically injure the dorsal medial cutaneous nerve. The incidence is higher in this study than prior reported cadaveric studies and may warrant extra care to protect vital structures. Level of Evidence: Level IV: Cadaver study

Traumatic Hallux Varus in Association with Agenesis of the Fibular Sesamoid: A Case Study

Hallux varus is most commonly seen iatrogenically following overaggressive lateral release, removal of the fibular sesamoid, or overaggressive removal of the medial eminence. There are several reported cases of traumatic hallux varus, although this is much less common. We present a case of traumatic hallux varus in a patient who was later found to have bilateral absence of her fibular sesamoids. We postulated that lack of her fibular sesamoid led to weakness of her lateral capsular ligaments, thereby making her more susceptible to this injury. We performed a repair using a split extensor hallucis longus tendon transfer that was transected proximally, rerouted the tendon under the deep transverse intermetatarsal ligament, and secured it to the first metatarsal with a Bio-Tenodesis (Arthrex, Inc, Naples, Florida) screw. At 22 months postoperatively, she has demonstrated maintenance of correction and has resumed use of normal shoe gear and participation in activities. Our goal was to demonstrate a repair for this condition that successfully maintained correction over time while still allowing for functionality of the first metatarsophalangeal joint.

Preoperative Picture Improves Postoperative Satisfaction in Bunion Surgery

Category: Bunion Introduction/Purpose: Hallux valgus (HV) is the most common conditions affecting the forefoot. Typically, the patient’s main concern is a prominent medial eminence (bunion) with difficulty with shoe wear and the cosmetic appearance of the toe. Patient satisfaction following HV correction surgery is between 73-94% however a poor cosmetic result can have a negative impact on the post-operative outcome. There is surprisingly a dearth of knowledge in the forefoot literature exploring the impact of cosmesis on the subjective outcome following HV surgery. The purpose of this prospective, blinded, randomized trial is to determine whether showing patients a preoperative photograph would improve post-operative satisfaction following HV corrective surgery. Methods: Patients undergoing HV corrective surgery were randomized to a picture group (P) or no picture group (NP). Inclusion criteria were patients over 18 and a diagnosis of HV. Pre-operatively, all patients had a picture taken of the operative foot. Patients were seen in follow up at 3 and 6 weeks and 3 months. P-group patients were shown the picture by the research assistant for 5 minutes at each visit. Patients completed the FFI and FAOS pre-operatively and at each post-operative visit. Patients also completed a satisfaction questionnaire at each post-operative visit which included a 5-point scale addressing overall satisfaction, satisfaction with the appearance of the foot and whether they would undergo the procedure again. Pre-operative and post-operative HVA and IMA were recorded by a fellowship trained orthopaedic surgeon not involved in the patient’s care. The operative surgeon was blinded to the treatment groups. Results: 29 patients were enrolled in the study (15P). No difference with respect to age, gender, smoking, presence of comorbidities, underlying diagnosis, HVA or IMA, FFI or FAOS. At 3 months, patients in the picture group were more likely to be “completely satisfied” with the appearance of their foot and this difference was statistically significant (p<0.05). There were no differences between treatment groups with respect to post-operative HVA, IMA, FAOS, or FFI. Conclusion: Hallux valgus corrective surgery is a very successful procedure with high post-operative patient satisfaction. Frequently reminding a patient of the pre-operative appearance of their foot, through the use of photographs, appears to have a beneficial impact with regards to patient satisfaction in the early post-operative period.

First Metatarsal Head and Medial Eminence Widths with and Without Hallux Valgus

Background: Resection of the medial eminence in hallux valgus surgery is common. True hypertrophy of the medial eminence in hallux valgus is debated. No studies have compared metatarsal head width in patients with hallux valgus and control patients. Methods: We reviewed 43 radiographs with hallux valgus and 27 without hallux valgus. We measured medial eminence width, first metatarsal head width, and first metatarsal shaft width in patients with and without radiographic hallux valgus. Results: Medial eminence width was 1.12 mm larger in patients with hallux valgus (P &lt; .0001). Metatarsal head width was 2.81 mm larger in patients with hallux valgus (P &lt; .001). Metatarsal shaft width showed no significant difference (P = .63). Conclusions: Metatarsal head width and medial eminence width are significantly larger on anteroposterior weightbearing radiographs in patients with hallux valgus. However, frontal plane rotation of the first metatarsal likely accounts for this difference.