TTA Rapid: Description of the Technique and Short Term Clinical Trial Results of the First 50 Cases

TTA-Rapid for treating the canine cruciate deficient stifle: Medium to long-term outcome and analysis of risk factors

BACKGROUND

This study aimed to evaluate medium to long-term outcomes following treatment of lameness associated with cranial cruciate ligament insufficiency using the tibial tuberosity advancement (TTA)-Rapid technique and to investigate risk factors associated with outcome, including tibial plateau angle (TPA).

METHODS

Patient records for cases treated over an 80-month period were examined retrospectively. An owner postal questionnaire using a clinical metrology instrument (Liverpool Osteoarthritis in Dogs) evaluated the outcome at least 6 months after surgery.

RESULTS

A total of 149 procedures were carried out in 120 dogs. Questionnaires were received for 64 dogs (53.3%), with a median follow-up time of 37.5 months. Outcome was judged to be satisfactory, based on frequency of lameness, in 63 (98.4%), while satisfactory outcomes were achieved in 61 (95.3%) based on severity of lameness and in 50 (78.1%) based on mobility score. Statistical analysis showed that age, bodyweight, TPA, meniscal injury and concurrent patellar surgery did not influence outcome, but time to follow-up positively correlated with mobility score.

LIMITATIONS

This study involved one surgeon in one centre with outcome data based on the completion of an owner questionnaire, although this used a validated clinical metrology instrument.

CONCLUSION

TTA-Rapid offers a treatment option for cranial cruciate-deficient stifles with a good medium to long-term outcome, and no risk factors were identified to suggest any limitations to its use.

Comparison and interobserver reliability of three different methods for measuring the amount of the tibial tuberosity advancement in the preoperative planning of TTAT

INTRODUCTION

The goal of preoperative planning techniques for advancement of the tibial tuberosity is to determine the amount of advancement required to achieve a postoperative patellar tendon angle of 90° and to select the optimal wedge size to achieve this target.

MATERIAL AND METHODS

Three radiographic methods for determining the advancement distance for the tibial tuberosity were evaluated for comparability and interobserver reliability. Among the methods developed, we decided to include the common tangent method, the tibial anatomy-based method, and the Bielecki method. For all techniques, radiographs were taken in mediolateral projection with the knee joint flexed at 135°. Three observers with different levels of experience independently evaluated and scored the degree of osteoarthritis for each stifle, as previously described, and performed measurements of the amount of advancement of the tibial tuberosity on 33 stifles using common tangent method, tibial anatomy-based method, and Bielecki method.

RESULTS

According to the results, the overall score for osteoarthritis in the mediolateral view was influenced by the experience of the observers, which contradicts the results from a previous study. Regarding the measurement methods used to assess advancement, poor interobserver reliability was found for common tangent method and Bielecki method, while only a slightly moderate interobserver agreement was found for tibial anatomy-based method.

DISCUSSION

These results are inconsistent with data collected by Bielecki and colleagues. Moreover, measurements from common tangent method and tibial anatomy-based method were overlapping, as confirmed previously. Conversely, Bielecki method showed no agreement with the other methods included in the present study, with a significantly higher mean rank, probably due to its correction formula. Based on the results of the present study, tibial anatomy-based method has better interobserver reliability and is easier to perform according to the observers.

Prospective measurement of outcomes and complications of tibial tuberosity advancement using novel mini plates in small breed dogs

Cranial cruciate ligament (CrCL) disease is a common orthopedic disease in canine patients. Tibial osteotomy procedures for the treatment of cranial cruciate ligament disease in small breed dogs (<15 kg) have previously been limited. A total of 22 client-owned dogs, 26 stifles, with cranial cruciate ligament disease were treated with novel mini-tibial tuberosity advancement plates. The most common intraoperative complications included the need for plate-cage overlap in 7 stifles (26.92%) and screw head fracture in 1 (3.85%). Post-operative complications included tibial tuberosity fracture (3.85%), post-operative medial patella luxation (7.69%), and persistent lameness (7.69%). Of the 26 stifles evaluated in the medium term (>6-12 months) post-operatively, 92.3% had no lameness, with the remaining 7.7% having Grade 1 lameness. A good to excellent clinical outcome was noted in all 26 stifles that underwent TTA with novel mini plates.

Meniscal Load and Load Distribution in the Canine Stifle after Modified Tibial Tuberosity Advancement with 9 mm and 12 mm Cranialization of the Tibial Tuberosity in Different Standing Angles

OBJECTIVES

 The aim of this study was to investigate the kinetic and kinematic changes in the stifle after a modified tibial tuberosity advancement (TTA) with 9 and 12 mm cranialization of the tibial tuberosity in different standing angles.

STUDY DESIGN

 Biomechanical ex vivo study using seven unpaired canine cadaver hindlimbs. Sham TTA surgery was performed. Motion sensors were fixed to the tibia and the femur for kinematic data acquisition. Pressure mapping sensors were placed between femur and both menisci. Thirty percent body weight was applied to the limbs with the stifle in 135 or 145 degrees of extension. Each knee was tested in 135 degrees with intact cranial cruciate ligament (CCL) and deficient CCL with 12 mm cranialization of the tibial tuberosity in 135 and 145 degrees of extension. The last two tests were repeated with 9 mm.

RESULTS

 Transection of the CCL altered kinematics and kinetics. Tibial tuberosity advancement with 12 mm cranialization sufficiently restored stifle kinematics in 135 and 145 degrees but 9 mm TTA failed to do so in 135 degrees. The same effects were seen for internal rotation of the tibia. After TTA, a significant reduction in the force acting on both menisci was detected.

CONCLUSION

 Tibial tuberosity advancement could restore stifle kinematics and meniscal kinetics after transection of the CCL ex vivo in the present study. Tibial tuberosity advancement reduced the contact force ratio on both menisci significantly. No changes of peak pressure and peak pressure location occurred following TTA under any of the tested experimental settings. Increased stifle extension (145 degrees) might lead to more stability, contradictory to biomechanical theory.

Comparison of Two Preoperative Radiographic Methods for Assessing Tibial Tuberosity Advancement to Achieve a Postoperative Patella Tendon Angle of 90° in Dogs

Previous studies have suggested that the preoperative methods used to plan tibial tuberosity advancement in dogs may result in under-advancement. Therefore, this cadaveric study compared the effectiveness of the common tangent method and the tibial-anatomy-based method for achieving a target patellar tendon angle (PTA) of 90° after the modified Maquet procedure. Twenty stifle joints of mesomorphic dogs were randomly assigned to the two measurement methods. Radiographs taken in the mediolateral projection were used to measure tibial tuberosity advancement, and the wedge size was selected accordingly. For each surgical procedure, a custom-made three-dimensional wedge matched to an OrthoFoam wedge was used as a spacer. Postoperative radiographs were used to measure the PTA and to evaluate the position of the wedge. The measured advancement was not significantly different between the two methods. For 60% of the cases, the advancement measured using the common tangent method was <5.3 mm and the wedge size was increased to match that of commercially available wedges. Consequently, there was a significant difference between the measurements and wedges selected between the two procedures. The postoperative PTA did not differ significantly between the two methods and was 90° ± 5° in 80% of the stifles. The position of the wedge relative to the osteotomy was not significantly different between the methods. In conclusion, the advancement determined using the tibial-anatomy-based method was generally consistent with the size of commercially available wedges, and the method yielded a mean postoperative PTA of 90°.

Comparison of the short-term complications of TTA-rapid and modified cTTA procedures

The objective of this retrospective study was to determine the complications of the first 30 tibial tuberosity advancement rapid (TTA-rapid) and 30 modified circular tibial tuberosity advancement (mcTTA) procedures performed by our team, and to compare the results with the findings reported in the literature. Our research was based on 30 procedures in each group. All dogs were client-owned. Data were collected only for the study of cases that had a minimum follow-up period of 3 months. Intraoperative (IO) and postoperative (PO) complications were assessed, with the latter divided into two subgroups: major and minor. Results obtained for the TTA-rapid group: IO complications 23.3% (7/30), major PO complications 13.3% (4/30), minor PO complications 16.7% (5/30). Results of the mcTTA group: IO complications 0% (0/30), major PO complications 3.3% (1/30), minor PO complications 20% (6/30). Comparing the complication rates, we found that there was a significant difference between the two groups in the occurrence of IO complications (P = 0.01054); however, there was no significant difference in the incidence of major (P = 0.3533) and minor (P > 0.9999) PO complications between groups. Our results are consistent with the findings reported in the literature and suggest that both techniques are efficient and carry a relatively low complication rate.

Modified Tibial Tuberosity Advancement Rapid in a Dog with One Contralateral Amputated Limb

Simple Summary

Cranial cruciate ligament disease is a very common source of pelvic limb lameness in dogs, and many techniques have been used to resolve this condition. Tibial tuberosity advancement (TTA) rapid technique is a new simplified option with very good results reported. Adding a small Steinmann pin distal to the cage prevents avulsion of the tibial tuberosity by quadriceps mechanism. In this report, we describe the first modified TTA rapid technique in a dog with a contralateral amputated limb. The dog was a five-year-old mixed breed with amputated right pelvic limb and difficulty walking. The dog started to walk unassisted second day postoperative, and at three months follow-up evaluation it showed no lameness and the osteotomy was completely healed.

Abstract

Cranial cruciate ligament disease (CCLD) is one of the most frequent causes of hindlimb lameness in dogs. Tibial tuberosity advancement (TTA) is a common surgery performed for CCLD. A modified, simplified technique (TTA Rapid) is also reported to have very good clinical outcomes. In this paper, we report a modified TTA Rapid technique to treat a CCLD in a dog with an amputated contralateral hindlimb. A 5-year-old mixed breed dog presented with amputated right hindlimb and difficulty walking. Pain and positive drawer sign were present at manipulation of left stifle joint. Radiographic findings of the stifle joint confirmed the presence of moderate osteoarthritis associated with CCLD, and modified TTA Rapid procedure was performed. Recovery from surgery was uneventful, and the dog was able to stand by his own by the second day postoperative. At three months follow-up evaluation, the dog was free of lameness and the osteotomy site was completely healed. This paper describes the first modified TTA rapid osteotomy technique performed in a dog with a contralateral amputated hindlimb.

Biomechanical testing of canine tibiae: Changes resulting from different tibial tuberosity advancement techniques - Pilot study

The objective of the present pilot study was to determine the force required to break (a) intact canine tibiae, (b) tibiae following the osteotomy of the tibial tuberosity and (c) tibiae following Tibial Tuberosity Advancement- (TTA-) rapid surgery. Six pairs of tibiae of dogs between 15 and 35 kg body weight were used in a cadaver study. Three groups were created with four tibiae in each group; intact (Group 1), osteotomy of the tibial tuberosity and tibial crest (Group 2) and TTA-rapid (Group 3). The tibiae were put under static axial compressive load, applied until failure. The force required to break the tibiae was termed maximal force (F max). The mean of F max was 8193.25 ± 2082.84 N in Group 1, 6868.58 ± 1950.44 N in Group 2 and 7169.71 ± 4450.39 N in Group 3. The sample size was small for a statistical analysis but as a preliminary result, we have determined the force (F max) required to break canine tibiae. Furthermore, we hypothesise that osteotomies result in weakening of the tibial structure.

Tibial Tuberosity Advancement Techniques (TTAT): A Systematic Review

(1) Background: Several surgical techniques were described for the treatment of cranial cruciate ligament rupture in dogs. This report aims to critically review the available literature focused on preoperative planning, surgical procedure, follow-up, and complications of cranial cruciate ligament rupture treated by tibial tuberosity advancement techniques; (2) Methods: three bibliographic databases: PubMed, Google Scholar, and Scopus were used for a board search of TTAT (canine OR dog). Five GRADE recommendations according to Grading of Recommendations Assessment, Development and Evaluation and Joanna Briggs Institute Critical Appraisal Checklists were applied to the studies included. Data regarding preoperative planning (a measure of advancement), meniscal disease (meniscectomy, meniscal release, and late meniscal tears), and postoperative patellar tendon angle were recorded. Time frame, outcome, and complications were classified according to Cook’s guidelines; (3) Results: from 471 reports yielded, only 30 met the inclusion criteria. The common tangent method was the most commonly reported measurement technique for preoperative planning. The 40.21% of stifles presented meniscal tears at surgery, while 4.28% suffered late meniscal tears. In short-, mid-and long-term follow-ups examined showed a full/acceptable function was shown in >90% of cases. Among all new generation techniques, minor complications were reported in 33.5% of cases and major complications in 10.67%; (4) Conclusions: Compared to traditional TTA, new generation TTAT resulted effective in the treatment of cranial cruciate ligament failure, showing a lower rate of late meniscal injury but a higher rate of minor complications.

Mechanical Testing of the New Cage for Tibial Tuberosity Advancement with the Cranial Implant Fixation (TTA CF) Technique—Ex Vivo Study on Sheep Model

Simple Summary

Tibial tuberosity advancement is a method of surgical treatment of cranial cruciate ligament rupture in animals.. In previous reports, the biomechanical effectiveness of tibial tuberosity advancement surgeries was evaluated by axial pressure on the tibial tuberosity to test the strength and resistance of the fixation or by pulling on the tuberosity. To our knowledge, there are no reports that examined the strength that is needed to pull out an implant from the tibia after tibial advancement. This study is the first report that focuses on pulling out the TTA implant, which corresponds to the biointegrity and ingrowth of the TTA cage with the tibia.

Abstract

Background: Modifications of tibial tuberosity advancement are well accepted for cranial cruciate rupture repair. We compared the loads that were needed to pull the TTA CF cage out in the two groups. The first group consisted of five sheep in which osteotomy and TTA CF cage fixation were performed as assumed preoperatively. The second group consisted of five sheep in which intraoperative or postoperative discrepancies from preoperative planning were found. This is also the first report describing biomechanical testing after tibial tuberosity advancement with cranial implant fixation (TTA CF) surgical procedures. Results: A total of 10 ovine proximal tibiae were tested biomechanically by tearing out TTA CF implants from the bone. The mean maximal loaded forces to pull out the cage in Group 1, in which fixation of the implant was performed as assumed preoperatively, was 878 ± 61 N, and in Group 2, in which discrepancies from preoperative planning were found, was 330 ± 55 N. The mean implant displacement under maximal load to failure was 2.6 mm and 2.2 mm in Groups 1 and 2, respectively. There was a significant difference between Group 1 and Group 2 in the maximal loads-to-failure; however, the difference in the displacement at maximal loaded forces to pull out the cage was not significant between the groups. Conclusions: The mean maximal loaded forces to pull out the cage was significantly lower in Group 2, where discrepancies from preoperative planning were found (878 ± 61 N vs. 330 ± 55 N). The lower forces that were needed to extract the TTA CF implant from the tibia can lead to the conclusion that biointegration of the implant is also weaker. Correct positioning of the osteotomy line and TTA CF implant is essential for good biointegrity and thus for limiting complications in the form of tibial tuberosity avulsion fracture or tibial shaft fracture.

Patellar luxation and concomitant cranial cruciate ligament rupture in dogs - A review

A patellar luxation and concomitant cranial cruciate ligament rupture is a common pathology in dogs. Diagnosis is based on clinical evidence of a patellar luxation and stifle joint instability. However, diagnostic imaging is required to assess the number of skeletal deformities and signs of instability. Surgical options include both soft tissue and osseous techniques, although, in most cases, a combination of multiple procedures is necessary to correct the patellar luxation and restore the stifle joint stability. Complication rates are generally low, but can include reluxation and implant-associated complications. This article describes the patellar luxation and cranial cruciate ligament rupture signs in dogs, including the clinical presentation and diagnosis, and discusses current treatment options.

Tibial Plateau Leveling Following Tibial Tuberosity Advancement: A Case Series

Persistent stifle instability is a recognized complication following tibial tuberosity advancement techniques (TTAT). The aim of this study is to report the feasibility and outcome of tibial plateau leveling techniques (TPLT) to treat dogs with persistent lameness, suspected to be secondary to persistent stifle instability, following (TTAT). Medical records of dogs presented for persistent lameness after TTAT were reviewed. Preoperative data included orthopedic examination, lameness score and radiographs. Inclusion criteria included performance of a surgery to address persistent lameness and suspected instability. Short-term follow up data included orthopedic examination and radiographs of the stifle. Long-term follow up was based on postoperative Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. Seven dogs were included in the study. Mean subjective preoperative lameness score was 3 ± 1.53. Mean preoperative patellar ligament angle relative to the tibial plateau (PLA^TP) was 94° and mean tibial plateau angle (TPA) was 28°. Six dogs had tibial plateau leveling osteotomy and one had modified cranial closing wedge ostectomy. Mean postoperative PLA^TP was 79° and mean TPA was 5°. Mean subjective lameness score at follow up was 0.57 ± 0.49. Minor complications were present in 2 dogs and major complication in 1 dog. Mean LOAD questionnaire score was 6.6/52. TPLT can be performed after TTAT and may improve clinical function and stability in these cases in which persistent instability is suspected.

Preliminary Clinical and Radiographic Evaluation of a Novel Resorbable Implant of Polylactic Acid (PLA) for Tibial Tuberosity Advancement (TTA) by Modified Maquet Technique (MMT)

Our objectives were to determine whether PLA implants can be used in TTA with successful results; secondly, to observe whether they provide a faster bone healing; finally, to determine whether weight or age influences bone healing scores. PLA cages were created with a 3D printer. TTA by MMT with PLA implants was performed in 24 patients. Follow-ups were carried out pre-surgical, at 1, 2, and 5 months and consisted of a radiographic study and a lameness assessment. A comparison was performed in terms of weight and age. Patients data, time between follow-up examinations, healing score, and lameness score were compared between patients using commercial software for statistically significant differences p < 0.05. Eighteen dogs finished the study. The ossification degrees presented statistically significant differences between each other. PLA implants maintained the advancement in 100% of cases. Comparing weight and age did not present any statistically significant differences between groups. Lameness presented statistically significant differences between follow-up examinations. Complications were observed in 20.8%. PLA implants for TTA provide good functional results, presenting an acceptable rate of complications. They provide a faster bone healing of the osteotomy gap, which was not affected by age or body weight, and have a clinical recovery time similar to metallic implants.

Bioactive glass-biopolymers‑gold nanoparticle based composites for tissue engineering applications

Biomaterials based on bioactive glass with gold nanoparticle composites have many applications in tissue engineering due to their tissue regeneration and angiogenesis capacities. The objectives of the study were to develop new composites using bioactive glass with gold nanospheres (BGAuSP) and gold nanocages (BGAuIND), individually introduced in alginate-pullulan (Alg-Pll) polymer, to evaluate their biocompatibility potential, and to compare the obtained results with those achieved when β-tricalcium phosphate-hydroxyapatite (βTCP/HA) replaced the BG. The novel composites underwent structural and morphological characterization followed by in vitro viability testing on fibroblast and osteoblast cell lines. Additionally, the biomaterials were subcutaneously implanted in Sprague Dawley rats, for in vivo biocompatibility assessment during 3 separate time frames (14, 30 and 60 days). The biological effects were evaluated by histopathology and immunohistochemistry. The physical characterization revealed the cross-linking between polymers and glasses/ceramics and demonstrated a suitable thermal stability for sterilization processes. The in vitro assays demonstrated adequate form, pore size of composites ranging from few micrometers up to 100 μm, while the self-assembled apatite layer formed after simulated body fluid immersion confirmed the composites' bioactivity. Viability assays have highlighted optimal cellular proliferation and in vitro biocompatibility for all tested composites. Furthermore, based on the in vivo subcutaneous analyses the polymer composites with BGAuNP have shown excellent biocompatibility at 14, 30 and 60 days, exhibiting marked angiogenesis while, tissue proliferation was confirmed by high number of Vimentin positive cells, in comparison with the polymer composite that contains βTCP/HA, which induced an inflammatory response represented by a foreign body reaction. The obtained results suggest promising, innovative, and biocompatible composites with bioactive properties for future soft tissue and bone engineering endeavours.

Comparison of Outcome and Complications in Dogs Weighing Less Than 12 kg Undergoing Miniature Tibial Tuberosity Transposition and Advancement versus Extracapsular Stabilization with Tibial Tuberosity Transposition for Cranial Cruciate Ligament Disease with Concomitant Medial Patellar Luxation

OBJECTIVE

 The aim of this study was to describe a technique for performing miniature tibial tuberosity transposition and advancement (mTTTA). The secondary objective of this study was to compare the short-term outcome and complications in small breed dogs weighing less than 12 kg undergoing surgical correction of cranial cruciate ligament disease with concurrent medial patellar luxation via either extracapsular stabilization with tibial tuberosity transposition (ECS + TTT) or mTTTA.

STUDY DESIGN

 This is a retrospective case comparison study.

RESULTS

 There was no significant difference in overall outcome between the ECS + TTT group and the mTTTA group when comparing 8-week postoperative radiographic healing scores as well as 2- and 8-week postoperative lameness scores.

CONCLUSION

 This study concluded that the mTTTA procedure was feasible and the overall outcome and complications for the dogs that underwent ECS + TTT and those that underwent mTTTA were comparable.

Prospective Evaluation of a Citrate-Based Biomaterial Wedge for a Modified Maquet Procedure in the Treatment of Cranial Cruciate Ligament Rupture in Dogs

OBJECTIVE

 The aim of this study was to describe short- and mid-term outcomes, complications, implant bioabsorption and owner satisfaction for a modified Maquet procedure (MMP) in which a novel bioabsorbable citrate-based implant is used as the wedge component to treat cranial cruciate ligament rupture in client-owned dogs.

STUDY DESIGN

 Prospective clinical study of dogs (n = 13) undergoing MMP (n = 15). Intraoperative complications, postoperative complications, clinical follow-up using a 5-point lameness score and radiographs at 8 weeks and 6 months postoperatively were obtained. Mid-term outcome was assessed via physical examination, radiographs, canine orthopaedic index and owner satisfaction questionnaires.

RESULTS

 No catastrophic complications occurred. Major complications occurred in 3/15 stifles. All were surgical site infections and one case required implant removal. Minor complications occurred in 9/15 stifles. Non-displaced cortical hinge fractures were the most common minor complication, and these occurred intraoperatively (4/15) or postoperatively (2/15). Three dogs achieved full function, eight dogs acceptable function and the outcome was unacceptable in two dogs. Most owners were satisfied with the procedure (11/13). Complete implant bioabsorption was not confirmed on mid-term radiographs.

CONCLUSION

 The described MMP with a citrate-based implant can produce satisfactory mid-term results. However, the long-term outcome of this procedure must be evaluated and technical modifications need to be implemented prior to larger-scale use of this implant.

Short-term outcomes and complications of 65 cases of porous TTA with flange: a prospective clinical study in dogs

Background

Cranial cruciate ligament rupture (CrCLR) is the most common orthopaedic cause of lameness in the hind limb in dogs. Many surgical treatments have been described, but tibial tuberosity advancement (TTA) is one of the most commonly used today. Since it was first described, TTA has evolved to reduce major complications and to arrest the progression of osteoarthrosis. The aim of this study was to assess a surgical technique called Porous TTA with flange prospectively. This study was performed in 61 dogs that underwent 65 Porous TTA with flange procedures, to validate it as an alternative CrCLR treatment. Complications and clinical outcomes (pain, lameness, weight bearing, flexion, extension, crepitation and atrophy) were reported over 3 months, i.e. at 3, 6 and 12 weeks postoperatively.

Results

The results showed a positive clinical outcome, a minor complication rate of 47.69% at the first review 3 weeks postoperatively, 10.77% at the second one (6 weeks after the surgery) and 4% at the third one (at 12 weeks). Major complications were observed only at the last review, with one case that had an infection requiring implant removal; this represented 1.5% of cases. Variables evaluated for a relationship with complication scores and improvement were body condition score, sex, age, breed, body weight, breed size, side of the affected limb, traumatic anamnesis and time of lameness before surgery. No relationship was detected.

Conclusions

Clinical outcomes and complications show that Porous TTA with flange is an efficient alternative for surgical treatment of CrCLR in dogs.

Biological response to an experimental implant for tibial tuberosity advancement in dogs: A pre-clinical study

In this study, we propose a novel bioresorbable bioactive implant for tibial tuberosity advancement (TTA). The implant consists of a gradually resorbing load-bearing shell which encompasses rapidly resorbing small casings loaded with silica-based bioactive glass (BG) particulates which promote bone formation and reduce the risk of infection. The shell and the casings are manufactured by 3D printing from two medical grade bioresorbable polymers (a polyglycolide/lactide based and a polydioxanone based) that have different degradation rates. The casings are expected to resorb within days after surgery to expose the BG particulates while the shell would retain the load-bearing properties of the implant for the time required by bone healing. Unlike the currently used metallic devices, the novel implant is resorbed and excreted from the body once its purpose is fulfilled. This study presents a logical progression from the in vitro characterisation of the materials and implants to the in vivo investigation of the experimental implants. This included mechanical testing of the materials, finite element analysis of a preliminary design of the novel TTA implant, assessment of the degradation behaviour of the polymers and the ion exchange of BG in simulated body fluid, and investigation of the biological response to the novel implants after implantation in rabbits. The osteointegration of the novel implants was comparable to the osteointegration of Ti6Al4V implants in the control group; the biological efficacy and safety were confirmed. The biological response was in line with the expectations. The proof of concept for the novel TTA implants was demonstrated.

Comparison of tension band wiring and other tibial tuberosity advancement techniques for cranial cruciate ligament repair: an experimental study

BACKGROUND

Cranial cruciate ligament (CCL) rupture is one of the most common causes of limb lameness in dogs. Surgical techniques based on tibial osteotomies such as tibial plateau leveling osteotomy and tibial tuberosity advancement are used to eliminate dynamic thrust. Tibial tuberosity advancement (TTA) uses an osteotomy fixated by cage, plates, forks and screws to change the relationship of the patellar tendon and tibial plateau angle. Tension band wiring technique is one of the most common surgical methods used to treat a tension fracture and remains the gold standard for the treatment of tibial tuberosity fractures. In this study, we compared experimentally the biomechanical effect of application of tension band wiring compared to other techniques for the fixation of the TTA osteotomy. The techniques compared to are standard commercially available systems for TTA fixation.

RESULTS

Tension band wiring (TBW) presented the higher resistance to failure compared to all the other surgical procedures, with the highest values found in the TBW group with 1.47 ± 0.07 N and the lowest in the TTA cage (0.82 ± 0.08) and TTA-2 (0.85 ± 0.06) groups with statistically significant differences in all cases (P < 0.001). TTA rapid and TTA plate groups exhibited a similar strength, and same happened between TTA-2 and TTA cage groups. All the other comparisons by pair were significantly different with P < 0.001.

CONCLUSIONS

Results suggest that fixating the osteotomy with tension band wiring increases the strength of the fixation and decrease the risk of implant failure. Further clinical studies are needed to demonstrate in vivo reliability and to test different variables such as size and weight of dogs. These results could have important clinical implications in the treatment of CCL ruptures.

Modified Triple Tibial Osteotomy for Combined Cranial Cruciate Ligament Rupture, Tibial Deformities, or Patellar Luxation

Proximal tibial deformities or patellar luxation may occur concurrently with cranial cruciate ligament rupture. The objective of this study was to describe the management of those conditions with a modified triple tibial osteotomy (TTO) in nine dogs. Medical records of dogs who underwent a modified TTO were reviewed. The mean pre- and postoperative patellar tendon angles were 104.2° and 92.9°, respectively. The mean pre- and postoperative mechanical medial proximal tibial angles were 99.5° and 91.5°, respectively. Medial patellar luxation was present in five dogs (55.6%) and treated in all five dogs with a tibial crest transposition. Tibial torsion was grossly resolved in two dogs (22.2%). Perioperative distal tibial crest fracture was treated by pins and a figure-of-eight tension-band wire in five dogs (55.6%). One major (surgical site infection) and three minor postoperative complications were observed. At the last follow-up, seven dogs (77.8%) had no lameness, one dog (11.1%) had mild lameness, and one dog (11.1%) had moderate lameness. Radiographic evaluation showed good (2/9; 22.2%) to excellent (7/9; 77.8%) bone healing. The visual analog scale evaluation revealed good-to-excellent owner satisfaction. Cranial cruciate ligament rupture, tibial deformities, and medial patellar luxation are difficult to treat together. A modified TTO may be used to treat these conditions.

Tibial tuberosity advancement technique in small breed dogs: study of 30 consecutive dogs (35 stifles)

OBJECTIVES

To assess the outcome and peri-operative complications of the tibial tuberosity advancement technique in small dogs with cranial cruciate ligament rupture.

MATERIALS AND METHODS

Cranial cruciate ligament rupture was diagnosed by positive drawer sign or tibial thrust test and confirmed at surgery in 30 dogs (35 stifles) weighing less than 15 kg. Clinical and radiographic follow-up was obtained at 4 and 12 weeks or later. Thigh diameter and affected and non-affected stifle joint flexion and extension angles were also measured.

RESULTS

At 4-week follow-up 26 of 35 (74%), eight of 35 (23%) and one of 35 (3%) showed no, mild and moderate lameness, respectively. Similarly, at 12 weeks or later the respective outcomes were 32 of 35 (91%), two of 35 (6%) and one of 35 (3%). The mean thigh diameter of affected limbs at 12 or more weeks was 96% of the mean of normal limbs and stifle range of motion reached 98% of normal extension and 97% of normal flexion. There were complications in two of 35 stifles: one screw partially inserted into the joint and postoperative wound dehiscence, both of which required surgical correction.

CLINICAL SIGNIFICANCE

The tibial tuberosity advancement technique leads to acceptable outcomes in small dogs with cranial cruciate ligament rupture.

Tibial Diaphyseal Fracture as a Major Complication of Tibial Tuberosity Advancement With Cranial Fixation (TTA CF)-A Case Report

This article reports a major complication of tibial tuberosity advancement with cranial fixation for the treatment of cranial cruciate ligament rupture in a Boxer. Twelve days postoperatively the dog underwent revision surgery for fracture of the tibia and tibial tuberosity. The tibial tuberosity fracture was secured to the tibial diaphysis using the 2 K-wires and a medial 3.5 dynamic compression plate was used to stabilize the tibial diaphysis fracture. The fracture was reduced and the plate applied using minimally invasive plate osteosynthesis to preserve the blood supply to the bone. Two weeks after revision surgery, the dog was using the operated limb without apparent lameness at a walk and trot. No complications were observed after revision surgery. Tibial tuberosity fracture and tibial diaphysis fracture as complications after tibial tuberosity advancement with cranial fixation healed with satisfactory clinical outcomes but revision surgery was required.

41 Cases of Treatment of Cranial Cruciate Ligament Rupture with Porous TTA: Three Years of Follow Up

Tibial Tuberosity Advancement (TTA) is a surgical technique based on a linear osteotomy that determines a cranial advancement of the tibial tuberosity in patients suffering from cranial cruciate ligament rupture (CCL). The aim is to neutralize the cranial tibial thrust (CTT) and to reach a 90° angle between the patellar tendon and the tibial plateau with a physiological knee extension of 135°. In our study, a Ti6AI4V ELI (Titanium Aluminium Vanadium) titanium scaffold for the Porous TTA, with excellent properties of osteointegration and osteoconduction when subjected to cyclic loading has been adopted. Based on the previous scientific work on an ovine model, the use of this type of porous scaffolds has subverted the previous models. Scaffold production technology is based on direct mechanical manufacturing called Electron Beam Melting (EBM). For this study, 41 dogs, different breeds, medium-large size, weighing between 10 and 80 kg, aged between 1 and 13 years, were enrolled. The inclusion criteria were based on clinical evaluations (different gaits), drawer test and tibial compression, LOAD score (Liverpool Osteoarthritis in Dogs questionnaire), radiographic diagnosis in sedation with a 135° positioning of the joint and baropodometric investigations (Stance Analyzer). The results show that Porous TTA is an excellent method for functional recovery of the knee joint following the partial and total rupture of the CCL.

Evaluation, Description of the Technique, and Clinical Outcomes After Tibial Tuberosity Advancement With Cranial Fixation (TTA CF) for Cranial Cruciate Ligament Rupture in 22 Dogs

The objective of this study is to describe a modified surgical technique for tibial tuberosity advancement with cranial fixation (TTA CF) in dogs with cranial cruciate insufficiency and to report long term clinical outcomes and complications. TTA CF was performed with a novel titanium implant. A description of the specific implant with guide, drill and saw guide, instrumentation, and template are provided, along with clinical outcomes, complications, owners' evaluation, and a 1-year postoperation follow-up. Twenty two mixed breed dogs, with a median body weight of 23 kg (range, 11-45 kg) were included. The median age at surgery was 4 years (range, 1-8 years). Clinical bone healing was seen at a mean 10 weeks (range 6-14 weeks). The minor complication rate was 27% (n = 6). No major complication occurred, and no revision surgery was required. Twenty-one (95%) dogs had a good to excellent outcome 1 year after surgery. Currently there is no accepted best treatment of the canine cranial cruciate ligament deficient stifle. Most of TTA techniques are based on fixing the implant from the medial side of tibia. We report a modified TTA technique with cranial fixation of a titanium implant and suggest that the TTA CF surgical technique may be a feasible alternative to existing surgical procedures.

A novel tibial tuberosity advancement technique with cranial implant fixation (TTA CF): a pilot study in sheep

Background

Cranial cruciate ligament rupture is the most frequent orthopedic disorder in human and animals. An array of surgical techniques have been described to stabilize the stifle joint in dogs, including intraarticular stabilization, extraarticular stabilization, and tibial osteotomy techniques. Tibial plateau leveling osteotomy and tibial tuberosity advancement with a lot of modifications are the most common. In this study we report the possibility of fixing the novel titanium implant for tibial tuberosity advancement with two screws in a craniocaudal direction. The aim of our study was to improve the clinical benefit of the tibial tuberosity advancement surgical technique where an attempt was made to reduce the number of screws and obtain a strong implant fixation with minimal bone traumatization. This way of attachment allows to distribute the forces evenly on medial and lateral side of osteotomy gap.

Results

Tibial tuberosity advancement with cranial implant fixation was performed in four sheep. Complete radiographic and clinical follow up was recorded. All four sheep had a complete osteotomy line healing at a mean of 10 weeks postoperative (range 8–12 weeks). None of the animals had osteotomy gap healing grades of poor. Minor complication included the minimally cracked Maquet hole on the postoperative radiographs, without displacement of the tibial crest which occurred in 2 sheep. Major complication grade 1, major complication grade 2 and catastrophic were not found.

Conclusions

The novel surgical technique for tibial tuberosity advancement with cranial implant fixation is technically comparable to the recent trend in tuberosity advancement techniques, where partial osteotomy of the cranial tibial tuberosity crest is performed. A cranial implant fixation allows to distribute the forces evenly on medial and lateral side of osteotomy gap, which may result in less number of major complications in dogs. A novel titanium implant decreases the tibial traumatisation by reducing the number of screws.

Evaluation and application of the TTA-rapid method in dogs with cranial cruciate ligament rupture

The objective of this study intended the application of the current technique of modified tibial tuberosity advancement (TTA)-rapid method in dogs with cranial cruciate ligament rupture (CrCL) and reports on the clinical outcome and complications. The study material consisted of 17 male dogs of different breeds between the ages of 2-8 years, average weight of 32 kg with a diagnosed unilateral CCL rupture. Hudson Visual Analog Scale (HVAS)-Walking Test Rating, Canine Brief Pain Inventory (CPBI)-Pain Rating) were examined, and rupture of the CCL was diagnosed based on direct radiographic examination. The pre-operative evaluation of the implant to be used in TTA-Rapid technique was determined by measuring radiographic images of the CCL in dogs. Post-operative evaluation in the 1st, 2nd, and at 3 month was performed by radiographic examination, gait and pain tests. Major complications were recorded in 17.6% of the cases. Fourteen (82.4%) dogs had a good to excellent outcome 3 months after surgery. Lameness and pain assessment were performed up to 15 days prior to the operation and 1, 2, and 3 months after the TTA-Rapid technique procedure.

It can be concluded that TTA-Rapid technique procedure is a fast, easy to learn and non-invasive treatment of CrCL ruptures in dogs.

Evaluation of a new method to determine the tibial tuberosity advancement distance required to reduce the patellar tendon-tibial plateau angle to 90° with the modified Maquet technique in dogs

OBJECTIVE To assess use of a new radiographic method to determine the distance by which the tibial tuberosity should be advanced to reduce the patellar tendon-tibial plateau angle (PTA) to 90° by means of the modified Maquet technique (MMT) in dogs. SAMPLE 24 pelvic limbs from 12 adult medium-sized to large-breed canine cadavers. PROCEDURES Radiographs of stifle joints at 135° extension in true lateral position were used to determine tibial tuberosity advancement distances for use in the MMT. A method was devised to incorporate the planned osteotomy axis; distal patellar translations of 0, 3, 5, or 10 mm; and advancement cage implant application level along the osteotomy site in advancement planning measurements. Concordance correlation coefficients (CCCs) were calculated to compare these adjusted advancement measurements with true advancement measurements obtained for the same joints in another study after treatment by MMT. Intraobserver, interobserver, and total agreement for selected measurements were determined by assessment of CCCs for results obtained by 3 blinded observers. RESULTS Agreement between true advancement measurements and measurements obtained with osteotomy axis and cage position method calculations that incorporated a 5-mm distal patellar translation distance was excellent (CCC, 0.96). Intraobserver and interobserver agreements for the planning measurements evaluated were good to excellent (CCC, 0.83 to 0.96). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the osteotomy axis and cage position method incorporating a 5-mm distal patellar translation distance has the potential to improve success rates for achieving a PTA of 90° in medium-sized to large-breed dogs undergoing MMT for treatment of cranial cruciate ligament rupture. Further research is warranted.

Tibial tuberosity advancement in small-breed dogs using TTA Rapid implants: complications and outcome

OBJECTIVE

To assess the perioperative complications and the outcome when treating small-breed dogs with cranial cruciate ligament insufficiency with tibial tuberosity advancement using the TTA Rapid implant.

MATERIALS AND METHODS

40 dogs (48 stifles) with cranial cruciate ligament insufficiency and body weight of 15 kg or less. Diagnosis was confirmed by arthroscopy or arthrotomy, followed by tibial tuberosity advancement surgery. Six weeks after surgery, the dogs were re-evaluated with clinical examination and radiography. Mid- to long-term outcome was assessed using client questionnaire.

RESULTS

Intraoperative complications consisted of four osteotomy-related fissures through the cranial cortex; two complete fissures were stabilised with a screw, the others healed without intervention. After surgery there were two tibial fractures and two incisional complications. Six weeks postoperatively, limb function was good to excellent in 43 dogs (94%). Two late meniscal injuries occurred. The overall major complication rate was 7/48 14·6%). Mid- to long-term follow-up information was available for 43 stifles: 34 stifles (79%) were free of lameness at a median of 72 weeks postoperatively. The outcome was rated excellent by 88% of the clients and good by 7%.

CLINICAL SIGNIFICANCE

The use of TTA Rapid implants is an alternative for treatment of cranial cruciate ligament insufficiency in small-breed dogs, with complication rates comparable to those recorded in larger breeds and to other techniques, and with a high degree of owner satisfaction.

Effect of proximal translation of the osteotomized tibial tuberosity during tibial tuberosity advancement on patellar position and patellar ligament angle

Background

Cranial cruciate ligament insufficiency is a common orthopaedic problem in canine patients. This cadaveric and radiographic study was performed with the aim of determining the effect of proximal translation of the tibial tuberosity during tibial tuberosity advancement (TTA) on patellar position (PP) and patellar ligament angle (PLA).

Results

Disarticulated left hind limb specimens harvested from medium to large breed canine cadavers (n = 6) were used for this study. Limbs were mounted to Plexiglass sheets with the stifle joint fixed in 135° of extension. The quadriceps mechanism was mimicked using an elastic band. Medio-lateral radiographs were obtained pre-osteotomy, after performing TTA without proximal translation of the tibial tuberosity, and after proximal translation of the tibial tuberosity by 3mm and 6mm. Radiographs were blinded to the observer for distance of tibial tuberosity proximalization following radiograph acquisition. Three independent observers recorded PP and PLA (tibial plateau method and common tangent method). Comparisons were made between the stages of proximalization using repeated measures ANOVA. Patellar position was found to be significantly more distal than pre-osteotomy, if the tibial tuberosity was not translated proximally (P = 0.001) and if it was translated proximally by 3mm (P = 0.005). The difference between pre-osteotomy PP and 6mm proximalization was not significant. The PLA was significantly larger if the tibial tuberosity was not translated proximally compared to tibial tuberosity proximalization of 6mm using the tibial plateau and the common tangent methods (P = 0.006 and P = 0.015 respectively).

Conclusions

Proximalizing the tibial tuberosity during TTA helps in maintaining vertical position of the patella in the patellar groove. Proximalization of the tibial tuberosity reduces PLA when compared to TTA without tibial tuberosity proximalization.

Comparison of desired radiographic advancement distance and true advancement distance required for patellar tendon-tibial plateau angle reduction to the ideal 90° in dogs by use of the modified Maquet technique

OBJECTIVE To evaluate the validity of 2 radiographic methods for measurement of the tibial tuberosity advancement distance required to achieve a reduction in patellar tendon-tibial plateau angle (PTA) to the ideal 90° in dogs by use of the modified Maquet technique (MMT). SAMPLE 24 stifle joints harvested from 12 canine cadavers. PROCEDURES Radiographs of stifle joints placed at 135° in the true lateral position were used to measure the required tibial tuberosity advancement distance with the conventional (A^M) and correction (A^E) methods. The MMT was used to successively advance the tibial crest to A^M and A^E. Postoperative PTA was measured on a mediolateral radiograph for each advancement measurement method. If none of the measurements were close to 90°, the advancement distance was modified until the PTA was equal to 90° within 0.1°, and the true advancement distance (TA) was measured. Results were used to determine the optimal commercially available size of cage implant that would be used in a clinical situation. RESULTS Median A^M and A^E were 10.6 mm and 11.5 mm, respectively. Mean PTAs for the conventional and correction methods were 93.4° and 92.3°, respectively, and differed significantly from 90°. Median TA was 13.5 mm. The A^M and A^E led to the same cage size recommendations as for TA for only 1 and 4 stifle joints, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Both radiographic methods of measuring the distance required to advance the tibial tuberosity in dogs led to an under-reduction in postoperative PTA when the MMT was used. A new, more accurate radiographic method needs to be developed.