Radiological outcome of hallux valgus deformity correction with metatarsal osteotomy from a single-center cohort - Best results achieved by foot and ankle surgeons.

BACKGROUND: To evaluate the radiological outcome, especially undercorrection of hallux valgus deformity correction with first metatarsal osteotomy. PATIENTS AND METHODS: 439 1st metatarsal osteotomies including 241 distal (55 %), 175 midshaft (40 %), and 23 proximal (5 %) were available for analysis with median follow-up time was 48 days (range 27-990 days). RESULTS: The postoperative HVA was normal in 237 (54 %), mild in 110 (25 %), moderate in 87 (20 %), and severe in 5 (1 %) of the cases. BMI (p = 0.0127), sex (p = 0.0004), preoperative HVA (p = 0.0028), and surgeons experience (p < 0.0001) were associated with radiological outcome, whereas age, hospital, and type of osteotomy had no effect. Foot and ankle surgeons achieved normal postoperative HVA in 76 %, general orthopedic surgeons in 41 %, and residents in 47 % of the operations. CONCLUSION: Radiological undercorrection was common. As foot and ankle surgeons achieved best radiological correction, hallux valgus deformity should be operated by specialists.

The motion between components in a mobile-bearing total ankle replacement measured by cone-beam CT scanning.

BACKGROUND: To measure the motion of polyethylene insert and implant components of mobile-bearing total ankle replacement (TAR) by cone-beam CT scanning. METHODS: 10 TAR patients with high amount of clinical motion after the CCI implant (Ceramic Coated Implant; Wright Medical Technology, Arlington, TN, USA) with average age at operation 64,3 years (range 47-84) and average clinical total range of motion 42 degrees (range 35-55) were included. RESULTS: The average total range of motion between the insert and the tibial component was 0.8mm (range 0-2) in the coronal plane, and 2.9mm (range 1-6) in the sagittal plane. There was wide variation in the axial rotation measurements between the components. CONCLUSION: We found measurable motion between the mobile-bearing insert and the tibial component in all planes. The relevance of this motion to the function and long-term survival of the TAR remains to be determined.

Low Rate of Peri-implant Osteolysis in Trabecular Metal Total Ankle Replacement on Short- to Midterm Follow-up.

BACKGROUND: Peri-implant osteolysis is one of the major complications related to total ankle replacement. The aim of this study was to investigate the short- to midterm incidence of peri-implant osteolysis using computed tomography (CT) as imaging method for the Trabecular Metal Total Ankle (TMTA) implant representing a novel total ankle replacement (TAR) implant design regarding material and surgical technique. METHODS: In total, 104 consecutive patients who had a primary TMTA replacement between March 2013 and October 2017 were included in the study. The radiographic evaluation included weightbearing anteroposterior and lateral views at baseline and after 3, 6, and every 12 months postoperatively. A helical CT was undertaken preoperatively and of the 80 patients available to follow up at least 12 months postoperatively, with average time interval between the TAR operation and the latest CT of 39 (range, 12-85) months. RESULTS: Eight of 80 patients had altogether 11 osteolytic lesions around the components on CT images. Seven lesions were found in tibia, 3 in talus, and 1 in distal fibula. Four of the tibial lesions were situated in the medial malleolus and were not in contact with the prosthesis component. The sizes of the osteolytic lesions ranged between 7 and 20 mm, and the average volume of the lesions was 689 mm3. CONCLUSION: We conclude that the risk of peri-implant osteolysis with the TMTA implant is minimal in short to midterm. The anatomic configuration, unique material, and surgical technique may all contribute to the TMTA implant having a low rate of peri-implant osteolysis. LEVEL OF EVIDENCE: Level IV, case series.

Medium to long-term results of 130 Ankle Evolutive System total ankle replacements-Inferior survival due to peri-implant osteolysis.

BACKGROUND: The study reports the medium to long-term results of 130 Ankle Evolutive System total ankle replacements operated at a single-centre. Previously high amount of peri-implant osteolysis was reported from the same material. METHODS: Between 2002 and 2008 one hundred and thirty consecutive ankles replaced with AES ankle prosthesis were followed both radiologically and clinically. RESULTS: The five-year survival was 87.3% (95% confidence interval (CI) 80.0-92.0%), and ten-year survival 74.9% (95% confidence interval (CI) 65.4-82.2%) at a median follow-up time of 96 months (range 2-161; 8 years). Peri-implant osteolysis was found in 91 (70%) ankles, marked in 78 (60%). 44 ankles (34%) have been revised by filling of the cavities, 24 (18%) by fusion, and 6 by further replacement, resulting in the revision rate of 58%. Osteolysis was the main reason for all revisions. The improvement of the Kofoed Score and pain points was significant (all p<0.0001), and the subjective patient satisfaction was good. CONCLUSIONS: Outcome of the current study was seriously affected by osteolysis and is inferior compared to previous reports.

Are periprosthetic osteolytic lesions in ankle worth bone grafting?

BACKGROUND: We retrospectively evaluated the medium-term follow-up of bone grafting due to periprosthetic osteolytic lesions in ankles. METHODS: 34 ankles (32 patients) with total ankle arthroplasty (TAA) underwent re operation. Indications were large periprosthetic osteolytic lesions or continuous growing of the lesions. The osteolytic lesions were imaged by CT before reoperation and once a year after that. The mean CT follow-up after re operation was 3.8 years (range, 2-6.2 years). Patient's clinical outcome was also monitored. RESULTS: Osteolysis continued to progress in 44 bone grafted lesions (68%) in CT follow-up. Pain (p=0.04) and location of the lesion (p=0.03) were associated with progression of osteolysis. In 18 bone grafted osteolytic lesions (28%) the radiological survival remained excellent. 25 out of 34 ankles showed improvement of the function after bone grafting. CONCLUSIONS: There is no established treatment protocol for osteolysis around TAA. Bone grafting is one alternative in the treatment of osteolytic lesions.

Long-term Results of Scandinavian Total Ankle Replacement.

BACKGROUND: The purpose of this study was to evaluate the long-term results of the Scandinavian Total Ankle Replacement (STAR) implant in a single center. METHODS: Between 1997 and 2002, 34 consecutive ankles were replaced with the STAR ankle prosthesis and reviewed in 2016. Patients were followed both radiologically and clinically; clinical outcomes were measured with the Kofoed ankle score and subjective measurements. The median follow-up period was 159 months (13.3 years; range, 13-202 months). RESULTS: The implant survival rate was 93.9% (95% confidence interval [CI], 92.2%-86.7%) at 5 years, 86.7% (95% CI, 69.3%-96.2%) at 10 years, and 63.6% (95% CI, 30.8%-89.0%) at 15 years. A total of 15 ankles (44%) had been revised: 2 by fusion, 3 by further replacement, 5 by insert exchange, and 5 by bone grafting for marked osteolysis. The improvements in the Kofoed ankle score and Kofoed ankle score for pain were statistically significant at every postoperative evaluation point compared to the preoperative values (all P < .0001), and subjective patient satisfaction was high. CONCLUSION: Our results were satisfactory and in agreement with previously reported findings of STAR implants. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Autoinflammation Around AES Total Ankle Replacement Implants.

BACKGROUND: Failure of total ankle replacement (TAR) can be characterized by early peri-implant osteolysis even in the presence of very modest numbers of wear particles. The hypothesis of the study was that this reaction is in part mediated by autoinflammatory responses mediated via damage-associated molecular patterns (DAMPs, danger signals) and pattern-recognizing danger signal receptors (PRRs). METHODS: Peri-implant tissue and control samples from 10 patients with AES implants were immunostained for hypoxia inducible factor-1α (HIF-1α), activated caspase-3, high-mobility group box 1 (HMGB1), receptor for advanced glycation end product (RAGE), and toll-like receptors TLR2 and TLR4. Results were evaluated on a 0 to 4 scale (from 0% to >50% stained area). RESULTS: Peri-implant tissue around failed TAR implants had a relatively high mean HIF-1α score of 3 on a scale, which however was similar in control samples. HMGB1 (a DAMP) was seen to be mobilized from nuclei to cellular cytoplasm, and the active caspase-3(+) cells were increased. All PRRs were increased in revision samples. CONCLUSIONS: Increased expression of HMGB1 and other danger signals together with increased PRR-dependent responsiveness could contribute to autoinflammatory peri-implantitis, multilocular cyst formation, and osteolysis in failed TAR implants. LEVEL OF EVIDENCE: Level IV, case series.

Total ankle arthroplasty: optimizing computed tomography imaging protocol.

OBJECTIVE: To evaluate parameters and positioning when imaging total ankle prostheses on computed tomography (CT). MATERIALS AND METHODS: An ankle prosthesis implanted into a pig's knee joint underwent 16 different CT imaging protocols. Four defects were drilled around prosthesis components simulating periprosthetic osteolytic lesions. The specimen with the implant was imaged in four different orientations with the tibial stem parallel to the table and at 25, 45, and 90° angles to it. The protocol consisted of scanning at 100, 120, and 140 kVp in every position with a pitch of 1.2. The scanning at 120 kVp in every position was repeated with a pitch of 1.0. RESULTS: CT proved to be a reliable imaging modality when studying periprosthetic lesions adjacent to the ankle prosthesis when the tibial stem alignment was parallel to the table. When imaging at higher angles, metal artifacts distorted the image, making the analysis of periprosthetic bone structure unreliable. There were no statistically significant differences between different tube voltages or pitch in volume measurements of the osteolytic lesions. CONCLUSIONS: CT is a reliable imaging method to evaluate periprosthetic bone structure around ankle prostheses when orientation of the prosthesis and acquisition parameters is optimized.

Does computed tomography add information on radiographic analysis in detecting periprosthetic osteolysis after total ankle arthroplasty?

BACKGROUND: The major longer term complications of ankle arthroplasty are periprosthetic osteolysis and aseptic loosening. Follow-up studies of total hip arthroplasties show that measurements of periprosthetic osteolytic lesions on radiographs underestimate the size compared with those made on computed tomography (CT), and some of the lesions may even remain undetected on radiographs. However, it is unclear whether the same applies to total ankle arthroplasty (TAA). METHODS: We retrospectively reviewed the radiographs of 123 patients who had undergone TAA with the Ankle Evolutive System (AES) implant. Of these, 43 (34.9%) had at least 1 large (greater than 10 mm) osteolytic lesion on radiographs at a minimum follow-up of 14 months (mean, 43.1 months; range, 14-85 months). Forty of the 43 patients underwent helical CT imaging. RESULTS: Computed tomography showed more osteolytic lesions than radiographs around both tibial and talar components. CT also showed larger lesions than radiographs in 9 of 10 zones around prosthetic components. The difference was highly significant in 3 zones around the talar component. CONCLUSION: Computed tomography showed more and larger periprosthetic lesions than radiographs around an ankle prosthesis. Because osteolysis is progressive in nature, it presumably leads to component failure. Considering our results, we recommend adding CT imaging to postoperative follow-up after TAA for patients with suspected or known periprosthetic lucencies on radiographs. LEVEL OF EVIDENCE: Level III, diagnostic study.

Circulating plastic adherent mesenchymal stem cells in aged hip fracture patients.

We examined the presence of circulating plastic adherent multipotent mesenchymal stem cells (MSCs) in fracture patients. Three patient groups (n = 10-18) were evaluated, including elderly females with a femoral neck fracture treated with cemented hemiarthroplasty, an age- and sex-matched group with hip osteoarthritis (OA) treated with cemented total hip arthroplasty (THA), and younger adults with surgically treated lower extremity fractures. The presence of circulating MSCs pre- and postoperatively was compared to bone marrow (BM) MSCs from the same subjects. Criteria for identifying MSCs included cell surface markers (CD105+, CD73+, CD90+, CD45-, CD14-), proliferation through several passages as well as osteogenic, chondrogenic, and adipogenic differentiation. Plastic adherent MSCs were found in peripheral blood (PB) from 22% of hip fracture patients, 46% of younger fracture patients, and in none of 63 pre- and postmenopausal women with hip OA. When detectable, circulating MSCs appeared between 39 and 101 h after fracture. PB derived MSCs did not differ from BM derived MSCs, except for a small population (<15%) of CD34+ cells among PB derived MSCs. This initial study indicates mobilization of MSCs into the circulation in response to fracture, even in very old patients, while circulating MSCs were not detectable before or after elective THA.

Total ankle replacement: a population-based study of 515 cases from the Finnish Arthroplasty Register.

BACKGROUND AND PURPOSE: Although total ankle replacement (TAR) is a recognized procedure for treatment of the painful arthritic ankle, the best choice of implant and the long-term results are still unknown. We evaluated the survival of two TAR designs and factors associated with survival using data from the nationwide arthroplasty registry in Finland. METHODS: 573 primary TARs were performed during the period 1982-2006 because of rheumatic, arthritic, or posttraumatic ankle degeneration. We selected contemporary TAR designs that were each used in more than 40 operations, including the S.T.A.R. (n = 217) and AES (n = 298), to assess their respective survival rates. The mean age of the patients was 55 (17-86) years and 63% of operations were performed in women. Kaplan-Meier analysis and the Cox regression model were used for survival analysis. The effects of age, sex, diagnosis, and hospital volume were also studied. RESULTS: The annual incidence of TAR was 1.5 per 10(5) inhabitants. The 5-year overall survivorship for the whole TAR cohort was 83% (95% CI: 81-86), which agrees with earlier reports. The most frequent reasons for revision were aseptic loosening of one or both of the prosthesis components (39%) and instability (39%). We found no difference in survival rate between the S.T.A.R. and AES designs. Furthermore, age, sex, diagnosis, and hospital volume (< 10 and > 100 replacements in each of 17 hospitals) did not affect the TAR survival. INTERPRETATION: Based on our findings, we cannot conclude that any prosthesis was superior to any other. A high number of technical errors in primary TARs suggests that this low-volume field of implant arthroplasty should be centralized to fewer units.