Tibial Tuberosity Transposition Research Articles

Biomechanical evaluation of a fixation technique with a modified hemicerclage for tibial tuberosity transposition: an ex vivo cadaveric study.

(1) To determine stiffness, load at failure, and mode of failure of a novel fixation method with a tension modified-hemicerclage (MH) for tibial tuberosity transposition, and (2) to compare the biomechanical properties of this novel fixation technique to 2 pins (2Pins) and 2 pins and tension band wire fixation (2Pins + TBW). Thirty cadaveric stifles from dogs between 5.2 and 13.1 kg were assigned to 3 treatment groups: Group 1: fixation technique with MH; Group 2: 2Pins; Group 3: 2Pins + TBW. Biomechanical testing was performed with the tibia positioned at an angle of 135° relative to vertical position. Tensile force was applied to the patellar ligament until catastrophic failure was observed. The mode of failure, the load at failure, and the stiffness were compared among treatment groups. The mean stiffness of the novel fixation (38.1 N/mm 7.1) and the 2Pins + TBW (40.2 N/mm 9.3) were greater than the 2Pins (26.7 N/mm 6.7). There was no significant difference between the novel fixation technique and 2Pins + TBW in stiffness and maximum load to failure. The 2Pins (284.3 N 70.5) failed at a significantly lower load than the tension modified-hemicerclage (555.7 N 225.9 N) and 2Pins + TBW (715.3 N 339.8 N). A fixation technique using a modified hemicerclage had the same strength and stiffness as the 2Pins + TBW and was stronger and stiffer than the 2 Pins technique in a cadaveric model.

Outcome of surgical correction of medial patellar luxation in dogs weighing less than 10 kg.

Varioustrochleoplasty techniques, including trochlear wedge recession (TWR) and trochlear block recession (TBR), are used to treat dogs with medial patellar luxation (MPL). However, the objective outcomes of these surgical proceduresare underreported. Medical records were obtained for dogs weighing less than 10kg that underwent either TWR or TBR and tibial tuberosity transposition to address grade I-III MPL. Long-term (at least 1 year after the last procedure) follow-up included orthopaedic and radiographic examinations, such as osteoarthritis score (OAS), ground reaction force (GRF) analysis and canine brief pain inventory (CBPI). Overall, 20 dogs (26 stifles) were followed up in the long term. Minor postoperative complications, medial patellar reluxation (MPR) and intermittent lameness occurred in 46.15%, 19.23% and 15% of the dogs, respectively. MPR occurred only in TWR-treated stifles, while mean OAS increased in all groups. Using the CBPI, the owners perceived an excellent or very good outcomein 95% of dogs. The limitations of the study include its retrospective observational nature, a lack of randomisation and a small sample size. Surgical treatment resulted in a favourable outcome. GRF analysis could detect subtle differences in weight bearing in dogs treated for MPL, which might not be apparent clinically. There might be a higher risk for reluxation for TWR. However, a larger-scale prospective study would be required to find which treatment is superior.

Medial Patellofemoral Ligament and Lateral Patellofemoral Ligament Reconstruction after Tibial Tuberosity Transposition in a Young Woman with Patellar Instability

In patients with reccurent lateral and medial patellar instability, isolated medial patellofemoral ligament (MPFL) reconstruction may be insufficient due to poor lateral retinacular tissue quality. In this report, we describe a case of a patient that underwent simultaneous MPFL and lateral patellofemoral ligament (LPFL) reconstruction on the left knee due to chronic bidirectional patellar instability. A 29-year-old female patient presented with first-time lateral patellar dislocation five years ago due to acute strain. She underwent a tibial tuberosity transposition in another hospital. After the surgery, she suffered from recurrent medial and lateral patellar dislocation and presented to our center. MPFL and concomitant LPFL reconstruction on the left knee was simultaneously performed due to bilateral patellar dislocation. The patella was stable postoperatively, and the patient underwent physiotherapy with successful results to date. Single-time patellar dislocation should be treated conservatively. Surgical treatment after the first episode of dislocation can magnitude the risk of postoperative complications. The simultaneous reconstructing of the LPFL yields patellar fixation indistinguishable from the native LPFL. These grafts provide separate tensioning depending on body anatomy, allowing for individualized stability. Anatomical MPFL reconstruction is supported by well-established high-quality research. Reconstructing the LPFL anatomically yields patellar fixation indistinguishable from the native LPFL.

Evaluación clínica de las complicaciones tras el tratamiento quirúrgico de las luxaciones de rótula en perros: Un estudio retrospectivo

Patellar luxation is one of the important orthopedic problem in dogs. Patellar luxation, which has been accepted as a developmental disorder in recent years, usually occurs medially in small breeds and laterally in large breeds. The aim of this study was to evaluate surgical treatment (femoral trochleoplasty, tibial tuberosity transpositions and imbrication techniques together), postoperative complications, early and late results in dogs with patellar luxation. Thirty–two dogs with grade 3 and grade 4 patella luxation were used in this study. While patellar luxation was treated in all cases, tibia fracture was seen in one dog as the most important complication. During tibial tuberosity transpositions technique, attention should be paid to the cutting process and the tibia should not be weakened. In conclusion, the combined use of femoral trochleoplasty, tibial tuberosity transposition and imbrication techniques can be used for patellar luxation. Complete recovery may not be possible in grade 4 patellar luxations.

Early Surgical Management of Medial Patellar Luxation in Juvenile Dogs.

The aim of this study was to analyse a series of five cases of early surgical treatment in juvenile canine patients with high-grade medial patellar luxation. Canine patients, with immature skeleton, affected by grade III or IV medial patellar luxation and treated by multimodal surgical techniques were selected. Five dogs of different breeds, mean age 7.2 ± 3.0 months, met the inclusion criteria. Simultaneous distal femoral varus and external tibial torsion were identified in three of the five cases, whereas in the others, femoral varus with associated tibial valgus and isolated external tibial torsion were observed. Four of the five patients were treated surgically with closing wedge osteotomy of the distal femur, and three of them underwent tibial tuberosity transposition simultaneously. Only two animals required trochleoplasty. Mean time to beginning of weight bearing was 9.8 ± 5.5 days, whereas time to bone healing was 55 ± 24 days. Bone realignment of the extensor apparatus and return to limb support were achieved in all cases. Postoperative reintervention was needed in one patient; however, it was not linked to the initial surgery. Patients were followed up to 1 year postoperatively, with maintenance of extensor alignment and no late complications. The early surgical approach has been shown to be effective in the definitive treatment of juvenile dogs affected by high-grade medial patellar luxation.

Comparison of the reoperation rates of three techniques for tibial tuberosity transposition in medial patellar dislocation

A common technique for the treatment of medial patellar luxation is the lateral transposition of the tibial tuberosity. Two variations of a new surgical method with a retention plate and fixation with a wire or a security plate, were tested against each other and against the existing fixation with Kirschner wires and a tension band by the number of reoperations. The new method using a retention plate and security plate showed the lowest rate of reoperations (5 %), followed by the new technique using retention plate and wire (14 %) and the existing fixation with Kirschner wires and a tension band (34 %). A possible explanation for the good result of the new method can be the fixation of the implants on the medial side of the tibia and the non-use of Kirschner wires.

Dome trochleoplasty for correction of patella alta and patella luxation in dogs > 20 kg.

To describe the dome trochleoplasty procedure and report the short-term outcomes and complications associated with a novel technique to correct patellar luxation and patella alta. 13 dogs (16 stifle joints) diagnosed with medial patellar luxation with concurrent patella alta in dogs > 20 kg. Medical records of dogs weighing > 20 kg that underwent a dome trochleoplasty for correction of a medial luxating patella were prospectively evaluated. The procedure described involves an osteotomy of the femoral trochlea, which is then translated and/or rotated to correct patellar luxation. Clinical results were assessed using subjective lameness scoring, radiographic evaluation, and the Canine Brief Pain Inventory (CBPI) tool. 16 stifle joints were included in this study. The overall complication rate was 50%. Major complications occurred in 43.8% of stifle joints due to pin migration and recurrent luxation of the patella. One dog experienced a catastrophic complication 4 months postoperatively. Uncomplicated osteotomy healing was present in 94% of dogs. The median initial lameness score was 2 (mean, 1.81; range, 0 to 4) and at the final recheck was 0 (mean, 0.31; range, 0 to 2). The CBPI scores were available for 50% of stifle joints. The median initial CBPI score was 45.5 (mean, 48.8; range, 32 to 74) and at the final recheck was 17.5 (mean, 20.5; range, 0 to 43). The dome trochleoplasty procedure offers an alternative technique for surgical correction of patellar luxation secondary to patella alta in large-breed dogs, but due to its higher complication and reluxation rates, it should be used cautiously and probably in combination with other corrective procedures, such as tibial tuberosity transposition, soft tissue imbrication, and/or soft tissue release rather than as a stand-alone procedure.

Complications and Long-Term Outcomes after Combined Tibial Plateau Leveling Osteotomy and Tibial Tuberosity Transposition for Treatment of Concurrent Cranial Cruciate Ligament Rupture and Grade III or IV Medial Patellar Luxation.

This study aims to report complications and long-term outcomes of combined tibial plateau leveling osteotomy and tibial tuberosity transposition (TPLO-TTT) for treatment of concurrent cranial cruciate ligament rupture and medial patellar luxation (MPL). This is a retrospective study. Dogs that underwent TPLO-TTT for treatment of combined cranial cruciate ligament rupture and grade III or IV MPL were included. Signalment, fixation method, and complications were recorded. Long-term outcome assessment (minimum 1 year postoperatively) was performed through clinical and radiographic reexamination at the authors' institution. Twenty-four stifles (22 dogs) were included. Twenty-one stifles had a grade III MPL, and 3 stifles had grade IV MPL. Four major complications consisting of surgical site infection (n = 3) and recurrent grade II MPL (n = 1) were observed. Dogs with surgical site infections were successfully treated with implant removal and oral antibiotics. No additional surgery was performed for the patient with recurrent MPL as no signs of lameness were observed. Minor complications occurred in five cases. At long-term evaluation (median: 27 months; range: 12-67 months), 21/22 dogs were clinically sound and 23/24 stifles had a complete resolution of MPL. TPLO-TTT can be considered as an effective surgical option to treat patients with concurrent cranial cruciate ligament rupture and MPL with a relatively low major complication rate. Owners should be warned of the potential need for implant removal.

Partial Parasagittal Patellectomy in Dogs: A Retrospective Case Series of 19 Dogs.

The aim of this study was to describe partial parasagittal patellectomy for the surgical management of patellar luxation, including surgical technique, proposed indications, complications, and outcomes in a cohort of dogs. This is a single-center retrospective clinical case series. Medical records (2019-2020) of dogs presenting for patellar luxation were reviewed. Clinical signs, luxation direction and grade, preoperative imaging and intraoperative findings, and complications were retrospectively retrieved. Owners were contacted via questionnaire for medium- and long-term follow-up. A total of 24 stifles in 19 dogs met the inclusion criteria. Intraoperative minor complications occurred in four stifles. A single minor complication occurred postoperatively with no major complications. Increased thickness and radiographic attenuation of the patellar ligament were noted in 14 stifles at radiographic reassessment. Re-luxation was not encountered, with long-term owner-assessed outcome as good to excellent in all cases. Partial parasagittal patellectomy, used in conjunction with block recession trochleoplasty and tibial tuberosity transposition, provided reliable resolution of patellar luxation in canine stifles with grade 2 or 3 luxation where width mismatch between the patella and the trochlea was noted intraoperatively. Long-term outcome appears to be good to excellent with a low rate of complication.

Evaluation of Surgical Technique and Clinical Results of a Procedure-Specific Fixation Method for Tibial Tuberosity Transposition in Dogs: 37 Cases.

The aim of this study was to describe the use of a procedure-specific fixation method for tibial tuberosity transposition and report clinical outcome. This is a multi-institutional case series, evaluating 37 cases that were treated surgically for medial patellar luxation (MPL) and in which the tibial tuberosity transposition (TTT) was performed using the Rapid Luxation Plating System (RLPS). Surgical technique, implants, clinical outcome, and complications are reported. Surgery was successfully performed in dogs weighing 2.5 to 36.2 kg. Postoperative minor complications occurred in 13 cases (35%) and major complications occurred in 3 cases (8%). No implant-related complications or tibial tuberosity avulsions or fractures were seen. Outcome related to surgery was good or excellent in all cases. The RLPS for TTT provides a feasible technique in a large range of patients with MPL and lowers the occurrence of implant-related complications and tibial tuberosity avulsion or fracture.

Outcomes and complications of a modified tibial tuberosity transposition technique in the treatment of medial patellar luxation in dogs.

To report a modification of the tibial tuberosity transposition (m-TTT) technique used to treat medial patellar luxation (MPL) in dogs, and report its complications. Retrospective case series. Dogs (n = 235) undergoing MPL correction, using m-TTT (n = 300 stifles). Medical records and client surveys were reviewed to determine complications associated with this technique and they were compared with previously reported complications using similar techniques. Short-term minor complications included low-grade reluxation (11 stifles, 3.6%), incisional seroma (nine stifles, 3%), pin-associated swelling (seven stifles, 2.3%), patellar desmitis (six stifles, 2%), superficial incisional infection (four stifles, 1.3%), pin migration (three stifles, 1%), tibial tuberosity (TT) fracture (two stifles, 0.6%), tibial tuberosity displacement and patella alta (one stifle, 0.3%), pin-associated discomfort (one stifle, 0.3%), trochlear block fracture (one stifle, 0.3%). Short-term major complications included pin migration (three stifles, 1%), incisional infection (two stifles, 0.6%), tibial tuberosity fracture (two stifles, 0.6%), and high grade reluxation (two stifles, 0.6%). Long-term follow-up examination data were available for 109/300 (36.3%) stifles. One minor complication and four major complications were documented. All long-term complications were due to pin migration. The overall major complication rate was 4.3% (13/300 stifles), with a minor complication rate of 15% (46/300 stifles). The owner survey indicated a 100% satisfaction rate. The m-TTT technique yielded acceptable complication rates, with high owner satisfaction. The m-TTT should be considered as an alternative technique for treating dogs with MPL requiring a tibial tuberosity transposition.

Tibial Tuberosity Transposition Tool Technique in Combination with Distal Femoral Lateral Closing Wedge Osteotomy for Patellar Luxation Treatment in Five Dogs

AbstractMedial patellar luxation is a multifactorial condition resulting from a misalignment of the stifle extensor mechanism. Several techniques have been described for correcting this condition, depending on the specific morphological changes identified. This case series describes the combination of tibial tuberosity transposition tool techniques and distal lateral femoral closing wedge osteotomy in the treatment of dogs with medial patellar luxation. A combination of these two techniques was used in five dogs with varying degrees of medial luxation of the patella resulting from distal femoral varus and less than 20 degrees distal external torsion of the tibia. The combination of techniques allowed the alignment of the stifle extensor mechanism and corrected medial patellar luxation in all dogs. Radiographic bone union occurred in all dogs, with a mean time of 30 ± 2 days for tibial osteotomy and 48 ± 16 days for the femur. There was no recurrence of patellar dislocation, and no complications developed in any animal during a 1-year-long observation period. This case series demonstrates that the combination of tibial tuberosity transposition tool techniques and distal lateral femoral closing wedge osteotomy can be an effective treatment for medial patellar luxation associated with distal femoral varus with external tibial torsion less than 20 degrees.

THE PATELLA THICKNESS TO FEMORAL TROCHLEA DEPTH RATIO THE AS A CHOICE PREDICTOR OFTHE PATELLAR LUXATION SURGICAL TREATMENT IN DOGS

Patellar luxation (PL) is a surgical pathology of the knee joint, the lack of timely correction of which can lead to the development of comorbid arthropathies associated with joint instability. There are several PL correction surgical methods, the most widely used of which is the transposition of tibial tuberosity combined with trochleoplasty. However, trochleoplasty requires dissection of the joint capsule, which increases surgical trauma, is associated with damage to articular cartilage, because of which the recovery period is prolonged, and the number of postoperative complications increases. Therefore, it is essential that the surgeon determines whether this surgical trauma is necessary. The aim of our study was to determine the value of the P-STOF index (Patella— Sulcus trochleae ossis femoris) in dogs, in which it is necessary to perform trochleoplasty. During the study, 15 cadavers of dogs weighing up to 12 kg were used (mean weight ±SD: 4.7±3.7 kg). The knee joint area radiography in tangential and mediolateral projections was performed on 30 unpaired pelvic limbs of cadavers of dogs to the depth of the femoral trochlear groove (Sulcus trochleae ossis femoris — STOF) and the craniocaudal thickness of the patella. After that, the joints were opened, and measurements were carried out using an electronic caliper. It was found that reliable results are obtained by measuring the depth of STOF by radiographs in the tangential projection and by measuring the craniocaudal thickness of the patella by radiographs in the mediolateral projection. The mean patella thickness to femoral trochlea depth ratio in dogs without knee arthropathies was 3.1±0.2 (the standard error of the mean is indicated) (95% CI 2.7–3.5) and 4.0±0.3 (95% CI 3.4–4.5) in dogs with identified knee arthropathies. Therefore, when the P-STOFF index value is more than 3.4, trochleoplasty is recommended, since this value represents the lower limit of the confidence interval in dogs with arthropathies.

Comparison of Hindlimb Conformation in Cats with and without Medial Patellar Luxation.

Medial patellar luxation (MPL) is the most common developmental cause of hindlimb lameness in cats. The association between femoral and tibial conformation and MPL measured on computed tomography (CT) has not been reported in cats. The aims were to report femoral and tibial conformation in cats with and without MPL and to report normal femoral and tibial angles. Angle of inclination of femoral neck (AI), anatomical lateral distal femoral angle (aLDFA), femoral trochanteric angle (FCT), angle of anteversion of femoral neck (AA), distal and proximal anteversion angle (DAA/PAA), overall tibial valgus (TV), tibial torsion (TT), tibial tuberosity displacement (TTD) and trochlear depth:patellar thickness ratio (T:P) were measured by three observers on CT of cats with and without MPL. Comparisons were made between groups. Inter-observer intraclass correlation coefficient (ICC) was calculated. Sixteen cats were recruited: eight control and eight with MPL. The aLDFA, PAA, TT, TTD and T:P were significantly less in cats with high-grade MPL. The AI, FCT, AA, DAA and TV were not significantly different. A high correlation was shown with inter-observer ICC in 33.33% and good correlation in 26.67% when comparing measurements between observers. This study suggests that cats with high-grade MPL have decreased TT, TTD and T:P and may require tibial tuberosity transposition and femoral trochleoplasty. The PAA, TT and aLDFA were decreased, although clinical significance may vary and these cats may not require correctional osteotomies. Results should be interpreted with caution as high/good levels of inter-observer ICC occurred in less than two-thirds of cases between observers.

Combined center of rotation of angulation-based leveling osteotomy and tibial tuberosity transposition: An ex vivo mechanical study.

To describe the technique of combined center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) with tibial tuberosity transposition (TTT) and to compare the load to failure between CBLO combined with TTT and CBLO or TTT alone. Ex vivo study. Twelve pairs of cadaveric pelvic limbs. Six pairs of cadaveric tibia were tested in each group (CBLO-TTT versus CBLO) and (CBLO-TTT versus TTT) with each limb randomly assigned to a treatment group. Construct stability was determined by applying a tensile force to each patellar tendon until failure occurred. Load at failure and mode of failure were recorded for each specimen. No difference in mean load to failure was identified between CBLO-TTT (897 N) and CBLO alone (943 N) (P=.81). There was also no difference in the mean load to failure between the CBLO-TTT (928 N) and TTT alone (1046 N) (P=.12). Performing a TTT in combination with a CBLO does not weaken the construct failure to load when compared with each procedure performed alone. A combined CBLO and TTT could be considered a viable option for concurrent management of a cranial cruciate ligament deficient stifle and medial patella luxation.

Determining the Variation in the Tibial Tuberosity Transposition Distance That Is Required to Correct the Quadriceps Angle With the Severity of Medial Patellar Luxation of the Canine Stifle Joint

The aim of this study was to evaluate the transposition distance in in vitro canine medial patellar luxation (MPL) models of different severity grades using a single radiograph of the stifle joint. Each MPL grade model was generated with manipulation and evaluated by palpating the stability of the patella. An anterior-posterior radiograph of the entire hind limb with extended hip and stifle joints, including the iliopubic eminence, was used for all measurements. The quadriceps angles and the percentage of the transposition distance to the maximum width of the proximal tibia were measured. Our results demonstrated that when the tibial tuberosity transposition procedure is performed in a clinical setting, the required distance to correct the abnormal direction of the extensor mechanism in the canine stifle joint was greater in severe grade MPL than in mild grade MPL.

Positive outcomes after surgical correction of grade IV medial patellar luxation in small breed dogs.

Background:Medial patellar luxation (MPL) is a common orthopedic condition in dogs. After surgical correction, the recurrent rates appear to be higher and outcomes worse in grade IV than in lower grade MPL.Aim:To describe the outcomes of surgical correction of canine grade IV MPL.Methods:This retrospective study analyzed the medical records of 16 dogs (11 females, 5 males; mean age = 5.05 years) with 22 stifle joints (8 left and 14 right) that underwent MPL surgery at Rakuno Gakuen University between May 2015 and October 2020. The procedures included capsulorrhaphy, trochlear block recession, tibial tuberosity transposition, medial retinacular release, and lateral fabellotibial suturing. The types of postsurgical complications, including a recurrence of MPL, were recorded.Results:Twelve of the 16 (75 %) dogs had concurrent contralateral MPL, and 2 dogs (12.5%) had concurrent cranial cruciate ligament rupture. The mean follow-up was 12.1 months. No lameness was observed. The outcomes of surgery for grade IV MPL were not associated with bilateral surgery, age, sex, body weight, or the preoperative quadriceps angle. Although none of the dogs showed any major or catastrophic complications following surgery, postoperative minor and major complications were observed in 8 of the 22 stifle joints (36.4%).Conclusion:Grade IV MPL is a complex orthopedic disease in dogs, which requires surgical patellar realignment to improve limb function. The surgical techniques used in this study were associated with a good prognosis without a surgical revision.

MPFL reconstruction and tibial tuberosity transposition in patients with patellar instability: May it troubleshots also trochlear dysplasia?

PurposeThis study aimed to highlight short- and medium-term outcomes of combined medial patello-femoral ligament (MPFL) reconstruction and anterior tibial tuberosity (ATT) transposition surgery in patients with recurrent patellar instability and different degrees of trochlear dysplasia.MethodsBetween January 2014 and May 2019, 25 patients with patellar instability underwent a surgical procedure combining the lowering/transposition of the ATT and the MPFL reconstruction. Each patient were preoperative assessed by Kujala score, International Knee Documentation Committee (IKDC), Tegner activity level scale. The assessment of instability predisposing factors was carried out with patellar height, tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, sulcus angle, patellar tilt and MPFL injuries. Functional outcomes were evaluated with Kujala, IKDC and Tegner scores at 3, 6 and 12 months after surgery.ResultsThe average age of the patients was 20 years (range 13–43 years). Pre- operative Caton–Deschamps index was pathological in 10 (40%). Sulcus angle was elevated in 13 patients (52%) and TT-TG distance was irregular in 17 patients (68%). Trochlear dysplasia was present in 13 patients (9 type A, 3 type B, 1 type C according to Dejour’s Classification). No re-dislocation occurred during the follow-up. There was a significant increase in the Kujala, IKDC and Lysholm scores after 3, 6 and 12 months, and the results were compared for the different follow-up times and patient’s trochlear dysplasia degree.ConclusionThis prospective observational longitudinal study identified good clinical outcomes in patients who underwent MPFL reconstruction and ATT transposition for patellar instability. Finally, the different risk factors for patellar instability examined, particularly the presence of trochlear dysplasia, did not significantly influence the final functional results, which range from good to excellent without re-dislocation episodes.

Tibial Tuberosity Transposition Fixation with a Locking Plate during Medial Patellar Luxation Surgery: An Ex Vivo Mechanical Study.

The purpose of this study was to compare the load at failure, stiffness and mode of failure between three types of tibial tuberosity transposition fixation techniques: (a) pin and figure-8 tension band wire (Pin-TBW), (b) locking plate with pin and a tension band wire (Plate-Pin-TBW) and (c) locking plate with a pin (Plate-Pin). Six pairs of raccoon dog cadaveric tibiae were tested in Phase I Pin-TBW versus Plate-Pin-TBW and seven pairs in Phase II Plate-Pin-TBW versus Plate-Pin. One limb of each pair was randomly assigned to one of two groups for each phase. A tensile force was applied to the patellar ligament until construct failure. Pin-TBW (342N ± 54.7N) failed at a lower load than Plate-Pin-TBW (469N ± 77.3N), p = 0.00748, with all Pin-TBW failing by fracture and the majority of Plate-Pin-TBW failing by rupture of patellar ligament. Pin-TBW group Phase I, normalized with Plate-Pin-TBW Phase I, failed at a lower load than Plate-Pin group Phase II, normalized with Plate-Pin-TBW Phase II, p = 0.00467. There was no significant difference in mean load at failure, stiffness or mode at failure between the groups in the Phase II study. Although ex vivo mechanical testing does not replicate the postoperative live dog or cat, these results demonstrate lower construct strength of the Pin-TBW construct compared with the Plate-Pin construct in the raccoon dog cadaver model.

Tibial tuberosity transposition advancement for treatment of concomitant cranial cruciate ligament rupture and medial patellar luxation in four feline stifles.

Case series summaryThree cats (four stifles) were diagnosed with varying grades of medial patellar luxation and stifle instability in cranial tibial thrust. Radiographs showed periarticular osteophytosis, intra-articular mineralization and opacification encroachment of the infrapatellar fat pad. Stifle exploration revealed either partial (n = 2) or complete (n = 2) cranial cruciate ligament tear and medial meniscal injury in all cases. Medial meniscectomy, partial parasagittal patellectomy, femoral trochleoplasty and tibial tuberosity transposition advancement using a 6 mm cage, two-fork plate and 4 mm spacer were performed in four stifles. Screws (2.0 mm) and washers were used in the cranial cage ears rather than conventional 2.4 mm screws. By the 2-week recheck, lameness was minimal and stifles were stable. Radiographic follow-up at 8 weeks showed appropriate progression of osseous union in all cases. One cat experienced a major complication, suffering tibial fracture following a lapse in exercise restriction, and revision surgery was performed successfully with subsequent osseus union of the osteotomy site. At the mid-term follow-up, all cats had a return to previous level of function, as assessed by both owner questionnaire and clinical evaluation.Relevance and novel informationTibial tuberosity transposition and advancement has been shown to be successful in dogs for the treatment of concomitant medial patellar luxation and cranial cruciate ligament rupture. To date, there have been no reports of tibial tuberosity transposition and advancement in cats. A benefit of this approach is concomitant alignment of the extensor mechanism and neutralization of the femorotibial shear force. Our case series describes successful use of tibial tuberosity transposition advancement in cats.