Tibial Tubercle Research Articles

Tibial Tubercle Trochlear Groove Distance Does Not Correlate With Patellar Tendon Length in Patients Who Underwent Anterior Cruciate Ligament Reconstruction

To examine the relationship between tibial tubercle-trochlear groove (TT-TG) distance and patellar tendon length. All healthy athletes who underwent anterior cruciate ligament reconstruction who had a magnetic resonance imaging (MRI) study of the knee on file between July 2018 and June 2019 at a single institution were retrospectively reviewed. Exclusion criteria included patients without an MRI study of the knee on file or with an MRI of insufficient quality precluding reliable calculation of TT-TG and patellar tendon length. MRIs were reviewed to calculate TT-TG, patellar tendon length, and Caton-Deschamps Index (CDI). Patient charts were reviewed to obtain anthropometric characteristics including sex, concomitant injuries, and previous knee procedures as well as age at time of MRI. Spearman correlations were used to assess the relationship between TT-TG, patellar tendon length, and CDI, with regression analysis performed to assess for relationships between TT-TG, patellar tendon length, and patient-specific factors. Overall, 235 patients (99 female [42.1%], 136 male [57.9%]; mean age: 30.0 years [23.0; 40.0]) were included. Inter-rater reliability between the 2 reviewers was 0.888 for TT-TG, 0.804 for patellar tendon length, and 0.748 for CDI, indicating strong agreement. The correlation between TT-TG and patellar tendon length was 0.021, indicating no true relationship. The correlation between TT-TG and CDI was -0.048 and that of patellar tendon length and CDI was 0.411, indicating a weak positive relationship. Regression analysis found that male sex is strongly correlated with a longer patellar tendon length (odds ratio 2.65, 95% confidence interval 1.33-3.97, P < .001). In this study, no correlation was found between TT-TG and patellar tendon length or CDI. Male sex was correlated with a longer patellar length. Level III.

Cadaveric comparison of two techniques for intraoperative placement of tibial plateau levelling osteotomies in dogs.

Both tibial tuberosity fractures and deviation from the planned postoperative tibial plateau angle have been associated with poor centring of tibial plateau levelling osteotomies (TPLOs). The aim of this cadaveric study was to compare two techniques for centring the osteotomy and preserving the tibial tuberosity width (TTW). Stifle radiographs were obtained from 20 limbs of 10 dogs. TPLO was planned on each stifle, and a two-wire technique (TWT) and a technique using the medial collateral ligament (MCL) as an intraoperative landmark were planned. The techniques were executed and marked with radiopaque pins. Further radiographs were obtained and analysed. On average, TWT resulted in a 20.4% increase in TTW and medial collateral ligament technique (MCLT) resulted in a 13.4% decrease. Expressed as a percentage of the radial saw size, the average error in the centring of the osteotomy arising from the TWT was 13.4% and that from the MCLT was 14.2%. This study had a small sample size and involved a single surgeon. Neither technique reliably identified the desired centre of the osteotomy, and both had a similar magnitude of error. MCLT resulted in reduced TTW, while TWT resulted in increased TTW. A reduced TTW has been associated with an increased risk of tibial tuberosity fracture, so MCLT is not recommended for clinical use.

Distribution, course, and spatial relationships of the saphenous nerve: A 3D neuroanatomical map for nerve stimulation.

The overall objective of this study was to construct a 3D neuroanatomical map of the saphenous nerve based on cartesian coordinate data to define its course in 3D space relative to bony and soft tissue landmarks. Ten lower limb embalmed specimens were meticulously dissected, digitized, laser scanned, and modelled in 3D. The course of the main branches, number of collateral branches, and relationship of saphenous nerve to the great saphenous vein were defined and quantified using the high-fidelity 3D models. In 60% of specimens, the saphenous nerve was found to have three branches in the leg, infrapatellar, anterior, and posterior. In 40% of specimens, the posterior branch was absent. Three landmarks were found to consistently localize the anterior branch: the medial border of tibia at the level of the tibial tuberosity, the medial border of tibia at the level of the mid-point of leg, and the mid-point of the anterior border of the medial malleolus. The posterior branch, when present, had variable branching patterns but did not extend as far distally as the medial malleolus in any specimen. Anatomically, the anterior and posterior branches at the level of the tibial tuberosity could be most advantageous for nerve stimulation due to their close proximity to the bifurcation of the saphenous nerve where the branches are larger and more readily localizable than distally. Additionally, the tibial tuberosity is a prominent landmark that can be easily identified in most individuals and could be used to localize the anterior and posterior branch using ultrasound or other imaging modalities. These findings will enable implementation of highly realistic computational models that can be used to simulate saphenous nerve stimulation using percutaneous and implanted devices.

Correlation of Tibial Tubercle Overgrowth With Increased Posterior Tibial Slope: A Novel Radiographic Assessment.

An elevated posterior tibial slope (PTS) is associated with an increased risk for anterior cruciate ligament and meniscal injury. Recent evidence suggests that the PTS is elevated in patients with Osgood-Schlatter disease. To determine whether there is an association between objective measures of anterior tibial tubercle growth and PTS. Cross-sectional study; Level of evidence, 3. A total of 100 radiographs were randomly selected from a sample of patients who had received a lateral knee radiograph that captured at least 15 cm of the tibia distal to the knee joint line at a single institution between December 2020 and March 2022. The PTS was measured, and tibial tubercle growth was quantified with 2 novel measurements. For these measurements, a line was drawn on the radiograph from the most anterosuperior point on the tibia to the point on the anterior cortex of the tibia 10 cm distal from the starting point. The tibial tubercle height (TTH) was measured as the perpendicular distance from this line to the most prominent portion of the anterior tibia. The anterior tibial tubercle angle (TTA) was measured as the angle between the endpoints of the line made previously and the most prominent portion of the tibial tubercle, with a more acute angle indicating a more prominent tibial tubercle. The relationship between TTA, TTH, and PTS was evaluated using a univariate linear regression model. The mean patient age was 33.1 ± 14.1 years. The mean TTA was 158.6°± 4.7°, the mean TTH was 8.8 ± 2.0 mm, and the mean PTS was 9.7°± 2.6°. A significant correlation was found between PTS and TTA (r = -0.46; β = -0.46; P < .001) as well as TTH (r = 0.43; β = 0.43; P < .001). Objective measures of anterior tibial tubercle overgrowth correlated with an elevated PTS. Every 2.2° of anterior TTA deviation from the mean and every 2.3 mm in TTH deviation from the mean correlated with a 1° difference in the PTS. This suggests a link between the development of the tibial tubercle and PTS, and it potentially helps to explain why the PTS is elevated in certain patients.

Change in Posterior Tibial Slope Angle After Displaced Pediatric Tibial Tubercle Fracture: A Model for Growth Modulation in the ACL-Deficient Knee.

Increased posterior tibial slope angle (PTSA) has been shown to be an important risk factor for anterior cruciate ligament (ACL) injury. PTSA modulation is not utilized routinely to reduce risk of primary rupture or graft failure. Displaced tibial tubercle (TT) fractures in the skeletally immature are associated with potential growth arrest and may be used as a model to study PTSA changes in this setting. To quantify the change in PTSA (ΔPTSA) after operative treatment of displaced TT fractures in skeletally immature patients. It was hypothesized that there would be a progressive decrease in PTSA after TT injury and that rate of ΔPTSA would be highest during peak growth velocity. Case series; Level of evidence, 4. Included were 22 patients (n = 23 knees; mean chronological and bone age at injury, 14 years; 86% male) who underwent surgery for displaced TT fracture. PTSA was measured on lateral radiographs at time of surgery and subsequent follow-up, and bone age at the time of injury was determined using radiographic standards. The rate of ΔPTSA for individual patient, total cohort, and sex-based subgroup trends were determined via linear regression (degrees per month; positive value indicates relatively anterior). Individual patient regression coefficients were averaged into bone age cohorts. Average follow-up was 17 months (range, 6-52 months). The mean PTSA was -12°± 2.4° at the time of injury, and the mean ΔPTSA for the cohort was 0.30°± 0.31° per month (range, -0.27° to 0.97° per month). Linear regression demonstrated a significant relationship between months postfixation and PTSA, demonstrating a ΔPTSA of 0.31° per month (95% confidence interval [CI], 0.24° to 0.38°; P < .001). The highest ΔPTSA was seen at bone age 14 years (mean, 0.58°± 0.44° per month). The mean absolute change in PTSA from injury to final follow-up was 4.1° (range, -3.4° to 21°). Our data suggested that PTSA becomes more anterior after operatively treated pediatric TT fractures and that ΔPTSA may be influenced by bone age. This concept may be useful in considering surgical modulation of excessive PTSA in the pediatric ACL-deficient knee.

Decreased Effective Patellar Tendon Length following Distalization Tibial Tubercle Osteotomy without Patellar Tendon Tenodesis.

Distalization tibial tubercle osteotomy (TTO) is an effective treatment for improving patellar height in patients with patella alta associated with patellofemoral instability and cartilage lesions. The addition of a patellar tendon tenodesis has been suggested; nonetheless, concerns exist regarding possible increased patellofemoral cartilage stresses. To evaluate pre- and postoperative patellar tendon length and alignment parameters on magnetic resonance imaging (MRI), as well as patient-reported outcome measures (PROMs) after distalization TTO without patellar tendon tenodesis. Case series; Level of evidence, 4. Twenty skeletally mature patients who underwent distalization TTO with or without anteromedialization at our institution between December 2014 and August 2021 were included. All patients underwent pre- and postoperative MRIs of the affected knee. The Caton-Deschamps index (CDI), the axial and sagittal tibial tubercle-trochlear groove (TT-TG) distances, the distances from the tibial plateau to the patellar tendon insertion and the tibial tubercle, and the patellar tendon length were assessed. PROMs included the International Knee Documentation Committee Subjective Knee Evaluation Form, the Knee injury and Osteoarthritis Outcome Score-Quality of Life subscale, the Kujala Anterior Knee Pain Scale, and the Veterans RAND 12-Item Health Survey mental and physical component scores. The mean patient age at surgery was 27.4 years (range, 14-42 years). Radiographic parameters demonstrated improved patellar height (CDI decreased from 1.36 to 1.11; P < .001) after distalization TTO. The distance from the tibial plateau to the patellar tendon insertion significantly decreased from 20.1 mm preoperatively to 17.9 mm postoperatively (P < .020), and the patellar tendon length decreased from 53.4 mm preoperatively to 46.0 mm postoperatively (P < .001). The patellar tendon insertion was not distalized after distalization TTO, likely because of scarring of the patellar tendon proximal to the osteotomy site. Patients demonstrated significant pre- to postoperative improvements on all PROMs (P≤ .024 for all ). There were 4 (20%) complications-2 cases of arthrofibrosis, 1 postoperative infection, and 1 osteotomy delayed union. Distalization TTO without patellar tendon tenodesis was associated with improved radiographic outcomes and PROMs. It provides an additional tool for surgical management of patellofemoral pathology with associated patella alta.

Less risk of patellofemoral degeneration without significant clinical and survivorship difference for distal tibial tuberosity high tibial osteotomy compared to biplanar high tibial osteotomy over a mid-term follow-up.

This study aims to compare the mid-term radiographic, clinical results and survivorship between distal tibial tuberosity high tibial osteotomy (DTT-HTO) and conventional biplanar medial open-wedge high tibial osteotomy (cOW-HTO). The weight-bearing line ratio (WBL%) and medial proximal tibial angle (MPTA) were evaluated using a standing anteroposterior view of lower extremity. The posterior tibial slope (PTS), Caton-Deschamps index (CDI), tilting angle (TT) and lateral shift ratio (LSR) were evaluated using the lateral views and Merchant views. The Knee Society (KS) knee and function score, Lysholm score, and Anterior Knee Pain Scale (Kujala score) were were used to evaluate the functional outcomes. All parameters were evaluated preoperatively and at the final follow-up. The postoperative complications and survivorship for both groups were also evaluated during the follow-up period. The WBL% and MPTA exhibited no significant differences between the two groups preoperatively and at the final follow-up. The postoperative CDI and TT in the cOW group decreased significantly compared with the DTT group (p = .037 and .041, respectively). The PF grade showed a significant increase after DTT-HTO and cOW-HTO (p = .036 and <0.001, respectively). Furthermore, the postoperative PF grade of cOW group was significantly higher than that of DTT group (p = .039). The KS knee and function score, Lysholm score, and Kujala score for both groups improved similarly at the final follow-up. The survivorship free of revision was 92.7 % in the DTT group and 94.2% in the OW group. Despite observing a lower risk of PF joint progression in DTT-HTO compared to cOW-HTO, the clinical outcomes and survivorship after DTT-HTO and cOWHTO were comparable over a mid-term follow-up.

Robot-Assisted Patellofemoral Arthroplasty.

Patellofemoral arthroplasty is indicated in patients with isolated patellofemoral arthritis in whom nonoperative treatment has failed2. The goal of the presently described procedure is to provide relief from patellofemoral arthritis pain while maintaining native knee kinematics2. Patient radiographs are carefully reviewed for isolated patellofemoral arthritis in order to determine the appropriateness of robotic-assisted patellofemoral arthroplasty. Magnetic resonance imaging can be performed preoperatively to help confirm isolated patellofemoral arthritis. We perform this procedure with use of the MAKO Surgical Robot (Stryker). Preoperative computed tomography is performed to plan the bone resection, the size of the implant, and the positioning of the device. The steps of the procedure include (1) medial parapatellar arthrotomy, (2) intraoperative inspection to confirm isolated patellofemoral arthritis, (3) patellar resurfacing, (4) placement of optical arrays and trochlear registration, (5) trochlear resection, (6) trialing of implants, (7) removal of the optical array, (8) impaction of final implants, (9) confirmation of appropriate patellar tracking, and (10) closure. Alternatives to patellofemoral arthroplasty include standard nonoperative treatment, bicompartmental arthroplasty, total knee arthroplasty, tibial tubercle osteotomy, partial lateral facetectomy, and arthroscopy2. Patellofemoral arthroplasty is indicated in patients with isolated patellofemoral arthritis in whom nonoperative treatment has failed2. Patellofemoral arthroplasty may be superior to total knee arthroplasty because it helps treat pain that affects patient quality of life and activities of daily living while also preserving greater tibiofemoral bone stock2. We recommend against performing patellofemoral arthroplasty in patients with arthritis of the tibiofemoral joints2. In properly selected patients, outcomes include improvement in patient pain and function1. One study found that robotic-assisted patellofemoral arthroplasty may result in improved patellar tracking compared with non-robotic-assisted patellofemoral arthroplasty1; however, functional outcomes were found to be similar between procedures, and data for all non-robotic-assisted controls were retrospectively captured1. Confirm isolated patellofemoral arthritis on radiographs and/or magnetic resonance imaging.Review the preoperative plan for appropriate positioning of the trochlear implant.○ Confirm coverage of the trochlear groove.○ Avoid medial overhang.○ Avoid lateral overhang.○ Avoid anterior femoral notching.○ Avoid impingement of the trochlear component into the notch.○ Avoid excessive prominence of the trochlear component on the anterior femoral cortex.○ General principles are to place the trochlear component in 0° to 6° of flexion and 0° to 2° of external rotation.Robotic-assisted trochlear resurfacing is accurate and efficient. CT = computed tomography.

Long leg cast versus hinged knee brace immobilization after surgical treatment of tibial tubercle fractures

Long leg cast versus hinged knee brace immobilization after surgical treatment of tibial tubercle fractures

Measurement of TT-TG can change with sequential MRIs due to variations in tibiofemoral rotation in patellofemoral instability patients.

There are various anatomic risk factors for patellofemoral instability (PFI) that help guide surgical treatment, including the tibial tubercle to trochlear groove (TT-TG) distance. However, no study has analysed the temporal changes in TT-TG prior to surgical intervention. This study sought to understand the variations in TT-TG over time for pediatric patients suffering from PFI prior to surgical intervention. The authors hypothesised that the TT-TG would substantially change between time points. Patients undergoing medial patellofemoral ligament (MPFL) reconstruction between 2014 and 2019 by one of two fellowship-trained orthopaedic surgeons were identified. Patients were included if they had two preoperative magnetic resonance imaging (MRI) performed on the same knee within 7.5 months of each other prior to any surgical intervention and had an initial TT-TG greater than 10 mm. After considering 251 patients for inclusion, 21 patients met the final inclusion criteria. The mean age was 14.5 ± 2.5 years and 61.9% were female. TT-TG was initially noted to be 15.1 ± 1.8 mm. At mean time aftersequential MRIs of 5.0 ± 1.9 months, TT-TG was noted to be 16.7 ± 3.2 mm. The differences between initial and subsequent TT-TG ranged from a 21.2% decrease to a 61.1% increase, with a mean difference of an 11.3% increase. Comparison between initial and subsequent TT-TG values demonstrated a significant difference (p = 0.017). Change in tibiofemoral rotation ranged from -9.2° to 7.5°. When comparing the change in TT-TG to change in tibiofemoral rotation, a significant correlation was found (p = 0.019). Despite only a mean time between MRIs of 5 months, variations in TT-TG ranged from a decrease of 21.2% to an increase of 61.1%. The significant relationship between the changes in TT-TG and changes in tibiofemoral rotation between MRIs suggest that TT-TG measurements may vary due to variations in tibiofemoral rotation at the time of individual MRIs. Level IV.

A Prospective Randomized Controlled Trial Investigating Quadriceps Versus Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction

Background: Numerous graft options are available when undertaking anterior cruciate ligament (ACL) reconstruction (ACLR), although a lack of high-quality evidence exists comparing quadriceps (QT) and hamstring (HT) autografts. Purpose: To investigate patient outcomes in patients undergoing HT versus QT ACLR. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: After recruitment and randomization, 112 patients (HT = 55; QT = 57) underwent ACLR. Patients were assessed pre- and postoperatively (6 weeks and 3, 6, 12, and 24 months), with a range of patient-reported outcome measures (PROMs), graft laxity (KT-1000 arthrometer; primary outcome variable), active knee flexion and extension range of motion (ROM), peak isokinetic knee extensor and flexor strength, and a 6-hop performance battery. Limb symmetry indices (LSIs) were calculated for strength and hop measures. Secondary procedures, ACL retears, and contralateral ACL tears were reported. Results: All PROMs and knee ROM measures significantly improved (P < .0001), and no other group differences (P > .05) were observed—apart from the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) score, which was significantly better in the HT group at 3 (P = .008), 6 (P = .010), and 12 (P = .014) months. No significant changes were observed in side-to-side laxity from 6 to 24 months (P = .105), and no group differences were observed (P = .487) at 6 (HT mean, 1.2; QT mean, 1.3), 12 (HT mean, 1.1; QT mean, 1.3), and 24 (HT mean, 1.1; QT mean, 1.2) months. While the HT group demonstrated significantly greater (P < .05) quadriceps strength LSIs at 6 and 12 months, the QT group showed significantly greater (P < .05) hamstring strength LSIs at 6, 12, and 24 months. The HT group showed significantly greater (P < .05) LSIs for the single horizontal (6 months), lateral (6 and 12 months), and medial (6 months) hop tests for distance. Up until 24 months, 1 patient (QT at 22 months) had a retear, with 2 contralateral ACL tears (QT at 19 months; HT at 23 months). Secondary procedures included 5 in the HT group (manipulation under anesthesia, notch debridement, meniscal repair, and knee arthroscopy for scar tissue) and 6 in the QT group (notch debridement, meniscal repair, knee arthroscopy for scar tissue, tibial tubercle transfer, and osteochondral autologous transplantation). Conclusion: Apart from the ACL-RSI, the 2 autograft groups compared well for PROMs, knee ROM, and laxity. However, greater hamstring strength LSIs were observed for the QT cohort, with greater quadriceps strength (and hop test) LSIs in the HT cohort. The longer-term review will continue to evaluate return to sports and later-stage reinjury between the 2 graft constructs. Registration: ACTRN12618001520224p (Australian New Zealand Clinical Trials Registry).

Combination of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release for patellofemoral instability provides good middle- to long-term outcomes in adolescents.

There are limited studies that have reported the middle- to long-term outcomes of combined procedures consisting of more than two procedures for patellofemoral instability. The current study aims to investigate and report the middle- to long-term outcomes of a combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release for patellofemoral instability in patients aged 18 years and below. In the cohort study, all patients aged 18 years old or younger who underwent a combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release for recurrent patellofemoral instability were included. A total of 21 patients were included in the study. All patients had no further patellofemoral dislocation, pain and apprehension following the 4-in-1 surgery (p < 0.01). There was a significant improvement in the Kujala score from 36.1 (SD 12.9) pre-operatively to 93.1 (SD 3.6) post-operatively (p < 0.001). The patients also had a statistically significant improvement in their radiological factors, including the patellar tilt angle (p < 0.001), sulcus angle (p = 0.001), trochlear groove depth (p = 0.041), tibial tubercle-trochlear groove distance (p < 0.001) and Caton-Deschamps index (p = 0.001). A combination procedure of tibial tubercle transfer, medial patellofemoral ligament reconstruction, trochleoplasty and lateral release leads to good middle- to long-term subjective, functional and radiographic outcomes for patients with recurrent patellofemoral instability and underlying predisposing factors of increased TT-TG distance of more than 20mm, Dejour B or D trochlear dysplasia and medial patellofemoral ligament rupture. IV.

Tibial tuberosity-trochlear groove distance is significantly decreased by medial closing wedge distal femoral osteotomy.

While medial closing wedge distal femoral osteotomy (MCWDFO) has been used to address patella instability combined with valgus malalignment, its impact on patellofemoral parameters remains uncharted. Hence, this study seeks to establish a three-dimensional (3D) planning of MCWDFO and measure its effect on the tibial tubercle - trochlear groove distance (TTTG) through simulation and calculation. MCWDFO with a stepwise increment of one-degree varisation (1°-15°) was performed on 3D surface models of 14 lower extremities with valgus malalignment and 24 lower extremities with neutral alignment of the lower limb, resulting in a total of 608 simulations. Anatomic landmarks were employed to measure hip-knee-ankle angle (HKA), TTTG, and femoral torsion for each simulation. A mathematical formula was adopted to calculate TTTG changes following MCWDFO, and subsequently the mean simulated and calculated TTTG values were compared. Following a standardised protocol, MCWDFO was performed without rotational changes. MCWDFO exhibited an almost linear reduction in TTTG, at a rate of approximately -1.05 ± 0.13 mm per 1° of varisation, demonstrating a strong negative correlation (R = -0.83; p < 0.001). Limb alignment did not exert an influence on TTTG change; however, it correlated with tibial plateau width. The mean difference between the simulated and calculated TTTG values amounted to 0.03 ± 0.03 mm per 1° varisation (p < 0.001). The TTTG distance is linearly reduced by 1.05 mm for every 1° of varisation within the varus correction range of 0°-15° during MCWDFO. Patients with combined valgus and patellar instability may benefit from MCWDFO due to frequently pathological TTTG. Level III, descriptive laboratory study.

Patients who undergo tibial tubercle anteromedialization with medial patellofemoral ligament reconstruction demonstrate similar rates of return to sport compared to isolated MPFL reconstruction.

To investigate the rate of return to sports and sport psychological readiness between patients who underwent isolated MPFLR (iMPFLR) compared to a matched cohort of patients who underwent MPFLR with anteromedializing tibial tubercle osteotomy (MPFLR/TTO). Patients who underwent primary MPFLR with or without TTO for recurrent patellar instability were retrospectively reviewed from 2012 to 2020 at a single institution. Preinjury sport and work information, Kujala, Tegner, Visual Analogue Scorefor pain, satisfactionand MPFL-Return to Sport after Injury (MPFL-RSI) score were collected. Two readers independently measured the tibial tuberosity-trochlear groove distance, Caton-Deschamps indexand Dejour classification for trochlear dysplasia. Patients in iMPFLR and MPFLR/TTO groups were matched 1:1 on age, sex, body mass indexand follow-up length. Multivariate regression analysis was performed to determine whether the MPFL-RSI was associated with a return to sport. This study included 74 patients at mean follow-up of 52.5 months (range: 24-117). These groups returned to sport at similar rates (iMPFLR: 67.6%, MPFLR/TTO: 73.0%, not significant [ns]), though iMPFLR patients returned more quickly (8.4 vs. 12.8 months, p = 0.019). Rates of return to preinjury sport level were also similar (45.9% vs. 40.5%, ns). Patients with Dejour B/C took more time to return to sport compared to patients with mild/no trochlear pathology (13.8 vs. 7.9 months, p = 0.003). Increasing MPFL-RSI score was significantly predictive of the overall return to sport (odds ratio [OR]: 1.08, 95% confidence interval [CI] [1.03, 1.13], p < 0.001) and return to preinjury level (OR: 1.07, 95% CI [1.04, 1.13], p < 0.001). Most patients in iMPFLR and MPFLR/TTO groups resumed work (95.7% vs. 88.5%, ns), though iMPFLR patients who returned to preinjury work levels did so more quickly (1.7 vs. 4.6 months, p = 0.005). Patients who underwent MPFLR with anteromedializing TTO demonstrated similar rates of return to sport and psychological readiness compared to an isolated MPFLR matched comparison group, though iMPFLRs returned more quickly. Patients with more severe trochlear pathology required more time to return to sports. Level III.

Podium Presentation Title: Outcomes of Medial Patellofemoral Ligament Reconstruction with and without Tibial Tubercle Osteotomy

Podium Presentation Title: Outcomes of Medial Patellofemoral Ligament Reconstruction with and without Tibial Tubercle Osteotomy

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

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). 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. 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. 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. 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.

Varus placement of the tibial component reduces the potential risk of fracture with adequate bony coverage in the Oxford unicompartmental knee arthroplasty

A short keel-cortex distance (KCD), especially to the posterior cortex, is a potential risk factor for tibial plateau fracture after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to evaluate the effect of tibial component alignment in the coronal plane and tibial proximal morphology on the KCD. Included in this study were 51 patients scheduled for primary Oxford medial unicompartmental knee arthroplasty (UKA). The anterior and posterior KCD were preoperatively assessed using 3D simulation software with the component set perpendicular to the tibial mechanical axis (neutral), 3° valgus, 3° varus, and 6° varus, relative to neutral alignment. We evaluated the existence of overhanging medial tibial condyle where the medial eminence line, the line including the medial tibial eminence parallel to the tibial axis, passes outside of the tibial shaft. In all component alignments, patients with a medial overhanging condyle had significantly shorter posterior KCD than those without. In patients with a medial overhanging condyle, the posterior KCD significantly increased when the tibial component was placed in 3° varus (4.6 ± 1.5 mm, P = 0.003 vs neutral, P < 0.001 vs 3° valgus) and 6° varus (5.0 ± 1.4 mm, P < 0.001 vs neutral, P < 0.001 vs 3° valgus) compared with in neutral (3.5 ± 1.9 mm) or 3° valgus (2.8 ± 1.8 mm). In OUKA, varus implantation increased the KCD. This could potentially decrease the risk of fracture, even in knees with the overhanging medial condyle. Conversely, valgus implantation of the tibial component shortened the KCD, and should therefore be avoided.

The effects of tibial tuberosity avulsion and repair on tibial plateau angle in dogs

ABSTRACT Aims To assess whether tibial tuberosity avulsion injury and subsequent surgical repair in skeletally immature dogs are associated with changes in tibial plateau angle (TPA) at skeletal maturity. Methods Skeletally mature (> 18 months of age) dogs that had previously undergone unilateral surgery when 4–8 months of age to repair tibial tuberosity avulsion were enrolled. Bilateral, mediolateral stifle radiographs were taken. TPA was measured digitally from the radiographs independently by two readers and compared between sides within dogs. As the number of dogs that would be enrolled for the main part of the study was unknown, to understand how the variation between left and right stifles within dogs would affect the power of the main study, 29 client-owned, skeletally mature dogs without stifle pathology were recruited prior to the main study for bilateral, mediolateral projection stifle radiographs. Variation in the differences in TPA between left and right stifles was used to estimate the likely power of the major part of the study for different numbers of enrolled dogs. Results From 29 dogs enrolled in the power assessment, the SD of the differences between left and right stifles was 2.1°. With 10 dogs (20 stifles) enrolled within the main part of the study, and if the SD of the differences between operated and non-operated stifles within a dog was the same as the SD of the differences between non-operated stifles within a dog (2.1°), the study would have power ≥ 0.8 if the mean difference in TPA between operated and non-operated stifles was ≥ 2.1°. Ten dogs were enrolled in phase II of the study. In 8/10 of these dogs, the TPA in the operated stifle was less than in the non-operated stifle. The mean TPA on the operated stifle was 6.4° less than on the non-operated stifle (95% CI = 2.4–10.3° less; p = 0.002). For surgery between 4 and 8 months of age, TPA at maturity increased by 2.7° (95% CI = 1.1–4.3°; p = 0.001) for each additional month of age at surgery. Conclusions and clinical relevance Based on this study, surgical repair of tibial tuberosity avulsion in skeletally immature dogs is associated with a smaller TPA at skeletal maturity. However, causality cannot be established from this cross-sectional study, and this association may be because stifles with a smaller TPA are predisposed to tibial tuberosity avulsion.

New posterior distal femoral hemiepiphysiodesis for treatment of recurvatum knee in a patient with cerebral palsy: a case report

Hyperextension of the knee (Genu recurvatum) is a rare deformity in the sagittal plane which can impact on walking by pelvis’, ankle’s and foot’s biomechanics changes. It can be caused by cerebral palsy, arthrogryposis poliomyelitis, traumatic tibial tuberosity arrest and generalized ligamentous hyperlaxity. Specially in cerebral palsy, factories like hamstrings lengthening and equinus deformity of the foot can produce this knee condition. The treatment methods to correct this deformity are more aggressive to date, such as quadricepsplasty, hamstring tenomyoplasty and femur or tibia osteotomies. We describe here the treatment of a patient with mild hemiparetic hypertonic cerebral palsy GMSCF I, with unilateral genu recurvatum, using a safe and minimally invasive technique with posterior hemiepiphysiodesis of the distal femur, performed with two transphyseal cannulated screws for correction. This technique has great potential for correcting the recurvatum knee in the immature skeleton during growth and can be a good alternative to the more aggressive methods currently used for the treatment of this deformity.

INCIDENCE AND SURGICAL TREATMENT OF COMPONENT BREAKAGE AFTER UNICOMPARTMENTAL AND TOTAL KNEE ARTHROPLASTY: A SINGLE-CENTRE LONG-TERM EXPERIENCE

Fractures of the prosthetic components after total knee arthroplasty (TKA) are rare but dangerous complications, sometimes difficult to diagnose and to manage. Aim of this study is to evaluate the incidence of component breakage and its treatment in our single institution's experience. We retrospectively review our institution registry. From 605 revision knee arthroplasties since 2000 to 2018, we found 8 cases of component breakage, of these 3 belonged to UKA, and 5 belonged to TKA. The UKA fractures were all on the metal tibial component; while 4 TKA fractures were ascribed to the liner (2 Posterior-Stabilized designs and 2 constrained designs) and only one case was on the femoral component. For every patient a revision procedure was performed, in two cases a tibial tubercle osteotomy was performed, while in one case (where the fracture was of the post cam) an arthroscopy was performed prior to the arthrotomy. All of the UKA fractures were treated with a standard revision implant. As regard the TKA, 2 liner fractures were treated with the only liner exchange, while the other 2 liner fractures and the fracture of the metallic component were treated with total knee revision. No intra- and post-operative complications were found. Component breakage after TKA is a serious complication. Its treatment, always surgical, can hide pitfalls, especially if the timing is not correct; indeed apart from the revision of one or more components, the surgeons must address any issues of management of bone defect and ligamentous stability.