Medial Patellar Plica Thickness as a Morphologic Predictor of the Medial Patellar Plica Syndrome

OBJECTIVE

The aim of this study was to evaluate the association between medial patellar plica (MPP) syndrome and the morphological features of the MPP, including length, width, and thickness, on knee magnetic resonance imaging (MRI).

MATERIALS AND METHODS

From 2018 to 2022, 167 patients diagnosed with isolated MPP syndrome based on both MRI and arthroscopic findings were included in the "study group" and 226 patients without knee pathology on both MRI and physical examination were included in the "control group." Finally, 393 patients (mean age, 38.9 ± 5.7 years) with 405 knee MRI examinations were included. Morphological MR features of MPP were assessed, including width, length, and thickness. Multivariate regression and receiver operating characteristic analyses were performed to identify the factors associated with MPP syndrome.

RESULTS

The mean thickness of MPP was significantly higher in the study group than control group (2.3 ± 0.5 mm vs 1.0 ± 0.8 mm, P < 0.001). Moreover, on multivariate analysis, MPP thickness was the only significant factor associated with MPP syndrome (odds ratio, 6.452; 95% confidence interval, 0.816-15.073; P = 0.002). On receiver operating characteristic analysis, thickness ≥1.8 mm was estimated as the optimal cutoff for predicting MPP syndrome with sensitivity of 75.9%, specificity of 65.4%, and area under the curve of 0.727 (95% confidence interval, 0.667-0.788; P < 0.001).

CONCLUSIONS

Measurement of MPP thickness on MRI could be a morphological predictor of MPP syndrome.

Reconstruction of medial meniscus posterior portion deficiency in pigs with an autologous patellar tendon graft: an experimental study

OBJECTIVE

This study was performed to investigate the effectiveness of two surgical procedures, autologous patellar tendon graft reconstruction and trans-tibial plateau pull-out repair, using a pig model. The primary focus was to assess the repair capability of medial meniscus posterior portion (MMPP) deficiency, the overall structural integrity of the meniscus, and protection of the femoral and tibial cartilage between the two surgical groups. The overall aim was to provide experimental guidelines for clinical research using these findings.

METHODS

Twelve pigs were selected to establish a model of injury to the MMPP 10 mm from the insertion point of the tibial plateau. They were randomly divided into three groups of four animals each: reconstruction (autologous tendon graft reconstruction of the MMPP), pull-out repair (suture repair of the MMPP via a trans-tibial plateau bone tunnel), and control (use of a normal medial meniscus as the negative control). The animals were euthanized 12 weeks postoperatively for evaluation of the meniscus, assessment of tendon bone healing, and gross observation of knee joint cartilage. The tibial and femoral cartilage injuries were evaluated using the International Society for Cartilage Repair (ICRS) grade and Mankin score. Histological and immunohistochemical staining was conducted on the meniscus-tendon junction area, primary meniscus, and tendons. The Ishida score was used to evaluate the regenerated meniscus in the reconstruction group. Magnetic resonance imaging (MRI) was used to evaluate meniscal healing.

RESULTS

All 12 pigs recovered well after surgery; all incisions healed without infection, and no obvious complications occurred. Gross observation revealed superior results in the reconstruction and pull-out repair groups compared with the control group. In the tibial cartilage, the reconstruction group had ICRS grade I injury whereas the pull-out repair and control groups had ICRS grade II and III injury, respectively. The Mankin score was significantly different between the reconstruction and control groups; histological staining showed that the structure of the regenerated meniscus in the reconstruction group was similar to that of the original meniscus. Immunohistochemical staining showed that the degree of type I and II collagen staining was similar between the regenerated meniscus and the original meniscus in the reconstruction group. The Ishida score was not significantly different between the regenerated meniscus and the normal primary meniscus in the reconstruction group. MRI showed that the MMPP in the reconstruction and pull-out repair groups had fully healed, whereas that in the control group had not healed.

CONCLUSION

Autologous patellar tendon graft reconstruction of the MMPP can generate a fibrocartilage-like regenerative meniscus. Both reconstruction and pull-out repair can preserve the structural integrity of the meniscus, promote healing of the MMPP, delay meniscal degeneration, and protect the knee cartilage.

Evaluation of Anatomical Variations with Morphological Measurements and Their Relationship to Meniscal Injury and Ligament Damage

The purpose of this study was to reveal the anatomical risk factors for anterior and posterior cruciate ligament (ACL and PCL) injuries and menisci injury. We aim to investigate whether there are significant relationships between tibial tubercle-trochlear groove (TT-TG) distance, patella angle, trochlear sulcus angle (TSA), trochlear groove depth (TGD), medial and lateral trochlea length (MT and LT), MT/LT ratio, lateral patellar tilt angle (LPTA), patella-patellar tendon angle (P-PTA), quadriceps-patellar tendon angle (QPA), Insall-Salvati index (ISI), medial and lateral trochlear inclination (MTI and LTI) measurements and important common pathologies such as ACL, PCL, medial and lateral meniscal injuries (MM and LM), peripatellar fat pad edema, chondromalacia, and effusion. Thus, the mechanisms of injury will be better understood by revealing important anatomical variations for meniscus and ligament damage. Three hundred eighty patients with knee magnetic resonance imaging examination were included in this study. Our patients who underwent knee magnetic resonance imaging were divided into groups according to the presence of MM tear, LM tear, ACL tear, PCL tear, peripatellar fat pad edema, chondromalacia and effusion. TT-TG distance, patella angle, TSA, TGD, MT, LT, MT/LT ratio, LPTA, P-PTA, QPA, ISI, MTI, and LTI were measured. In patients with ACL tear, age, LT, ML/LT ratio, and QPA measurements were found to be significantly higher. There was no significant difference between the participants' LPTA value and the presence of ACL tear, MM and LM injury. MT and ML/LT ratio were found to be significantly lower in the group with MM tear (p <0.001). The TT-TG distance was found to be significantly lower in the group with LM tear. Increased age, LT, ML/LT ratio, and QPA are predisposed risk for ACL tear. Decreased MT and ML/LT ratio are among the risk factors for MM tear. The anatomical variations are associated with ligament and meniscal injury.

AN INTRATENDINOUS GANGLION CYST OF THE PATELLAR TENDON: A RARE CAUSE OF ANTERIOR KNEE PAIN

Ganglion cysts in the knee region can manifest as anterior knee pain. Unlike synovial cysts, these lesions lack synovial epithelial lining and occur secondary to mucoid degeneration of connective tissue because, often in response to chronic irritation and repetitive traumas. However, an intratendinous location is a rare finding. In the knee region, infrapatellar fat pad, the alar folds, and the anterior cruciate ligament are recognized to degenerate into ganglion. There are few case reports describing an involvement of the patellar tendon. We present the clinical case of a 72 years old male patient suffering from anterior knee pain attributed to an intratendinous ganglion cyst of the patellar tendon, obviously after a single traumatic event. After aspiration of the ganglion cyst the patient reported no complaints, and there has been no recurrence during the latest follow-up examination.

Tendon and motor phenotypes in the Crtap-/- mouse model of recessive osteogenesis imperfecta

Osteogenesis imperfecta (OI) is characterized by short stature, skeletal deformities, low bone mass, and motor deficits. A subset of OI patients also present with joint hypermobility; however, the role of tendon dysfunction in OI pathogenesis is largely unknown. Using the Crtap-/- mouse model of severe, recessive OI, we found that mutant Achilles and patellar tendons were thinner and weaker with increased collagen cross-links and reduced collagen fibril size at 1- and 4-months compared to wildtype. Patellar tendons from Crtap-/- mice also had altered numbers of CD146+CD200+ and CD146-CD200+ progenitor-like cells at skeletal maturity. RNA-seq analysis of Achilles and patellar tendons from 1-month Crtap-/- mice revealed dysregulation in matrix and tendon marker gene expression concomitant with predicted alterations in TGF-β, inflammatory, and metabolic signaling. At 4-months, Crtap-/- mice showed increased αSMA, MMP2, and phospho-NFκB staining in the patellar tendon consistent with excess matrix remodeling and tissue inflammation. Finally, a series of behavioral tests showed severe motor impairments and reduced grip strength in 4-month Crtap-/- mice - a phenotype that correlates with the tendon pathology.

2017 Marathon of Rome: Anthropometry and Sport Profile in 350 Runners and Association With Achilles and Patellar Tendinopathy

BACKGROUND

Achilles and patellar tendinopathy are common in runners. Despite the relevance of the problem, causative factors remain poorly understood. This cross-sectional study evaluated the association between Achilles and patellar tendinopathy and age, sex, weight, height, number of marathons, and impact profile in runners who participated in the 2017 Marathon of Rome.

METHODS

At the 2017 Marathon of Rome, 350 athletes (256 men and 94 women; mean age: 44.8 years, range 12-80 years) filled in the VISA-A and VISA-P questionnaires. A fully trained orthopedic surgeon made a diagnosis of Achilles and patellar tendinopathy according to clinical criteria.

RESULTS

Ninety-five participants were diagnosed with Achilles tendinopathy and 96 with patellar tendinopathy. There was evidence of a statistically significant positive association between age and Achilles and patellar tendinopathy, with no effect of sex, weight, and height on the presence of Achilles tendinopathy. There was no evidence of a statistically significant positive association between the number of marathons and impact profile and VISA-A score. There was a statistically significant association between VISA-P score and impact profile. Finally, there was evidence of a statistically significant positive association between VISA-A score and VISA-P score (P = 0.007).

CONCLUSIONS

In marathon runners, there was no evidence of a statistically significant association between sex, weight, height, number of marathons, and Achilles and patellar tendinopathy. However, age was associated with Achilles and patellar tendinopathy, and impact profile was associated with patellar tendinopathy.

Reduced Levels of Aligned Fibrillar Structure Are Not Associated With Achilles and Patellar Tendon Symptoms

OBJECTIVE

To investigate whether the mean cross-sectional area (mCSA) of aligned fibrillar structure (AFS) was associated with the presence and severity of symptoms.

DESIGN

Prospective cohort study.

PARTICIPANTS

One hundred seventy-five elite male Australian football players completed monthly Oslo Sports Trauma Research Center overuse injury questionnaires for both the Achilles and patellar tendon over the season to ascertain the presence and severity of symptoms. At the start of the preseason, participants underwent ultrasound tissue characterization (UTC) imaging of the Achilles and patellar tendon.

MAIN OUTCOME MEASURES

Images were classified as normal or abnormal based on gray-scale ultrasound. Based on UTC quantification, the mCSA of AFS was compared between those with and without current symptoms.

RESULTS

No difference in the mCSA of AFS was observed between those with or without tendon symptoms (P < 0.05). Similar to previous findings, 80% to 92% of abnormal tendons had similar amounts of mCSA of AFS compared with normal tendon. If reduced mCSA of AFS was present, it was not associated with the presence or severity of symptoms.

CONCLUSIONS

The prevalence, development, or severity of symptoms was not associated with decreased levels of AFS in the Achilles or patellar tendon. This suggests that a lack of structural integrity is not linked to symptoms and questions the rationale behind regenerative medicine. Most tendons are able to compensate for areas of disorganization and maintain tissue homeostasis.

Effects of morphological changes in the patellar tendon on the development of anterior knee pain after intramedullary nailing for tibial shaft fractures: A retrospective comparative study

OBJECTIVE

This study aimed to investigate the effects of morphological changes of the patellar tendon (length, width, and thickness) on the development of anterior knee pain (AKP) after intramedullary nailing (IMN) of tibial shaft fractures.

METHODS

A total of 39 patients, treated by IMN using the transpatellar approach for tibial shaft fractures, were retrospectively reviewed and included in the study. The patients were then divided into 2 groups based on the presence of AKP: group A, patients who developed AKP (9 men, 9 women; mean age=35.39±9.32 years), and group B, patients without AKP (13 men, 8 women; mean age=41.38±14.78 years). To assess the morphological changes in the patellar tendon, magnetic resonance imaging was performed on the operated and unoperated, contralateral knees of the patients. The patellar tendon index (PTI) was calculated using the length, width, and thickness of the patellar tendon, and a set of variables was established to be a proportion of the measurements of the operated knees to those of the unoperated ones (operated/healthy PTI ratio). PTI ratios were compared between both the groups. Furthermore, the morphological features of the patellar tendon, including the length, width, and thickness, were examined within the groups as independent variables. To assess pain intensity in group A, a 10-cm visual analogue scale (VAS) was used. To evaluate functional status, the Lysholm knee scoring system was used.

RESULTS

The PTI ratio was significantly higher in group A (1.37±0.12) than in group B (1.03±0.08) (p<0.001). In group A, the mean VAS score was 5.35±1.11, and a moderate linear correlation was found between PTI ratios and VAS scores (r=0.494, p=0.044). The mean Lysholm score was significantly lower in group A (80.17±3.05) than in group B (89.76±3.05) (p<0.001). In group A, the width and thickness of the patellar tendon were found to be significantly different between the operated and unoperated knees (p=0.024 and p=0.002, respectively). In group B, there was no difference between the operated and unoperated knees in terms of the 3 measurements (length, width, and thickness) (p=0.762, p=0.753, and p=0.118, respectively).

CONCLUSION

Evidence from this study revealed that morphological changes occurring in the patellar tendon after IMN for tibial shaft fractures using a transpatellar approach may have a significant role in the development of AKP. The increase in the tendon width and thickness may be the cause of pain and insufficient knee function in such patients.

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Bilateral changes in tendon structure of patients diagnosed with unilateral insertional or midportion achilles tendinopathy or patellar tendinopathy

PURPOSE

Changes in tendon structure are commonly seen in patients with unilateral achilles (AT) or patellar (PT) tendinopathy but might also be present on the asymptomatic side, indicating a higher risk for developing symptoms. The aim of this study is to compare tendon structure of the symptomatic side with the asymptomatic side in AT and PT patients and control subjects.

METHODS

A total of 46 patients with unilateral AT (16 insertional and 30 midportion) and 38 with unilateral PT were included. For the control group, a total of 18 Achilles tendons and 25 patellar tendons were scanned. Tendon structure was assessed using ultrasound tissue characterisation (UTC), which quantifies tendon organisation dividing the structure into four different echo types (I-IV).

RESULTS

There were significant differences in echo types I, III, and IV between symptomatic and asymptomatic sides and controls. Additionally, there was a significant difference between the symptomatic and the asymptomatic side for all tendinopathy locations. In the insertional AT tendon portion, the symptomatic side showed a higher percentage of echo type III. For the midportion AT, the symptomatic side showed a lower percentage of echo type I and a higher percentage of echo types III and IV. For the patellar tendon, the symptomatic side showed a higher percentage of echo types III and IV. All differences were higher than the minimal detectable changes.

CONCLUSION

Although patients have symptoms unilaterally, the tendon structures are compromised on both sides. These results stress the importance of monitoring both symptomatic and asymptomatic tendon structures and in addition highlight that the asymptomatic side should not be used as reference in clinical practice.

LEVEL OF EVIDENCE

III.

Plethora of Traumatic Lesions of Bilateral Knee Extensor Mechanism in Osteogenesis Imperfecta

INTRODUCTION

Injuries to the quadriceps extensor mechanism are rare in patients with Osteogenesis Imperfecta (OI). To the best of our knowledge, non-union of the patella in OI, either as an isolated problem or in combination with an acute fracture, has not been previously reported.

CASE REPORT

We describe how we surgically approached both the fracture and the non-union simultaneously. The surgical technique and steps are described in detail. Post-operative course was uneventful and the outcome was favorable, with full return of function for the patient.

CONCLUSION

A review of various knee extensor mechanism injuries in OI is described as illustrated in a single patient. The unusual simultaneous surgical treatment of a non-union and an acute fracture in the same patella shows that despite the severely compromised bone in this rare bone disease the bone still has a capacity to heal with a functional outcome.

Relaxin inhibits patellar tendon healing in rats: a histological and biochemical evaluation

BACKGROUND

Female patients are more likely to have tendon injuries than males, especially those who has a higher concentration of relaxin. Previous studies have demonstrated that relaxin attenuates extracellular matrix (ECM) formation. However, the mechanism of relaxin on tendon repair remains unclear. We hypothesize that relaxin inhibits tendon healing by disrupting collagen synthesis.

METHODS

A patellar tendon window defect model was established using Sprague-Dawley rats. The center of the patellar tendon was removed from the patella distal apex and inserted to the tibia tuberosity in width of 1 mm. Then, the rats were injected with saline (0.2 μg/kg/day) or relaxin (0.2 μg/kg/day) for two and four weeks, which was followed by biomechanical analysis and histological and histochemical examination.

RESULTS

Mechanical results indicated that relaxin induces a significant decrease in tear resistance, stiffness, and Young's modulus compared to those rats without relaxin treatment. In addition, it was shown that relaxin activates relaxin family peptide receptor 1(RXFP1), disturbs the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteases (TIMPs), and reduces the deposition of collagen in injury areas.

CONCLUSIONS

Relaxin impairs tendon healing in rats. Also, relaxin might lead to tendon injury more commonly for females than males.

Histopathological changes in the infrapatellar fat pad in an experimental rabbit model of early patellofemoral osteoarthritis

BACKGROUND

The purpose of this study was to characterise the histopathological changes in the infrapatellar fat pad (IPFP) in the early stage of patellofemoral osteoarthritis (PFOA).

METHODS

Sixty-four New Zealand white rabbits were randomly divided into experimental (n = 24), sham (n = 16), and control groups (n = 24). In the experimental group, denoted as the patellar ligament uneven shortening group (US group), the patellar ligament (PL) was folded eight millimetres and sutured. After eight weeks, all animals were euthanised, and magnetic resonance imaging (MRI) evaluation, wet IPFP weight measurement, and histopathological and immunohistochemistry analysis were performed to analyse the histopathological changes in the IPFPs.

RESULTS

The maximum cross-sectional area (CSA) of the IPFPs in the sagittal position of MRI in the control group, sham group, and US group were 45.50 ± 7.19 mm², 45.88 ± 6.60 mm² (vs. control group, P = 0.907), and 53.83 ± 8.24 mm² (vs. control group, P = 0.015; vs. sham group, P = 0.035), respectively. The MRI intensity of the IPFPs in the control group, sham group, and US group were 115.53 ± 28.85, 108.53 ± 26.73 (vs. control group, P = 0.589), and 154.52 ± 18.48 (vs. control group, P = 0.002; vs. sham group, P = 0.002), respectively. The wet weight of the IPFPs in the control group, sham group, and US group were 0.32 ± 0.05 g, 0.32 ± 0.04 g (vs. control group, P = 0.895), and 0.38 ± 0.06 g (vs. control group, P = 0.017; vs. sham group, P = 0.033), respectively. The Osteoarthritis Research Society International (OARSI) scores of the IPFPs in the US group were 6.00 ± 1.91, which was higher than the scores of 2.50 ± 2.02 (P < 0.001) in the control group and of 2.75 ± 1.67 (P = 0.001) in the sham group.

CONCLUSIONS

The histopathological changes of the IPFPs as determined via MRI and microscopic structure appeared to occur much earlier than cartilage damage in PFOA. Furthermore, detecting and treating the IPFP changes may offer aid in the diagnosis and treatment of PFOA.

Ultrasonographic comparison of bilateral patellar tendon dimensions in patients treated via intramedullary tibial nailing using a transpatellar approach

Objective

One of the most common complications following intramedullary nailing of a tibial shaft fracture is anterior knee pain. The etiology of pain remains unclear. Patellar tendon entry point is the most suspected reason for anterior knee pain. This study, sonographically examined the patellar tendons of patients treated via intramedullary nailing.

Methods

Thirty-two patients with a tibial shaft fracture requiring intramedullary nailing via a transpatellar approach were included in the study. After all patients were grouped by reference to the presence of anterior knee pain, bilateral patellar tendon ultrasonography was performed.

Results

Thirty-two patients were included in the study. Patients were measured postop average in 38.3 months (10th months - 84th months). It was determined that 10 patients of total 32 (31.3%) had anterior knee pain. There were no statistically differences between study groups in the length of patellar tendon. In the painless group; patellar tendon was wider and thicker in the operated side than the non operated side. The mean differences in the thickness between operated side versus non – operated side of the painless group were 5.3 ± 1.8 in the operated side and 3.9 ± 1.4 in the non – operated side (p = 0.007 < 0.05). The corresponding values for width of the patellar tendon was 29.6 ± 3.3 in the operated side and 27.6 ± 3.8 in the non – operated side (p = 0.007 ˂ 0.05). As a result, there were no statistically significant differences between width and thickness of the patellar tendons in the painful group, on the contrary, in the painless group; patellar tendons were wider and thicker in the operated side than those in the non - operated side. Mean values for thickness of the operated and non-operated side were 5.9 ± 2.3 and 4.2 ± 2.0, respectively (p = 0.059 > 0.05). Mean values for width of the operated and non-operated side were 30.2 ± 4.5 and 28.5 ± 4.0, respectively (p = 0.103 > 0,05).

Conclusion

Based on the ultrasonographic investigation of their patellar tendons after intramedullary nailing of a tibial shaft fracture, in the painless patients group; the patellar tendon was wider and thicker in the operated side than the non – operated side, however, in the painful patients there were no statistically significant differences between this parameters. Although the number of patients was not sufficient to conclude precise relation between patellar tendon entry point and anterior knee pain, we determined that thicker and wider tendon might be less related to anterior knee pain.

Level of evidence

Level IV, therapeutic study.

Middle patellar tendon to posterior cruciate ligament (PT-PCL) and normalized PT-PCL: New magnetic resonance indices for tibial tubercle position in patients with patellar instability

BACKGROUND

To demonstrate whether the distance between the middle point of the patellar tendon and posterior cruciate ligament (PT-PCL) calculated on a single axial MR image could be an alternative measure to tibial tubercle-PCL (TT-PCL) distance for TT lateralization without the need of imaging processing. To show that normalization of PT-PCL (nPT-PCL) against the maximum diameter of the tibial plateau may help to identify patients with patellar instability (PI).

METHODS

MR scans of 30 patients (13 females, age 32 ± 13 years) with known PI and 60 patients (31 females, age 39 ± 19 years) with no history of PI were reviewed. Two operators calculated TT-PCL, and PT-PCL nPT-PCL. Intraclass correlation coefficient, Student's t-test, Receiver Operator Characteristic curves, Spearman's Rho and McNemar's test were used.

RESULTS

Interobserver reproducibility was 0.894 for PT-PCL for TT-PCL (95% CI = 0.839-0.930) and 0.866 for TT-PCL (95% CI = 0.796-0.912). The PT-PCL was 23.5 ± 3.8 mm in patients and 20.0 ± 2.7 mm in controls (P < 0.001). The TT-PCL was 22.9 ± 3.9 mm in patients and 20.5 ± 2.7 mm in controls (P = 0.002). Correlation between the PT-PCL and TT-PCL was R = 0.838, P < 0.001. The PT-PCL had 66.6% (95% CI = 0.542-0.790) diagnostic yield. The nPT-PCL was significantly higher in patients (0.302 ± 0.03) than controls (0.271 ± 0.03; P < 0.001) with 73.9% (95% CI = 0.628-0.851) diagnostic yield.

CONCLUSION

The PT-PCL correlated with TT-PCL, with 66.6% diagnostic yield. The nPT-PCL may represent an additional index, with 73.9% diagnostic yield.

Treatment of Osgood-Schlatter disease: review of the literature

BACKGROUND

Osgood-Schlatter disease (OSD) is a self-limiting condition which occurs commonly in adolescence.

PURPOSE

The objective of this article is to review published literature regarding pathophysiology, diagnosis and treatment of OSD.

METHODS

A search of the literature was performed on the electronic databases PubMed, Cochrane and SCOPUS databases between 1962 and 2016 for pathophysiology, diagnosis and treatment of Osgood-Schlatter disease.

RESULTS

OSD, also known as apophysitis of the tibial tubercle, is a common disease with most cases resolving spontaneously with skeletal maturity. In pathophysiology, the most accepted theory is repetitive knee extensor mechanism contraction. The pain is localized to the anterior aspect of the proximal tibia over the tibial tuberosity. They may describe a dull ache exacerbated by jumping or stair climbing. Radiological evaluation may indicate superficial ossicle in the patellar tendon. Osgood-Schlatter is a self-limited disease and generally ceases with skeletal maturity. Treatment is usually symptomatic. Adults with continued symptoms may need surgical treatment if they fail to respond to conservative treatment. Surgical procedures include open, bursoscopic and arthroscopic technique. Arthroscopic surgery is beneficial over an open procedure due to early postoperative recovery, no incisional scar in front of the tuberosity that usually causes discomfort in kneeling with a better cosmetic result and the ability to address concomitant intra-articular pathology.

CONCLUSION

Osgood-Schlatter syndrome runs a self-limiting course, and usually complete recovery is expected with closure of the tibial growth plate. Overall prognosis for Osgood-Schlatter syndrome is good, except for some discomfort in kneeling and activity restriction in a few cases. Arthroscopic techniques seem to be the best choice of treatment of unresolved Osgood-Schlatter lesions.

Peritendinous injection of platelet-rich plasma to treat tendinopathy: A retrospective review

Objective

The aim of this study was to determine factors associated with the likelihood of a better clinical outcome after the peritendinous injection of PRP for the treatment of chronic tendinopathy and identify whether PRP represents an effective treatment option for chronic tendinopathies.

Methods

The study included 214 patients (86 males and 128 females; mean age: 39.3 (18–75) years) who received PRP injections for tendinopathy refractory to conventional treatments. The mean duration of symptoms at the moment of the PRP treatment was 8.3 months. Primary outcome measurement was perceived improvement in symptoms for each anatomic compartment for upper and lower limbs at 6 months after treatment. Also, a visual analog scale (VAS) score (pain intensity on a 0–10 scale) was used for pain scoring questionnaire before treatment, 6 weeks and 6 months following the PRP injection(s). To identify factors associated with the likelihood of a better clinical outcome, patients were categorized on the basis of their perceived improvement in symptoms 6 months after the PRP injection(s)—that is, as lower (less than 50% global improvement) or higher (more than 50% global improvement).

Results

A visual analogue scale score and perceived improvement in symptoms were significantly lower after peritendinous injection in 6-week and 6-month follow-ups compared with the baseline (P < 0.001) except for peroneal and Achilles tendons. Overall, 83% of patients indicated moderate to complete improvement in symptoms. The most common injection sites were the lateral epicondyle, Achilles, and patellar tendons. Furthermore, 30% of patients received only 1 injection, 30% received 2 injections, and 40% received 3 or more injections. A total of 85% of patients were satisfied (more than 50% global improvement) with the procedure. In addition, upper limb tendons, increase in the age, and female gender were associated with a higher likelihood of perceived improvement in symptoms.

Conclusions

In the present retrospective study assessing PRP injections in the treatment of chronic tendinopathy, a moderate improvement (>50%) in pain symptoms was observed in most of the patients. Our research found that results were most promising with patellar and lateral epicondylar tendinopathy in the short to medium term. Female patients, patients with upper extremity tendinopathy and older patients appeared to benefit more from PRP injection.

Level of evidence

Level IV, Therapeutic study.

Patellar tendon ossification after retrograde intramedullary nailing for distal femoral shaft fracture: A case report and review of the literature

RATIONALE

Retrograde femoral nailing was one of the most important treatment means for distal femoral shaft fracture. However, studies regarding heterotopic ossification of the patellar tendon after retrograde intramedullary nailing for distal femoral shaft fracture are limited. We herein present a rare complication, namely heterotopic ossification of the patellar tendon, after retrograde intramedullary nailing for displaced femoral shaft fracture.

PATIENT CONCERNS

We present a case of 25-year-old male with displaced femoral shaft fracture who was treated by retrograde intramedullary nailing.

DIAGNOSES

During the period of follow-up, the patient developed symptomatic heterotopic ossification of the patellar tendon with extensively hard ossification area.

INTERVENTIONS

Open surgery was recommended, but the patient has refused further treatment.

OUTCOMES

The patient resulted in pain and restricted the range of motion of the affected knee.

LESSONS

This case stresses the importance of longer-term follow-up and further attention into the possibility of heterotopic ossification of the patellar tendon.

Why are bone and soft tissue measurements of the TT-TG distance on MRI different in patients with patellar instability?

PURPOSE

To determine whether the tibial tuberosity-to-trochlear groove distance (TT-TG) and patellar tendon-to-trochlear groove distance (PT-TG) are equal, whether the bony and cartilaginous points coincide in the trochlea, and whether the insertion of the PT coincides with the most anterior point of the TT in patients with patellar instability.

METHODS

Fifty-three MRI scans of patients with patellar instability were examined. TT-TG and PT-TG were measured by three examiners in 31 knees. Additionally, the bone-cartilage distance in the trochlea [trochlear cartilage to trochlear bone (TC-TB)] and the distance between the mid-point of the PT insertion and the most anterior point of the TT (PT-TT) were measured by one examiner. The intraclass correlation coefficient was used to evaluate the reliability of the measurements between the three examiners. The relationships between the measurements were determined, the means of the measurements were calculated, and the correlations between PT-TG and TT-TG, PT-TT, and TC-TB were assessed.

RESULTS

The ICC was above 0.8. PT-TG was 3.7 mm greater than TT-TG. The TC and TB coincided in 73 % of cases, and the mean TC-TB was 0.3 mm. The PT was lateral to the TT in 94 % of the cases, and the mean PT-TT was 3.4 mm. The Pearson's correlation coefficients between PT-TG and TT-TG, PT-TT, and TC-TB were 0.946, 0.679, and 0.199, respectively.

CONCLUSION

TT-TG underestimated PT-TG, primarily due to the lateralization of the PT insertion relative to the most anterior point of the TT.

CLINICAL RELEVANCE

our study shows that in patients with patellar instability, there are differences in the absolute values of TT-TG and PT-TG, as previously reported for patients without patellar instability. Hence, normal cut-off values based on case-control studies of TT-TG cannot be equivalently used when measuring PT-TG to indicate TT medialization in patients with patellar instability. It is also important to note that the clinical outcomes cannot be directly compared between patients evaluated using TT-TG versus PT-TG measurements.

LEVEL OF EVIDENCE

III.

[Running and causes of running-related injuries]

Running is one of the most popular sports among the adult Danish population. Overuse injuries of the knee, such as runners knee, jumpers knee, patello-femoral pain syndrome and patello-femoral pre-arthrosis, are common and cause reduction of the health beneficial physical activity. Treatment should primarily focus on adjustment of training habits and physiotherapeutic guided rehabilitation. Other treatment options include changing landing pattern during running, corticosteroid injections, non-steroid anti-inflammatory drugs and ultimately surgery.

Tendon Reattachment to Bone in an Ovine Tendon Defect Model of Retraction Using Allogenic and Xenogenic Demineralised Bone Matrix Incorporated with Mesenchymal Stem Cells

Background

Tendon-bone healing following rotator cuff repairs is mainly impaired by poor tissue quality. Demineralised bone matrix promotes healing of the tendon-bone interface but its role in the treatment of tendon tears with retraction has not been investigated. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds.

Materials and Methods

In an ovine model, the patellar tendon was detached from the tibial tuberosity and a complete distal tendon transverse defect measuring 1 cm was created. Suture anchors were used to reattach the tendon and xenogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5), or allogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5) were used to bridge the defect. Graft incorporation into the tendon and its effect on regeneration of the enthesis was assessed using histomorphometry. Force plate analysis was used to assess functional recovery.

Results

Compared to the xenograft, the allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009). In the allogenic group this was accompanied by greater remodeling of the demineralised bone matrix into tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039). No failures of tendon-bone healing were noted in either group.

Conclusion

Demineralised bone matrix used with minimally manipulated mesenchymal stem cells promotes healing of the tendon-bone interface in an ovine model of acute tendon retraction, with superior mechanical and histological results associated with use of an allograft.

Mechanically-enhanced three-dimensional scaffold with anisotropic morphology for tendon regeneration

Tissue engineering has showed promising results in restoring diseased tendon tissue functions. Herein, a hybrid three-dimensional (3D) porous scaffold comprising an outer portion rolled from an electrohydrodynamic jet printed poly(ɛ-caprolactone) (PCL) fiber mesh, and an inner portion fabricated from uniaxial stretching of a heat-sealed PCL tube, was developed for tendon tissue engineering (TE) application. The outer portion included three layers of micrometer-scale fibrous bundles (fiber diameter: ~25 µm), with an interconnected spacing and geometric anisotropy along the scaffold length. The inner portion showed orientated micro-ridges/grooves in a parallel direction to that of the outer portion. Owning to the addition of the inner portion, the as-fabricated scaffold exhibited comparable mechanical properties to those of the human patellar tendon in terms of Young's modulus (~227 MPa) and ultimate tensile stress (~50 MPa). Compared to the rolled electrospun fibers, human tenocytes cultured in the tendon scaffolds showed increased cellular metabolism. Furthermore, the 3D tendon scaffold resulted in up-regulated cell alignment, cell elongation and formation of collagen type I. These results demonstrated the potential of mechanically-enhanced 3D fibrous scaffold for applications in tendon TE, with desired cell alignment and functional differentiation.

Stepwise Differentiation of Mesenchymal Stem Cells Augments Tendon-Like Tissue Formation and Defect Repair In Vivo

: Tendon injuries are common and present a clinical challenge, as they often respond poorly to treatment and result in long-term functional impairment. Inferior tendon healing responses are mainly attributed to insufficient or failed tenogenesis. The main objective of this study was to establish an efficient approach to induce tenogenesis of bone marrow-derived mesenchymal stem cells (BMSCs), which are the most common seed cells in tendon tissue engineering. First, representative reported tenogenic growth factors were used as media supplementation to induce BMSC differentiation, and the expression of teno-lineage transcription factors and matrix proteins was compared. We found that transforming growth factor (TGF)-β1 significantly induced teno-lineage-specific gene scleraxis expression and collagen production. TGF-β1 combined with connective tissue growth factor (CTGF) elevated tenomodulin and Egr1 expression at day 7. Hence, a stepwise tenogenic differentiation approach was established by first using TGF-β1 stimulation, followed by combination with CTGF for another 7 days. Gene expression analysis showed that this stepwise protocol initiated and maintained highly efficient tenogenesis of BMSCs. Finally, regarding in situ rat patellar tendon repair, tendons treated with induced tenogenic BMSCs had better structural and mechanical properties than those of the control group, as evidenced by histological scoring, collagen I and tenomodulin immunohistochemical staining, and tendon mechanical testing. Collectively, these findings demonstrate a reliable and practical strategy of inducing tenogenesis of BMSCs for tendon regeneration and may enhance the effectiveness of cell therapy in treating tendon disorders.

SIGNIFICANCE

The present study investigated the efficiency of representative tenogenic factors on mesenchymal stem cells' tenogenic differentiation and established an optimized stepwise tenogenic differentiation approach to commit tendon lineage differentiation for functional tissue regeneration. The reliable tenogenic differentiation approach for stem cells not only serves as a platform for further studies of underlying molecular mechanisms but also can be used to enhance cell therapy outcome in treating tendon disorders and develop novel therapeutics for tendon injury.

The effects of substance p on tendinopathy are dose-dependent: an in vitro and in vivo model study

OBJECTIVES

Substance P (SP) is known to be involved in neuropathic pain, chronic inflammation, and tendinopathy. The present study evaluated the effects of different doses of SP on tendon-derived stem cells (TDSCs) in vitro and tendons in vivo.

METHODS

For the in vitro study, TDSCs cultured in growth medium with different concentrations of SP (negative control, 0.1 nM, and 1.0 nM). The effects of SP on TDSCs were examined with respect to their ability to proliferate and differentiate. For the in vivo study, we injected different doses of SP (saline control, 0.5 nmol, and 5.0 nmol) into rat patella tendons to investigate the effects of SP on tendons.

RESULTS

Low and high doses SP significantly enhanced the proliferation ability of TDSCs. Low-dose of SP induced the expression of tenocyte-related genes; however, high-dose of SP induced the expression of non-tenocyte genes, which was evident by the high expression of PPARγ and collagen type II. In the in vivo study, only high-doses of SP (5.0 nmol) induced the tendinosis-like changes in the patella tendon injection model. Low doses of SP (0.5 nmol) enhanced the tenogenesis compared with saline injection and the high-dose SP group.

CONCLUSIONS

SP enhances the proliferation of TDSCs in vitro and the effects of SP on tendinopathy are dose-dependent in vivo.

Real-time sonoelastography of the quadriceps tendon in patients undergoing chronic hemodialysis

OBJECTIVES

This study aimed to compare sonoelastographic findings for the quadriceps tendon in patients with chronic renal failure who were in a dialysis program to findings in a control group.

METHODS

Fifty-three randomly allocated patients (mean age, 54.3 years; range, 27-86 years) with chronic renal failure who were in a dialysis program 3 days a week between January and May 2012 were included. The measurements were performed in both knees of 53 patients undergoing dialysis and 25 individuals in the control group. The tendons were classified as follows: type 1, very stiff tissue (blue); type 2, stiff tissue (blue-green); and type 3, intermediate tissue (green-yellow) according to color mapping.

RESULTS

The mean quadriceps tendon thicknesses in the patient group were 4.9 mm (range, 1.9-6.5 mm) for the right knee and 4.9 mm (1.4-6.5 mm) for the left knee; the values in the control group were 5.4 mm (3.6-7.0 mm) for the right knee and 5.4 mm (3.4-7.0 mm) for the left knee. The mean elasticity scores in the patient group were 3.14 (1.03-5.23) for the right knee and 3.33 (1.29-5.00) for the left knee; in the control group, the values were 3.79 (1.73-5.23) and 3.69 (1.23-5.53) for the right and left knees, respectively (right knee, P = .025; left knee, P = .018; Mann-Whitney U test). The quadriceps tendons were significantly thinner in the patient group (right knee, P = .054; left knee, P = .015; Mann-Whitney U test).

CONCLUSIONS

Quadriceps tendons in patients with chronic renal failure are thinner and have lower elasticity scores compared to controls.

MPFL reconstruction: technique and results

Patellar instability is a common problem, and medial patellofemoral ligament (MPFL) injury is inherent with traumatic patellar dislocations. Initial nonoperative management is focused on reconditioning and strengthening the dynamic stabilizers of the patella. For those patients who progress to recurrent instability, further investigation into the predisposing factors is required. MPFL reconstruction is indicated in patients with recurrent instability and insufficient medial restraint due to MPFL injury. A technique of MPFL reconstruction is outlined. This procedure may also be performed in combination with other realignment procedures.

The effects of scaffold architecture and fibrin gel addition on tendon cell phenotype

Development of tissue engineering scaffolds relies on careful selection of pore architecture and chemistry of the cellular environment. Repair of skeletal soft tissue, such as tendon, is particularly challenging, since these tissues have a relatively poor healing response. When removed from their native environment, tendon cells (tenocytes) lose their characteristic morphology and the expression of phenotypic markers. To stimulate tendon cells to recreate a healthy extracellular matrix, both architectural cues and fibrin gels have been used in the past, however, their relative effects have not been studied systematically. Within this study, a combination of collagen scaffold architecture, axial and isotropic, and fibrin gel addition was assessed, using ovine tendon-derived cells to determine the optimal strategy for controlling the proliferation and protein expression. Scaffold architecture and fibrin gel addition influenced tendon cell behavior independently in vitro. Addition of fibrin gel within a scaffold doubled cell number and increased matrix production for all architectures studied. However, scaffold architecture dictated the type of matrix produced by cells, regardless of fibrin addition. Axial scaffolds, mimicking native tendon, promoted a mature matrix, with increased tenomodulin, a marker for mature tendon cells, and decreased scleraxis, an early transcription factor for connective tissue. This study demonstrated that both architectural cues and fibrin gel addition alter cell behavior and that the combination of these signals could improve clinical performance of current tissue engineering constructs.

Achilles and patellar tendon morphology in dancers with and without tendon pain

OBJECTIVES

To examine Achilles and patellar tendon morphology in dancers with and without tendon pain.

METHODS

Fifty-three dancers with and without Achilles and/or patellar tendon pain participated. Eleven age-matched non-dancers served as controls. Longitudinal ultrasound images of the middle and distal Achilles and proximal and distal patellar tendons were acquired. To assess macromorphology, the thickness of the middle and distal Achilles and proximal and distal patellar tendons were measured. Micromorphology was analyzed by selecting 2 x 2-mm2 regions of interest in the tendons; spectral analysis using the fast Fourier transform was run for several kernels (2 x 2-mm2 subimages) within each image, and the peak spatial frequency (PSF) was extracted. A one-way ANOVA compared asymptomatic, symptomatic, and control tendon thickness and PSF.

RESULTS

Macromorphology: There was no significant difference between asymptomatic and symptomatic dancers in middle or distal Achilles tendon thickness and distal patellar tendon thickness. Proximal patellar tendons in control subjects were thinner than those in asymptomatic (p=0.036) and symptomatic (p=0.003) dancers. Micromorphology: There was no significant difference in PSF between asymptomatic and symptomatic dancers and controls in the Achilles or patellar tendon.

CONCLUSION

Increased proximal patellar tendon thickness without changes in tendon micromorphology suggests that tendon adaptations are more likely activity-related and less likely influenced by degeneration.

Changes in morphological and elastic properties of patellar tendon in athletes with unilateral patellar tendinopathy and their relationships with pain and functional disability

BACKGROUND

Patellar tendinopathy (PT) is one of the most common knee disorders among athletes. Changes in morphology and elasticity of the painful tendon and how these relate to the self-perceived pain and dysfunction remain unclear.

OBJECTIVES

To compare the morphology and elastic properties of patellar tendons between athlete with and without unilateral PT and to examine its association with self-perceived pain and dysfunction.

METHODS

In this cross-sectional study, 33 male athletes (20 healthy and 13 with unilateral PT) were enrolled. The morphology and elastic properties of the patellar tendon were assessed by the grey and elastography mode of supersonic shear imaging (SSI) technique while the intensity of pressure pain, self-perceived pain and dysfunction were quantified with a 10-lb force to the most painful site and the Victorian Institute of Sport Assessment-patella (VISA-P) questionnaire, respectively.

RESULTS

In athletes with unilateral PT, the painful tendons had higher shear elastic modulus (SEM) and larger tendon than the non-painful side (p<0.05) or the dominant side of the healthy athletes (p<0.05). Significant correlations were found between tendon SEM ratio (SEM of painful over non-painful tendon) and the intensity of pressure pain (rho  = 0.62; p = 0.024), VISA-P scores (rho  = -0.61; p = 0.026), and the sub-scores of the VISA-P scores on going down stairs, lunge, single leg hopping and squatting (rho ranged from -0.63 to -0.67; p<0.05).

CONCLUSIONS

Athletes with unilateral PT had stiffer and larger tendon on the painful side than the non-painful side and the dominant side of healthy athletes. No significant differences on the patellar tendon morphology and elastic properties were detected between the dominant and non-dominant knees of the healthy control. The ratio of the SEM of painful to non-painful sides was associated with pain and dysfunction among athletes with unilateral PT.

[Bilateral rupture of patellar tendons in young patients with no notion of systemic disease or corticosteroid therapy: report of a case and review of the literature]

Les lésions du tendon rotulien sont moins communes que celles du tendon quadricipital. Les lésions bilatérales sont encore plus rares et sont souvent associées à une notion de tendinopathie, d'injection de corticoïdes ou de maladies systémiques tels que le lupus érythémateux, l'ostéomalacie ou l'insuffisance rénale chronique. Nous rapportons le cas d'un patient de 26 ans victime d'une rupture bilatérale du tendon rotulien suite à une réception de saut. Le patient n'avait pas d'antécédents de tendinopathie ni de maladies systémiques. Le diagnostic a été suspecté devant une position anormalement haute des deux rotules avec une impossibilité d'extension active des deux jambes. L’échographie a confirmé le diagnostic. Le patient a été traité par la technique de laçage selon Judet protégée par un cadrage. La rupture bilatérale du tendon rotulien est rare. La plupart des patients rapportent une notion de maladie systémique ou un antécédents de chirurgie du genou. Nous rapportons le cas d'une lésion rare dans la littérature, une rupture bilatérale des tendons rotuliens sans notions de maladies auto-immunes ni de traitement avec des corticostéroïdes. Les lésions bilatérales présentent certaines particularités diagnostiques et thérapeutiques. En effet l'objectivation d'une rotule haute peut être rendu difficile par un aspect controlatéral semblable. Concernant le volet thérapeutique, deux difficultés sont à noter la première réside dans l'absence de référence comparative pour la hauteur patellaire. La deuxième difficulté est l'obligation de différer l'appui à 45 jours. Ce qui est contraignant pour le patient. La technique de laçage décrite par judet couplée à un cadrage provisoire protégeant la suture nous a donné des résultats satisfaisants.

Scx-transduced tendon-derived stem cells (tdscs) promoted better tendon repair compared to mock-transduced cells in a rat patellar tendon window injury model

We hypothesized that the transplantation of Scx-transduced tendon-derived stem cells (TDSCs) promoted better tendon repair compared to the transplantation of mock-transduced cells. This study thus aimed to investigate the effect of Scx transduction on the expression of lineage markers in TDSCs and the effect of the resulting cell line in the promotion of tendon repair. Rat non-GFP or GFP-TDSCs were transduced with Scx or empty lentiviral vector (Mock) and selected by blasticidin. The mRNA expressions of Scx and different lineage markers were examined by qRT-PCR. The effect of the transplantation of GFP-TDSC-Scx on tendon repair was then tested in a rat unilateral patellar tendon window injury model. The transplantation of GFP-TDSC-Mock and scaffold-only served as controls. At week 2, 4 and 8 post-transplantation, the repaired patellar tendon was harvested for ex vivo fluorescent imaging, vivaCT imaging, histology, immunohistochemistry and biomechanical test. GFP-TDSC-Scx consistently showed higher expressions of most of tendon- and cartilage- related markers compared to the GFP-TDSC-Mock. However, the effect of Scx transduction on the expressions of bone-related markers was inconclusive. The transplanted GFP-TDSCs could be detected in the window wound at week 2 but not at week 4. Ectopic mineralization was detected in some samples at week 8 but there was no difference among different groups. The GFP-TDSC-Scx group only statistically significantly improved tendon repair histologically and biomechanically compared to the Scaffold-only group and the GFP-TDSC-Mock group at the early stage of tendon repair. There was significant higher expression of collagen type I in the window wound in the GFP-TDSC-Scx group compared to the other two groups at week 2. The transplantation of GFP-TDSC-Scx promoted healing at the early stage of tendon repair in a rat patellar tendon window injury model.

Does patellar rim electrocautery have deleterious effects on patellar cartilage?

BACKGROUND

Circumpatellar electrocauterization to destroy pain receptors during total knee arthroplasty without patellar resurfacing is commonly used to decrease postoperative knee pain. We aimed to evaluate the effect of denervation with electrocauterization on patellar cartilage.

METHODS

Twenty rabbits were randomly assigned to two equally sized case and control groups. The rabbits in the case group underwent surgery via the anterior midline skin incision and medial parapatellar arthrotomy, followed by denervation electrocauterization at a depth of 1 mm and a distance of 3 mm from the outer border of the patella. In the control group, surgery was identical to that performed in the case group, but without patellar denervation. Twelve weeks after surgery, all rabbits were sacrificed. Range of motion, macroscopic evaluation of cartilage using modified Outerbridge scoring, and histopathological assessment using a modified histologic scoring system for cartilage were evaluated.

RESULTS

Three rabbits died during the study. Nine cases and eight animals from the control group were included in the final evaluation. All rabbits had passive full range of motion. Mean Outerbridge score was 2.0 in the case group and 0.37 in the control group (p=0.002). There were statistically significant differences in cellularity (p=0.016), loss of matrix (p=0.004), and clustering of chondrocytes (p=0.008) between the two groups. Microscopic variables as a whole were statistically significant (p=0.001).

CONCLUSIONS

Circumpatellar electrocauterization may result in cartilage destruction. So, we encourage caution in using routine electrocauterization in patients undergoing total knee arthroplasty.

LEVEL OF EVIDENCE

level II.

A rare case of enchondromatosis of the knees and hands with involvement of Hoffa's fat pad and peri-articular soft-tissues

We report a case of a 56-year old man with chronic pain in both knees for several years. This patient had already undergone surgery on his left knee in 2002 after an x-ray showed multiple lytic and well margined lesions in the distal femur and proximal tibia with ground-glass matrix, involving Hoffa's fat pad and the patellar ligament. Histology was consistent with an enchondroma. The most recent MRI examination showed enchondromatosis involving both knees with bilateral extension into Hoffa's fat pad and the patellar ligament. Subsequently, we performed an additional radiographic examination of the hands and feet, as well as an MRI of both hands to identify other possible enchondromas in the most common sites for this disease. Enchondromatosis with soft tissue involvement is extremely rare, and involvement of Hoffa's fat pad has not been reported in the scientific literature. The clinical presentation of this case and the general aspects of Enchondromatosis are discussed.

Patellar tendinopathy - recent developments toward treatment

Patellar tendinopathy (PT) is a clinical and chronic overuse condition of unknown pathogenesis and etiology marked by anterior knee pain typically manifested at the inferior pole of the patella. PT has been referred to as "jumper's knee" since it is particularly common among populations of jumping athletes, such as basketball and volleyball players. Due to its common refractory response to conservative treatment, a variety of new treatments have emerged recently that include dry-needling, sclerosing injections, platelet-rich plasma therapy, arthroscopic surgical procedures, surgical resection of the inferior patellar pole, extracorporeal shock wave treatment, and hyperthermia thermotherapy. Since PT has an unknown pathogenesis and etiology, PT treatment is more a result of physician experience than evidence-based science. This review will summarize the current literature on this topic, identify current research efforts aimed to understand the pathological changes in abnormal tendons, provide exposure to the emerging treatment techniques, and provide suggested direction for future research.

Impact of knee flexion on patella length in osteoarthritic patients undergoing total knee arthroplasty

PURPOSE

This study used magnetic resonance imaging (MRI) to evaluate in vivo preoperative changes in the length of the patellar tendon (LPT) in patients undergoing total knee arthroplasty (TKA). We sought to answer two questions: first, does the LPT change with flexion? Second, does the LPT show a gender-specific pattern?

METHODS

Eighty-five knees in 76 consecutive osteoarthritic patients were evaluated. The age range was 56-90 years (mean 70). The study included 62 females and 14 males. MRI was performed at full extension and at 30°, 60°, 90°, and full flexion.

RESULTS

There were significantly different patterns between genders (p < 0.001). The main shortenings occurred earlier, at 30°, in females and later, at 60°, in males. In females, LPT values in full extension were significantly longer than those measured at other flexion angles. In male subjects, significant differences in LPT values were found between full extension versus 90° (p < 0.001) and full flexion (p < 0.001), and between 60° versus 90°(p = 0.030) and full flexion (p = 0.030).

CONCLUSION

These differences might influence the gender-specific complications related to the extensor mechanism after TKA. These data provide useful information for surgeons attempting to achieve a satisfactory balance between joint gaps in the patellar reduced position intraoperatively.

Masses in the extensor mechanism of the knee: an unusual presentation of gout

Tophaceous gout presenting as a soft tissue mass in an unusual location can pose a diagnostic challenge for radiologists. Tophi sometimes occur in a variety of unusual anatomic locations making them difficult to distinguish from tumors such as sarcomas. We report two cases of gout in the extensor mechanism of the knee, with imaging findings that were initially concerning for a neoplasm. One mass occurred in the patellar tendon and the other mass involved the quadriceps tendon. Both lesions had enigmatic imaging findings and to arrive at a definitive diagnosis, incisional biopsies were performed.

A rare case of open bicondylar Hoffa fracture with extensor mechanism disruption

The incidence of open bicondylar Hoffa fractures is extremely rare. We report one such case of a 42-year-old woman who presented to the emergency department with an open injury over the knee. Imaging revealed bicondylar Hoffa fracture. The patient was taken up for debridement and internal fixation. Intraoperative findings included an entrapped patella between the fracture fragments and extensor mechanism disruption. Hoffas fracture was fixed with lag screws and patellar tendon repaired on to the inferior patella. The patient was started on early postoperative range of motion exercises. The fracture united at 12 weeks with 120° knee flexion at 2 year follow-up.

Platelet-rich plasma application in the management of chronic tendinopathies

Platelet-rich plasma (PRP) may represent a new therapeutic option for chronic tendinopathies. Platelets release various cytokines and growth factors which promote angiogenesis, tissue remodeling, and wound healing. We made an extended literature review of the use of PRP in chronic tendinopathies: epicondylitis, rotator cuff, patellar and calcaneal tendinopathies, and plantar fasciitis. Medline, Embase and Google Scholar were used (until July 31, 2012). Clinical studies on PRP and tendinopathies published in English and French language peer-reviewed journals were included. Articles with a high level of evidence were given special consideration. Despite the proven efficacy of PRP on tissue regeneration in experimental studies, there is currently scanty tangible clinical evidence with respect to its efficacy in chronic tendon disorders. The few studies that have been performed appear unlikely to be comparable. Randomized controlled studies with appropriate placebo groups are needed to determine the real effectiveness of PRP for treating chronic musculoskeletal injuries.

Estimation of frontal alignment error of the extramedullary tibial guide on the bi-malleolar technique: a simulation study with magnetic resonance imaging

PURPOSE

The bi-malleolar technique for the extramedullary tibial guide is a representative method for determining the ankle center in total knee arthroplasty (TKA). The purpose of this study is to estimate three-dimensionally the lateral errors (difference between the real ankle center and the bi-malleolar center) and the varus angular errors of this technique under the condition that the malleolar prominences were correctly identified.

METHODS

Magnetic resonance images of 51 lower limbs from 51 healthy volunteers were analyzed. The lateral errors were measured, including or excluding the subcutaneous thickness, along the line perpendicular to the transmalleolar axis (TMA) or along the tibial anteroposterior (AP) axis. Furthermore, we evaluated the effects of the tibial torsion and the difference between the subcutaneous thicknesses on the malleoli on the lateral error.

RESULTS

When including the skin, the mean lateral errors of the ankle center observed along the line perpendicular to the TMA and along the tibial AP axis were 3.7 ± 1.4mm and 1.2 ± 1.5mm, respectively. The mean angular errors were 0.6 ± 0.2° and 0.2 ± 0.3°, respectively. A significant correlation between the tibial torsion and the lateral error was noted when observed along the tibial AP axis. The difference between the subcutaneous thicknesses on the malleoli affected the lateral error.

CONCLUSION

The errors were small enough to determine the mechanical axis of the tibia if the tibial guide could catch the bi-malleolar prominences of the ankle accurately and align along the tibial AP axis.

Simultaneous bilateral patellar tendon avulsion in an adolescent

A 13-year-old boy sustained an injury to both knees upon landing after a forceful jump in a soccer game. Plain radiography and magnetic resonance imaging demonstrated bilateral distal patellar tendon avulsions without fracture of the tibial tuberosities and the physes. To our knowledge, this particular injury has not been previously described in the literature. Open surgeries and internal fixation were performed with excellent functional outcome. This type of injury was similar to the well-recognised acute tibial tuberosity avulsion fracture in terms of the pathogenesis and treatment. We propose a further subtype of this injury pattern.

Arthroscopic repair of medial patellofemoral ligament avulsion in acute patellar dislocation in skeletally immature patient--a case report

Acute patellar dislocation is a severe injury to the knee and usually manifests with symptoms such as giving way, a sensation of lateral displacement of the patella accompanied by hemarthrosis and tenderness over the medial epicondylar region to palpation. Spontaneous reduction of the patella makes the diagnosis more difficult in initial evaluation. Radiographs often show a small bony avulsion at the medial border of the patella, which may represent an injury to the medial restraints. Magnetic resonance imaging may show a bone bruise on the medial patella, and/or on the lateral femoral condyle. The medial patellofemoral ligament (MPFL) may be avulsed distally, proximally or sustain in interstitial tear. Arthroscopic findings include hematoma and chondral or osteochondral lesions located on the central or medial facet of the patella or on the anterior lateral femoral condyle. We report a case of a patellar avulsion of medial patellofemoral ligament in a skeletally immature patient.

The association of infrapatellar fat pad oedema with patellar maltracking: a case-control study

OBJECTIVE

To look for any association between oedema in the superolateral portion of the infrapatellar fat pad and patellar maltracking.

MATERIALS AND METHODS

We compared two groups of knee MRI with regard to five patellar maltracking parameters. The first group included 100 knees with evidence of oedema in the superolateral aspect of the infrapatellar fat pad (the study group). The second group included another 100 knee MRI that had a normal infrapatellar fat pad (the control group). The five patellar maltracking parameters assessed were the trochlear depth, tibial tuberosity-trochlear groove distance (TTTG), patellar translation, patellofemoral angle (PFA) and the Insall-Salvati index.

RESULTS

There was a statistically significant difference in the Insall-Salvati index, patellar translation and PFA between the two groups (p value of <0.001, <0.001 and 0.004 respectively, Student's t test). There was a higher prevalence of patella alta, lateral patellar displacement (LPD) and lateral patellar tilt in the study group (p value of <0.001, <0.001 and 0.011 respectively, Fisher's exact test). Sixty out of 100 knees in the study group had at least one abnormal patellar maltracking parameter in comparison to 16 out of 100 knees in the control group (p < 0.001, Fisher's exact test).

CONCLUSION

Oedema in the superolateral portion of Hoffa's fat pad, the MRI feature of fat pad impingement, is associated with patellar maltracking.

Magnetic resonance imaging in patellar lateral femoral friction syndrome (PLFFS): prospective case-control study

OBJECTIVES

To describe morphologic abnormalities and signs of patellar lateral femoral friction syndrome (PLFFS) detected by magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Prospective study of 56 knees (21 patients and 30 controls) studied by 3Tesla MRI. Comparative analysis of clinical data, quantitative and qualitative imaging criteria in a population of patients with anterior knee pain associated with an abnormal MRI signal along the lateral alar folds of the infrapatellar fat pad, a characteristic sign of PLFFS, and a control population with no anterior knee pain or abnormal signal from the infrapatellar fat pad.

RESULTS

Patients with PLFFS have anterior and/or lateral knee pain. Their knee has anatomical predispositions for instability, primarily with patella alta (P<0.0001), patellar tilt more than 13.5° (P<0.0001), a patellar nose length less than 9 mm (P=0.0037), a patellar nose ratio less than 0.25 (P<0.0001), a TT-TG distance more than 10 mm (P<0.0001), and a trochlear prominence more than 4 mm (P=0.0056). In 35% of patients, patellar chondropathy is visible, and 48% of patients have patellar or trochlear subchondral abnormalities.

CONCLUSION

Anterior, lateral, and medial knee pain may be related to PLFFS. Anatomical predispositions contributing to instability are found in these patients. There may be associated chondropathies and osteochondropathies.

Emerging ideas: the effect of hypercholesterolemia on tendons

BACKGROUND

High levels of total cholesterol, triglycerides, and low-density lipoprotein are toxic to the vascular endothelium and thus have long been associated with atherosclerosis. Several clinical studies have suggested that elevated cholesterol also has a negative effect on tendon structure and function. Data from our preliminary studies show that the patellar tendons of hypercholesterolemic knockout mice exhibit reduced baseline elastic modulus and strength postinjury compared with controls.

QUESTIONS/HYPOTHESES

We therefore hypothesized elevated cholesterol would be associated with diminished tendon mechanical properties.

METHOD OF STUDY

Using hypercholesterolemic (B6.129P2-Apoetm1Unc/J) mice, patellar tendons from control (C57BL/6) and knockout mice will be injured surgically at two different times. Subsequently, mechanical testing will be performed and data evaluated for differences in baseline and in healing between cholesterol groups. For healing assessment, data from the injured limb of each animal will be normalized to that of the sham-operated contralateral limb.

SIGNIFICANCE

We anticipate that such studies eventually will enable us to elucidate the link between elevated cholesterol and tendon disease. If a mechanistic cause of hypercholesterolemia causing tendon disease is clarified, then potentially therapeutic interventions such as the use of pharmacotherapy may be used to help combat this. In the future, it may become worthwhile to consider the presentation of tendinopathy as a trigger to measure serum cholesterol just as one might consider measuring serum glucose in patients presenting with adhesive capsulitis.

Reconstruction of chronic patellar tendon rupture with semitendinosus tendon: case report

Chronic patellar tendon rupture is a rare injury whose treatment poses technical difficulties. Surgical repair is mandatory to restore the extensor mechanism of the knee. Many different surgical methods of patellar tendon reconstruction have been described. We present the case of a 48-year-old male patient who sustained patellar tendon rupture 8 months before surgery. A semitendinosus tendon graft and the modified Ecker technique were used for the reconstruction of the patellar tendon. Full extension was achieved alongside high patient satisfaction. However, the patient required prolonged intensive rehabilitation.

[Spontaneous patellar tendon rupture as a result of morbid obesity]

We present the case of spontaneous damage to the patellar tendon in a patient with pathologic obesity (BMI = 41), without comorbid conditions. Damage occurred during normal load combined with the movement of the knee extension when inserting a foot in flip-flops. Surgical treatment was performed in a matter of urgency and the patellar tendon was sutured in half the length of. Six weeks of immobilization was used and then rehabilitation. After four months efficient gait and a good range of motion was achieved. Please note that obesity is a disease of civilization and cause further disease. These include acute injuries resulting from a sudden overload.

[Treatment of patellar instability in children and adolescents]

To address recurrent patellar instability in children and young adolescents a variety of therapeutic options exist either as non-operative or operative treatment. Recent options, such as reconstruction of the medial patellofemoral ligament have evoked a new focus of attention on this topic. The intention of this article is to present diverse therapeutic options and to evaluate them by reference to the current literature.

Patellar tendinopathy: histopathological examination and follow-up of surgical treatment

PURPOSE OF THE STUDY

The aim of this study was to determine the exact localization of the histopathological process (bone, bone-tendon junction or tendon), and to determine whether the underlying pathologic process is predominantly of inflammatory or degenerative nature, then to evaluate the outcome of the surgical treatment of patellar tendinopathy.

MATERIALS

A prospective cohort study was performed in order to analyze the outcome of surgical treatment of patellar tendinopathy, as well as to document histopathological changes in bone, bone-tendon junction, and in the patellar ligament in 34 professional athletes treated with patellar apicotomy. All the patients included in the study were classified as stage 3 according to Blazina and showed no improvement after at least 6 months of conservative treatment. The postoperative follow-up was from 1 to 8 years with a mean value of 4.7 years.

METHODS

The postoperative results were analyzed using a semiquantitative scoring system where the functional outcome was classified as very good if the athlete returned to his sporting activity without any negative side effects, good if the athlete resumed his sporting activities with modest painful sensations present only at the maximum level of physical exertion, and poor if any reduction of athletic activity was present. In twenty patients a histopathological examination of resected bone and tendon tissue was performed. The specimens were stained with hematoxylin-eosin and examined under a light microscope using polarization. Special stains used were Alcian blue, to detect any increase in ground substance, and Prussian blue which enhances conspicuity of hyaline degeneration and enables detection of hemosiderin. Immunohistochemistry was performed in order to analyze presence of blood vessels, leukocytes and histiocytes.

RESULTS

Very good results were achieved in 20 of operated knees, good results were achieved in 12 of knees and poor results were achieved in 2 of operated knees. Pathological changes in the bone were found in 35% of analyzed specimens, abnormality at the bone-tendon junction were found in 75% of the specimens, and changes in the patellar tendon were found in all extracted specimens. The histopatholological nature of the lesions found within the tendon tissue in all of the analyzed specimens belongs to the group of degenerative changes.

DISCUSSION

Currently a consenus has been established that the expression tendinitis is "out", and the term tendinopathy should be used instead. No inflammatory cells and no increase in prostaglandins can be detected in the tendons. Histopathological studies of the tissue fibrils affected by tendinosis characteristically demonstrate hypercellularity, hypervascularity, lack of inflammatory infiltrates, and disorganization and loosening of collagen fibers.

CONCLUSION

The clinical results and histopathological examination in our series justified our operative method. In the chronic stage these lesions are irreversible and constitute permanent intratendinous lesions. It thus seems logical to excise these lesions from their origin at the apex of the patella and entry into the adjacent tendon. It is also recommended on the basis of our and other authors' research that the term patellar tendinopathy should be used instead of tendonitis/tendinitis.

Patella tendon rupture after arthroscopic resection of the prepatellar bursa--a case report

The use of arthroscopic techniques for excision of the pre-patellar bursa has become more common in recent years for the treatment of prepatellar bursitis. The current literature includes several case series that report few complications with this technique. We report the case of a 73-year-old male who sustained a low-energy patella tendon rupture 2 months after arthroscopic resection of the prepatellar bursa. We hypothesize that during arthroscopic excision of the prepatellar bursa there was an iatrogenic injury to the patellar tendon, which contributed to the subsequent rupture. Surgical repair was successfully performed using an open technique with a 1-year follow-up. To our knowledge, this is the first case report of patella tendon rupture following arthroscopic excision of the prepatellar bursa.