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Background: Tarsometatarsal (TMT) arthrodesis is a common operative procedure for end-stage arthritis of the TMT joints. To date, there is no consensus on the best fixation technique for TMT arthrodesis and which joints should be included. Methods: Thirty fresh-frozen feet were divided into one group (15 feet) in which TMT joints I-III were fused with a lag screw and locking plate and a second group (15 feet) in which TMT joints I-III were fused with 2 crossing lag screws. The arthrodesis was performed stepwise with evaluation of mobility between the metatarsal and cuneiform bones after every application or removal of a lag screw or locking plate. Results: Isolated lag-screw arthrodesis of the TMT I-III joints led to significantly increased stability in every joint ( P < .05). Additional application of a locking plate caused further stability in every TMT joint ( P < .05). An additional crossed lag screw did not significantly increase rigidity of the TMT II and III joints ( P > .05). An IM screw did not influence the stability of the fused TMT joints. For TMT III arthrodesis, lag-screw and locking plate constructs were superior to crossed lag-screw fixation ( P < .05). TMT I fusion does not support stability after TMT II and III arthrodesis. Conclusion: Each fixation technique provided sufficient stabilization of the TMT joints. Use of a lag screw plus locking plate might be superior to crossed screw fixation. An additional TMT I and/or III arthrodesis did not increase stability of an isolated TMT II arthrodesis. Clinical Relevance: We report the first biomechanical evaluation of TMT I-III arthrodesis. Our results may help surgeons to choose among osteosynthesis techniques and which joints to include in performing arthrodesis of TMT I-III joints.

Background: The modified Lapidus procedure is an accepted treatment option for patients with moderate to severe hallux valgus. Placing a plate plantar on the tension side of the arthrodesis has been shown to be biomechanically superior and has provided good clinical results. There is some concern about interference of the plantar placed plates on the tendon insertions. The purpose of this study was to determine a “safe zone” for plantar plate placement without irritation of the tendons. Methods: Twenty-nine embalmed right feet were used for this study. The anatomy of the insertion of the peroneus longus (PL) tendon and tibialis anterior (TA) tendon on the medial cuneiform and first metatarsal were analyzed. Six different plate designs for plantar plating of the first tarsometatarsal fusion were included. The fit to the bone and contact to tendon insertion were analyzed. Results: The PL showed a main insertion to the first metatarsal and a lesser insertion to the medial cuneiform. The TA inserted onto the medial cuneiform and first metatarsal in all cases in our series. There was a “safe zone” between the TA and PL insertion areas for plate placement. Straight, Y- and U-shaped plates could be placed without compromising the tendon insertion. Depending on the design, even preshaped plates may have to be bent to allow a good fit to the plantar side of the first tarsometatarsal joint. Conclusion: Plantar plating for modified Lapidus arthrodesis can be safely performed, without damaging the plantar tendon insertion area of the PL and TA. Clinical Relevance: The exact knowledge of the anatomy of the plantar region of the tarsometatarsal joint can help to improve plate placement.

Background: Distinguishing between patients with a true Morton’s neuroma and other forefoot pathology can be difficult. The aim of this study was to evaluate the diagnostic accuracy of routine magnetic resonance imaging (MRI) when compared to clinical examination for Morton’s neuroma. Methods: We retrospectively identified 71 patients who underwent operative treatment due to the diagnosis of Morton’s neuroma between 2007 and 2013. All patients had a MRI preoperative. Our study group comprised 58 female and 13 male patients with a mean age of 57 (range, 38-92) years. We compared the results of preoperative MRI and the patient’s clinical assessment with postoperative histopathological results. Results: Typical clinical signs were found in 65 cases. Most common symptoms were plantar pain (92%) and increased pain on walking (89%). A Morton’s neuroma was detected on MRI in 59 of 71 cases. Its sensitivity was 0.84 and its specificity was 0.33. The positive and negative predictive values were 0.97 and 0.08, respectively. For the presence of main clinical symptoms we found a sensitivity of 0.94 and a specificity of 0.33. The positive predictive value was 0.97 and the negative predictive value was 0.20. Conclusion: MRI under routine conditions had a good detection rate for the evaluation of Morton’s neuroma. However, its accuracy was not as high as the accuracy of clinical assessment. Level of Evidence: Level IV, retrospective series.

Background: The flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon are routinely used in reconstructive foot and ankle surgery. The tendons cross in the chiasma plantare and show variable interconnections. This can complicate harvesting of the tendons. Previous anatomical studies were inconclusive and did not reference the connections to surgically relevant landmarks. The purpose of this study was to integrate these conflicting results, introduce a thorough classification system, and analyze the position of the interconnections relative to the surgically relevant bone landmarks. Methods: Sixty embalmed feet of 30 cadavers were analyzed anatomically with respect to the individual cross-links in the planta pedis. All feet were photo documented. The interconnections were classified in a modified classification system and distances to surgically relevant anatomic landmarks measured. Results: A proximal to distal connection from the FHL to the FDL was found in 95% of the feet (types I and III), in 3% there was a proximal to distal connection from the FDL to the FHL (type II) tendon only, and in 30% a crossed connection (type III) was found. The average point of branching of the FHL and FDL tendon was 5.3 and 4.6 cm distal to the medial malleolus, respectively. Conclusion: Our modified classification system accommodated all found variations. In over 90% of the feet, a proximal to distal connection from the FHL to the FDL was found, which might contribute to the residual function of the lesser toes after FDL transfer. Clinical Relevance: The exact knowledge of the anatomy of the crossing of FDL and FHL in the plantar foot is essential to facilitate tendon harvesting, reduce morbidity and explain possible postoperative functional loss.

Background: This study was conducted to evaluate the treatment of severe foot deformities using the Taylor spatial frame. Materials and Methods: The treatment of seven patients with nine severe foot deformities was reviewed. The mean age of the patients at surgery was 16 years with a mean followup of 21.5 months. The following parameters were assessed: etiology of deformity, date of surgery, surgical procedure, age at surgery, previous surgical or conservative treatments, preoperative symptoms, preoperative and postoperative deformity and affected side, complications during correction, duration of TSF, duration of hospital stay, occurrence of secondary osteoarthritis, recurrence of deformity, surgical revisions or subsequent surgeries. The pre- and postoperative deformity was assessed clinically. The final outcome was categorized as good, fair, or poor. Results: The results were good in eight feet and poor in one foot. Early complications included pin tract infection, temporary hypoesthesia and temporary shortening of the tendon of the flexor digitorum longus. Recurrence of deformity occurred in no patient. One patient required a subtalar arthrodesis for symptomatic, secondary osteoarthritis in one foot. Conclusion: The present study showed that TSF is a viable solution to correct severe foot deformities but we believe a surgeon should be aware of the possible complications. Level of Evidence: IV, Retrospective Case Series