Arthroscopic defect size measurement in osteochondral lesions of the talus underestimates the exact defect size and size measurement with arthro-MRI (MR-A) and high-resolution flat-panel CT-arthro imaging (FPCT-A).

PURPOSE: The size of osteochondral lesions of the talus (OLTs) is highly relevant for their treatment. In addition to intraoperative measurement of defect size, preoperative planning by means of magnetic resonance imaging (MRI) or computed tomography (CT) is crucial. METHODS: Four defects of different sizes and depths were created on the talar joint surface in 14 cadaver feet. All defects were evaluated, both arthroscopically and via arthrotomy with a probe. Arthro-MRI (MR-A) and high-resolution flat-panel CT arthro scans (FPCT-A) were acquired. Length, width, and depth were measured for every defect and the defect volume was calculated. To determine the exact defect size, each talar defect was filled with plastic pellets to form a cast and the casts were scanned using FPCT to create a 3D multiplanar reconstruction data set. Finally, the surgically measured values were compared with the radiological values and the exact defect size. RESULTS: Overall, the surgically measured values (both arthroscopic and open) underestimated the exact defect size (p < 0.05). Arthroscopically determined defect length and width showed the largest deviation (p < 0.05) and underestimated the size in comparison with MR-A and FPCT-A. The FPCT-A measurements demonstrated higher correlation with both the arthroscopic and open surgical measurements than did the MR-A measurements (p < 0.05). CONCLUSION: The exact defect size is underestimated on intraoperative measurement, in both arthroscopic and open approaches. Arthroscopic defect size measurement underestimates defect size in comparison with MR-A and FPCT-A. FPCT-A was shown to be a reliable imaging technique that allows free image reconstruction in every plane and could be considered as the new reference standard for preoperative evaluation of defect size in OLT.

Preexisting and treated concomitant ankle instability does not compromise patient-reported outcomes of solitary osteochondral lesions of the talus treated with matrix-induced bone marrow stimulation in the first postoperative year: data from the German Cartilage Registry (KnorpelRegister DGOU).

PURPOSE: The purpose of this study was to compare the subjective ankle function within the first year following matrix-induced bone marrow stimulation (M-BMS) of patients with a solitary osteochondral lesion of the talus (OCLT) with and without concomitant chronic ankle instability (CAI). METHODS: Data from the German Cartilage Registry (KnorpelRegister DGOU) for 78 patients with a solitary OCLT and a follow-up of at least 6 months were included. All patients received M-BMS for OCLT treatment. The cohort was subdivided into patients with OCLT without CAI treated with M-BMS alone (n = 40) and patients with OCLT and CAI treated with M-BMS and additional ankle stabilisation (n = 38). The Foot and Ankle Ability Measure (FAAM), the Foot and Ankle Outcome Score (FAOS), and the Numeric Rating Scale for Pain (NRS) were used to assess patient-reported outcomes (median (minimum-maximum)). RESULTS: From preoperatively to 12 months postoperatively, patients with OCLT without CAI treated with M-BMS alone had a significant improvement of all subscales in the FAAM [activity of daily living 64.3 (10-100) to 88.1 (39-100); sports 34.4 (0-100) to 65.6 (13-94), functional activities of daily life 50 (0-90) to 80 (30-100), functional sports 30 (0-100) to 70 (5-100)] and FAOS [pain 61.1 (8-94) to 86.1 (50-100), symptoms 60.7 (18-96) to 76.8 (29-100), activities of daily living 72.1 (24-100) to 91.9 (68-100), sport/recreational activities 30.0 (0-70) to 62.5 (0-95), quality of life 31.3 (6-50) to 46.9 (19-100)]. Within the first year, patients with OCLT and CAI treated with M-BMS and ankle stabilisation also showed significant improvement in the FAAM [activity of daily living 68.8 (5-99) to 90.5 (45-100); sports 32.8 (0-87.5) to 64.1 (0-94), functional activities of daily life 62.5 (25-100) to 80 (60-90), functional sports 30 (0-100) to 67.5 (0.95)] and the FAOS [pain 66.7 (28-92) to 87.5 (47-100), symptoms 57.1 (29-96) to 78.6 (50-100), activities of daily living 80.1 (25-100) to 98.5 (59-100), sport/recreational activities 35.0 (0-100) to 70.0 (0-100), quality of life 25.0 (0-75) to 50.0 (19-94)]. The pain level decreased significantly in both groups. No significant difference was found between both groups regarding the subscales of FAAM, FAOS and the NRS 1 year postoperatively. CONCLUSION: Improvements in subjective ankle function, daily life activities and sports activities were observed within the first year following M-BMS. Our results suggest that preexisting and treated ankle instability did not compromise subjective outcome in patients treated with M-BMS in the first postoperative year. LEVEL OF EVIDENCE: Level IV.

[Conversion osteotomy for arthrosis of the ankle joint (supramalleolar and inframalleolar)-What can be expected? : Critical review of the literature]. / Umstellungsosteotomien bei Arthrose am Sprunggelenk (supra- und inframalleolar) ­ Was kann man erwarten? : Kritische Übersicht der Literatur.

The aim of supramalleolar conversion osteotomy is to reduce the pain of the patient and stop or at least slow down joint degeneration. The indication for supramalleolar osteotomy is asymmetric osteoarthritis of the ankle joint with varus or valgus deformity. Good clinical results for arthritis can be achieved in the early or middle stages. Besides closing and opening wedge osteotomies dome osteotomy is sometimes indicated, especially for larger deformities. The preoperative preparation of individual patient-specific section blocks facilitates the intraoperative implementation and seems to increase the precision. Further studies are necessary to support this. The indications for additional procedures, such as fibular osteotomy are still being discussed. Inframalleolar osteotomy and soft tissue interventions are frequently necessary for balancing the foot.

Foot and Ankle Surgical Incision Closure With Three Different Materials.

There is no clear recommendation for wound closure material in foot and ankle surgery. Thus, we hypothesized that there was no difference in clinical outcomes among 3 suture materials, namely, absorbable sutures, nonabsorbable sutures, and metallic staples. This study compared the 3 materials for wound closure in foot and ankle surgery. In this prospective randomized study, 124 patients were randomly divided into the nonabsorbable suture group, absorbable suture group, and staple group. ASEPSIS score, Hollander Wound Evaluation Scale, and numerical rating scale (regarding pain and satisfaction) were collected at first dressing changes, suture removal, and 6 weeks after surgery. Suture time and incision length were recorded. No significant differences were detected for the ASEPSIS and Hollander Wound Evaluation Scale scores. There was significantly more pain after 6 weeks in the nonabsorbable suture group. The closure time (13 s/cm) with staples was significantly lower in the nonabsorbable suture group than in the other groups. Regardless of wound closure material, male sex and obesity appeared to be associated with a higher risk for the occurrence of wound complications. The 3 suture materials showed no significant differences regarding the frequency of wound complications. Staples and absorbable sutures should therefore be considered in the repertoire of suture materials used in foot and ankle surgery.

[Diagnosis and Therapy of Acute Achilles Tendon Ruptures]. / Diagnose und Therapie der akuten Achillessehnenruptur.

Diagnosis and Therapy of Acute Achilles Tendon Ruptures Abstract. Acute Achilles tendon ruptures are a common pathology and often affect young athletic patients. Diagnosis is mostly clinical and by ultrasound. Conservative and operative treatment algorithms exist. The result of the treatment is mostly influenced by the elongation of the tendon during healing. Operative procedures tend to lead to less elongation but have a complication risk. After-treatment should be functional to reduce complication rate and faster rehabilitation. Treatment results are good in general, but some weakness is often found on the injured side.

[Mini implants in foot and ankle surgery: an alternative to total joint replacement or joint fusion]. / Mini-Implantate am Fuß- und Sprunggelenk: Eine Alternative zur Vollprothese oder Versteifung.

Mini implants are increasingly used in foot and ankle surgery. They preserve the joints' functions, are easy to insert and easy to convert to an alternative treatment. Early surgical attempts using silastic implants did not bring the expected success. First achievements where reached with modern metallic mini implants in the first metatarsophalangeal (MTP) joint and the ankle joint. For a few years now, a polyvinyl alcohol implant has been used to treat the arthritic first MTP joint. Even severe arthritic joints can be treated with an implant made of polylactide. This implant can also be used in the treatment of Lisfranc joint pathologies. To address severe osteochondral defects of the talus, an innovative hemiarthroplasty implant has been suggested. This article gives a summary of currently used mini implants. Their application as possible alternatives to total joint replacement or joint fusion are critically reviewed in the light of the current literature.

Biomechanical evaluation of naviculocuneiform fixation with lag screw and locking plates.

BACKGROUND: There have been no biomechanical evaluations of naviculocuneiform (NC) joint fixation. This study compared biomechanically 3 different fixation constructs for NC-1-3 joint fixation. METHODS: The present study compared the three fixation constructs lag screw with locking plate for each NC joint, two crossed lag screws for each NC joint and a separate lag screw for each NC joint with bridging locking plates. NC-1-3 fixation was performed stepwise, and rotation of each joint was evaluated after the application of each lag screw or locking plate and their removal. RESULTS: All examined fixation techniques led to a significant reduced rotation of the NC joints. For NC-1 rotation decreased from 2.8° (Range 1.2-6.6°) to 0.6° (0.2-3.0°) for lag screw and locking plate (p = 0.002) and from 5.0° (1.7-9.8°) to 1.0° (0.1-3.6°) for crossed lag screws (p = 0.002). For NC-2, locking plate constructs were better with 0.2° (0.1-0.5°) compared to crossed lag screw osteosynthesis with 0.9° (0.2-1.6°) (p = 0.011). CONCLUSION: Each evaluated fixation technique led to a reduced NC joint rotation. The fixation of any NC joint had no relevant effect on the adjacent NC joints. The results might support surgeons treating NC joint disorders.

Feasibility and reliability of DEXA analysis after total ankle arthroplasty: A cadaver study.

BACKGROUND: Although the outcomes of total ankle arthroplasty (TAA) have improved, unsolved problems such as stress shielding remain. Although dual energy X-ray absorptiometry (DEXA) is the "gold standard" for evaluation of these issues, it is rarely used in patients after TAA. This study aimed to establish a scan technique and to assess the mechanical changes in bone density caused by bone stock preparation. METHODS: Eight fresh-frozen cadaver legs were investigated by DEXA before TAA, with implant in situ, and after implant removal. Scan surface, bone mineral content, and bone mineral density were analysed to assess mechanical bone mass changes. RESULTS: We examined data for density changes by bone compression after TAA, and found "good" results for internal reliability but only "acceptable" results for external reliability. CONCLUSIONS: The results were reliable and reproducible. Using the present data, mechanical and biological processes can be considered together to understand the postoperative phases of bone remodelling after TAA.

Concomitant ankle instability has a negative impact on the quality of life in patients with osteochondral lesions of the talus: data from the German Cartilage Registry (KnorpelRegister DGOU).

PURPOSE: The purpose of this study was to compare patients with osteochondral lesions of the talus (OCLT) with and without concomitant chronic ankle instability (CAI). METHODS: Data from the German Cartilage Registry (KnorpelRegister DGOU) for 63 patients with a solitary OCLT were used. All patients received autologous matrix-induced chondrogenesis (AMIC) for OCLT treatment. Patients in group A received an additional ankle stabilisation, while patients in group B received AMIC alone. Both groups were compared according to demographic, lesion-related, and therapy-related factors as well as baseline clinical outcome scores at the time of surgery. The Foot and Ankle Ability Measure (FAAM), the Foot and Ankle Outcome Score (FAOS), and the Numeric Rating Scale for Pain (NRS) were used. RESULTS: Patients in group A were older compared to group B [median 34 years (range 20-65 years) vs. 28.5 years (range 18-72 years)]; the rate of trauma-associated OCLTs was higher (89.7% vs. 38.3%); more patients in group A had a previous non-surgical treatment (74.1% vs. 41.4%); and their OCLT lesion size was smaller [median 100 mm2 (range 15-600 mm2) vs. 150 mm2 (range 25-448 mm2)]. Most OCLTs were located medially in the coronary plane and centrally in the sagittal plane in both groups. Patients in group A had worse scores on the FAOS quality-of-life subscale compared to patients in group B. CONCLUSION: Patients with OCLT with concomitant CAI differ from those without concomitant CAI according to demographic and lesion-related factors. The additional presence of CAI worsens the quality of life of patients with OCLT. Patients with OCLT should be examined for concomitant CAI, so that if CAI is present, it can be integrated into the treatment concept. LEVEL OF EVIDENCE: IV.

Manipulation under anesthesia as a therapy option for postoperative knee stiffness: a retrospective matched-pair analysis.

INTRODUCTION: Due to demographic changes, total knee arthroplasty (TKA) is one of the most frequently performed orthopedic surgeries. Therapies for associated postoperative complications, such as postoperative knee stiffness (PKS), are becoming increasingly important. The aim of this retrospective matched-pair analysis was to evaluate mid-term-results following manipulation under anesthesia (MUA). MATERIALS AND METHODS: Fifty-one patients with PKS were evaluated and 51 matched-pair patients without PKS after primary TKA were chosen for the control group. In addition to the range of motion, the functionality was recorded by Knee Society Score (KSS), Western Ontario and Mc Masters Universities Osteoarthritis Index (WOMAC), and Short-Form-12 Questionnaire (SF-12). Experience of pain was mapped using a 10-point Numeric Rating Scale (NRS), and the analgesic requirement was mapped using the WHO step scheme. A final follow-up examination was conducted approximately three years after TKA. To evaluate potential risk factors for the development of PKS, TKA alignment was measured via postoperative X-ray images. RESULTS: Improvement of the average knee flexion of 35.7° and total flexion of 107.4° was detected in PKS patients after MUA. The flexion of the control group was 112.4°; no significant between-group difference was present regarding prosthesis type, sex, age and BMI. Regarding KSS, WOMAC, and SF-12, the MUA cohort achieved statistically-relevant lower overall scores than the control group, p = 0.006, p = 0.005, p = 0.001, respectively. Significantly higher experiences of pain and a higher need for analgesics in MUA patients were reported (p = 0.001 and p < 0.001, respectively). Radiological evaluation of the prosthesis alignment did not show any differences between the two groups. CONCLUSIONS: MUA can improve mobility after PKS, whereby MUA seemed to be a functional therapy option for PKS. Compared to the control group, the MUA group showed lower functional values and an increased experience of pain. A correlation between prosthesis malalignment and MUA could not be detected radiologically. Further studies are necessary to investigate the reasons for PKS.

Treatment concepts for pes valgoplanus with concomitant changes of the ankle joint : Tibiotalocalcaneal arthrodesis, total ankle replacement and joint-preserving surgery.

Concomitant valgus deformities of the ankle joint are found in approximately 3% of patients with symptomatic flat foot deformities. Conservative treatment is mostly successful only in the short term or in low-demand patients. The operative treatment of flat foot deformities follows the standard algorithm for flat foot treatment. The ankle joint can be treated while retaining mobility or by arthrodesis depending on the degree and rigidity of the deformity, degenerative changes, patient factors and expectations. Achieving an orthograde hindfoot and midfoot is obligatory for successful treatment as well as in ankle reconstructive or arthrodesis procedures.

Short term results of dynamic splinting for hallux valgus - A prospective randomized study.

Background Hallux valgus is a common diagnosis in orthopedics. Only a few studies have analyzed the effects of conservative therapy. Therefore, the current study analyzed the effect of a dynamic hallux valgus splint. Methods Seventy patients were included in this prospective randomized trial. Patients with a hallux valgus were treated using a dynamic splint or underwent no treatment. Clinical and radiological parameters were evaluated. Results We found no significant changes in hallux valgus angle, intermetatarsal I-II angle, AOFAS score, FAOS or SF-36 score between the groups. However, a significant between-group difference was found for pain during walking and running and in the FAOS subscale for pain and pain at rest at follow-up. Conclusions Wearing a dynamic hallux valgus splint does provide some pain relief in patients with a symptomatic hallux valgus, but showed no effect on hallux valgus position. Level of evidence: 1.

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.

Ankle morphometry based on computerized tomography.

BACKGROUND: Thorough understanding of the morphometry of the ankle joint is crucial to optimize conservative and operative therapy of ankle joint disorders. Despite recent improvements, basic anatomic and biomechanical correlations of the ankle joint including the orientation of the ankle joint axis and joint morphology as its key biomechanical features are not sufficiently recorded to date. The aim of this study was the evaluation of the ankle morphometry to gain information about the ankle joint axis. MATERIAL AND METHODS: In this study 98 high-resolution CT-scans of complete Caucasian cadaver legs were analysed. Using the software Mimics and 3-Matic (Materialize) 22 anatomic parameters of the talocrural joint were assessed, including the length, width and surface area of the tibial and talar articular areas. Additionally, the radii of the articular areas, the medial distal tibial angle and the height of the talar dome were determined. RESULTS: The radius of the central trochlea tali was 44.6±4.1mm (mean±SD). The central trochlea tali arc length was 40.8±3.0mm and its width was 27.4±2.5mm. Additionally we determined 47.0±4.4mm for the tibial sagittal radius, 27.6±3.0mm for the tibial arc length and 27.4±2.5mm for the central tibial width. CONCLUSION: The present study describes the three-dimensional morphometry of Caucasian ankle joints in detail. This dimensional analysis of the ankle joint will inform the development and placements of implants and prostheses.

Bioabsorbable magnesium versus standard titanium compression screws for fixation of distal metatarsal osteotomies - 3 year results of a randomized clinical trial.

BACKGROUND: For the treatment of hallux valgus commonly distal metatarsal osteotomies are performed. Persistent problems due to the hardware and the necessity of hardware removal has led to the development of absorbable implants. To overcome the limitations of formerly used materials for biodegradable implants, recently magnesium has been introduced as a novel implant material. This is the first study showing mid-term clinical and radiological (MRI) data after using magnesium implants for fixation of distal metatarsal osteotomies. MATERIAL AND METHODS: 26 patients with symptomatic hallux valgus were included in the study. They were randomly selected to be treated with a magnesium or standard titanium screw for fixation of a modified distal metatarsal osteotomy. The patients had a standardized clinical follow up and MRI investigation 3 years' post-surgery. The clinical tests included the range of motion of the MTP 1, the AOFAS, FAAM and SF-36 scores. Further on the pain was evaluated on a VAS. RESULTS: Eight patients of the magnesium group and 6 of the titanium group had a full clinical and MRI follow up 3 years postoperatively. One patient was lost to follow-up. All other patients could be interviewed, but denied full study participation. There was a significant improvement for all tested clinical scores (AOFAS, SF-36, FAAM, Pain-NRS) from pre-to postoperative investigation, but no statistically relevant difference between the groups. Magnesium implants showed significantly less artifacts in the MRI, no implant related cysts were found and the implant was under degradation three years postoperatively. CONCLUSION: In this study, bioabsorbable magnesium implants showed comparable clinical results to titanium standard implants 3 years after distal modified metatarsal osteotomy and were more suitable for radiologic analysis. LEVEL OF EVIDENCE: 2.

Stability of supramalleolar osteotomies using different implants in a sawbone model.

BACKGROUND: With ankle arthritis often affecting young patients, joint-sparing treatments instead of total joint replacement should be considered. Only a few implants were specially developed for supramalleolar osteotomies (SMOT). This study was performed to analyse the stability of different implants and their appropriateness for SMOT. METHODS: Twenty-five bone models (Sawbone Europe, Malmö, Sweden) were used for biomechanical testing. SMOT were performed as a uniplanar osteotomy, leaving 5 mm of lateral bone intact with a standardized gap of 8 mm. Five different plates commonly used for SMOT were assessed. For axial stability, the constructs were tested during 100 cycles for each load (150N and 800N) at a rate of 0.5 Hz. For rotational stability, each construct was subject to 100 cycles of 5 Nm torque at a rate of 0.25 Hz, performing three runs with an axial preload of 0N, 150N, or 800N. Ultimate axial load was performed for one-half and ultimate rotational load was performed for the other half of the constructs. In addition, the stiffness of the different constructs after failure was tested. RESULTS: All constructs showed high stability and could be tested until maximum cyclic load. There was no significant difference between the five plates, neither for stiffness (axial or rotational) nor for failure load (axial or rotational). One plate indicated superiority in axial failure testing without any significant difference. CONCLUSION: All implants could be tested until maximum load. The intact hinge apparently provides enough support to compensate for lower moment of inertia of some plates. LEVEL OF EVIDENCE: Not applicable.

Does a foot-drop implant improve kinetic and kinematic parameters in the foot and ankle?

INTRODUCTION: Unlike the drop foot therapy with ortheses, the therapeutic effect of an implantable peroneus nerve stimulator (iPNS) is not well described. IPNS is a dynamic therapy option which is placed directly to the motoric part of the peroneal nerve and evokes a dorsiflexion of the paralysed foot. This retrospective study evaluates the kinematics and kinetics in drop foot patients who were treated with an iPNS. MATERIALS AND METHODS: 18 subjects (mean age 51.3 years) with a chronic stroke-related drop foot were treated with an implantable peroneal nerve stimulator. After a mean follow-up from 12.5 months, kinematics and kinetics as well as spatiotemporal parameters were evaluated and compared in activated and deactivated iPNS. Therefore, a gait analysis with motion capture system (Vicon Motion System Ltd®, Oxford, UK) and Plug-in-Gait model was performed. RESULTS: The study showed significantly improved results in ankle dorsiflexion from 6.8° to 1.8° at the initial contact and from -7.3° to 0.9° during swing phase (p ≤ 0.004 and p ≤ 0.005, respectively). Likewise, we could measure improved kinetics, i.a. with a statistically significant improvement in vertical ground reaction force at loading response from 99.76 to 106.71 N/kg (p = 0.043). Enhanced spatiotemporal results in cadence, douple support, stride length, and walking speed could also be achieved, but without statistical significance (p > 0.05). CONCLUSIONS: The results show statistically significant improvement in ankle dorsiflexion and vertical ground reaction forces. These facts indicate a more gait stability and gait efficacy. Therefore, the use of an iPNS appears an encouraging therapeutic option for patients with a stroke-related drop foot.

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

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.

The value of arthroscopic neosynovium biopsies to diagnose periprosthetic knee joint low-grade infection.

INTRODUCTION: The diagnostic algorithm in cases of assumed low-grade infection after total knee arthroplasty is discussed controversial. The aim of this study was to evaluate the reliability of neosynovium biopsies via knee arthroscopies in predicting a periprosthetic knee joint infection (PJI). METHODS: From 2010 to 2015, 56 consecutive patients received a diagnostic arthroscopy of the knee joint by reason of an assumed PJI. In 34 cases, a revision arthroplasty was performed after the diagnostic arthroscopy. The microbiologic and histologic results from neosynovium biopsies were compared to intraoperative findings of the consecutively performed revision arthroplasty. RESULTS: The arthroscopic neosynovium biopsies had a sensitivity of 0.88 (0.47-1.0 95 % confidence interval), a specificity of 0.88 (0.7-0.98), a positive predictive value of 0.7 (0.35-0.93), and a negative predictive value of 0.96 (0.79-1.0). The accuracy was 0.88. We determined a higher sensitivity of neosynovium biopsies compared to C-reactive protein (p = 0.038) and white blood cell count (p < 0.001) in serum. The itemized evaluation of histologic results showed a significant higher sensitivity compared to microbiologic results (p = 0.045) and a higher accuracy. CONCLUSIONS: The analysis of arthroscopic neosynovium biopsies can be helpful to verify or exclude a PJI in selected patients. Especially, histologic assessment showed a high accordance with final results. Level of evidence IV, retrospective study.

Tibiocalcaneal arthrodesis as a limb salvage procedure for complex hindfoot deformities.

INTRODUCTION: Tibiocalcaneal (TC) arthrodesis is a limb salvage method for patients with severe deformities combined with necrosis and/or luxation of the talus. The aim of this study was to examine the clinical and radiological outcome of TC arthrodesis. MATERIALS AND METHODS: This retrospective study identified 12 patients with luxation and/or necrosis of the talus, due to charcot neuroarthropathy (83.3 %) or traumatic injuries (16.7 %). All patients underwent TC arthrodesis by an external fixator or nail arthrodesis. The mean follow up was 18 (6-36) months with a mean age of 51.3 (30-66) years. The data were collected using the AOFAS score as well as clinical and radiological examination during regular follow up. RESULTS: Seven (58.3 %) patients were treated with an external fixator, four (33.3 %) with nail arthrodesis and one (8.3 %) patient rejected both fixation methods. Four (100 %) patients achieved radiological and clinical bone union after nail arthrodesis and four (57.1 %) patients after external fixation. Three (42.9 %) patients treated by an external fixator showed a radiological moderate bone fusion, but a stable, asymptomatic non-union. One (8.3 %) case ended up in transfemoral amputation. Eleven patients (91.7 %) regained independent mobilization. The mean AOFAS score improved from 24.3 preoperatively to 66.7 postoperatively (p < 0.05). The postoperative satisfaction rate was good to excellent in 83.3 %. CONCLUSION: TC arthrodesis is a promising and effective method for the treatment of severe ankle deformities with talus luxation. It allows patient's return to mobility with good to excellent patient satisfaction.