Discipline-specific Torque-Velocity Profiles and Musculotendinous Morphology in Athletes.

OBJECTIVES: The aim of this study was to compare torque-velocity profiles, muscle architecture, tendon dimensions, and bilateral-symmetry between competitive cyclists (CY), competitive runners (RN), ice-hockey players (IH), basketball players (BP), and physically-active individuals (CN) (n=10 for each group). METHODS: Vastus lateralis (VL) muscle and patellar tendon (PT) structures were determined with B-mode ultrasonography, and maximal knee extensor isokinetic torque was assessed at three different velocities. RESULTS: Optimal torque and velocity were lower in runners than CY, BP and IH (p<0.05). Maximal power was similar between the athlete groups but greater than CN (p<0.05). Furthermore, RN and BP reached their peak-torque at longer muscle lengths compared to IH and CY (p<0.05). RN had the lowest VL muscle thickness and the greatest fascicle length, while CY had the greatest pennation angle (p<0.05). CY had the greatest PT thickness, particularly at the proximal and medial sites, while BP at the distal point (p<0.05), with similar trends observed for PT cross-sectional-area. CONCLUSIONS: Our findings show that even if power generating capacity is similar between athletic disciplines, there are discipline-specific muscle adaptations, where particularly runners appear to have muscles adapted for speed rather than torque development, while in cyclists, velocity is sacrificed for torque development.

Ultrashort Echo Time Quantitative Magnetic Resonance Imaging of the Cruciate Ligaments in Normal Beagles.

OBJECTIVE: The aim of this study was to provide normative ultrashort echo time magnetic resonance imaging (UTE MRI) data of the patellar ligament (PL), cranial cruciate ligament (CrCL) and caudal cruciate ligament (CdCL) in non-lame Beagles. STUDY DESIGN: Eight stifles from four subjects obtained immediately postmortem were imaged using UTE MRI in the true sagittal plane. Regions of interest were drawn manually and the total (T2*), short T2* (T2*S) and long T2* (T2*L) values of the signal decay were calculated to evaluate the bound and free water components of the tendon. The T2*S, T2*L and T2* values were compared between the PL, CrCL and CdCL RESULTS: The mean and standard deviation of T2*S, T2*L and T2* were as follows: 0.54 ± 0.13, 4.65 ± 1.08 and 8.35 ± 0.82 ms for the PL; 0.46 ± 0.14, 5.99 ± 0.52 and 8.88 ± 0.4 ms for the CrCL and 0.41 ± 0.13, 7.06 ± 0.57 and 9.26 ± 0.18 ms for the CdCL. Significant differences were found between the T2*L component of the PL and each CrCL/CdCL and a smaller difference was noted between the T2*L of the CrCL and CdCL (p = 0.05). No difference of the T2*S value was found between any of the ligaments. CONCLUSION: Establishing normative UTE data of the canine stifle is valuable for comparison in future studies in which normal and damaged ligaments may be evaluated, particularly in those affected limbs in which no instability is identified on physical examination in which normal and damaged ligaments may be evaluated.

Specific collagen peptides increase adaptions of patellar tendon morphology following 14-weeks of high-load resistance training: A randomized-controlled trial.

ABSTRACTThe purpose of this study was to investigate the effect of a supplementation with specific collagen peptides (SCP) combined with resistance training (RT) on changes in structural properties of the patellar tendon. Furthermore, tendon stiffness as well as maximal voluntary knee extension strength and cross-sectional area (CSA) of the rectus femoris muscle were assessed. In a randomized, placebo-controlled study, 50 healthy, moderately active male participants completed a 14-week resistance training program with three weekly sessions (70-85% of 1 repetition maximum [1RM]) for the knee extensors. While the SCP group received 5g of specific collagen peptides daily, the other group received the same amount of a placebo (PLA) supplement. The SCP supplementation led to a significant greater (p < 0.05) increase in patellar tendon CSA compared with the PLA group at 60% and 70% of the patellar tendon length starting from the proximal insertion. Both groups increased tendon stiffness (p < 0.01), muscle CSA (p < 0.05) and muscular strength (p < 0.001) throughout the intervention without significant differences between the groups. The current study shows that in healthy, moderately active men, supplementation of SCP in combination with RT leads to greater increase in patellar tendon CSA than RT alone. Since underlying mechanisms of tendon hypertrophy are currently unknown, further studies should investigate potential mechanisms causing the increased morphology adaptions following SCP supplementation.Trial registration: German Clinical Trials Register identifier: DRKS00029244..

A daily supplementation of 5 g of specific collagen peptides during 14 weeks of high-load resistance training increase patellar tendon hypertrophy compared to the same training regimen and placebo.The resistance training-induced CSA increase, which was most pronounced on proximal and medial patellar tendon sites, is uniformly potentiated along the entire tendon length by supplementation.Patellar tendon stiffness, CSA of the rectus femoris muscle and maximal voluntary knee extension strength increase due to training independently from supplementation.Increased tendon CSA as a result of a stimulating effect of the supplementation with specific collagen peptides on collagen synthesis might be able to decrease tendon stress and support tendon healing.

The equine patellar ligaments and the infrapatellar fat pad - a microanatomical study.

BACKGROUND: Interpretation of patellar ligament (PL) ultrasonography may be difficult, as hypoechoic or heterogenous echogenicity are common findings. Verifying suspected disease of equine PLs by histopathology is also problematic as descriptions of normal PL vascularity and histology are scarce. The current study describes the PL and infrapatellar fat pad (IFP) vascular pattern from computed tomography scans of barium perfused normal equine specimens (n = 8; age 10 days to 18 years), as well as routine histology to serve as a reference for future investigations into PL pathology and IFP disease. RESULTS: The PLs received a bipolar blood supply. Vascular architecture consisted of numerous distinct longitudinal vessels with several horizontal connections, which branched into extensive latticeworks of smaller vessels throughout the ligaments. Several vascular connections between the PLs and the IFP were identified. One distinct longitudinal vessel was seen entering each of the IFP lobes at the distocranial aspect, branching extensively into lobar vascular networks which anastomosed by several horizontal branches at the mid portion of the IFP where the two lobes merge. Histologically, there were large variations in PL interfascicular endotenon thickness, vascularity and fatty infiltration; these parameters increased with age for the intermediate and medial PL. Areas of metaplastic tenocytes / chondroid metaplasia were identified in all investigated adult medial PLs; in 2/7 in the intermediate PL and in 4/7 in the lateral PL. The adult IFP consisted of white unilocular adipose tissue, organized in lobules separated by thin connective tissue septa increasing in thickness towards the periphery and the distocentral aspect. CONCLUSIONS: The equine PLs and IFP are highly vascularized structures with ample vascular connections suggestive of crosstalk. This, together with the large variation in PL endotenon thickness, vascularity and fatty infiltration, should be taken into consideration when assessing potential PL histopathology as these changes increase with age and are found in horses without clinical signs of stifle disease. Metaplastic tenocytes / chondroid metaplasia should be considered a normal finding throughout the medial PL and is not age dependent. The role of the equine IFP in stifle disease has yet to be elucidated.

Quantifying the Relationship Between the Medial Quadriceps Tendon-Femoral Ligament and Patellar Borders: A Pediatric Cadaveric Study.

BACKGROUND: The medial patellofemoral complex (MPFC) is a structure composed of the medial quadriceps tendon-femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The pediatric MPFL anatomy has been well described, but the precise anatomy of the MQTFL has only recently been described and studied in skeletally immature patients. PURPOSE: To describe the anatomic relationship between the MQTFL and its insertion on the quadriceps tendon and patella in pediatric specimens. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 22 pediatric cadaveric knee specimens were dissected to analyze attachment of the MQTFL to the quadriceps tendon and patella. Dissection was facilitated using lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate MQTFL fibers from its undersurface. RESULTS: The mean specimen age was 7.4 years. Specimens were divided based on age into a younger cohort (1-2 years), middle cohort (4-8 years), and older cohort (9-12 years). The quadriceps tendon attachment (QTA) of the MQTFL proximal to the patella extended a median of 5.0 mm in the younger cohort, 11.4 mm in the middle cohort, and 12.0 mm in the older cohort, with significant differences found between the younger and middle cohorts (P < .047) and the younger and older cohorts (P < .001). The QTA as a percentage of patellar articular height averaged 44.4% across all specimens. The vertical height of the patella measured a median of 14.0 mm, 22.3 mm, and 27.3 mm in the younger, middle, and older cohorts, respectively. CONCLUSION: This study expands on the recently described anatomy of the pediatric MPFC to quantify the anatomic relationship between the MQTFL attachment to the quadriceps tendon and patella in a more clinically relevant cohort of donor specimens. CLINICAL RELEVANCE: As access to pediatric cadaveric tissue is extremely limited, a better understanding of MPFC and MQTFL anatomy will support surgeons in preoperative planning and intraoperative considerations for their approach to MQTFL and MPFL reconstruction. This may facilitate improved anatomic surgical stabilization of the patellofemoral joint in pediatric patients.

The relationship between additional heads of the quadriceps femoris, the vasti muscles, and the patellar ligament.

INTRODUCTION: The quadriceps femoris consists of four muscles: the rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis. However, the effect of additional quadriceps femoris heads on the vasti muscles and patellar ligaments is unknown. The aims of the present study are to determine the relationship between additional quadriceps femoris heads and the vasti muscles and patellar ligaments and to review the morphology of the vastus lateralis, vastus medialis, and vastus intermedius. MATERIALS AND METHODS: One hundred and six lower limbs (34 male and 19 female cadavers) fixed in 10% formalin were examined. RESULTS: On all lower extremities, the vastus lateralis consisted of superficial, intermediate, and deep layers. The vastus medialis, on the other hand, consisted of only the longus and obliquus layers. The quadriceps head had one or more supplementary heads in 106 dissected limbs from 68 cadavers (64.1%). The distal portion of the patella was wider in lower limbs without supplementary heads than in type IA but narrower than in type IIIA. In general, the distal portion of the patella was narrower in specimens with a supplementary head than in those without (19.03 SD 3.18 mm vs. 20.58 SD 2.95 mm, p = 0.03817). Other patellar ligament dimensions did not differ significantly. CONCLUSION: The quadriceps femoris muscle is characterized by high morphological variability. Occurrence of extra heads is at the level of 64.1%. The vastus lateralis consists of three parts (superficial, intermediate, and deep), and vastus medialis consists of two (longus and oblique).

Impact of plantaris ligamentous tendon.

There are countless morphological variations among the muscles, tendons, ligaments, arteries, veins and nerves of the human body, many of which remain undescribed. Anatomical structures are also subject to evolution, many disappearing and others continually emerging. The main goal of this pilot study was to describe a previously undetected anatomical structure, the plantaris ligamentous tendon, and to determine its frequency and histology. Twenty-two lower limbs from 11 adult cadavers (11 left, and 11 right) fixed in 10% formalin were examined. The mean age of the cadavers at death was 60.1 years (range 38-85). The group comprised six women and five men from a Central European population. All anatomical dissections of the leg and foot area accorded with the pre-established protocol. Among the 22 lower limbs, the PLT was present in 16 (72.7%) and absent in six (27.3%). It originated as a strong fan-shaped ligamentous tendon from the superior part of the plantaris muscle, the posterior surface of the femur and the lateral aspect of the knee joint capsule. It inserted to the ilio-tibial band. Histologically, a tendon and ligament were observed extending parallel to each other. A new anatomical structure has been found, for which the name plantaris ligamentous tendon is proposed. It occurs around the popliteal region between the plantaris muscle, the posterior surface of the femur, and the ilio-tibial band.

Can Achilles and patellar tendon structures predict musculoskeletal injuries in combat soldiers?

Aiming to investigate whether Achilles tendon (AT) structure and patellar tendon (PT) structure are risk factors for musculoskeletal injuries in combat soldiers, 168 participants were recruited from an infantry commander's course. The AT and PT were examined pre-course using UTC to capture the structure of four echo-type fibers (I-IV). All injuries were assessed by military physicians pre-course and throughout the 14-week course. Soldiers who were injured during the course had a significantly higher pre-course prevalence of AT and PT echo-type III and echo-type IV compared to soldiers that were not injured during the course. Variables that were found to be associated with injured/non-injured participants were echo-type III + IV of the PT (OR = 1.44, 95% CI = 1.24-1.68) and echo-type III of the AT (OR = 1.69, 95% CI = 1.35-2.12). ROC analyses showed that the best model, exhibiting both high sensitivity and low specificity, was that participants with PT echo-type III + IV > 10% or AT echo-type III >8.5% had the highest risk of being injured during the course. In conclusions, the tendon structure at the beginning of high-intensity activity or physical training program might be a risk factor for subsequent injury during the course. Soldiers and high-level athletes should be aware of the cutoff points for fiber types in tendon structure that might put them at high risk for future injury. At-risk soldiers/athletes should be provided with an intervention program before they start their training program, with the aim of improving the tendon structure and preventing subsequent injury.

Relationship of the Medial Patellofemoral Ligament Origin on the Distal Femur to the Distal Femoral Physis: A Systematic Review.

BACKGROUND: The relationship between the medial patellofemoral ligament (MPFL) and the distal femoral physis has been reported in multiple studies. PURPOSE: To determine the distance from the MPFL central origin on the distal femur to the medial distal femoral physis in skeletally immature participants. STUDY DESIGN: Systematic review. METHODS: A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Multiple databases were searched for studies investigating the anatomic origin of the MPFL on the distal femur and its relationship to the medial distal femoral physis in skeletally immature participants. Study methodological quality was analyzed with the Anatomical Quality Assessment tool, with studies categorized as low risk, high risk, or unclear risk of bias. Continuous variable data were reported as mean ± SD. Categorical variable data were reported as frequency with percentage. RESULTS: Seven articles were analyzed (298 femurs, 53.7% male patients; mean age, 11.7 ± 3.4 years). There was low risk of bias based on the Anatomical Quality Assessment tool. The distance from the MPFL origin to the distal femoral physis ranged from 3.7 mm proximal to the physis to 10.0 mm distal to the physis in individual studies. Six of 7 studies reported that the MPFL origin on the distal femur lies distal to the medial distal femoral physis in the majority of specimens. The MPFL originated distal to the medial distal femoral physis in 92.8% of participants at a mean distance of 6.9 ± 2.4 mm. CONCLUSION: The medial patellofemoral ligament originates distal to the medial distal femoral physis in the majority of cases at a mean proximal-to-distal distance of 7 mm distal to the physis. However, this is variable in the literature owing to study design and patient age and sex.

Femoral Origin Anatomy of the Medial Patellofemoral Complex: Implications for Reconstruction.

PURPOSE: To report the shape and orientation of the medial patellofemoral complex (MPFC) footprint on the medial femur and describe the difference between the proximal (medial quadriceps tendon femoral ligament, MQTFL) and distal (medial patellofemoral ligament, MPFL) fibers. METHODS: In 20 cadaveric knees, the MPFC footprint on the medial femur was exposed. Images of the medial femur were analyzed using ImageJ software. The length and width of the MPFC footprint were described to the nearest 0.1 mm; the angle of its long axis was described relative to the axis of the femoral shaft (0.1°). The footprint's most proximal and distal margins were described in relation to the adductor tubercle and medial epicondyle. The differences between each were compared using paired t tests. RESULTS: 17 knees from 10 cadavers were included in this study. The MPFC footprint had a length of 11.7 ± 1.8 mm and a width of 1.7 ± 0.4 mm. The long axis of the footprint was at an angle 14.6° ± 16.6° anterior to the axis of the femoral shaft. The most proximal (MQTFL) fibers originated 7.4 ± 3.8 mm anterior and 1.8 ± 4.7 mm distal to the adductor tubercle and 4.1 ± 2.9 mm posterior and 8.4 ± 5.6 mm proximal to the medial epicondyle. The most distal (MPFL) fibers originated 4.9 ± 4.2 mm anterior and 12.7 ± 4.3 mm distal to the adductor tubercle, as well as 7.1 ± 2.4 mm posterior and 0.5 ± 5.6 mm distal to the medial epicondyle. The distal margin of the femoral MPFC footprint was 10.9 ± 1.7 mm distal (p < .001) and 2.6 ± 3.2 mm more posterior (p = .005) than the proximal margin. CONCLUSIONS: The femoral footprint of the MPFC has a length almost 7 times greater than its width, with the distal margin being 10.9 mm distal and 2.6 mm posterior to the proximal margin. CLINICAL RELEVANCE: This differential anatomy within the femoral origin suggests that MPFL and MQTFL reconstruction may require separate positions of femoral fixation to recreate the anatomy of these fibers.

Tibiofemoral rotation alignment in the normal knee joints among Chinese adults: a CT analysis.

BACKGROUND: Consensus on tibial rotation in total knee arthroplasty (TKA) remains controversial. The present study aimed to investigate the closest anatomical reference to surgical epicondylar axis (SEA) among 10 tibial markers in Chinese adults. METHODS: This study included examination of 122 normal lower extremities. Briefly, 10 axes were drawn on the axial sections: transverse axis of tibia (TAT), axis of medial edge of patellar tendon (MEPT), axis of medial 1/3 of patellar tendon attachment (M1/3), Akagi line, Insall line, axis of medial border of tibial tubercle (MBTT), and axis of anterior border of the tibia 1-4 (ATC1-4). The mean angles between TAT and SEA and that between other axes and the line perpendicular to SEA were measured. Pairwise differences among the 10 tibial axes were examined by applying one-way analysis of variance (ANOVA) and paired t-test. RESULTS: In all the knees, the mean angles of M1/3, Akagi line, Insall line, MBTT, ATC1, ATC2, ATC3, and ATC4 axes were compared to the line perpendicular to the projected SEA and found to be 10.2 ± 5.1°, 1.4 ± 5.0°, 11.9 ± 5.4°, 3.6 ± 4.8°, 12.0 ± 6.9°, 7.2 ± 8.6°, 7.1 ± 10.4°, and 6.6 ± 13.5° external rotation, respectively, and the MEPT axis was 1.6 ± 4.5° internal rotation. The mean angle for TAT was 4.1 ± 5.3° external rotation. The M1/3 and Insall line were significantly more externally rotated than Akagi line, MEPT, MBTT, TAT, ATC2, ATC3, and ATC4 axes. No significant differences were noted between the TAT axis and the MBTT axis and among the ATC2, ATC3, and ATC4 axes. CONCLUSION: The Akagi line, MBTT, and TAT showed good consistency with SEA in the axial femorotibial alignment with knee in extension. The middle segment of the anterior tibial crest also demonstrated good alignment consistency with SEA for the axial femorotibial alignment. Hence, these markers can be used as reliable references for rotational alignment of the tibial component in TKA.

Sonographic Measurement of the Patellar Tendon Should Predict Autograft Bone Patellar Tendon Bone (BPTB) Size: Comparison of Anatomical and Clinical Findings.

The use of BPTB autograft is frequently used in ACL reconstruction, however, the risk of potential failure in patients with an anatomically unfavorable patellar tendon may predispose to reconstruction failure. Anatomical study of the extensor apparatus of the knee can provide knowledge about the best option obtain the graft and perform a better preoperative planning. Musculoskeletal ultrasound is a simple, reproducible, affordable technique that could be valid for patellar tendon evaluation. The objective of this study is to evaluate the reproducibility of the patellar tendon measurements by ultrasound and compare them with anatomical measurements, both in cadaver and patients undergoing ACLR. The study consists of two phases; first anatomical study in cadaver. The ultrasound measurement was performed by determining the length, width and thickness of the patellar tendon, both by ultrasound and anatomical dissection. The second phase is a cohort of 42 patients pending surgical ACLR. Previous ultrasound and intraoperative measurements were obtained. Regarding the anatomical study, statistical analysis did not show any differences comparing the measurements in length (p = ns) and thickness (p = ns) of the patellar tendon, although differences were obtained when comparing the results obtained for the width of the tendon after the ultrasound and anatomical measurement (p < 0.001). Same results were obtained in second phase of the study. The reproducibility of ultrasound measurements of the PT is comparable to intraoperatively measurements (without width measurement). These findings can be useful for preoperative planning in the reconstruction of ACL with BPTB Graft and to assess technical modifications prior to surgery.

The Ribbon-shaped Femoral Footprint of the Medial Patellofemoral Ligament: Implications for Reconstruction.

The medial patellofemoral ligament (MPFL) is the primary static stabilizer to lateral translation of the patella and serves as part of the medial patellar soft tissue restraints. Because of the sensitivity of MPFL graft function after reconstruction to the position of the femoral tunnel, many studies have aimed to identify the exact point of the femoral origin, as well as defining techniques to confirm this position intraoperatively. We describe the ribbon-shaped footprint of the MPFL on the medial femur and the associated difficulty in identifying the origin as a single "point." Varying isometry and biomechanical functions have been shown to exist within the most proximal and most distal fibers, suggesting the function of the MPFL may not be fully recreated with a tubular graft in a round tunnel. We review the anatomical descriptions of the elongated femoral footprint of the MPFL and describe our surgical technique to recreate this.

Identifying the optimal inlet for antegrade tibial intramedullary nailing via magnetic resonance imaging.

INTRODUCTION: Tibial shaft fractures treated with antegrade rigid tibial intramedullary nailing has been supported worldwide. However, the optimal inlet for nailing is still controversial. Practically, varied inlets may significantly affect the tibial alignment. This retrospective study intended to utilize magnetic resonance imaging (MRI) to investigate the optimal inlet for antegrade tibial nailing. METHODS: MRIs of 100 consecutive adult patients (50 men and 50 women, average 27 years) were used in this study. All patients had MRIs for meniscus or knee ligament injuries. There were no fractures or prior bony anomalies. The center of the tibial width (TW) at the level of the tibial tubercle (TT) was considered the optimal inlet and was positioned on the axial view of the MRIs. Various related anatomic landmarks were investigated concomitantly. All parameters were compared statistically. RESULTS: The medial edge of the patellar tendon (PT) was 55% from the lateral end of the TW. The apex of the TT was 38% from the lateral end of the TW. The lateral edge of the PT was 19% from the lateral end of the TW. The TT was 2.5 cm distal to the tibial articular surface. The PT width was 2.3 cm. Except for the TW, the distance from the TT to the articular surface, and PT width between genders (p < 0.001), all other parameters showed no statistical significance (p >  0.05). CONCLUSIONS: The optimal inlet for antegrade rigid tibial intramedullary nailing may be at a site 3 mm laterally to the medial edge of the PT. There are normally no differences for the nail inlet between men and women. The PT splitting approach for nail insertion may require modification.

Does Magnetic Resonance Imaging Provide Superior Reliability for Achilles and Patellar Tendon Cross-Sectional Area Measurements Compared with Ultrasound Imaging?

This study investigated the reliability of Achilles and patellar tendon cross-sectional area (CSA) measurement using ultrasound imaging (USI) and magnetic resonance imaging (MRI). Fifteen healthy adults were imaged twice on two occasions, interrupted by a tendon loading protocol. Tendon CSA segmentations were conducted by an experienced and an inexperienced rater blinded to information regarding subject, session and loading status. USI provided good test-retest reliability (intra-class correlation coefficient [ICC] 2,1 > 0.85, standard error of measurement [SEM] 5%-6%), while with MRI it was excellent (ICC 2,1 > 0.92, SEM 4%) for the experienced rater. This study suggests that MRI provides superior reliability for tendon CSA measurements compared with USI. However, the difference in reliability between the methods was small, and the results were inconclusive regarding objectivity and sensitivity to change when assessed based on the effect of loading. We concluded that both methods can be used for reliable CSA measurements of the Achilles and patellar tendons when using a highly standardized measurement protocol and when conducted by an experienced rater.

Differential pattern of Doppler signals at lower-extremity entheses of healthy children.

BACKGROUND: Ultrasonography might be an important imaging method for assessing the pediatric enthesis. To diagnose pathology, knowledge of physiological findings is essential but limited. OBJECTIVE: To provide a detailed ultrasonographic assessment of four lower-extremity entheses in healthy adolescents as a reference for the correct interpretation of findings in children with rheumatic diseases. MATERIALS AND METHODS: The quadriceps tendon, proximal and distal patella tendon, and Achilles enthesis were examined in B-mode, Power and color Doppler in 41 boys and girls ages 11-14 years in neutral position and 30° flexion. We assessed Doppler signals at various distances from the enthesis and analyzed the data using a marginal logistic regression model with generalized estimating equation. We assessed agreement between observers using weighted kappa and we determined agreement on repeat scans using prevalence- and bias-adjusted kappa. RESULTS: Doppler signals were predominantly in the quadriceps and distal patella tendon with odds ratios of 50.85 and 21.35 (P<0.001) compared to the Achilles tendon. They were within 2 mm or 5 mm of the enthesis (odds ratios [ORs] of 4.58 and 4.24, P<0.001), without significant difference between flexion and neutral position and between the right and the left legs. Agreement between first and second assessment was good, with aggregate kappas from 0.79 to 0.90. The inter-reader agreement was also good, with aggregate kappas ranging from 0.75 to 0.95. CONCLUSION: We found a differential Doppler pattern in lower-extremity entheses, with signals present mostly in the quadriceps and distal patella entheses.

Y sign: new landmark for anteromedial portal placement in knee arthroscopy.

PURPOSE: During arthroscopy training process, determination of anteromedial portal is more difficult in contrast with anterolateral portal and frequently results in suboptimal position, and longer operating times. The aim of our study was to identify an anatomical landmark which could facilitate anteromedial portal placement. METHODS: The relationship of the cutaneous veins at the anteromedial side of the knee was analysed regarding the optimally placed anteromedial portal and anatomical landmarks of the anteromedial part of the knee in 70 patients undergoing knee arthroscopy. The study was designed as case series. RESULTS: In 70% of the patients, the joining of the cutaneous veins was seen after transillumination resembling Y letter. In the remaining 30% of patients, a solitary vein with a curve which corresponds to the joining point was observed. The curve and the joining was located adjacent to optimally placed anteromedial portal measured 2 cm ± 0.3 from the medial patellar tendon border, and 1.1 cm ± 0.1 from the palpable edge of the medial tibial plateau. CONCLUSIONS: The "Y sign" can assist knee arthroscopy trainees in anteromedial portal placement, with the resulting avoidance of multiple puncturing of the skin with the needle, shorter operating room times to find the optimal portal placement, and potential reduction of damage to intraarticular structures.

Ultrasonographic assessment of patellar tendon thickness at 16 clinically relevant measurement sites - A study of intra- and interrater reliability.

OBJECTIVES: To determine intra- and interrater reliability of ultrasonographic imaging (USI) measurements of patellar tendon (PT) thickness using 16 measurement sites covering the entire tendon. DESIGN: Reliability study. SETTING: Physiotherapy outpatient clinic. PARTICIPANTS: Twenty healthy and physically active volunteers (9 women). Mean age: 24 years (SD ±â€¯2.73). Mean body mass: 75.8 kg (SD ±â€¯11.8). MAIN OUTCOME MEASURES: Intraclass correlation coefficient (ICC) and 95% limits of agreement (LOA) in cm and in percentage relative to the mean PT thickness. RESULTS: Intrarater reliability ranged from 0.59 to 0.87 and 0.59 to 0.93 for examiners I and II, respectively. Interrater reliability ranged from 0.37 to 0.89. Measurement precision for examiner I ranged from 0.05 to 0.09 cm (17.5%-26.7%) while ranging from 0.04 to 0.13 cm (13.3%-38.7%) for examiner II. Interrater measurement precision ranged from 0.07 to 0.15 cm (19.1%-42.5%). CONCLUSION: In an attempt to replicate daily clinical USI practice, this was the first study extensively assessing reliability throughout the full range of the patellar tendon - revealing a considerable variation in intra- and interrater reliability as well as measurement precision throughout the 16 individual PT sites. In a clinical context, the low interrater reliability and precision found at the proximal tendon insertion site may have implications for USI of the symptomatic PT, as this is the site mainly associated with underlying pathologic changes. Further reliability studies are needed to clarify the region-specific reliability of the full length PT.

The lateral patellar retinaculum defect: anatomical study using ultrasound.

OBJECTIVE: The purpose of this study was to evaluate whether ultrasound allows precise assessment of a focal defect at the lateral patellar retinaculum (LPR) and to determine its anatomical significance. MATERIALS AND METHODS: This work was initially undertaken in four cadaveric specimens and followed by high-resolution ultrasound study in 48 healthy adult volunteers (96 knees) by two musculoskeletal radiologists. Dimension and location of the LPR defect and its relations to adjacent anatomical structures were analyzed. RESULTS: A focal defect of the LPR through which vessels penetrated was constantly identified by ultrasound in our population. The mean transverse diameter of the defect was 2.4 mm (range, 1-6 mm). The defect was located a mean of 23.7 mm (range, 18-30 mm) proximal to the lateral tibial plateau and 6.6 mm (range, 4-9 mm) lateral to the patellar tendon. Anatomical dissection demonstrated that the LPR defect is related to perforating vessels that originate from the peripatellar anastomotic ring. CONCLUSIONS: The focal defect of the LPR can be depicted by ultrasonography. Reproducible anatomical landmarks for its detection could be defined. Our data suggest the LPR defect may be considered a normal variant rather than a pathologic change.

Does knee position during wound closure alter patella height following total knee arthroplasty?

BACKGROUND: Patella infera is a known complication of total knee arthroplasty, and the method of soft tissue closure is a possible contributing factor. The aim of our study was to evaluate the effect of knee position during surgical closure of capsule, subcutaneous tissue and skin on patella tendon length after total knee arthroplasty. METHODS: A three arm retrospective cohort study was conducted in a single institution over a 3-year period; 75 patients were divided, by surgeon preference, into three groups (Flexed, Extended and Hybrid) of 25 patients. All groups had standardized prosthesis, intraoperative and postoperative protocols, and differed in knee position at closure. Patellar tendon length was assessed radiologically using Insall Salvati ratio (ISR) and modified Insall Salvati ratio, with a 12-month follow-up. Intraclass correlation coefficients were used to assess intraobserver variability. RESULTS: There was a small but significant difference in preoperative to initial postoperative ISR change between Flexed and Extended groups (Extended group mean ISR change = -0.05; t = -2.31, P = 0.025, independent samples t-test), which was not sustained at 12 months. The incidence of patella infera was similar in Flexed and Extended groups at 12 months with only one case seen in the Hybrid group. CONCLUSION: Our study suggests that knee position during soft tissue closure does not have a sustained impact on patella tendon length after knee replacement. A small but statistically significant reduction in patella height was found in the Extended group initially after surgery but this effect was not sustained at 12 months.