Long-term outcomes after pantarsal arthrodesis with medial plate fixation without external coaptation in 30 dogs.

OBJECTIVE: To report long-term outcomes of dogs treated with pantarsal arthrodesis (PTA) with medial plate fixation without external coaptation. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned dogs (n = 30). METHODS: Medical records of dogs that had undergone a PTA with a medially applied plate without adjunctive rigid external coaptation were reviewed. Data collected included signalment, complications, and assessment of function at last physical examination. Follow-up information was obtained by phone conversations with owners. Complications were classified as minor, major II, major I, and catastrophic. RESULTS: Thirty-six PTA were performed in 30 dogs. Recorded complications included eight (22.2%) minor complications, 11 (30.6%) major II complications and 11 (30.6%) major I complications. One (2.8%) dog required amputation because of catastrophic complication. Owners provided follow-up for 26 dogs at a median duration of 1215 days (range, 325-3495) after surgery. The outcome was reported as full function in 12 dogs and acceptable function in 14 dogs, with no owners reporting unacceptable function. The owner of the dog in which amputation was required was not contacted. Incorrect contact details prevented owner follow-up in the other three dogs, but all had acceptable function at last veterinary follow up. CONCLUSION: Dogs treated with PTA by medially applied plate had a high incidence of complications requiring surgical or medical management, although full or acceptable function was achieved in 29 of 30 dogs. CLINICAL SIGNIFICANCE: Pantarsal arthrodesis offers a predictably good medium to long-term outcome in spite of a high risk of complications.

"The chisel test"--a useful operative, technique for determining adequate, compression during arthrodesis.

Healing of an arthrodesis occurs optimally when the prepared joint surfaces are held rigidly under compression [1]. We routinely use the "Chisel test" intra-operatively to determine whether we have achieved adequate compression and rigidity after fixation of our foot and ankle fusions. This previously un-reported technique uses tools already on hand when performing an arthrodesis and takes seconds to perform.

Knee arthrodesis with the Ilizarov external fixator as treatment for septic failure of knee arthroplasty.

BACKGROUND: The authors report the results of femoral-tibial fusion with an Ilizarov circular external fixator following septic loosening of knee prosthesis. MATERIALS AND METHODS: The series included 17 patients with a mean age of 62.9 years, treated from 1990 to 2007 with femoral-tibial fusion. The Cierny-Mader classification was used for clinical and anatomopathological evaluation; the Engh classification was used to assess the bone defect. Surgical treatment differed according to these criteria. RESULTS: Healing was achieved in 13 out of 17 patients at the first surgical attempt in a mean time of 9.3 months. Mean follow-up was 30 months. Of the four complications, two patients had an intolerance to the external fixator that led to its early removal, and the other two had a septic intraarticular nonunion. CONCLUSIONS: The Ilizarov circular external fixator is a very reliable fixation system due to its low cost, versatility, stability under load, and low risk of septic dissemination. Nevertheless, an appropriate patient selection and a good surgeon's experience are necessary.

Arthrodesis of the equine proximal interphalangeal joint: a biomechanical comparison of 2 different LCP systems.

OBJECTIVE: This study compares the mechanical stability and surgical usability of 2 locking plate systems (Kyon ALPS-20 and Synthes PIP-LCP system) for arthrodesis of the equine proximal interphalangeal joint (PIJ). MATERIAL AND METHODS: The experimental ex vivo study included 6 pairs of cadaver distal limbs (n = 12). All specimens were derived from Warmblood horses of various ages that were euthanized for non-orthopedic reasons. Of the 12 limbs collected, 3 left and 3 right distal limb specimens were randomly assigned to each system for implantation. Two abaxial 4.5-mm cortical screws were inserted transarticularly in all cases. Both systems were implanted according to the manufacturer's instructions with the plates placed centrally between the 2 transarticular screws. The ALPS-20 systems were implanted using Kyon B-6.4-mm monocortical locking screws in all positions. The LCP systems were implanted axially using 2 Synthes 5-mm locking screws in the proximal and distal positions, with a standard 4.5-mm cortical screw inserted in the middle position. All constructs underwent CT-scans after implantation and biomechanical testing to detect implant deformation. Uniaxial mechanical loading was applied via a servo-hydraulic test system at a test speed of 50 mm/s, up to a maximum displacement of 80 mm. The resulting load-displacement curves were used to calculate yield point, stiffness, and maximum force for each construct. The measured values were evaluated for statistical significance (p < 0.05) between the 2 plate systems via one-factor ANOVA (Tukey test). The statistical power was verified for yield force, stiffness, and maximum load. RESULTS: No statistically significant differences between the 2 preparation groups were calculated across all of the measured parameters (p > 0.05). The ALPS system implants showed no signs of deformation, either in the plates or the screws. In contrast, the LCP demonstrated visible deformation, which had already occurred at the time of implantation from the tightening of the middle screw, as well as during the subsequent testing of the implants. After biomechanical testing, deformations ranging between 3.1° and 7.0° were measured in 4 LCPs. A total implant failure was observed for 2 LCPs. CONCLUSION AND CLINICAL RELEVANCE: Both systems demonstrated comparable mechanical properties in the present study's ex vivo test model for equine PIJ arthrodesis. As such, the Kyon ALPS-20 may be a good alternative to the Synthes LCP for equine PIJ arthrodesis.

Computer Assisted Surgery (CAS) guided arthrodesis of the foot and ankle: an analysis of accuracy in 100 cases.

BACKGROUND: Computer Assisted Surgery (CAS) has shown the potential to increase the accuracy of surgical procedures in different fields of orthopedic surgery. The clinical experiences of 100 cases with CAS guided arthrodeses were evaluated. MATERIALS AND METHODS: Two navigation systems were used (VectorVision/Navivision, Brainlab). Patients with unilateral foot and/or ankle correction arthrodesis from January 1st, 2005 to March 31st, 2008 were included. The correction was planned on the basis of clinical findings, radiographs and computer tomography. Time spent, accuracy, and problems that occurred with CAS guidance were analyzed. The accuracy was assessed by intraoperative three-dimensional imaging with ISO-C 3D or ARCADIS-3D (Siemens). The deviation from the achieved correction in comparison with the planned correction was analyzed. RESULTS: One hundred patients were included (ankle, n = 19; subtalar, n = 23; ankle and subtalar, n = 12; midfoot/tarsometatarsal (TMT), n = 28, others, n = 18). The average time needed for preparation was 356 seconds (5 minutes, 56 seconds) (range, 4 to 30 minutes), the correction took an average of 28 (range, 12 to 140) seconds. The CAS system encountered malfunctions in 3 procedures (3%). In the remaining cases, all the achieved corrections were within a maximum deviation of 2 degrees/mm when compared to the planned correction (p < 0.05). CONCLUSION: With CAS guidance for the correction of deformities of the foot and ankle, a surgeon can achieve a high degree of accuracy with a rapid correction. The high accuracy may lead to improved clinical outcomes.

An in vitro comparison of a 2.7/3.5 mm hybrid plate alone and combined with crossed K-wires for canine pancarpal arthrodesis.

Several techniques have been described for canine pancarpal arthrodesis (PCA) with dorsal plating becoming the most accepted method for ease of placement despite the proposed biomechanical disadvantages. The aim of this study was to compare the biomechanical effects of the addition of crossed K-wires to a standard 2.7/3.5 mm hybrid PCA plate. A 2.7/3.5 mm hybrid PCA plate, alone and combined with crossed K-wires were tested. Six pairs of cadaver forelimbs were collected from medium-sized dogs with an average weight of 24 kg by elbow disarticulation. The limbs were potted and fixed in an Instron load cell (Instron, High Wycombe, UK) and axially loaded to failure. Load displacement data and mode of failure were recorded and stiffness, yield load and ultimate load at failure were calculated. The yield load (kN) of the plate and K-wire construct (1.278+/-0.11) was significantly higher than for the plate construct alone (1.002+/-0.07) (p=0.00056). However, the differences between the two constructs in stiffness and failure loads were not significant.

Arthrodesis after failed total ankle replacement.

We present a series of 16 patients treated between 1993 and 2006 who had a failed total ankle replacement converted to an arthrodesis using bone grafting with internal fixation. We used tricortical autograft from the iliac crest to preserve the height of the ankle, the malleoli and the subtalar joint. A successful arthrodesis was achieved at a mean of three months (1.5 to 4.5) in all patients except one, with rheumatoid arthritis and severe bone loss, who developed a nonunion and required further fixation with an intramedullary nail at one year after surgery, before obtaining satisfactory fusion. The post-operative American Orthopaedic Foot and Ankle Society score improved to a mean of 70 (41 to 87) with good patient satisfaction. From this series and an extensive review of the literature we have found that rates of fusion after failed total ankle replacement in patients with degenerative arthritis are high. We recommend our method of arthrodesis in this group of patients. A higher rate of nonunion is associated with rheumatoid arthritis which should be treated differently.

Failure mode and bending moment of canine pancarpal arthrodesis constructs stabilized with two different implant systems.

OBJECTIVE: To compare failure mode and bending moment of a canine pancarpal arthrodesis construct using either a 2.7 mm/3.5 mm hybrid dynamic compression plate (HDCP) or a 3.5 mm dynamic compression plate (DCP). STUDY DESIGN: Paired in vitro biomechanical testing of canine pancarpal arthrodesis constructs stabilized with either a 2.7/3.5 HDCP or 3.5 DCP. SAMPLE POPULATION: Paired cadaveric canine antebrachii (n=5). METHODS: Pancarpal arthrodesis constructs were loaded to failure (point of maximum load) in 4-point bending using a materials-testing machine. Using this point of failure, bending moments were calculated from system variables for each construct and the 2 plating systems compared using a paired t-test. To examine the relationship between metacarpal diameter and screw diameter failure loads, linear regression was used and Pearson' correlation coefficient was calculated. Significance was set at P<.05. RESULTS: HDCP failed at higher loads than DCP for 9 of 10 constructs. The absolute difference in failure rates between the 2 plates was 0.552+/-0.182 N m, P=.0144 (95% confidence interval: -0.58 to 1.68). This is an 8.1% mean difference in bending strength. There was a significant linear correlation r=0.74 (P-slope=.014) and 0.8 (P-slope=.006) between metacarpal diameter and failure loads for the HDCP and 3.5 DCP, respectively. CONCLUSION: There was a small but significant difference between bending moment at failure between 2.7/3.5 HDCP and 3.5 DCP constructs; however, the difference may not be clinically evident in all patients. CLINICAL RELEVANCE: The 2.7/3.5 HDCP has physical and mechanical properties making it a more desirable plate for pancarpal arthrodesis.

Total ankle arthroplasty versus ankle arthrodesis-a comparison of outcomes over the last decade.

BACKGROUND: The surgical treatment of end-stage tibiotalar arthritis continues to be a controversial topic. Advances in surgical technique and implant design have lead to improved outcomes after both ankle arthrodesis (AA) and total ankle arthroplasty (TAA), yet a clear consensus regarding the most ideal form of treatment is lacking. In this study, the outcomes and complications following AA and TAA are compared in order to improve our understanding and decision-making for care and treatment of symptomatic tibiotalar arthritis. METHODS: Studies reporting on outcomes and complications following TAA or AA were obtained for review from the PubMed database between January 2006 and July 2016. Results from studies reporting on a minimum of 200 total ankle arthroplasties or a minimum of 80 ankle arthrodesis procedures were reviewed and pooled for analysis. All studies directly comparing outcomes and complications between TAA and AA were also included for review. Only studies including modern third-generation TAA implants approved for use in the USA (HINTEGRA, STAR, Salto, INBONE) were included. RESULTS: A total of six studies reporting on outcomes following TAA and five reporting on outcomes following AA met inclusion criteria and were included for pooled data analysis. The adjusted overall complication rate was higher for AA (26.9%) compared to TAA (19.7%), with similar findings in the non-revision reoperation rate (12.9% for AA compared to 9.5% for TAA). The adjusted revision reoperation rate for TAA (7.9%) was higher than AA (5.4%). Analysis of results from ten studies directly comparing TAA to AA suggests a more symmetric gait and less impairment on uneven surfaces after TAA. CONCLUSIONS: Pooled data analysis demonstrated a higher overall complication rate after AA, but a higher reoperation rate for revision after TAA. Based on the existing literature, the decision to proceed with TAA or AA for end-stage ankle arthritis should be made on an individual patient basis.

Prospective comparison of subtalar arthroereisis with lateral column lengthening for painful flatfeet.

We prospectively compared subtalar arthroereisis with lateral column calcaneal lengthening for the treatment of painful flatfeet. Twenty-four feet (mean age of patients 12.8 years) were treated. Kinematic motion analysis, pedobarometry, and radiography were performed, and the Oxford Ankle-Foot Questionnaire for Children was administered for each patient before surgery and at the 1-year follow-up. We found statistically significant improvements in both groups, with no difference in their outcomes. Both groups showed significantly improved hindfoot and midfoot motion and positioning. Hindfoot range of motion was preserved. Radiography and pedobarometry also revealed significant improvements. Subtalar arthroereisis is a valid and potentially less-invasive alternative to lateral column lengthening that merits further investigation.

Cellular contribution of bone graft to fusion.

Although a number of studies have examined the fate of graft-derived cells during the process of fusion, there remains no consensus regarding their exact contribution to bone formation within the fusion mass. We developed two chimeric mouse isograft fusion models that allowed us to track the fate of graft cells within the host fusion bed. Cortical/cancellous bone graft (1:1 ratio of pelvic to vertebral body bone) from male mice was placed between (a) the tibia and fibula or (b) the coccygeal spine transverse processes of syngeneic female hosts. Both models were characterized histologically and histochemically. Graft-derived cells were then identified by fluorescent in situ hybridization for Y-chromosome sequences present in only the graft (male) cells. When the fusion mass was healing but not yet fused (at 1 and 2 weeks), numerous graft-derived cells were observed throughout the fusion site. The predominant graft-derived cell types included chondrocytes, osteoblasts, and fibroblasts. Chondrocytes arose from precursor cells in the graft de novo. as cartilage was not transplanted during the surgical procedure. By the time a mature fusion mass had formed (at 6 weeks), graft-derived cells persisted as osteocytes within the cortical rim surrounding the fusion mass. These osteocytes likely differentiated from graft-derived precursors that had directly formed bone, because transplanted osteocytes within cortical bone graft fragments were noted to rarely survive even at 1 and 2 weeks. Collectively, our results demonstrate for the first time that bone graft contributes cells that, in conjunction with host cells, directly form bone within the fusion mass during all phases of fusion rather than just the early phases.

The salvage of open grade IIIB ankle and talus fractures.

Between 1983 and 1989, 11 open grade IIIB ankle or talus fractures were treated according to protocol including debridement, temporary placement of antibiotic beads, soft tissue coverage (including seven free vascular tissue transfers), intravenous antibiotics and fusion using an anterior plate, and bone graft. All patients had a minimum of three separate hospitalizations. Each had at least five operative procedures performed with an average of 8.2/patient (range: 5-12). The total in-patient hospital stay averaged 61.6 days (20-107 days) and in patient costs averaged $62,174.43/patient (range: $33,535.06-$143,847.45). Overall hospital cost averaged $1,009.32/day. Follow-up averaged 47.8 months (range 32-85 months), with an average time to union of 4.4 months. Fusion rate and muscle flap success was 100%. Although fusion and eradication of infection in this specific group of patients was possible, significant functional and psychosocial disability remained. Eight of eleven patients had significant pain, difficulty with stairs, and limited ambulation. All changed jobs or were unemployed. Patients with open grade IIIB tibiotalar injuries with significant bone loss may therefore benefit from early amputation. A multicenter randomized clinical outcome study is needed.

First metatarsal-phalangeal joint arthrodesis: a biomechanical assessment of stability.

BACKGROUND: First metatarsal phalangeal joint (MTP) arthrodesis is a commonly performed procedure for the treatment of hallux rigidus, severe and recurrent bunion deformities, rheumatoid arthritis and other less common disorders of the joint. There are different techniques of fixation of the joint to promote arthrodesis including oblique lag screw fixation, lag screw and dorsal plate fixation, crossed Kirschner wires, dorsal plate fixation alone and various types of external fixation. Ideally the fixation method should be reproducible, lead to a high rate of fusion, and have a low incidence of complications. METHODS: In the present study, we compared the strength of fixation of five commonly utilized techniques of first MTP joint arthrodesis. These were: 1. Surface excision with machined conical reaming and fixation with a 3.5 mm cortical interfragmentary lag screw. 2. Surface excision with machined conical reaming and fixation with crossed 0.062 Kirschner wires. 3. Surface excision with machined conical reaming and fixation with a 3.5 mm cortical lag screw and a four hole dorsal miniplate secured with 3.5 mm cortical screws. 4. Surface excision with machined conical reaming and fixation with a four hole dorsal miniplate secured with 3.5 mm cortical screws and no lag screw. 5. Planar surface excision and fixation with a single oblique 3.5 mm interfragmentary cortical lag screw. Testing was done on an Instron materials testing device loading the first MTP joint in dorsiflexion. Liquid metal strain gauges were placed over the joint and micromotion was detected with varying loads and cycles. RESULTS: The most stable technique was the combination of machined conical reaming and an oblique interfragmentary lag screw and dorsal plate. This was greater than two times stronger than an oblique lag screw alone. Dorsal plate alone and Kirschner wire fixation were the weakest techniques. CONCLUSIONS: First MTP fusion is a commonly performed procedure for the treatment of a variety of disorders of the first MTP joint. The most stable technique for obtaining fusion in this study was the combination of an oblique lag screw and a dorsal plate. This should lead to higher rates of arthrodesis.

Biomechanical evaluation of calcaneocuboid distraction arthrodesis: a cadaver study of two different fixation methods.

Calcaneocuboid distraction arthrodesis can be used to treat stage 2 posterior tibial tendon dysfunction. Nonunion, graft resorption, and implant failure have been reported after this procedure. This study compared two of the most commonly used methods for fixation of calcaneocuboid distraction arthrodesis. Twelve pairs of cadaver feet underwent simulated calcaneocuboid distraction arthrodesis. One specimen in each pair was fixed with two crossed 3.5 mm cortical lag screws. The contralateral specimen was fixed with a cervical H-plate. The calcaneus was fixed and a load was applied to the plantar aspect of the cuboid at a rate of 5 mm/minute until joint separation of 3 mm or fracture occurred. The average applied load to failure at 1.0 mm of joint separation was 30.5 +/- 11.6 N for the crossed screws and 77.7 +/- 36.4 N for the cervical H-plate (p = 0.001). The average stiffness at 1.0 mm of joint separation was 27.5 +/- 10.9 N/mm for the crossed screws and 43 +/- 21.2 N/mm for the cervical H-plate (p = 0.036). The higher stiffness and load to failure may account for the decreased nonunion rate noted anecdotally by some surgeons with H-plate fixation over crossed screw fixation for calcaneocuboid distraction arthrodesis.

Ankle fusion in a high risk population: an assessment of nonunion risk factors.

Between July 1992 and April 1996, 88 ankle fusions were performed at our institution. Sixty-seven of these had adequate follow-up for evaluation for union of the fusion, including adequate records and/or radiographs. The average age of patients was 43 years. There were 37 men and 24 women. The charts were reviewed to determine what level of trauma had resulted in posttraumatic arthritis (low energy, high energy, or open fracture). Alcohol use, drug abuse, diabetes, peripheral vascular disease, psychiatric history, smoking, or technical problems were also assessed. A chi-square analysis was used to evaluate the statistical significance. Nineteen of sixty-seven ankle fusions progressed to nonunion (28%). Eighty-five percent of the patients had posttraumatic arthritis. Among 17 patients with a history of open trauma, nine patients developed a nonunion (P < 0.03). A trend toward significance was noted for patients who were smokers, drank alcohol, had diabetes, had a psychiatric disorder, or used illegal drugs. Even with current techniques, this study demonstrates that a high risk population in a trauma center is at risk for nonunion after an ankle fusion caused by multiple risk factors, including a history of open trauma, tobacco use, alcohol use, illegal drug use, a history of psychiatric disorders, or diabetes.

Why do ankle arthrodeses fail in patients with rheumatic disease?

Solid and painless fusion was achieved in 117/130 patients (90%) with rheumatic diseases after primary ankle arthrodesis at the authors' institution. Operations were performed using internal fixation according to the Adams technique. Critical retrospective analysis of failures in 13 patients (11 nonunions, one postoperative low-grade infection, and one painful arthrodesis) revealed errors in the primary operative technique in 10/13 ankles (77%), resulting typically from the surgeon's attempt to overcompensate a malaligned ankle while ignoring correction of the hindfoot deformity (subtalar complex). The optimum of 0-5 degrees of valgus was found in only 5/13 patients (38%). All four patients with varus alignment presented with malleolar pain. Bone grafting was adequate even in those patients with failure, whereas immobilization time was suboptimal in one patient (eight weeks). Patient satisfaction was lowered in every case of nonunion. Revision arthrodesis of failed primary fusion was successful in 10/13 patients (77%), however three additional stress fractures, two painful ankles without nonunions, and one superficial wound infection were detected. Ankle arthrodesis is a demanding procedure, and the operation should always be performed by an experienced surgeon, taking into account the alignment, ligament, and muscle balance of the rheumatoid ankle and hindfoot. Correction and rebalancing of these factors and the use of bone grafts are of crucial importance when considering the optimal conditions for fusion. Nonunions, infections, and stress fractures occurring after the primary arthrodesis are severe complications, leading eventually to revision operations and problems with osteoporotic bone, fragile soft tissues, and skin.

Peg-in-hole, end-to-end, and V arthrodesis. A comparison of digital stabilization in fresh cadaveric specimens.

The proximal interphalangeal joint arthrodesis is frequently performed to correct hammer toe deformities. This study was conducted to compare the inherent stability of the three proximal interphalangeal joint arthrodeses--peg-in-hole, end-to-end, and V constructs--in the sagittal plane by means of load-to-failure testing of 30 fresh-frozen cadaveric specimens fixated with a 0.045 Kirschner wire. The peg-in-hole construct was associated with significantly higher peak loads at failure compared with the other two procedures. Furthermore, the peg-in-hole construct had significantly higher stiffness values as compared with the V procedure. This study thus provides evidence that the peg-in-hole procedure is the most biomechanically stable surgical construct for proximal interphalangeal joint fusions under sagittal plane loading.