Effect of Patella Alta on the Native Anatomometricity of the Medial Patellofemoral Complex: A Cadaveric Study

2020 ◽  
Vol 48 (6) ◽  
pp. 1398-1405
Author(s):  
Adam B. Yanke ◽  
Hailey P. Huddleston ◽  
Kevin Campbell ◽  
Michael L. Redondo ◽  
Alejandro Espinoza ◽  
...  
Keyword(s):  
Attachment Site ◽  
Quadriceps Tendon ◽  
Length Change ◽  
Patellar Height ◽  
Extensor Mechanism ◽  
Patella Alta ◽  
Similar Length ◽  
Custom Made ◽  
Length Changes ◽  
Medial Patellofemoral Complex

Background: Patella alta has been identified as an important risk factor for lateral patellar instability and medial patellofemoral complex (MPFC) reconstruction failure. Purpose: To evaluate the length changes of the MPFC at multiple possible reconstruction locations along the extensor mechanism in varying degrees of patella alta throughout knee motion. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen cadaveric knees were used in this study. The MPFC was identified and dissected with the patellar tendon and quadriceps tendon. A custom-made jig was utilized to evaluate lengths from 0° to 90° of flexion with physiological quadriceps loading. Length was measured with a 3-dimensional robotic arm at 4 possible reconstruction locations along the extensor mechanism: the midpoint patella (MP), the MPFC osseous center (FC), the superior medial pole of the patella (SM) at the level of the quadriceps insertion, and 1 cm proximal to the SM point along the quadriceps tendon (QT). These measurements were repeated at 0°, 20°, 40°, 60° and 90° of flexion. Degrees of increasing severity of patella alta at Caton-Deschamps index (CDI) ratios of 1.0, 1.2, 1.4, and 1.6 were then investigated. Results: Patella alta and MPFC attachment site location significantly affected changes in MPFC length from 0° to 90° of flexion ( P< .0005). Length changes at attachment MP showed no difference when CDI 1.0 was compared with all patella alta values (CDI 1.2, 1.4, 1.6; P > .05). Similarly, FC showed no difference in length change from 0° to 90° until CDI 1.6, in contrast to proximal attachments (SM, QT), which demonstrated significant changes at CDI 1.4 and 1.6. When length changes were analyzed at each degree of flexion (0°, 20°, 40°, 60°, 90°), Spearman correlation analysis showed a moderate negative linear correlation for QT at CDI 1.0 ( r= −0.484; P = .002) and 1.6 ( r = −0.692; P < .0005), demonstrating constant loosening at the QT point at normal and elevated patellar height. In contrast, no differences in length were observed for MP at CDI 1.0 throughout flexion, and at CDI 1.6, there was a difference only at 0° ( P < .05). Points FC and MP at CDI 1.6 had similar length change properties to points SM and QT at CDI 1.0 ( P > .05), suggesting that distal attachments in the setting of patella alta may provide similar length changes to proximal attachmentswith normal height. Conclusion: Anisometry of the MPFC varies not only with attachment location on the extensor mechanism but also with patellar height. Increased patellar height leads to more significant changes in anisometry in the proximal MPFC attachment point as compared with the distal component. In the setting of patella alta, including a CD ratio of 1.6, the osseous attachments of the MPFC remain nearly isometric wheras the proximal half length changes increase significantly. Clinical Significance: The results of this study support the idea that the MPFC should be considered as 2 separate entities (proximal medial quadriceps tendon femoral ligament and distal medial patellofemoral ligament) owing to their unique length change properties.

scholarly journals Effect of Patella Alta on the Native Anatomometricity of the Medial Patellofemoral Complex: A Cadaveric Study

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0045
Author(s):  
Hailey Huddleston ◽  
Kevin Campbell ◽  
Michael Redondo ◽  
Alejandro Espinoza ◽  
Jorge Chahla ◽  
...  
Keyword(s):  
Quadriceps Tendon ◽  
Length Change ◽  
Patella Alta ◽  
Constant Length ◽  
Cadaveric Specimen ◽  
Inferior Aspect ◽  
Attachment Sites ◽  
Custom Made ◽  
Length Changes ◽  
Medial Patellofemoral Complex

Objectives: Patella alta has been identified as an important risk factor for lateral patellar instability and medial patellofemoral complex (MPFC) reconstruction failure. To our knowledge, no prior study has analyzed the anisometry of the MPFC in the setting of patella alta as this may play a role in the postoperative outcomes and could affect surgical technique. Methods: Eight (n=8) fresh frozen cadaveric knees were used in this study. No IRB approval was needed at our institution due to the use of cadaveric specimen. The MPFC was identified and dissected along with the patellar tendon, and quadriceps tendon. A custom-made jig was utilized to evaluate MPFC lengths from 0-90° of flexion. Length was measured at four possible reconstruction locations (midpoint patella [MP], MPFC osseous center [FC], superior medial pole of the patella [SM], and quadriceps tendon [Q]) along the extensor mechanism using a 3D robotic arm. These measurements were repeated at 0, 20, 40, 60 and 90° degrees of flexion. Degrees of increasing severity of patella alta at Caton-Deschamps index (CDI) ratios of 1.0, 1.2, 1.4, and 1.6, were then investigated. Results: CDI and attachment sites significantly affect changes in MPFC length from 0-90° of flexion (p < 0.0005). Proximal attachment points had more robust length changes than distal ones and increases in CDI enhanced these differences. Point Q at CDI 1 was similar to SM at 1.2 (p = 0.234), SM and FC at 1.4 (p = 0.89 and p = 0.073) and FC at 1.6 (p = 0.928). SM at CDI of 1 was similar to FC at 1.2 and 1.4 (p = 0.414 and p = 0.503) and MP at 1.6 (p = 0.473), while FC at CDI 1 was similar to the FC at 1.2 (p = 0.157) and MP at 1.4 and 1.6 (p = 0.068 and p = 0.519). Finally, the MP was similar at CDI 1.2 (p = 0.888) and 1.4 (p = 0.385) compared to at CDI of 1. At the quadriceps points, MPFC length and flexion degrees showed a moderate negative linear correlation at a CDI of 1 (r = -0.484, p = 0.002) and 1.6 (r = -0.692, p < 0.0005) (Fig 1). At the MP location at a CDI ratio of 1.6, significant differences were seen at 0° vs 90° (p = 0.027), 0° vs 60° (p = 0.044), 0° vs 40° (p = 0.016), and 0° vs 20° (p = 0.044), suggesting differing length change properties between the Q and MP attachment sites. Conclusions: Anisometry varies with location of the patellar attachment and with patellar height within the MPFC. The superior aspect of the MPFC demonstrated the most isometric behavior, increasing linearly with increasing flexion. The inferior aspect of the MPFC retains a relatively constant length at 20 to 90° of flexion. Increasing CDI amplified these results. These findings demonstrate that proximal based grafts loosen significantly before engaging in the trochlea and this effect is exaggerated in the setting of patella alta. Furthermore, this data suggests that soft tissue surgical reconstructions may be modified to correct for patella alta in place of performing distalization, which carries significant morbidity.

scholarly journals Medial collateral ligament reconstruction graft isometry is effected by femoral position more than tibial position

2021 ◽  
Author(s):  
Christoph Kittl ◽  
James Robinson ◽  
Michael J. Raschke ◽  
Arne Olbrich ◽  
Andre Frank ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Knee Flexion ◽  
Length Change ◽  
Collateral Ligament ◽  
Complex Behaviour ◽  
Femoral Attachment ◽  
Attachment Sites ◽  
Custom Made ◽  
Length Changes ◽  
Graft Length

Abstract Purpose The purpose of this study was to examine the length change patterns of the native medial structures of the knee and determine the effect on graft length change patterns for different tibial and femoral attachment points for previously described medial reconstructions. Methods Eight cadaveric knee specimens were prepared by removing the skin and subcutaneous fat. The sartorius fascia was divided to allow clear identification of the medial ligamentous structures. Knees were then mounted in a custom-made rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights. Threads were mounted between tibial and femoral pins positioned in the anterior, middle, and posterior parts of the attachment sites of the native superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL). Pins were also placed at the attachment sites relating to two commonly used medial reconstructions (Bosworth/Lind and LaPrade). Length changes between the tibiofemoral pin combinations were measured using a rotary encoder as the knee was flexed through an arc of 0–120°. Results With knee flexion, the anterior fibres of the sMCL tightened (increased in length 7.4% ± 2.9%) whilst the posterior fibres slackened (decreased in length 8.3% ± 3.1%). All fibre regions of the POL displayed a uniform lengthening of approximately 25% between 0 and 120° knee flexion. The most isometric tibiofemoral combination was between pins placed representing the middle fibres of the sMCL (Length change = 5.4% ± 2.1% with knee flexion). The simulated sMCL reconstruction that produced the least length change was the Lind/Bosworth reconstruction with the tibial attachment at the insertion of the semitendinosus and the femoral attachment in the posterior part of the native sMCL attachment side (5.4 ± 2.2%). This appeared more isometric than using the attachment positions described for the LaPrade reconstruction (10.0 ± 4.8%). Conclusion The complex behaviour of the native MCL could not be imitated by a single point-to-point combination and surgeons should be aware that small changes in the femoral MCL graft attachment position will significantly effect graft length change patterns. Reconstructing the sMCL with a semitendinosus autograft, left attached distally to its tibial insertion, would appear to have a minimal effect on length change compared to detaching it and using the native tibial attachment site. A POL graft must always be tensioned near extension to avoid capturing the knee or graft failure.

scholarly journals Length change pattern of the medial structures of the knee and related reconstructions

2020 ◽  
Vol 8 (9_suppl7) ◽  
pp. 2325967120S0053
Author(s):  
Arne Olbrich ◽  
Elmar Herbst ◽  
Christoph Domnick ◽  
Johannes Glasbrenner ◽  
Michael J. Raschke ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Knee Flexion ◽  
Insertion Site ◽  
Length Change ◽  
Collateral Ligament ◽  
Femoral Insertion ◽  
Superficial Medial Collateral Ligament ◽  
Custom Made ◽  
Length Changes ◽  
Length Reduction

Introduction: Aim of the study was to investigate the length changes of the medial structures and related reconstructions. It was assumed that the three fibre sections (anterior/middle/posterior) of the superficial medial collateral ligament (sMCL) have different length change patterns, which cannot be imitated by current reconstructions. Hypotheses: The three fibre sections (anterior/middle/posterior) of the superficial medial collateral ligament (sMCL) cannot be imitated by current reconstructions. Methods: Measurements were made on eight cadaveric knees. The knee joints were clamped in a custom-made open chain extension structure. For this purpose, the portions of the quadriceps and the iliotibial tract were aligned according to their fibre direction and statically loaded using hanging weights. The respective tibial and femoral insertion points of the sMCL anterior/middle/posterior fibres were marked by small pins. Similarly, pins were inserted at the tibial and femoral attachment sites of the posterior oblique ligament (POL). In order to imitate the Lind reconstruction, a pin was additionally inserted on the tibial semitendinosus insertion site. Pin combinations accounting for the anterior/middle/posterior sMCL, the POL, and the Lind reconstruction were connected using a high resistant suture. Then the length change patterns were measured using a rotary encoder from 0-120° knee flexion. Statistical analysis was performed using 2-way repeated-measures ANOVA and a post-hoc Bonferroni correction (p <0.05). Results: The anterior and posterior fibres of the sMCL showed a reciprocal behaviour (p< 0.001). The anterior fibres showed a length reduction (2%) up to a flexion of 20°, followed by an elongation of 5% at 120° flexion, which means that the anterior fibres are tight in knee flexion. Conversely, the posterior fibres of the MCL showed an initial length reduction of 4% at 20° flexion. This was followed by an isometric range (20° - 80°) and a further length reduction of 8% in deep flexion (120°). Thus, the posterior fibres of the MCL were tight in extension. The three parts of the POL showed a constant reduction of 25% between 0° and 120°. The Lind reconstruction with the tibial pin at the semitendinosus insertion site showed similar length changes compared to the sMCL (n.s.). Furthermore, the Lind reconstruction was dependent on the femoral placement of the pins (p <.001). The tibial placement had no significant influence. Conclusion: The anterior portion of the sMCL was tight in flexion, whereas the posterior portion was tight in extension. This reciprocal behavior could not be imitated by a single point to point reconstruction. When surgically applying these reconstructions, special attention should be paid to the femoral insertion.

New variant of bipartite patella with traumatic separation and complete disruption of the extensor mechanism of the knee

2021 ◽  
Vol 14 (1) ◽  
pp. e236773
Author(s):  
Kiran Kumar Naikoti ◽  
Raghuram Thonse
Keyword(s):  
Functional Recovery ◽  
Tendon Rupture ◽  
Case Reports ◽  
Quadriceps Tendon ◽  
Extensor Mechanism ◽  
Quadriceps Tendon Rupture ◽  
Bipartite Patella ◽  
New Variant ◽  
Complete Disruption ◽  
Type 3

Very few case reports have been reported on traumatic separation of the bipartite patella along with quadriceps tendon rupture. These reports relate to separation of superolateral bipartite patella (Saupe type 3). We describe a new variant which to our knowledge has not been described or classified so far, which is purely a superior bipartite patella with traumatic separation and complete functional disruption of the extensor mechanism of the knee in a young patient working in the army which was managed with open reduction and internal fixation along with repair of the extensor mechanism of the knee achieving complete functional recovery.

The location and mechanism of electromotility in guinea pig outer hair cells

1993 ◽  
Vol 70 (2) ◽  
pp. 549-558 ◽  
Author(s):  
R. Hallworth ◽  
B. N. Evans ◽  
P. Dallos
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Length Change ◽  
Opposite Polarity ◽  
Outer Hair Cells ◽  
Response Amplitude ◽  
Change Function ◽  
Length Changes ◽  
Diameter Change

1. The microchamber method was used to examine the motile responses of isolated guinea pig outer hair cells to electrical stimulation. In the microchamber method, an isolated cell is drawn partway into a suction pipette and stimulated transcellularly. The relative position of the cell in the microchamber is referred to as the exclusion fraction. 2. The length changes of the included and excluded segments were compared for constant sinusoidal stimulus amplitude as functions of the exclusion fraction. Both included and excluded segments showed maximal responses when the cell was excluded approximately halfway. Both segments showed smaller or absent responses when the cell was almost fully excluded or almost fully included. 3. When the cell was near to, but not at, the maximum exclusion, the included segment response amplitude was zero, whereas the excluded segment response amplitude was nonzero. In contrast, when the cell was nearly fully included, the excluded segment response amplitude was zero, but the included segment response amplitude was still detectable. A simple model of outer hair cell motility based on these results suggests that the cell has finite-resistance terminations and that the motors are restricted to a region above the nucleus and below its ciliated apex (cuticular plate). 4. The function describing length change as a function of command voltage was measured for each segment as the exclusion fraction was varied. The functions were similar at midrange exclusions (i.e., when the segments were about equal length), showing nonlinearity and saturability. The functions were strikingly different when the segment lengths were different. The effects of exclusion on the voltage to length-change functions suggested that the nonlinearity and saturability are local properties of the motility mechanism. 5. The diameter changes of both segments were examined. The segment diameter changes were always antiphasic to the length changes. This finding implies that the motility mechanism has an active antiphasic diameter component. The diameter change amplitude was a monotonically increasing function of exclusion for the included segment, and a decreasing function for the excluded segment. 6. The voltage to length-change and voltage to diameter-change functions were measured for the same cell and exclusion fraction. The voltage to diameter-change function was smaller in amplitude than the voltage to length-change function. The functions were of opposite polarity to each other, but were otherwise similar in character. Thus it is likely that the same motor mechanism is responsible for both axial and diameter deformations.

scholarly journals Quadriceps reconstruction with suture anchor and Achilles allograft combination in quadriceps tendon re-rupture after primary surgical repair: A novel technique

2021 ◽  
Author(s):  
Erhan Okay ◽  
Mehmet Cenk Turgut ◽  
Abbas Tokyay
Keyword(s):  
Suture Anchor ◽  
Surgical Repair ◽  
Primary Repair ◽  
Full Range ◽  
Knee Extensor ◽  
Quadriceps Tendon ◽  
Extensor Mechanism ◽  
Surgical Options ◽  
Knee Extensor Mechanism

Quadriceps ruptures are one of the pathological conditions of the knee extensor mechanism, accounting for 3% of all tendon injuries. These injuries cause substantial disability of the extensor mechanism. Primary repair is the treatment of choice in acute presentation. In the setting of chronic conditions, the treatment becomes more challenging. Available surgical options include lengthening procedures, and reconstruction with auto graft or allografts. The traditional Scuderi and Codivilla techniques are challenging to perform in degenerative or traumatic retracted ruptures. There is no standard effective treatment in these patients, which yields the best clinical and biomechanical outcomes. An 18 - year-old male patient with quadriceps re-rupture after a primary repair was managed with allograft reconstruction using suture anchors. At six years of follow-up, the patient gained a full range of motion with excellent clinical outcomes. He returned to his previous work. In conclusion, quadriceps reconstruction using suture anchor and Achilles allograft combination is a feasible technique in neglected cases who present with quadriceps tendon re-rupture after primary surgical repair.

scholarly journals A rare case of patellar fracture with quadriceps tendon rupture

2021 ◽  
Vol 7 (2) ◽  
pp. 406
Author(s):  
K. N. Subramanian ◽  
Ganesan G. Ram ◽  
Muthukumar S. ◽  
Mathiyazhagan Babu
Keyword(s):  
Patellar Tendon ◽  
Rare Case ◽  
Tendon Rupture ◽  
Quadriceps Tendon ◽  
Extensor Mechanism ◽  
Patella Fracture ◽  
Patellar Fracture ◽  
Quadriceps Tendon Rupture ◽  
Patellar Tendon Rupture ◽  
Bone Level

<p>Quadriceps tendon rupture is the rarest injury with an incidence of 1.37/1,00,000/year. A patellar fracture is the most common injury associated with extensor mechanism lag, but it is rarely found to have quadriceps rupture rather than patellar tendon rupture. Normally when patella fracture occurs the force is disseminated at the bone level rather than at the muscular level. In this case, the force has disseminated at both muscle and bone leading to fracture of patella and quadriceps tendon rupture. Here we report a case of patellar fracture along with quadriceps tendon rupture.<strong></strong></p>

Soft tissue extensor mechanism tendon ruptures of the knee

2021 ◽  
pp. 1-9
Author(s):  
John-Henry Rhind ◽  
Patrick Lancaster ◽  
Usman Ahmed ◽  
Michael Carmont
Keyword(s):  
Emergency Medicine ◽  
Soft Tissue ◽  
Acute Care ◽  
Quadriceps Tendon ◽  
Tendon Injuries ◽  
Extensor Mechanism ◽  
Patella Tendon ◽  
Tendon Ruptures ◽  
Serious Injuries ◽  
Prompt Diagnosis

Ruptures of the extensor mechanism of the knee are serious injuries requiring prompt diagnosis and treatment. They can be divided into soft tissue and bony causes. Soft tissue tendon injuries can be either partial or complete. Rupture of the quadriceps tendon is an uncommon injury and is more frequent in patients over the age of 40 years. Patella tendon ruptures are even rarer and are more frequent in patients under the age of 40 years. Causes can be direct or indirect. Complete ruptures of the quadriceps tendon or patella tendon benefit from early surgical management, while partial ruptures may be managed non-operatively. This article gives an overview of the presentation, assessment and management of soft tissue extensor mechanism tendon ruptures for core surgical, acute care common stem and emergency medicine trainees.

How Does Isolated Medial Patellofemoral Ligament Reconstruction Influence Patellar Height?

2020 ◽  
Vol 48 (4) ◽  
pp. 895-900 ◽  
Author(s):  
Francesco Luceri ◽  
Julien Roger ◽  
Pietro Simone Randelli ◽  
Sébastien Lustig ◽  
Elvire Servien
Keyword(s):  
Patellar Instability ◽  
Medial Patellofemoral Ligament ◽  
Case Series ◽  
Patellofemoral Instability ◽  
Patellar Height ◽  
Patella Alta ◽  
Level Of Evidence ◽  
Normal Limits ◽  
Patient Reported ◽  
History Of

Background: Reconstruction of the medial patellofemoral ligament (MPFL) is the gold standard treatment for recurrent patellar dislocation. Patella alta has been reported in about half of patients with recurrent patellofemoral instability. Hypothesis: MPFL reconstruction (MPFLr) has a beneficial role in the correction of patellar height in patients with mild patella alta (Caton-Deschamps index [CDI] between 1.20 and 1.40). Study Design: Case series; Level of evidence, 4. Methods: Skeletally mature patients, with no history of previous or concomitant knee surgical procedures, who underwent isolated MPFLr using hamstring autograft for recurrent patellar instability between 2005 and 2018, were included in this study. The authors calculated CDI, modified Insall-Salvati index (MISI), and Blackburne-Peel index (BPI) ratios. Measurements done by 2 independent observers were calculated and used to compare pre- and postoperative patellar height (patella alta: CDI >1.20). Results: A total of 89 patients (95 knees) were included in the study, with a mean age of 25.0 years (range, 15.0-45.0 years). There were 70% women and 30% men. We found patella alta in 35.8% of cases preoperatively. Among them, 79.4% had reduced patellar height indices, within normal limits, postoperatively (mean follow-up, 18.4 ± 12.0 months). All the ratios showed a significant reduction in patellar height after surgery (CDI: 0.19 [range, –0.05, 0.60]; MISI: 0.22 [–0.14, 0.76]; BPI: 0.18 [–0.08, 0.59]; P < .00001). The CDI of 79.4% of the study knees was reduced to within normal limits postoperatively. The CDI was maintained within normal limits postoperatively in 93.4% of the knees with normal patellar height and reduced to normal in 50% of the knees with severe patella alta before surgery . No patient reported patella infera before surgery, whereas this condition was found in 8.2% of study patients postoperatively. A moderate correlation was reported between preoperative radiographic indices and their reduction after surgery (CDI: P < .001, ρ = 0.39; MISI: P < .001, ρ = 0.39; BPI: P < .001, ρ = 0.48). Conclusion: The higher the preoperative patellar height, the more important is the lowering effect of MPFLr using the hamstring for patellar instability. Bony procedures should not be indicated in patients with patellar instability and a CDI between 1.20 and 1.40.

The Monitoring of Shrinkage of the PVA Cement-Plates

2013 ◽  
Vol 438-439 ◽  
pp. 280-282 ◽  
Author(s):  
Michaela Kostelecká ◽  
Jiří Kolísko
Keyword(s):  
Length Change ◽  
Free Shrinkage ◽  
Significant Difference ◽  
Length Changes ◽  
The Difference ◽  
Matrix Influence

This paper presents results of a series of shrinkage tests. Described tests were performed on asbestos-free plates. The shrinkage represents very important role in monitoring of length changes for different orientation of the fibers. The results showed that humidity significantly influenced dimensions change of tested fibrecement plates. Length change ratio of dried plates and saturated plates represented the most significant difference that reached 0.25 %. Influence of fibres orientation on the length change was not confirmed. The difference in both measured direction was the same because of varied humidity impact. Elimination of free shrinkage is predominantly given by matrix, influence of fibers is not significant.

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