Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability.

Cite this article: Bone Jt Open 2022;3(3):268–274.

Distal femoral physeal fractures can cause of growth distrurbance which frequently requires further surgical intervention. The aim of this study was to determine if tibial tuberosity ossification at the time of injury can predict further surgery in patients who have sustained a physeal fracture of the distal femur. We retrospectively investigated all patients who had operative treatment for a distal femoral physeal fracture at a paediatric level one trauma center over a 17 year period. Logistic regression analysis was performed investigating associations between the need for further surgery to treat growth disturbance and tibial tuberosity ossification, age, Salter Harris grade, mode of fixation or mechanism of injury. 74 patients met the inclusion criteria. There were 57 boys (77%) and 17 girls (23%). The average age at time of injury was 13.1 years (range 2.-17.1 years). Following fixation, 30 patients (41%) underwent further surgery to treat growth disturbance. Absence of tibial tuberosity fusion to the metaphysis was significantly associated with need for further surgery (p = < 0 .001). Odds of requiring secondary surgery after tibial tuberosity fusion to metaphysis posteriorly (compared with not fused) were 0.12, 95% CI (0.04, 0.34). The estimate of effect of tibial tuberosity ossification on reoperation rates did not vary when adjusted for gender, mechanism, fixation and Salter Harris grade. When accounting for age, the odds of further operation if the tibial tuberosity is fused to the metaphysis posteriorly (compared with not fused) were 0.28, 95% CI (0.08, 0.94). Tibial tuberosity ossification stage at time of injury is a predictor of further surgery to treat growth disturbance in paediatric distal femoral fractures. Children with distal femoral physeal fractures whose tibial tuberosity was not fused to the metaphysis posteriorly were 8.3 times more likely to require further surgery

Patellofemoral instability (PFI) is a common cause of knee pain and disability in the paediatric population. Patella alta, lateralised tibial tubercle, medial patellofemoral ligament (MPFL) deficiency, genu valgum and trochlear dysplasia are well known risk factors. A prospective database was created including patients referred through our physiotherapy pathway following first-time patella dislocation. Patella alta and lateralisation of the tibial tuberosity was treated with a Fulkerson-type tibial tubercle osteotomy(TTO). Medial patellofemoral ligament was reconstructed using quads tendon autograft pull-down technique. A modified Sheffield protocol was used postoperatively allowing weightbearing in a hinged knee brace. Forty patients were identified with 8 patients having bilateral presentations. Male to female ratio was 12:28 with an age range of 4–17 years. Eight patients had congenital PFI, five patients acquired PFI through traumatic patella dislocation and twenty-seven patients developed PFI from recurrent dislocations. Structural abnormalities were found in 38(95%) of patients. Patella alta (Caton-Deschamps index >1.2) was identified in 19(47%) patients, genu valgum in 12(30%) patients, increased tibial tubercle-trochlear groove distance(TT-TG>20mm) was present in 9(22.5%) patients and persistent femoral anteversion(> 20 deg) in 7(17%) patients. Eight patients were treated with TTO and MPFL reconstruction, three patients with MPFL reconstruction alone and five patients had guided growth for genu valgum correction. Ten patients are awaiting surgery. No postoperative patients had recurrence of PFI at their latest follow up. PFI is a common problem in the adolescent paediatric population with identifiable structural abnormalities. Correcting structural pathology with surgery leads to predictable and safe outcomes

Background. The importance of total ankle replacement (TAR) implant orientation in the axial plane is poorly understood with major variation in surgical technique of implants on the market. Our aims were to better understand the axial rotational profile of patients undergoing TAR. Methods. In 157 standardised CT Scans of end-stage ankle arthritis patients planning to undergo primary TAR surgery, we measured the relationship between the knee posterior condylar axis, the tibial tuberosity, the transmalleolar axis(TMA) and the tibiotalar angle. The foot position was measured in relation to the TMA with the foot plantigrade. The variation between medial gutter line and the line bisecting both gutters was assessed. Results. The mean external tibial torsion was 34.5±10.3°(11.8–62°). When plantigrade the mean foot position relative to the TMA was 21±10.6°(0.7–38.4°) internally rotated. As external tibial torsion increased, the foot position became more internally rotated relative to the TMA(pearson correlation 0.6;p< 0.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA(pearson correlation −0.4;p< 0.01). The mean difference between the medial gutter line and a line bisecting both gutters was 4.9±2.8°(1.7°-9.4°). More than 51% of patients had a difference greater than 5°. The mean angle between the medial gutter line and a line perpendicular to the TMA was 7.5°±2.6°(2.8°-13.7°). Conclusion. There is a large variation in rotational profile of patients undergoing TAR, particularly between the medial gutter line and the transmalleolar axis. Surgeon designers and implant manufacturers need to develop consistent methods to guide surgeons towards judging appropriate axial rotation of their implanton an individual basis. We recommend careful clinical assessment and CT scanspre-operatively to enable the correct rotation to be determined

Introduction: The mechanobiology and response of bone formation to strain under physiological loading is well established, however investigation into exceedingly soft scaffolds relative to cancellous bone is limited. In this study we designed and 3D printed mechanically-optimised low-stiffness implants, targeting specific strain ranges inducing bone formation and assessed their biological performance in a pre-clinical in vivo load-bearing tibial tuberosity advancement (TTA) model. The TTA model provides an attractive pre-clinical framework to investigate implant osseointegration within an uneven loading environment due to the dominating patellar tendon force. A knee finite element model from ovine CT data was developed to determine physiological target strains from simulated TTA surgery. We 3D printed low-stiffness Ti wedge osteotomy implants with homogeneous stiffness of 0.8 GPa (Ti1), 0.6 GPa (Ti2) and a locally-optimised design with a 0.3 GPa cortex and soft 0.1 GPa core (Ti3), for implantation in a 12-week ovine tibial advancement osteotomy (9mm). We quantitatively assessed bone fusion, bone area, mineral apposition rate and bone formation rate. Optimised Ti3 implants exhibited evenly high strains throughout, despite uneven wedge osteotomy loading. We demonstrated that higher strains above 3.75%, led to greater bone formation. Histomorphometry showed uniform bone ingrowthin optimised Ti3 compared to homogeneous designs (Ti1 and Ti2), and greater bone-implant contact. The greatest bone formation scores were seen in Ti3, followed by Ti2 and Ti1. Results from our study indicate lower stiffness and higher strain ranges than normally achieved in Ti scaffolds stimulate early bone formation. By accounting for loading environments through rational design, implants can be optimised to improve uniform osseointegration. Design and 3D printing of exceedingly soft titanium orthopaedic implants enhance strain induced bone formation and have significant importance in future implant design for knee, hip arthroplasty and treatment of large load-bearing bone defects

Purpose. The literature indicates that the tibial component in total knee arthroplasty (TKA) should be placed in internal rotation not exceeding 18 to the line connecting the geometrical center of the proximal tibia and the middle of the tibial tuberosity. These landmarks may not be easily identifiable intraoperatively. Moreover, an angle of 18 is difficult to measure with the naked eye. Method. The angle at the intersection of lines from the middle of the tibial tuberosity and from its medial border to the tibial geometric center was measured in 50 patients with normal tibia. The geometric center was determined on an axial CT slice at 10mm below the lateral tibial plateau and transposed to a slice at the level of the most prominent part of the tibial tuberosity. Similar measurements were performed in 25 patients after TKA in order to simulate the intra operative appearance of the tibia after making its proximal resection. Results. This angle was found similar (p=0.43) in normal and operated tibiae (mean 20.4, range 15–24 versus 20.7, range 16–25, respectively). In 89.3% of the patients the angle ranged from 17–24. No statistical difference (p=0.55) was found between women and men in both normal (mean 20.7, range 16–25 versus 19.9, range 15–24) and operated tibiae (mean 21.4, range 19–24 versus 20, range 16–25). Conclusion. In 90% of the patients the medial border of the tibial tuberosity is in internal rotation of 1724 to the line connecting its middle to the tibial geometric center. Since this anatomical landmark may be more easily identifiable intraoperatively than the commonly used medial 1/3, this data can and provide surgeons a quantitative reference point. Together with routine intra operative ancillary measurements the rotation of the tibial component can be more accurately determined

INTRODUCTION: The techniques to stabilize the patella can be divided into two groups: the first group seeks to change the direction of the extensor mechanism in order to medialize the extending force vector of the quadriceps muscle, e.g. by a distal medialization of the tibial tuberosity or a proximal realignment; the second seeks to reconstruct the medial patellofemoral ligament (MPFL). The goal of this study was therefore to measure changes in patellofemoral kinematics in the intact, MPFL deficient knee, after medial transfer of the tibial tuberosity, after proximal realignment as well as after reconstruction of the MPFL. METHODS: Eight fresh frozen right knee specimens were mounted in a knee simulator in which isokinetic flexion-extension motions were simulated. Extension cycles were simulated from 120° flexion to full knee extension with an extension moment of 31 Nm. Movement of the patella relative to the femur was measured using an ultrasound based 3D motion analysis system (Zebris, Isny, Germany). During the first test cycles, patellar movement under intact knee conditions were measured, while a constant 100 N laterally oriented force was applied by means of a steel cable attached to the patella. Subsequently, patellar movement was again measured after: transecting the MPL (deficient knee), performing a medialization of the tibial tuberosity, after reconstruction of the transected MPL using a semitendinosus autograft and after proximal realignment. RESULTS: The patella of the intact knee moved along a medial path with a maximum attained position of 8.8 mm at 25° of knee flexion. The patella of the deficient knee moved up to 4.6 mm (p=0.04) in the medial direction at maximal extension at 30° of knee flexion. After medial transfer of the tibial tuberosity patellar movement reached a maximum medial position of 12.8 mm (p=0.04) at 22° of knee flexion with the laterally oriented force. With a reconstructed MPL, the patella attained a maximum medial position 14.8 mm (p=0.04) at 24.0° of knee flexion. Following proximal realignment, the patella moved on a medial, but significant (p=0.03) different path up to 13.8 mm medially at 30° of knee flexion. In addition, following medialization of the tibial tuberosity and proximal realignment, the center of the patella was significantly (p=0.03) more internally rotated (tilted) than the physiologic patella. DISCUSSION: The shape of the movement curves after the stabilizating procedures resulted in a medialization relative to intact and deficient conditions. With the reconstructed medial patellofemoral ligament, the patella moved along the most medially oriented path with physiologic tilting. The results suggest that a semi-tendinous autograft can provide sufficient stabilization to prevent lateral displacement or subluxation with physiologic patellar tilt

Medial transfer of the tibial Tuberosity remains the treatment of choice for skeletally mature patients with patellar malalignment (recurrent dislocation, subluxation with or without patellar tilt). As many patients with patellar malalignment have patellar articular cartilage lesion or patella alta, anteriorisation and distalisation of the tibial tuberosity is advised. Material and Methods: Tibial tuberosity transfer was performed in our center on 80 knees in 66 patients (40 females, 26 males) during the past 13 years (mean age 23 range 15 – 52). One surgeon supervised all the operations. The average follows-up was 6.2 years (one to thirteen years). All patients were examined clinically for the purpose of this study. The Lisholm and Karlsson scoring system were used to evaluate the results. Radiographs of both knees were also taken. Fifteen knees had no dislocation of the patella prior to the operation, seventeen knees had 1 to 10 eleven knees had 10 to 50, ten knees 50 to 100, and twenty-seven knees had more than hundred dislocations of the patella prior to surgery. Ten of these knees had daily dislocations of the patella. All operations were done either by selective epidural anesthesia (only sensory and not motor) or general anesthesia without muscle relaxant using quadriceps muscle stimulation. The mean tibial tuberosity medialisation, anteriorisation and distalisation was 1.4 cm (0–2.5 cm) 0.4cm (0–1.1cm) and 0.87cm (0–1.2cm) respectively. Results: When interviewed by an independent examiner 87% of the patients reported improvement and only 4.3% (3 patients) reported worsening of their condition after the operation. 84% of the patients stated they would have the operation again. All patients had full active range of motion on both knees without extension lag. At the final evaluation visit the Lisholm and Karlsson scores were good and excellent in 72% and 72.5%, 18.8% and 23.5% had fair results and only 8.7% and 4.4% had poor results respectively. The poor results correlated well with the degree of the patella cartilage damage found during surgery, poor selection of patients and extreme ligamentous laxity. There were two complications: one non-union of the tibial tuberosity treated successfully with bone grafting and one non displaced fracture bellow the osteotomy, treated conservatively. Both had excellent results. Conclusion: We conclude that distal patella re-alignment done by tibial tuberosity transfer is a reliable technique for the treatment of patello femoral pain secondary to mal-alignment

Introduction and Objective. The geometry of the proximal tibia and distal femur is intimately linked with the biomechanics of the knee and it is to be considered in total knee arthroplasty (TKA) component positioning. The aim of the present study was to evaluate the proximal tibial torsion in relation to the flexion-extension axis of the knee in healthy and pathological cohort affected by knee osteoarthritis (OA). Materials and Methods. We retrospectively analyzed computed tomography scans of OA knee of 59 patients prior to TKA and non-arthritic knee of 39 patients as control. Posterior condylar angle (PCA), femoral tibial torsion (TEAs-PTC and TEAs-PTT), proximal tibial torsion (PTC-PTT and PCAx-PTC) and distance between tibial tuberosity and the trochlear groove (TT-TG) were measured. Results. No differences were found for gender, age, TG-TT and PCAn angles. Statistically significant differences were found for all the other angles considered. Significant relation was found between Tibial Torsion and TEA-PTT angles, between PCAx-PTC and TEA-PTC, between TEA-PTT and TEA-PTC and between PCAx-PTC and TEA-PTT. All measures, except TG-TT and PCAn angles, showed high validity (AUC > 75%) in detecting OA, with TEA-PTT displaying the highest validity with an AUC of 94.38%. Conclusions. This is the first study to find significant differences in terms of proximal tibia geometry and anatomy between non arthritic and OA knees. It is conceivable that such anatomy could be implicated in the development of OA. Based on our data, the TEAs is a valid reference for correct positioning of tibial component in TKA. Indeed, setting the tibial component parallel to TEAs makes the prosthetic knee more similar to the native non-arthritic knee

Introduction. Tibial tuberosity and trochlear groove (TT-TG) distance has been investigated for the patients with primary patellofemoral subluxation/dislocation. To date, TT-TG distance after TKA has not been evaluated, and the effect of postoperative TT-TG distance on patellar tracking is unknown. The purpose of the current study was to investigate the effect of TT-TG distance and rotational position of the femoral and tibial components on patellar tilt after TKA. Methods. Consecutive 115 knees for the diagnosis of osteoarthritis were included in the current study. TKA was performed using posterior cruciate ligament sacrificed prosthesis. A total of 17 men and 96 women with an average age of 75.3 years were included at the time of the surgery. Computed tomography (CT) was taken after TKA in full extension. Postoperative TT-TG distance was measured as a reference of surgical epicondylar axis (SEA) of the femur. Patellar tilt was defined as the angle of the patellar component relative to SEA. Femoral and tibial component rotation was measured as the angle relative to SEA and tibial antero-posterior (AP) axis. Tibial AP axis was defined as the line connecting medial one-third of the tibial tuberosity and center of medial-lateral width. Pearson correlation coefficients were calculated to determine the correlations between patellar tilt and TT-TG distance and between patellar tilt and femoral and tibial component rotation. Results. TT-TG distance had significant correlation with patellar tilt (Figure 1; r = 0.254, p = 0.006), whereas femoral component rotation (p = 0.092) and tibial component rotation (p = 0.062) were not correlated with patellar tilt. Concerning the effect on TT-TG distance, femoral component rotation (r = 0.248, p = 0.008) and tibial component rotation (r = −0.567, p < 0.001) were correlated with TT-TG distance. Conclusion. The current study investigated the effect of TT-TG distance on patellar tilt with postoperative CT scan. Greater TT-TG distance resulted in more patellar tilt, which might have negative effects on patellar tracking. In previous clinical studies, femoral component and tibial component rotation affected patellar maltracking. In the current study, however, component rotation itself did not affect patellar tilt. Postoperative TT-TG distance includes information of rotational and medial-lateral positioning of the femoral and tibial components, and can be a useful indicator to predict patellar maltracking after TKA. For any figures or tables, please contact authors directly

Patella recurrent dislocation and patellofemoral pain syndrome instability many young people and especially athletes. In the present study we present the results of the extension mechanism realignment through the Fulkerson oblique osteotomy of the tibial tuberosity and soft tissue balancing. During the last two years 10 patients (7 men, 3 women, mean age 29.3/ range 20–39) were treated operatively for recurrent dislocation of the patella using the Fulkerson procedure. All patients underwent knee arthroscopy for the treatment of potential chondral damage or loose bodies and for lateral retinacular release. After that we performed oblique tibial tuberosity osteotomy, medialization and internal fixation with 2 cortical screws. This oblique osteotomy allows also the anteriorization of tibial tuberosity as we move it medially. In addition, we performed medial placation. All the patients used functional knee brace locked to 0° right after the operation and with gradual ROM increase till the 8th p.o. week. The patients had no initial or long term complication. During their last follow up examination had a painless knee with full ROM and marked improvement of the patella tracking. The mean Lysholm score was 90.5. No patella dislocation was referred. Our findings show that the Fulkerson osteotomy procedure, with an additional intervention on the lateral and medial patella retinacular, is an excellent option for the treatment of recurrent patella instability and relief of the patellofemoral pain

Improper rotation of the femoral and tibial components in total knee arthroplasty may leads to various patellofemoral(PF) complications. As for the femoral component, alignment it to the epicondylar axis of the femur has been a widely used method. The tibial component traditionally has been aligned to the medial 1/3 of the tibial tuberosity. However, there is no consensus concerning how to determine the tibial component rotation. The purpose of the current study is to evaluate the influence rotational alignment of tibial component upon PF joint. We divided the cases to two groups. Group A: 41cases 50knees (OA 34cases, RA16cases). The average age was 69.5(35~84). Group B: 30cases 30knees (OA 25 cases, RA 5cases). The average age was 72.6(59~86). In group A, the anteropostrior (AP) axis was defined as the line connecting the medial 1/3 of tibial tuberosity and the center of PCL attachment. In group B, the line connecting the medial edge of patellar tendon attachment and the center of PCL attachment was defined as AP axis. We measured the PF alignment on postoperative X-rays. Tangential radiographs were used to measure the amount of patellar tilt (tilting angle: TA), subluxation and patellar lateral shift (LS). Group A showed that tilting angle 14±4°, lateral shift 0.3±0. These values of group B were 12±5°,0.2±0.1, respectively. In rotation of tibial component, Insall reported that the landmark in front of tibia was medial 1/3 tibial tuberosity. Akagi et,, al reported that the landmark was midial edge of patellar tendon attachment. This study indicated that the latter had better alignment in patellofemoral joint

Introduction. Following total knee arthroplasty (TKA), some patients show patella baja. It is possible that patella baja after posterior stabilized (PS)-type TKA causes the patellar clunk syndrome and limitation of flexion. The purpose of this study was to examine patellar height before and after PS-type TKA and identify the factors related to the change in patellar height. Methods. Lateral X-ray films were taken at 90 degrees flexion before and after TKA using fluoroscopy in 87 patients (95 knees) (Fig. 1a, b). The components and surgical technique for TKA were Scorpio NRG (Stryker) and the modified gap control technique, respectively. The Insall-Salvati ratio (ISR) and the Labelle-Laurin method (LL) were measured as parameters of patellar height (Fig. 1c, d). Posterior condylar offset (PCO) (Fig. 1e), the distance from the anterior femoral line to the tibial tuberosity (TA), and the distance from the tibial tuberosity to the posterior condyle of the femur [TP; {TA-F (the length of the femoral condyle)}] (Fig. 1f) were examined as parameters that could be associated with the change in patellar height. All parameters were divided by patellar length to compensate for the expansion rate in each photograph. The mean LL/P, PCO/P, TA/P, and TP/P before TKA were set at 100%. Results. The mean ISR was not significantly different before and after TKA, but the mean LL before TKA was significantly decreased after TKA (−231%). The mean PCO/P of the femur were not significantly different after TKA. The mean length of TA/P and TP/P increased significantly after TKA (TA/P: 103%, TP/P: 110%). Sex, patellar replacement, lateral release of the patella and MCL release were not significantly related with the difference in LL after TKA. The difference in LL after TKA was significantly correlated with the distance from the tibial tuberosity to the posterior condyle of the femur (R. 2. = 0.44, Fig. 2). The difference in LL after TKA was not correlated with flexion motion after TKA. The patellar clunk syndrome after TKA was not seen in any of the cases. Discussion. The patellar height defined by the length from the anterior femoral line to the top of the patella was lower after PS-type TKA than before TKA, although the ISR did not change after TKA. The changing patellar height correlated with the difference in the distance from the tibial tubercle to the posterior condyle of the femur before and after TKA. Since the PCO was not significantly changed after TKA, it appears that the length of proximal tibia was prolonged. The prolonged proximal tibia and the distal positioning of the patella after TKA might be due to the reduced pre-operative instability of the knee and the inferior traction of the patellar tendon and quadriceps muscle. In conclusion, the patellar height after PS-type TKA decreased after surgery. The change in patellar height was due to the length of proximal tibia

Purpose: To present the results of the tibial tuberosity osteotomy as part of the surgical approach for total knee replacement. Material and Methods: Tibial tuberosity osteotomy was performed during TKR for better exposure in 19 knees corresponding to 19m patients (9 male, 10 female), with average age 76 years (68–80). Four of the procedures were revisions. Fifteen were primary TKR, ten of which had been subjected to high tibial osteotomy previously. The rest þve patients had excessive valgus deformity (over 20 degrees), and they were approached through a lateral parapatelar incision. In two cases screws only were used to stabilize the osteotomised tubercle, and wire loops in the rest of them. Patients were instructed for partial weight bearing for six weeks postoperatively. Results: All osteotomies united in less than four months. In three cases (including the two with only screw þxation), proximal migration of the tuberosity was noted, but less than 2cm. No skin problems were encountered. Three patients,(22%), complained for anterior knee pain. Preoperative mean range of movement was 75 degrees, and improved to 90 degrees postoperatively. Average blood loss was 850 cc. Conclusions: The tibial tuberosity osteotomy offers excellent exposure in the revision and difþcult primary TKR, but it lengthens the operative time, and the blood loss is higher

Purpose of the study: Injury to the infrapatellar branches of the medial saphenous vein are incriminated in disorder of the anterior aspect of the knee after bone-tendon-bone ligamentoplasty procedures. We have demonstrated in an anatomic study the usefulness of a minimal two-way approach for harvesting the patellar transplant in order to preserve the nerve branches. The purpose of this clinical study was to evaluate the feasibility of this method and its impact on the sensitivity of the anterior aspect of the knee after ligamentoplasty in comparison with the usual harvesting technique. Material and methods: This non-randomized prospective controlled contemporary study included 47 consecutive patients. The graft was harvested via two vertical incisions, one on the apex of the patella, the other on the eminence of the anterior tibial tuberosity. After harvesting the patellar splint, discision of the patellar tendon fibers was performed subcutaneously to the tibial tuberosity. Before removing the graft via the tibial incision with a forceps inserted via the inferior incision without injuring the peritendon. A tibial piece was then harvested. The ligamentoplasty was performed as usual using two anterolateral and anteromedial arthroscopic portals. The tibial tunnel was drilled first on the tibial tuberosity. These 47 knees were compared with 34 knees where the conventional approach was used (control group). We assess: harvesting time, width of the tendon transplant, quality of the graft, requirement to convert to conventional harvesting technique. Patients were reviewed at six weeks, three months and six months to assess anterior pain, dysesthesia, surface area of hypo or anesthesia and at six months kneeling problem. Results: Conversion was not necessary for any of the knees. Mean harvesting time was 17 minutes (control group ten minutes). A good quality graft was obtained in all cases. Thirty-five patients were reviewed at six months. No sensorial disorders were noted in 18 patients. Sensorial disorders were noted in 17 patients (permanent hypoesthesia in the control group). None of the patients presented anesthesia. The mean surface area presenting a sensorial disorder was 13.6 cm. 2. at six weeks (37.8 cm. 2. in the control group) and 8.85 cm. 2. at six months (23.4 cm. 2. in the control group). Mean gain compared with the control group was 62%. There were two cases of anterior pain at six months and no case of dysesthesia. Sixteen patients could kneel normally (none in the control group); kneeling was not possible in one patient. Discussion: The infrapatellar branches of the medial saphenous nerve are often injured when harvesting a bone-tendon-bone graft for ligamentoplasty. Anterior disorders would in part be correlated with the degree of sensorial impairment on the anterior aspect of the knee. The subcutaneous harvesting technique presented here with two minimal incisions appears to be an attractive alternative. Conclusion: Our study confirmed the feasibility of this harvesting technique which significantly reduces the surface area of sensorial disorders and avoids most kneeling problems

Introduction. Tendon injuries remain challenging, secondary healing and prolonged immobilisation result in suboptimal outcome. Previous study by our group showed that demineralised bone matrix (DBM) can result in faster healing of a tendon enthesis. The aim of this study is to test different ways augmenting tendon with DBM to enhance tendon repair and regeneration. Methods. DBM strips were prepared from tibias of mature ewes. Patella, patellar tendon and tibias were dissected and the distal 1 cm of the patellar tendon was excised. 4 models were designed;. Model-1, DBM strip was used to bridge the gap between the tendon and the tibial tuberosity. The DBM strip was stitched to the tendon using one bone anchor. Model-2, similar to model 1 with the use of 2 anchors. Model-3, similar to model 2, construct was off loaded by continuous thread looped twice through bony tunnels sited in the patella and in the tibial tuberosity. Model-4, similar to model 3 with 3 threads as off loading loop. All models were tested for pullout force and mode of failure. Results. The median failure force for model-1 (N=5) was 250N while for model-2 (N=5) was 290N. In model-3 and model-4 failure of the off loading loop was used as end point, 6 samples were tested in each model. Median failure force of model-3 was 767N and for model-4 was 934N. There was no statistical significance between model-1 and model-2 (p=0.249), however statistical significance was found between other models (p=< 0.006). Discussion. A study published in 1996 proved that cortical DBM can be used as ACL graft with evidence of ligamentisation. DBM provides a biologic scaffold with potential for use as ligament and tendon replacement. Our study shows that a tendon rupture can be augmented with DBM giving intial appropriate mechanical strength suitable for in-vivo use

The purpose of this study was to investigate the bone anatomy in determining the rotational alignment in total knee arthroplasty (TKA) using CT scan. Axial CT images of eighty-four varus osteoarthritic knees undergoing TKA were analysed. On the images of the distal femur and the proximal tibia, base line for anterior-posterior axis of each component was drawn based on the epicondylar axis for the femur and medial one-third of the tibial tuberosity for the tibia. Angle between these two lines was analysed as the rotational mismatch between the components when they were determined based on the anatomical landmark of each bone. Thirty-eight knees (45%) showed more than 5-degree mismatch and seven knees (8.3%) showed the mismatch more than 10-degree. There was a tendency to put the tibial component in external rotation relative to the femoral component when they were aligned to medial one-third of the tibial tuberosity. The results have indicated that the landmark of each bone was the intrinsic cause of the rotational mismatch between the components. The surgeons performing TKA surgery should aware of this fact and should align the tibial component in a compromised position, if necessary, to have overall satisfactory clinical outcome

We describe a previously unpublished and possibly unrecognised association between injuries to the posterior cruciate ligament and Osgood-Schlatter disease. Over a two-year period the authors have treated thirty patients with isolated or combined injuries to the posterior cruciate ligament, confirmed with MR1 or examination under anaesthetic/arthroscopy. Five of these had previously suffered from Osgood-Schlatter disease as adolescents, leaving them with prominent tibial tuberosities. We feel there may be a significant association between these two conditions and the importance of this association is twofold: – firstly, at the time of injury the prominent tibial tuberosity impacts first and results in increased posterior translation of the tibia rendering the posterior cruciate ligament more prone to injury – secondly, during examination of the injured knee, the prominence of the tibial tubercle may make a posterior sag sign less obvious thus obscuring the diagnosis unless one is diligent. We believe that patients who have previously suffered with Osgood-Schlatter disease are vulnerable to posterior cruciate ligament injury and this should be borne in mind whilst examining them following knee injuries

We performed an advancement and medial transfer of the tibial tuberosity based on Fulkerson's principle to treat intractable anterior knee pain associated with patellofemoral maltracking diagnosed by dynamic MRI. Between January 1998 and July 2000 twenty-two patients had 28 knees operated for anterior knee pain. There were 4 men and 18 women with a mean age of 28 years (range 18-41). Indications for surgery were [a] failure to improve after six months of physiotherapy and [b] patellofemoral maltracking evident in dynamic MRI. Mean follow-up was for 37 months (23 – 42). Knee instability score modified by Fulkerson was employed for objective and subjective assessment. Objectively 22 (79%) knees achieved good to excellent results. Four knees (14%) had fair, and two (7%) had poor results. Excellent and very good results were seen in 20 knees. These patients were a younger age group (mean age 21 years) and had minimal degeneration (grade I-II) of the patellofemoral joints. Two patients achieved good results. One of them had moderate (grade III) and one minimal (II) arthritis. Three knees with fair results had advanced (grade IV or V) and one had moderate (grade III) arthritis. Out of two patients who had a poor result, one had advanced degeneration (grade V) that later required a patellofemoral joint resurfacing. The other was a 24 year old woman with grade II changes. She was treated by the pain therapy team. Anterior displacement of the tuberosity in the presented study was kept to 5 mm to avoid the possible complications of wound break down. The overall length and depth of the osteotomy was also reduced to minimise risk of fracture and commence early mobilisation. Based on our results there is a strong case of justification for Anteromedialisation of tibial tuberosity using a smaller length of osteotomy and lesser degree of anteriorisation in carefully selected patients with Patellofemoral arthralgia associated with maltracking patella

Purpose of the study: The form of the anterior tibial tuberosity (ATT) has not been described in anatomy studies. Insertion of the patellar tendon can, by its form, modify the lever arm of the extensor system and induce pathological conditions having an impact on the form of the apex or tip of the patella. The purpose of this work was to analyse the types of tibial tuberosities observed on the radiographs of 50 patients. Material and method: Fifty patients were included in this prospective study. The form of the ATT was defined by two angles. These angles were measured on the strictly lateral x-ray. The ATT-shaft angle (ATT-d) was defined by the intersection between the anatomic axis of the tibial diaphysis and the anterior cortical of the ATT which corresponds to the insertion of the patellar tendon. The ATT-metaphysis angle (ATT-M) was defined by the angle between the tangents of the anterior metaphyseal cortical and the anterior cortical of the ATT. The height of the patella was also measured as described by Caton and Deschamps. The form of the patella on the lateral was described according to the Grelsamer criteria, and its form on the 30° axial view according to the Wiberg classification. The presence of trochelar dyplasia was determined using the Dejour method. The statistical analysis accepted p < 0.05 as significant. The coefficients of correlation R were calculated with a ½ log covariance matrix [1+R]/[1−R]. Results: The form of the ATT was given by the minimal value between the ATT-D and the ATT-M. This angle measurement revealed major variation. Three types of ATT were defined: type I 0≤ATT-M≤15 and ATT-D≤5, type II 15 < ATT-M < 20 and 5 < ATT-D < 10 and type III 20≤ATT-M 10≤ATT-D. There was an obvious correlation with the form of the patellar apex. The type III form of the patella was always associated with a type I ATT; there was a significantly association between patella type I and ATT type II and patella type III and ATT type I. There was no correlation with the height of the patella or with the form of the trochlea or the patella. Conclusion: The form of the ATT is quantifiable and becomes a parameter to consider in the analysis of patellofemoral osteoarthritis