Daiwei Yao

Does BMI influence clinical outcomes after total knee arthroplasty

INTRODUCTION Obesity is a common problem in the western European countries. Since the association between obesity and the emergence of gonarthrosis is approved, it is more important to gain reliable information about this patient group. The aim of the present retrospective study is to evaluate clinical outcomes of German obese patients after total knee arthroplasty (TKA). PATIENTS AND METHODS Between 2001 and 2009 a total of 199 patients with 230 TKA were included in the present study. The collective was divided into four groups in relation to their Body-Mass-Index (BMI); group 1: BMI < 25 kg/m2, n = 24; group 2: BMI 25-30 kg/m2, n = 80, group 3: BMI 30-40 kg/m2, n = 109; group 4: BMI> 40 kg/m2, n = 17. Clinical outcome measurement was scored postoperatively using the knee society score (KSS), hospital for special surgery score (HSS) and the visual analogue scale (VAS). Furthermore complications and subjective patient satisfaction were noted. RESULTS We did not detect any significant differences in the clinical scores between the BMI-subgroups. However we measured statistically significant worse results in case of infection and instability in all BMI subgroups (p> 0.01). CONCLUSION While infection and instability may have a negative influence for the clinical outcome, we did not detect any significant correlation between obesity and exiting complications. Obesity has no significant correlation to influence the outcome after TKA implantation negatively.

Surgical Management of Charcot Deformity for the Foot and Ankle—Radiologic Outcome After Internal/External Fixation

Charcot neuropathy (CN) is a severe joint disease that makes surgical planning very challenging, because it is combined with ankle instability, serious deformities, and recurrent ulceration. The aim of the present study was to examine the rate of bone fusion after external or internal fixation in patients with CN. We retrospectively examined 58 patients with CN who had undergone reconstruction of the ankle either with tibiotalocalcaneal or tibiocalcaneal arthrodesis. The mean age was 59.1 (range 26 to 81) years at surgery. Of the 58 patients, 38 were treated using intramedullary nail arthrodesis and 19 using an external fixator (1 patient received neither). At a mean follow-up period of 31.3 (range 12 to 57) months, limb salvage and bone fusion had been achieved in 94.83%. The mean time to bone fusion was 12 (range 6 to 18) months. Three patients (5.2%) required a more proximal amputation. All but these 3 patients gained independent mobilization in custom feet orthoses or off the shelf orthoses. Of the 58 patients in the present cohort, 56 (96.6%) would undergo surgery again. In conclusion, internal and external fixation both lead to promising results in the treatment of CN. Internal fixation should be preferred when no indications of ulcer or infection are present.

Results of HemiCAP® Implantation as a Salvage Procedure for Osteochondral Lesions of the Talus

ABSTRACT Osteochondral defects (OCDs) of the talus remain a surgical challenge, especially after failed primary treatment. The aim of the present study was to examine the clinical outcomes after HemiCAP® implantation for OCDs of the medial talar dome after failed previous surgery. Our retrospective study included 11 patients, who had undergone surgery from June 2009 to September 2012 for an OCD of the medial talar dome and received a HemiCAP® on the talus after failed previous surgery for OCD. The data were acquired using patients’ medical records and standardized questionnaires, including the Foot and Ankle Outcome Score (FAOS), University of California at Los Angeles (UCLA) activity score, EQ‐5D, numerical rating scale (NRS), and Short‐Form 36‐item Health Survey (SF‐36). Using these scores, the possibility of returning to work and sports was determined. Any complications and the need for revision surgery were recorded. One patient refused to participate in the study, leaving 10 patients for evaluation. The mean age was 47.64 ± 10.97 years. The mean follow‐up period was 43.5 ± 35.51 months. The FAOS and SF‐36 subscale scores and the EQ‐5D and UCLA activity scores did not improve significantly (p < .05). The mean postoperative pain score on the NRS improved significantly from 6.6 ± 1.77 preoperatively to 5.1 ± 2.02 postoperatively (p < .05). A greater body mass index led to worse postoperative outcomes with higher scores on the pain‐NRS and less satisfaction (p < .05). Ten revisions for ongoing pain were performed in 7 patients (70.0%) within a mean of 28.4 ± 13.35 months of the initial procedure, and 6 patients (60%) indicated they would undergo surgery again. The results of the present study have shown that implantation of the HemiCAP® as a salvage procedure for OCDs of the talus is challenging and does not consistently lead to good clinical results. Also, overweight patients appear to have an increased risk of postoperative dissatisfaction and persistent ankle pain. &NA; Level of Clinical Evidence: 4

Introducing a Surgical Procedure for an Implantable FES Device and Its Outcome

The adult paralytic foot or drop foot is a secondary related foot deformity, which usually arises due to neurogenic damage (Kunst et al. in Stroke 42:2126–2130, 2011; Truelsen et al. in European Journal of Neurology 13:581–598, 2006). The lack of neural innervation of the muscles, which play a major role in ankle dorsiflexion—M. tibialis anterior, Mm. peronei, M. extensor digitorum longus, and M. extensor halluces longus—can cause a secondary malposition of the foot. As a dorsiflexion of the ankle cannot be actively provoked, this leads to a domination of the flexors and as a secondary outcome to a shortening of these muscles and their tendons. Similarly, it may also lead to a malposition in supination (www.mayoclinic.org/diseases-conditions/foot-drop/basics/definition/con-20032918).

The geometrical axis of the talocrural joint—Suggestions for a new measurement of the talocrural joint axis

BACKGROUND Despite intensive research there is no consensus about the talocrural joint axis. The aim of the present study is a new method to determinate the geometric rotational axis of the talocrural joint. METHODS We analyzed 98 CT-scans of full cadaver Caucasian legs. We generated three-dimensional reconstruction models of the talus. A best fitting cone was orientated to the talar articular surface. The geometric rotational axis was defined to be the axis of this cone. RESULTS The geometric rotational axis of the talocrural joint is orientated from lateral-distal to medial-proximal (85.6°±10 compared to anatomical tibial axis in torsional plane), from posterior-distal to anterior-proximal (81.43°±44.35 compared to anatomical tibial axis in sagittal plane) and from posterior-medial to anterior-lateral (169.2°±5.91 compared to intermalleolar axis in axial plane). CONCLUSIONS The consideration of our results might be helpful for better understanding of ankle biomechanics.

One-Stage Metatarsal Interposition Lengthening With an Autologous Fibula Graft for Treatment of Brachymetatarsia

Objective: Brachymetatarsia is defined as the pathological shortening of a metatarsal bone, which can cause cosmetic problems and pain in the forefoot. The main surgical treatment options are: extension osteotomy, interposition of a bone graft, and callus distraction. Usually, a bone graft from the iliac crest is used for the interposition osteotomy. The operative technique of graft extraction from the fibula has not been described in the literature yet. Methods: Eight feet with brachymetatarsia in 5 patients were evaluated retrospectively. The minimum follow-up period was 2 years. Via a dorsal V/Y skin incision, a central osteotomy on the metatarsal bone was done. A graft was obtained from the anterior fibula. The graft was inserted and fixed by a locking plate. Additional soft tissue procedures were done. Results: We had bony consolidation in all cases. The mean extension was 9.01 mm (5.49 to 12.54 mm). This corresponded to a mean 20.3% extension of the entire metatarsal. High patient satisfaction as well as high satisfaction regarding the cosmetic results were achieved. There were no postoperative complications. The range of motion of the metatarsal-phalangeal joint IV was 20% less preoperative in terms of plantar flexion. Standing up on tiptoes was possible in all patients postoperatively. One patient reported mild symptoms after sports activities. Conclusions: Because of its anatomy the graft adapts to the metatarsal IV bone. As our study showed, harvesting from the distal fibula causes no functional restriction. In terms of wound and bone healing as well as pain symptoms, this method should be considered as an alternative to the standard iliac graft.

Comparison of Anatomic Structures at Risk With 2 Lateral Lengthening Calcaneal Osteotomies

Background: Lateral lengthening calcaneal osteotomies (LLCOT) are commonly used to treat flexible pes planovalgus deformity. Different operative techniques have been described. The aim of this study was to examine which anatomic structures were affected by 2 different osteotomy techniques. Methods: Two experienced foot and ankle surgeons each performed an Evans (E)- or Hintermann (H) osteotomy on 7 cadaver feet. The mean age of the donors was 80.4 ± 4.4 years. Eight left and 6 right feet were prepared. Previously identified structures at risk were prepared and evaluated. Results: After H-LLCOT, there was no damage of the peroneus longus tendon, whereas after E-LLCOT, damage was noted in 1 case (14.3%). The peroneus brevis tendon was once cut after H-LLCOT and eroded after E-LLCOT. In one cadaver, the sural nerve was partially damaged after H-LLCOT but in no case after E-LLOCT. The calcaneal anterior and medial articular facets were intact after H-LLCOT in 100% and 85.7% and after E-LLCOT in 42.9% and 71.4%, respectively. The posterior articular surface was not affected in any cadaver. Conclusion: Anatomic structures can be damaged after both osteotomies. With the Hintermann osteotomy, the calcaneal anterior and medial articular surface can be protected to a larger extent than with the Evans osteotomy. Clinical Relevance: The Hintermann osteotomy seems to be superior, regarding damage of the articular surfaces of the subtalar joint. These findings have to be correlated with biomechanical and clinical studies before a final recommendation can be given, which osteotomy is superior.

Hip and knee effects after implantation of a drop foot stimulator

BACKGROUND An active ankle dorsiflexion is essential for a proper gait pattern. If there is a failure of the foot lifting, considerable impairments occur. The therapeutic effect of an implantable peroneus nerve stimulator (iPNS) for the ankle dorsiflexion is already approved by recent studies. However, possible affection for knee and hip motion after implantation of an iPNS is not well described. OBJECTIVE The objective of this retrospective study was to examine with a patient cohort whether the use of iPNS induces a lower-extremity flexion withdrawal response in the form of an increased knee and hip flexion during swing phase. METHODS Eighteen subjects (12 m/6 w) treated with an iPNS (ActiGait®, Otto Bock, Duderstadt, Germany) were examined in knee and hip motion by gait analysis with motion capture system (Vicon Motion System Ltd®, Oxford, UK) and Plug-in-Gait model after a mean follow up from 12.5 months. The data were evaluated and compared in activated and deactivated iPNS. RESULTS Only little changes could be documented, as a slight average improvement in peak knee flexion during stand phase from 1.0° to 2.5° and peak hip flexion in stance from 3.1° to 2.1° In contrast, peak knee flexion during swing appeared similar (25.3° to 25.7°) same as peak hip flexion during swing. In comparison with the healthy extremity, a more symmetric course of the knee flexion during stand phase could be shown. CONCLUSIONS No statistical significant improvements or changes in hip and knee joint could be shown in this study. Only a more symmetric knee flexion during stand phase and a less hip flexion during stand phase might be hints for a positive affection of iPNS for knee and hip joint. It seems that the positive effect of iPNS is only based on the improvement in ankle dorsiflexion according to the recent literature.

Outcomes after Lengthening Calcaneal Osteotomy for Flexible Flatfoot Deformity– Evans versus Hintermann Osteotomy

Category: Hindfoot Introduction/Purpose: Evans and Hintermann calcaneal osteotomies are commonly used to correct flexible pes planovalgus deformity. Both methods are well accepted with good clinical results. The aim of this study was to compare the outcomes after Evans or Hintermann osteotomy. Methods: We retrospectively examined 49 patients who were operated for the treatment of flexible flatfoot deformity between October 2007 and March 2014. Sixteen Evans and 36 Hintermann osteotomies were performed. The data was collected using clinical and radiological examination as well as clinical scores (FAOS, SF-36) during regular follow-up. A paired t-test was used for statistical analysis. A one-way anova with the Holm-Sidak’s multiple comparisons test was used to compare non-parametric data. Results: The mean age was 39.6 ± 18.69 years in the Hintermann (H) group and 32.8 ± 17.86 years in the Evans (E) group. The mean follow up was 67.67 ± 20.57 months in the E- and 39.71 ± 12.77 months in the H-group. In both groups FAOS and SF-36 improved significantly (p<0.05). The hindfoot alignment improved significantly in both groups (p<0.05). The mean time to return to work and sports was 14.25 ± 8.92 and 19.0 ± 18.62 weeks in the E-group, 19.36 ± 16.71 and 28.25 ± 20.07 weeks in the H- group. Seven patients of each group needed an implant removal; one patient underwent an arthrodesis of the subtalar joint in the E-group. There were no significant differences between the outcomes of both groups. Conclusion: Both surgical techniques lead to good correction of the flatfoot deformity and show a significant improvement of the clinical outcome scores. Neither of these two surgical techniques can be identified as being superior.