Patellar tendinitis: pathology and results of treatment

Surgical Management of Patellar Tendinopathy Results in Improved Outcomes and High Rates of Return to Sport: A Systematic Review

Although the majority of patients with patellar tendinopathy (PT) can be treated nonoperatively, operative management may be indicated for recalcitrant cases. While several surgical techniques have been described, there is limited understanding of postoperative outcomes and expectations regarding return to activity and sport. The purpose of this study was to characterize the clinical outcomes associated with the surgical management of PT with an emphasis on return to sport (RTS) rates. We hypothesized that surgical management would lead to clinically important improvements in patient-reported outcomes (PROs) with high rates of RTS and RTS at the same level. A comprehensive search of the PubMed, Medline, and Embase databases was performed in December 2020. Level of evidence studies I through IV, investigating results of surgical management for PT (PRO, functional outcomes, pain, and/or RTS), were included. The search was performed in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Forty clinical studies reporting on surgery for PT satisfied inclusion criteria, with 1,238 total knees undergoing surgery for PT. A comparison of pre- and postoperative Victorian Institute of Sport Assessment, patellar tendon (VISA-P) scores (mean difference: 41.89, p < 0.00001), Lysholm scores (mean difference: 41.52, p < 0.00001), and visual analogue scale (VAS) pain scores (mean difference: 5, p < 0.00001) demonstrated clinically and statistically significant improvements after surgery. The overall RTS rate following operative management was 89.8% (95% confidence interval [CI]: 86.4-92.8, I ² = 56.5%) with 76.1% (95% CI: 69.7.5-81.9, I ² = 76.4%) of athletes returning to the same level of activity. Surgery for PT provides meaningful improvement in patient reported outcomes and pain while allowing athletes to RTS at high rates with levels of participation similar to that of preinjury. Comparative studies of open and/or arthroscopic surgery are still limited but current evidence suggests better rates of RTS for arthroscopic surgery compared with open surgery. This is a systematic review of level-I to -IV studies.

Patellar mobility and lower limb kinematics during functional activities in individuals with and without patellar tendinopathy

STUDY DESIGN

Case-control.

OBJECTIVE

To examine whether patients with patellar tendinopathy (PT) display greater patellar mobility and different lower body kinematics than patients without PT.

BACKGROUND

PT is a common overuse condition of the patellar tendon that can cause pain and impair function. Subjects with overuse knee problems display different hip and knee functional mechanics, specifically valgus collapse. Patellar hypermobility has not been specifically studied as a possible risk factor for PT.

METHODS

11 patients with PT and 11 controls without PT, age 18 to 40, were studied. Using a patellofemoral arthrometer (PFA), maximal lateral and medial patellar displacement was measured. 3-D motion analysis was performed to determine lower extremity joint motions during single-leg step down and drop vertical jump tests.

RESULTS

Patients with PT had significantly increased lateral patellar mobility compared to controls (12.21 ± 3.33 mm vs. 9.19 ± 1.92 mm, P = .017). PT patients showed significantly greater peak hip adduction with both drop vertical jump (2.7° ± 6.3° vs. -5.6° ± 4.2°; P = .003) and step down (17.0° ± 3.8° vs. 12.5° ± 4.4°, P = .024). PT patients demonstrated increased peak ankle external rotation with drop vertical jump (-21.1° ± 5.9° vs. -14.8° ± 5.5°, P = .023) and step down (-15.6° ± 5.5° vs. -9.0° ± 6.0°, P = .017).

CONCLUSIONS

Patients with PT exhibit increased lateral patellar mobility, hip adduction, and ankle external rotation. The effects of increased patellar mobility deserve further study in the development, management, and prevention of PT.

The association of patellar tendinosis with patellar maltracking and Hoffa's fat pad impingement: A case-control MRI study

OBJECTIVES

To assess whether proximal or distal patellar tendinosis is associated with patellar maltracking parameters and superolateral Hoffa's fat pad impingement.

METHODS

Institutional radiology database was reviewed for knee MRI scans performed over a 7-year period identifying cases of unequivocal patellar tendinosis, which were separated into 2 groups: proximal and distal tendinosis. For each group of proximal and distal patellar tendinosis, a control group of age and gender matched subjects was assigned. The scans were evaluated for patellar maltracking parameters including patellar alta, tibial tuberosity lateralization, trochlear dysplasia and lateral patellar tilt and for presence of superolateral Hoffa's fat pad edema. These parameters were compared between the case and control groups.

RESULTS

Out of 9852 MRI scans, 94 patellar tendinosis cases were included (65 proximal and 29 distal tendinosis) and matched with equal numbers of controls. In the proximal patellar tendinosis group, more subjects had patella alta (22 versus 6, p = 0.0006), lateralization of tibial tuberosity (16 versus 7, p = 0.0495) and superolateral Hoffa's fat pad edema (16 versus 4, p = 0.0073) compared to the control group. In the distal patellar tendinosis group, there was no significant difference in the prevalence of any maltracking indicator or superolateral Hoffa's fat pad edema compared to the control group.

CONCLUSION

Proximal patellar tendinosis was associated with patellar maltracking parameters including patella alta, lateralized tibial tuberosity and superolateral Hoffa's fat pad impingement. No association was demonstrated between distal patellar tendinosis and patellar maltracking indicators or superolateral Hoffa's fat pad impingement.

The effect of Kinesio-tape® on pain and vertical jump performance in active individuals with patellar tendinopathy

BACKGROUND

Patellar tendinopathy is a common inflammatory condition in athletes who undergo large volumes of running and jumping. Kinesio-tape® (KT) is proposed to provide pain relief; however, its effect has not been examined on patellar tendinopathy.

OBJECTIVE

To examine the effects of KT on pain modulation for active individuals with patellar tendinopathy during functional activities.

METHODS

Thirteen symptomatic knees from seven college-aged females (6 bilateral; 1 unilateral) were included. Participants underwent three data collection sessions with KT, sham, and no tape (NT) in a randomized order. During the session, participants performed a maximum vertical jump, single-leg squats and isometric knee extension. The KT intervention was applied according to the KT manual and the sham utilized the same pattern without tension. Pain level was evaluated using the numeric pain scale before, during and after each activity. Function was assessed as maximum vertical jump height and maximum isometric strength. A separate repeated measures ANOVA was used to compare each dependent variable (pain level, vertical jump height, and isometric strength) among the conditions.

RESULTS

Reported pain scores were significantly lower (p = 0.05) during the maximal vertical jump test for KT (3.38 ± 1.26) compared to NT (4.54 ± 2.22). Significantly lower jump heights were found under KT (17.73 ± 3.06in) during the maximum vertical jump test compared to sham (18.65 ± 2.17in, p = 0.000) and NT (18.18 ± 2.93in, p = 0.008).

CONCLUSIONS

The use of the KT tape with a tendon corrective strip and muscle facilitative strip was effective for decreasing pain associated with patellar tendinopathy during jump landing but led to decreased maximum jump height.

CLINICAL TRIAL IDENTIFIER

NCT04153877.

Quadriceps tendinopathy: a review, part 2-classification, prognosis, and treatment

Overuse injuries of the extensor mechanism of the knee are common in both athletes and non-athletes and usually occur during activities associated with repetitive loading, stress, and knee extension. Numerous reports have been published describing extensor mechanism injuries in athletes, but there is a paucity of studies that focus on quadriceps tendinopathy in the non-athlete population. In addition, there is no universally accepted classification system for tendon pathology. Therefore, we performed a comprehensive literature review of these studies. This review consists of 2 parts. In the previous part we reviewed: (I) epidemiology and (II) diagnosis of quadriceps tendinopathy in the athlete as well as the general population. In this part we discuss: (I) classification; (II) prognosis; and (III) treatment results.

Quadriceps tendinopathy: a review-part 1: epidemiology and diagnosis

Overuse injuries of the extensor mechanism of the knee are common in both athletes and non-athletes and usually occur during activities associated with repetitive loading, stress, and knee extension. Historically, they have been labeled as Jumper's knee due to the high prevalence seen in the athletic community. In many published reports, the name "patellar tendinopathy" is used to describe this disorder of the quadriceps tendon at the patellar insertion, and the names are often used interchangeably. Numerous reports have been published describing extensor mechanism injuries in athletes, but there is a paucity of studies that focus on quadriceps tendinopathy. In addition, there is no universally accepted classification system for tendon pathology. Therefore, we performed a comprehensive literature review of these studies. This review consists of 2 parts. In the first part we review: (I) epidemiology and (II) diagnosis of quadriceps tendinopathy in the athlete as well as the general population. In the second part we discuss: (I) classification; (II) prognosis; and (III) treatment results.

Non-uniformity in the healthy patellar tendon is greater in males and similar in different age groups

There is increasing evidence that tendons are heterogeneous and take advantage of structural mechanisms to enhance performance and reduce injury. Fascicle-sliding, for example, is used by energy-storing tendons to enable them to undergo large extensions while protecting the fascicles from damage. Reductions in fascicle-sliding capacity may thus predispose certain populations to tendinopathy. Evidence from the Achilles tendon of significant superficial-to-deep non-uniformity that is reduced with age supports this theory. Similar patellar tendon non-uniformity has been observed, but the effects of age and sex have yet to be assessed. Healthy adults (n = 50, 25M/25F) from a broad range of ages (23-80) were recruited and non-uniformity was quantified using ultrasound speckle-tracking during passive knee extension. Significant superficial-to-deep non-uniformity and proximal/distal variations were observed. No effect of age was found, but males exhibited significantly greater non-uniformity than females (p < 0.05). The results contrast with previous findings in the Achilles tendon; in this study, tendons and tendon regions at high risk for tendinopathy (i.e. males and proximal regions, respectively) exhibited greater non-uniformity, whereas high-risk Achilles tendons (i.e. older adults) previously showed reduced non-uniformity. This suggests that non-uniformity may be dominated by factors other than fascicle-sliding. Anatomically, the varied proximal attachment of the patellar tendon may influence non-uniformity, with quadriceps passive resistance limiting superficial tendon movement, thus linking flexibility, non-uniformity and injury risk. This study also provides evidence of a differential effect of aging on the patellar tendon compared with evidence from prior studies on other tendons necessitating further study to elucidate links between non-uniformity and injury.

Nonuniform Deformation of the Patellar Tendon During Passive Knee Flexion

The purpose of this study was to evaluate localized patterns of patellar tendon deformation during passive knee flexion. Ultrasound radiofrequency data were collected from the patellar tendons of 20 healthy young adults during knee flexion over a range of motion of 50°-90° of flexion. A speckle tracking approach was used to compute proximal and distal tendon displacements and elongations. Nonuniform tissue displacements were visible in the proximal tendon (P < .001), with the deep tendon undergoing more distal displacement than the superficial tendon. In the distal tendon, more uniform tendon motion was observed. Spatial variations in percent elongation were also observed, but these varied along the length of the tendon (P < .002), with the proximal tendon remaining fairly isometric while the distal tendon underwent slight elongation. These results suggest that even during passive flexion the tendon undergoes complex patterns of deformation. Proximal tendon nonuniformity may arise from its complex anatomy where the deep tendon inserts onto the patella and the superficial tendon extends to the quadriceps tendon. Such heterogeneity is not captured in whole tendon average assessments, emphasizing the relevance of considering localized tendon mechanics, which may be key to understanding tendon behavior and precursors to injury and disease.

Ultrasonography of Jumper's Knee

The aim of the study was to evaluate the role of ultrasonography (US) in the management of jumper's knee. Sixty-two cases of clinically suggested jumper's knee, 52 asymptomatic contralateral knees and 100 asymptomatic knees of healthy middle aged men were examined. In the symptomatic group US was normal in 25 cases, all recovered with conservative therapy. In 31 symptomatic knees the findings were consistent with jumper's knee as a hypoechoic lesion located in the upper insertion of the patellar tendon in 23 cases and in the distal insertion in one case. In 7 cases the lesion was situated in the insertion of the quadriceps tendon. Surgery was performed on 20 knees and in all of them there was a lesion matching the lesion detected by US. In 6 cases US findings were pathologic, but different from jumper's knee. US findings consistent with jumper's knee could not be detected in the asymptomatic group.

Results of Surgical Treatment of Chronic Patellar Tendinosis (Jumper's Knee): A Systematic Review of the Literature

PURPOSE

To review the literature concerning surgical treatment options for chronic patellar tendinosis (jumper's knee), a common problem among athletes. When conservative treatment fails, surgical treatment is required.

METHODS

Systematic review of the literature concerning the results of current surgical treatment options for chronic patellar tendinosis. All articles of studies with an evidence level ≥IV from January 2000 until February 2015 presenting the surgical outcome after arthroscopic as well as open treatment of chronic patellar tendinosis were included. The literature research of the PubMed database was performed using the following key words: "patellar" and "tendinitis," "tendonitis," "tendinosis" or "tendinopathy"; "inferior patellar pole"; "jumper's knee"; "surgical treatment" and "open" or "arthroscopic patellar tenotomy."

RESULTS

A systematic review of the literature was performed especially to point out the effectiveness of arthroscopic treatment of chronic patellar tendinosis. The results revealed good clinical results for arthroscopic as well as open treatment of chronic patellar tendinosis that is refractory to conservative treatment in athletes. An average success rate of 87% was found for the open treatment group and of 91% for the arthroscopic treatment group. However, after open surgery, the mean time of return to the preinjury level of activity is 8 to 12 months, with a certain number of patients/athletes who cannot return to the preinjury level of activity.

CONCLUSIONS

Minimally invasive, arthroscopically assisted or all-arthroscopic procedures may lead to a significantly faster return to sporting activities and may, therefore, be the preferred method of surgical treatment.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

A single application of low-energy radial extracorporeal shock wave therapy is effective for the management of chronic patellar tendinopathy

PURPOSE

Extracorporeal shock wave therapy (SWT) is effective for the management of chronic recalcitrant tendinopathy. The objective of the current study was to assess whether a standardized, single treatment SWT is effective for the management of chronic patellar tendinopathy

METHODS

Thirty-three patients with chronic patellar tendinopathy received low-energy SWT. Thirty-three patients with chronic patellar tendinopathy received other forms of non-operative therapy (control group). Evaluation was by change in Visual Analogue Scale (VAS), Victoria Institute of Sport Assessment score for patellar tendinopathy (VISA-P) score and by Roles and Maudsley Score.

RESULTS

Mean pre-treatment VAS scores for the control and SWT groups were 7.5 and 7.8, respectively. One month, 3 months, and 12 months after treatment, the mean VAS for the control and SWT groups were 6.7 and 4.3 (p < 0.001), 5.9 and 3.5 (p < 0.001), and 5.1 and 2.7 (p < 0.001), respectively. One month, 3 months, and 12 months after treatment, the mean VISA for the control and SWT groups were 50.7 and 65.5 (p < 0.001), 52.1 and 71 (p < 0.001), and 54.9 and 74.5 (p < 0.001), respectively. At final follow-up, the number of excellent, good, fair, and poor results for the SWT and control groups were 8 and 3 (p < 0.001), 17 and 10 (p < 0.001), 5 and 16 (p < 0.001), and 3 and 4 (p < 0.001), respectively. The percentage of patients with excellent ("1") or good ("2") Roles and Maudsley Scores (i.e. successful results) 12 months after treatment was statistically greater in the SWT group compared to the control group (p < 0.001).

CONCLUSION

A single application of radial SWT is an effective treatment for chronic patellar tendinopathy.

LEVEL OF EVIDENCE

III.

Management of tendinopathy

Overuse disorders of tendons, or tendinopathies, present a challenge to sports physicians, surgeons, and other health care professionals dealing with athletes. The Achilles, patellar, and supraspinatus tendons are particularly vulnerable to injury and often difficult to manage successfully. Inflammation was believed central to the pathologic process, but histopathologic evidence has confirmed the failed healing response nature of these conditions. Excessive or inappropriate loading of the musculotendinous unit is believed to be central to the disease process, although the exact mechanism by which this occurs remains uncertain. Additionally, the location of the lesion (for example, the midtendon or osteotendinous junction) has become increasingly recognized as influencing both the pathologic process and subsequent management. The mechanical, vascular, neural, and other theories that seek to explain the pathologic process are explored in this article. Recent developments in the nonoperative management of chronic tendon disorders are reviewed, as is the rationale for surgical intervention. Recent surgical advances, including minimally invasive tendon surgery, are reviewed. Potential future management strategies, such as stem cell therapy, growth factor treatment, and gene transfer, are also discussed.

Passage and concentration-dependent effects of Indomethacin on tendon derived cells

Background

Non-steroidal anti-inflammatory drugs (NSAID) are commonly used in the treatment of tendinopathies such as tendonitis and tendinosis. Despite this, little is known of their direct actions on tendon-derived cells. As NSAIDs have been shown to delay healing in a number of mesenchymal tissues we have investigated the direct effects of indomethacin on the proliferation of tendon-derived cells.

Results and Discussion

The results obtained were dependent on both the type of cells used and the method of measurement. When measured using the Alamar blue assay, a common method for the measurement of cell proliferation and viability, no effect of indomethacin was seen regardless of cell source. It is likely that this lack of effect was due to a paucity of mitochondrial enzymes in tendon cells.

However, when cell number was assessed using the methylene blue assay, which is a simple nuclear staining technique, an Indomethacin-induced inhibition of proliferation was seen in primary cells but not in secondary subcultures.

Conclusion

These results suggest that firstly, care must be taken when deciding on methodology used to investigate tendon-derived cells as these cells have a quite different metabolism to other mesenchymal derive cells. Secondly, Indomethacin can inhibit the proliferation of primary tendon derived cells and that secondary subculture selects for a population of cells that is unresponsive to this drug.

Quadriceps tendinosis and patellar tendinosis in professional beach volleyball players: sonographic findings in correlation with clinical symptoms

The purpose was to assess quadriceps and patellar tendinosis in professional beach volleyball players and to correlate ultrasound findings with clinical symptoms. During a grand-slam beach volleyball tournaments all 202 athletes (100 men and 102 women) were invited to participate at this study. Sixty-one athletes (38 male, mean age 29.6, 23 female, mean age 27.1) were included. The dominant leg was right in 51 (84%) and left in ten athletes (16%). Lysholm knee score and pain during the game was assessed using a visual analogue scale. Sonography of the quadriceps tendon and the patellar tendon was performed by a blinded sonographer. Sonographic findings were compared between both legs and correlated to clinical findings using a regression analysis. Quadriceps tendinosis was diagnosed in 13 (21%, dominant leg)/21 (34%, non-dominant leg), patellar tendinosis in 13(21%)/18(30%). Only sonographic findings at the quadriceps tendon were significantly associated with pain: thickness of the quadriceps tendon (mean diameter 6.9 mm/7.1 mm, significant for both legs P = 0.011/P = 0.030), abnormal echo texture (11/16; P = 0.001/P = 0.228), areas with positive power Doppler signals (mean number 0.3/0.4; P = 0.049/0.346), calcifications (mean number: 0.9/1.1; P = 0.021/0.864). A relationship between findings at patellar tendon was not found. Quadriceps tendinosis is as common as patellar tendinosis in professional beach volleyball players. Thickening and structure alteration of the quadriceps tendon is associated with anterior knee pain during beach volleyball.

The influence of the lower patellar pole in the pathogenesis of chronic patellar tendinopathy

Resection of the lower patellar pole provides good results in the treatment of jumper's knee. Therefore we hypothesized that the length of the lower patellar pole is increased in patients with chronic patellar tendinopathy. Cohort study, level of evidence 2. Between 2000 and 2005, 25 patients with chronic patellar tendinopathy underwent conservative and surgical treatment in our clinic. All of them had preoperative MRI were three independent examiners measured the Caton Index, the length and the ratio of the articular and non-articular patellar surface, tendon length and thickness and the thickness and length of the hypodens lesions in the patellar tendon. The measurements were compared with 50 MRI of a control group with no clinical patellofemoral disorders or patellar tendinopathy. Significant changes in tendon thickness (9.42+/-2.87 vs. 4.88+/-1.13; P<0.0001), a longer non-articular surface of the patella (10.62+/-2.86 vs. 7.098+/-2.53; P<0.0001) and significant higher ratio between the articular and the non-articular patellar surface (0.32 vs. 0.24; P<0.0001) were found in the jumper's knee group. No significant changes were seen in the length of the articular surface or the Caton Index. The development of chronic patellar tendinopathy in athletes might be associated with a longer lower patellar pole as patients with jumper's knee showed a longer non-articular patellar surface compared with the control group.

Arthroscopic resection of the lower patellar pole in patients with chronic patellar tendinosis

PURPOSE

The aim of this prospective study is to evaluate the clinical results of arthroscopic resection of the lower patellar pole in patients with patellar tendinosis.

METHODS

Twenty patients underwent an arthroscopic resection of the lower patellar pole between 2002 and 2004. All of them were evaluated at 6 weeks and 3, 6, 12, and 24 months after surgery using the Tegner activity level, the Lysholm score, the Kujala score, a modified jumper's knee classification according to Blazina, and visual analog scales for pain, function, and satisfaction. Clinical evaluation was performed 2 years after surgery. In addition, magnetic resonance imaging was performed preoperatively and at a 2-year follow-up.

RESULTS

By 6 weeks postoperatively and at every other follow-up visit, significant improvements were seen in the Lysholm score (P = .001), the Kujala score (P = .001) and the visual analog scales. The Tegner score improved significantly by 3 months postsurgery (P = .01). Two years after surgery, the Tegner score improved from 4.4 +/- 2.9 to 7.95 +/- 1.6 (P < .0001); the Lysholm score from 57.1 +/- 17.1 to 97.3 +/- 4.4 (P < .0001); and Kujala score from 53.7 +/- 14.7 to 95.4 +/- 7.8 (P < .0001). The jumper's knee classification showed excellent (stage 0) or good (stage I) results in 18 of 20 patients. At follow-up, all but one magnetic resonance image showed hypodens areals in the proximal aspect of the patellar tendon, and small osteophytes were seen in some cases at the resection area. These findings did not seem to have any influence on the results.

CONCLUSIONS

The arthroscopic resection of the lower patellar pole as a minimal invasive method to treat jumper's knee provides satisfactory clinical results in knee function and pain reduction with fast recovery and return to sport activities.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Excessive apoptosis in patellar tendinopathy in athletes

BACKGROUND

The pathogenesis of tendon overuse injuries is poorly understood. The histopathology underlying tendinopathy at various anatomical locations is similar and may reflect a common pathologic process.

HYPOTHESIS

Apoptosis contributes to the pathophysiology in patellar tendinopathy.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

We compared biopsy specimens from the patellar tendon in patients with patellar tendinopathy diagnosed clinically and with typical magnetic resonance image findings with biopsy specimens from a control group without any previous or current knee complaints to suggest patellar tendinopathy. The presence of apoptosis was examined with immunohistochemical methods using a polyclonal antibody recognizing active caspase-3, confirmed by labeling DNA strand breaks (F7-26 antibody) and nuclear morphology (fragmentation and condensation).

RESULTS

The number of apoptotic cells per unit area (4.5 mm(2)) was 0.91 +/- 0.81 (SD) in tendinopathic samples and 0.21 +/- 0.21 in controls (P = .026). Although the tendinopathic samples displayed increased cellularity (average 162.5 nuclei/mm(2) vs 98.9 nuclei/mm(2)), the apoptotic index was higher (0.42% vs 0.17%, P = .014).

CONCLUSION

Increased apoptotic cell death is a feature of patellar tendinosis. The role of apoptosis within the broader framework and time course of tendon overuse injury remains to be established.

Surgical treatment of chronic patellar tendinosis: a systematic review

There is no consensus in the literature on the best surgical procedure for patellar tendinosis when nonoperative treatment fails. With a systematic review, we asked whether surgical treatment of the inferior pole of the patella, closing of the paratenon, or immobilization affected the percentage of patients reporting good to excellent results (percent success). We completed a systematic review of surgical treatment for patellar tendinosis. A literature search of Medline, CINAHL, and Sport Discus revealed 30 articles on treatment of patellar tendinosis. Ten met our initial inclusion criteria. Most studies were retrospective and used varying techniques. Outcome measures were individual to the specific article, making it difficult to compare the results of the studies. Studies that described surgical treatment of the inferior pole of the patella had 70.9% success compared to 91.7% for those that performed no patella bony work. Closure of the paratenon was reported in seven studies with 84.8% success compared to 91.5% for the other studies. Immobilization was used in four studies with 82.4% success compared to 94.9% success for four studies that did not immobilize postoperatively. Care must be taken when comparing these weighted averages since only two of the nine studies described exactly the same technique. Ideally, prospective controlled studies with validated assessment tools and activity scores are required to determine the best treatment for our patients.

Distal patellar tendinosis: an unusual form of jumper's knee

Jumper's knee is a common problem in athletes participating in sports that involve running and jumping. Typically activity related pain is felt at the proximal insertion of the patellar tendon. Symptoms and findings in the more distal parts of the patellar tendon are unusual. All of the patients in this retrospective study were active athletes suffering from distal patellar tendinosis. There were 19 men and four women. The mean age of the patients was 24 years (range 12-32). All of the patients were operated on after conservative treatment lasting for an average of 23 months had failed. After a mean postoperative follow-up of 42 months 21 of the knees were rated good meaning that the athlete had returned to the prior level of activity without any symptoms. In three knees the result was fair as the patients benefited from the operation but there were some remaining symptoms. No poor results were reported. All patients were able to return to their previous level of sports 8-12 weeks after surgery. Operative treatment seems to give good results in most cases after unsuccessful conservative treatment of the unusual distal patellar tendinosis in athletes.

Recalcitrant patellar tendinosis in elite athletes: surgical treatment in conjunction with aggressive postoperative rehabilitation

BACKGROUND

Recalcitrant patellar tendinosis is difficult to treat, and results are varied.

HYPOTHESIS

Surgical removal of necrotic tissue, surgical stimulation of remaining tendon, and aggressive and specific rehabilitation after patellar tendonectomy will allow athletes to return to sports.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From December 1996 to July 2002, 16 high-level athletes (4 professional, 2 Olympic, 9 collegiate, 1 preparatory), aged 16 to 25 years (mean, 19.7 years), with 22 symptomatic patellar tendons had failed nonoperative care of their patellar tendinosis symptoms and were unable to compete effectively in their sports. Magnetic resonance imaging showed confirmation of disease, with typical findings being necrosis in the posterior half of an abnormally thick patellar tendon, often in conjunction with partial tearing of the posterior half with a compensatory enlargement of the anterior half. Each patient then underwent tendonectomy of the necrotic portion in conjunction with stimulation of the remaining tendon by making multiple longitudinal cuts in the tendon. Patients participated in a postoperative rehabilitation protocol that included immediate range of motion, full flexion, and immediate high-repetition, low-resistance quadriceps muscle exercise.

RESULTS

Subjective improvement was noted in all athletes. Return to the same sport at prior level of intensity was accomplished by 14 of 16 patients (87.5%) at a mean of 8.1 months (range, 3-12 months).

CONCLUSION

Overall, tendonectomy, surgical tendon stimulation, and aggressive postoperative rehabilitation were found to be a safe, effective way to return high-level athletes to their sports.

Biomechanical basis for tendinopathy

Tendinopathy affects millions of people in athletic and occupational settings and is a nemesis for patients and physicians. Mechanical loading is a major causative factor for tendinopathy; however, the exact mechanical loading conditions (magnitude, frequency, duration, loading history, or some combinations) that cause tendinopathy are poorly defined. Exercise animal model studies indicate that repetitive mechanical loading induces inflammatory and degenerative changes in tendons, but the cellular and molecular mechanisms responsible for such changes are not known. Injection animal model studies show that collagenase and inflammatory agents (inflammatory cytokines and prostaglandin E1 and E2) may be involved in tendon inflammation and degeneration; however, whether these molecules are involved in the development of tendinopathy because of mechanical loading remains to be verified. Finally, despite improved treatment modalities, the clinical outcome of treatment of tendinopathy is unpredictable, as it is not clear whether a specific modality treats the symptoms or the causes. Research is required to better understand the mechanisms of tendinopathy at the tissue, cellular, and molecular levels and to develop new scientifically based modalities to treat tendinopathy more effectively.

Etiology of Patellar Tendinopathy in Athletes

Objective:

To review the etiology of patellar tendinopathy as it relates to clinical management of chronic patellar-tendon disease in athletes.

Data Sources:

Information was gathered from a MEDLINE search of literature in English using the key wordspatellar tendinitis, patellar tendonitis, patellar tendinosis, patellar tendinopathy,andjumper’s knee.

Study Selection:

All relevant peer-reviewed literature in English was reviewed.

Data Synthesis:

The etiology of patellar tendinopathy is multifactorial, incorporating both intrinsic and extrinsic factors. Age, muscle flexibility, training program, and knee-joint dynamics have all been associated with patellar tendinopathy. The roles of gender, body morphology, and patellar mobility in patellar tendinopathy are unclear.

Conclusions:

The pathoetiology of patellar tendinopathy is a complex process that results from both an inflammatory response and degenerative changes. There is a tremendous need for research to improve our understanding of the pathoetiology of patellar tendinopathy and its clinical management.

Patellar tendinopathy in athletes: current diagnostic and therapeutic recommendations

Formerly known as 'jumper's knee', patellar tendinopathy gives rise to considerable functional deficit and disability in recreational as well as professional athletes. It can interfere with their performance, often perseveres throughout the sporting career and may be the primary cause to end it. The diagnosis of patellar tendinopathy is primarily a clinical one but new imaging techniques, such as Doppler ultrasonography, may provide additional diagnostic value. Current therapeutic protocols are characterised by wide variability ensuing from anecdotal experience rather than evidence. Moreover, numerous reports in recent years have shattered previous doctrines and dogmatic belief on tendon overuse. Histopathological and biochemical evidence has indicated that the underlying pathology of tendinopathy is not an inflammatory tendinitis but a degenerative tendinosis. Consequently, pain in chronic patellar tendinopathy is not inflammatory in nature, but its exact origin remains unexplained. In pursuit of pathology- and evidence-based management, conservative therapy should be shifted from anti-inflammatory strategies towards a complete rehabilitation with eccentric tendon strengthening as a key element. If conservative management fails, surgery is opted for. However, considering the heterogeneity of surgical procedures and the absence of randomised studies, no conclusive evidence can be drawn from the literature regarding the effectiveness of surgical treatment for patellar tendinopathy. Parallel with the improved knowledge on the pathophysiology and pain mechanisms in patellar tendinopathy, new treatment strategies are expected to emerge in the near future.

Prevalence of jumper's knee among elite athletes from different sports: a cross-sectional study

BACKGROUND

The prevalence of jumper's knee across different sports has not been examined, and it is not known if there is a gender difference. Data from surgical case series indicate that there may be a high prevalence in sports with high speed and power demands.

HYPOTHESIS

The aim of this study was to estimate the prevalence of jumper's knee in different sports among female and male athletes and to correlate the prevalence to the loading characteristics of the extensor mechanism in these sports.

STUDY DESIGN

Cross-sectional study; Level of evidence, 4.

METHODS

The authors examined approximately 50 Norwegian male and female athletes at the national elite level from each of the following 9 sports: athletics (male athletes: high jump, 100- and 200-m sprint), basketball (male athletes), ice hockey (male athletes), volleyball (male athletes), orienteering (male athletes), road cycling (male athletes), soccer (male and female athletes), team handball (male and female athletes), and wrestling (male athletes). The examination included an interview on individual characteristics (weight, age, height, and training background), a clinical examination, and self-recorded Victorian Institute of Sport Assessment score from 0 (worst) to 100 (best).

RESULTS

The overall prevalence of current jumper's knee was 14.2% (87 of 613 athletes), with a significant difference between sports with different performance characteristics (range, 0%-45%). In addition, 51 athletes (8%) reported previous symptoms. The prevalence of current symptoms was highest in volleyball (44.6%+/-6.6%) and basketball (31.9%+/-6.8%), whereas there were no cases in cycling or orienteering. The prevalence of current jumper's knee was lower among women (5.6%+/-2.2%) compared with men (13.5%+/-3.0%; chi2 test, P=.042). The duration of symptoms among athletes with current jumper's knee (n=87) was 32+/-25 (standard deviation) months, with a Victorian Institute of Sport Assessment score of 64+/-19.

CONCLUSION

The prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors. The symptoms are often serious, resulting in long-standing impairment of athletic performance.

Tratamento cirúrgico da tendinite distal da patela

A tendinite distal da patela é uma doença que acomete principalmente jovens esportistas e caracteriza-se por dor referida na extremidade distal da patela junto à inserção do ligamento patelar. O tratamento inicial preconizado é sempre conservador com fisioterapia. A grande maioria tem boa resposta a este tipo de conduta, mas em alguns raros casos os sintomas não regridem exigindo uma mudança de conduta. Para este grupo usamos o tratamento cirúrgico com técnica derivada de Trillat que se baseia na utilização de um enxerto de parte do tendão do músculo Grácil implantado dentro do ligamento patelar, inserido intra-ósseo na patela e fixado na tuberosidade anterior da tíbia. Foram operados seis pacientes, sendo que em dois casos a operação foi bilateral, totalizando oito joelhos. O seguimento mínimo foi de três anos, com avaliação final dentro do índice considerado como EXCELENTE, conforme a cotação ARPÉGE, para todos os joelhos.

Patellar tendonitis and patellar dislocations

Common sports injuries, such as patellar tendonitis and patellar dislocation, can be treated either surgically or with rehabilitation and physical therapy. Most patients with patellar tendonitis will respond well to conservative measures; however, some recalcitrant cases will require surgical intervention. To date, the literature is not able objectively to identify the patients best suited to surgery. Likewise, in the case of patellar dislocations, it is still unclear which patients respond best to conservative therapy and which respond best to surgical treatment, although evidence continues to accumulate. A practical approach to this problem can be deduced from the available evidence, but more well-designed clinical trials are needed for the establishment of definitive treatment protocols.

Thermal microdebridement does not affect the time zero biomechanical properties of human patellar tendons

BACKGROUND

Thermal microdebridement for the treatment of chronic tendinopathy has recently been introduced. The effect of thermal microdebridement on the biomechanical properties of human tendons, however, remains unknown.

HYPOTHESIS

Thermal microdebridement does not affect the biomechanical properties of human patellar tendons in a cadaveric model at the time of initial treatment.

STUDY DESIGN

Controlled laboratory study.

METHODS

The central 15 mm of 12 matched, human (mean age, 71 years; 8 male, 4 female), fresh-frozen patellar tendons was divided into 3 equal 5-mm specimens. The treatment group (n = 12) underwent thermal microdebridement with a radiofrequency probe. A sham treatment group (n = 12) underwent insertion of a deactivated probe. The control group (n = 12) underwent no treatment. After treatment, each specimen was tested to failure in a servo-hydraulic materials testing machine at an elongation rate of 3 mm/s. One-way repeated measures analysis of variance was used to determine differences between groups.

RESULTS

No significant difference in ultimate stress at failure, elastic modulus, strain energy density, or strain at maximum load was found between the groups. The ultimate stress at failure for the treatment, sham, and control groups was 61.0, 66.7, and 63.0 MPa, respectively (P = .653), and the strain at maximum load was 0.12, 0.11, and 0.09, respectively (P = .279).

CONCLUSIONS

Thermal microdebridement does not affect the biomechanical properties of cadaveric human patellar tendons at the time of initial treatment.

CLINICAL RELEVANCE

It may be safe to proceed with aggressive rehabilitation after thermal microdebridement of the patellar tendon. However, the results in this cadaveric model should be interpreted with caution. Additional studies using an in vivo model will be required to completely assess the effects of thermal microdebridement on the biomechanical properties of human patellar tendons.

Types and epidemiology of tendinopathy

During the last few decades, the role of sports and physical activity has become more and more important in all modern communities. The risk of tendon injury has thus increased, and prevention has become important. Epidemiologic studies are important when planning prevention programs for tendon injuries. Because of individual sport cultures and different sport habits in different countries, national epidemiologic studies are of importance in each individual country.

Patellar tendinopathy

Patellar tendinopathy is a common and serious condition in athletes. Although there have been many advances in the understanding of the histopathology, imaging, and surgical outcomes in this condition in the past decade, successful management of athletes with patellar tendinopathy remains a major challenge for both the practitioner and patient. There is a definite need for further prospective studies into etiological factors and randomized controlled trials into treatment choices.

Performance characteristics of volleyball players with patellar tendinopathy

BACKGROUND

Patellar tendinopathy is assumed to result from chronic tendon overload. There may be a relationship between tendon pain and jumping ability.

HYPOTHESIS

There is no difference in performance characteristics between volleyball players with patellar tendinopathy and those without.

STUDY DESIGN

Prospective cohort study.

METHOD

We examined the performance of the leg extensor apparatus in high-level male volleyball players with patellar tendinopathy (N = 24) compared with a control group (N = 23) without knee symptoms. The testing program consisted of different jump tests with and without added load, and a composite jump score was calculated to reflect overall performance.

RESULTS

The groups were similar in age, height, and playing experience, but the patellar tendinopathy group did more specific strength training and had greater body weight. They scored significantly higher than the control group on the composite jump score (50.3 versus 39.2), and significant differences were also observed for work done in the drop-jump and average force and power in the standing jumps with half- and full-body weight loads.

CONCLUSIONS

Greater body weight, more weight training, and better jumping performance may increase susceptibility to patellar tendinopathy in volleyball players.

Cross-sectional outcome analysis of athletes with chronic patellar tendinopathy treated surgically and by extracorporeal shock wave therapy

OBJECTIVE

To compare the outcome of chronic patellar tendinopathy treated surgically and by extracorporeal shock wave therapy.

DESIGN

Cross-sectional outcome analysis.

SETTING

University Hospital Pellenberg, Leuven, Belgium.

PATIENTS AND INTERVENTIONS

Of a total of 27 patients (28 knees) with chronic patellar tendinopathy, 13 were treated surgically, and 14 (15 knees) received extracorporeal shock wave therapy.

MAIN OUTCOME MEASUREMENTS

Functional outcome questionnaire: Victorian Institute of Sport Assessment score, Visual Analog Scale, and Roles and Maudsley classification.

RESULTS

At an average of 6 months of follow-up, the mean Victorian Institute of Sport Assessment and Visual Analog Scale scores for the extracorporeal shock wave therapy group were 78.8 +/- 28.7 and 9 +/- 2, respectively, which improved to 83.9 +/- 28.6 and 9 +/- 2, respectively, at 22.1 months. The surgery group scored 70.7 +/- 22.2 points on the Victorian Institute of Sport Assessment at an average of 26.3 months of follow-up (p = 0.41 and p = 0.18) and 8 +/- 3 on the Visual Analog Scale (p = 0.14). In the extracorporeal shock wave therapy group, 5 (33%) patients rated their pain status at 22.1 months as excellent, 5 (33%) as good, 2 (13%) as fair, and 2 (13%) as poor. In the surgery group, 4 (33%) evaluated the result as excellent, 3 (25%) as good, 3 (25%) as fair, and 2 as poor (17%).

CONCLUSIONS

Extracorporeal shock wave therapy shows a comparable functional outcome to surgery in a cross-sectional analysis of patients with chronic proximal patellar tendinopathy resistant to conservative treatment.

Relation between ankle joint dynamics and patellar tendinopathy in elite volleyball players

OBJECTIVE

Ankle joint complex dynamics developed during volleyball spike jumps take-offs and landings were quantified to assess potential relations between these joint dynamics and patellar tendinopathy.

DESIGN

Three-dimensional kinematic data provided information about movements of the lower limbs, while the kinetic data permitted analysis of ground reaction forces as players took-off and landed from full-speed spike jumps.

SETTING

Simulated volleyball court with net in a biomechanics research laboratory.

PARTICIPANTS

10 members of the Canadian Men's National Volleyball Team. From history and physical examination, 3 of the 10 players had patellar tendon pain associated with activity and were diagnosed with patellar tendinopathy at the time of the study. Investigators were blinded about the injury status of the players.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Three-dimensional kinematics and joint moments of the ankle, knee, and hip joints.

RESULTS

Our analysis revealed that maximal external tibial rotation occurred at or near maximal dorsiflexion while maximal internal tibial rotation coincided with maximal plantarflexion. The plantarflexion moment was 3 to 10 times greater than all the other moments measured, with the maximal plantarflexor moment being calculated at 0.4 BWm (360 Nm). In blinded logistic regression analyses, we found one of the dynamics variables (inversion moment during the landing of the spike jump) was a significant predictor of patellar tendinopathy.

CONCLUSIONS

Coupling the results of the current analysis of ankle joint complex dynamics with previously reported results of knee joint dynamics related to patellar tendinopathy suggests that a cluster of variables linked to patellar tendinopathy includes: high ankle inversion-eversion moments, high external tibial rotation and plantarflexion moments, large vertical ground reaction forces, and high rate of knee extensor moment development.

Long-term prognosis for jumper's knee in male athletes. A prospective follow-up study

BACKGROUND

Little information is available on the long-term outcome of jumper's knee, a common problem among athletes.

PURPOSE

Our aim was to determine the 15-year prognosis of jumper's knee.

STUDY DESIGN

Prospective case control.

METHODS

The prognosis for jumper's knee was studied using two groups: athletes with jumper's knee and nonsymptomatic control athletes. At baseline, all subjects participated in standardized clinical examinations and measurements, and 15 years later they were asked to respond to a questionnaire.

RESULTS

Twenty athletes with jumper's knee and 16 athlete control subjects responded (response rate 74% and 84%, respectively). The jumper's knee group reported significantly more knee symptoms according to their Kujala score and more knee pain after repeated squatting. Fifty-three percent of the subjects in the jumper's knee group (9 of 17) reported that they had quit their sports career because of their knee problem, compared with 7% of the control athletes (1 of 14). Patellar height was associated with knee symptoms at follow-up.

CONCLUSION

Jumper's knee causes mild but long-lasting symptoms after an athletic career.

Significance of ultrasonographically detected asymptomatic tendinosis in the patellar and achilles tendons of elite soccer players: a longitudinal study

BACKGROUND

Chronic tendinosis of the Achilles or patellar tendons, or both, is one of the most frequent and severe conditions that affects athletes in sports such as soccer. It can often end an athlete's sports activity.

HYPOTHESIS

Ultrasonography of asymptomatic tendons can be used to predict which athletes will develop tendon symptoms.

STUDY DESIGN

Longitudinal study.

METHODS

Using ultrasonography of the ankle and knee, we examined 54 elite soccer players in the top Danish soccer league before and after a single season (in January and December).

RESULTS

At the start of the season, ultrasonography had revealed abnormalities in 29% of those examined. Eighteen percent (18 of 98 tendons) were observed to have abnormal sonographic findings in the patellar tendon at the initial examination in January. These athletes were found to have a 17% risk of developing symptomatic jumper's knee during the 12-month season. Eleven percent (11 of 96 tendons) were observed to have abnormal sonographic findings in the Achilles tendon at the initial examination; it was calculated that they had a 45% risk of developing symptoms of Achilles tendinosis. Only one of the players with normal tendons in January actually developed symptoms by the end of the season.

CONCLUSIONS

For the first time it is now possible to identify risk factors for the development of serious tendon disorders in asymptomatic athletes. Future studies may be directed at developing preventive treatment to reduce the risk of chronic, therapy-resistant symptoms of tendinosis and ruptures.

Patellar tendon fiber strains: their differential responses to quadriceps tension

This study tested the hypothesis that the posterior fibers of the patellar tendon are subjected to higher tensile strains than the anterior fibers in response to quadriceps tension. The quadriceps tendon was loaded to 1 kN in 10 human cadaver knees and the tensile strain was measured in the anterior and posterior fibers of the patellar tendon. The central third patellar tendon was divided into anterior and posterior halves which were tensile tested to failure. The mean strain at 1 kN load was 1.7% (90 degrees flexion), 2.7% (60 degrees ), and 3.9% (10 degrees ) anteriorly, and 3.2% (90 degrees ) 4.6% (60 degrees ), and 4.9% (10 degrees ) posteriorly. Quadriceps loading caused significantly greater strains in the posterior fascicles between 60 degrees and 90 degrees knee flexion. The material properties in the anterior and posterior regions were similar, except that failure strain was significantly higher posteriorly. Thus the posterior fascicles are adapted to sustain significantly greater tensile strains before failing. This suggests that the higher overall levels of tensile strain in the posterior fibers are not sufficient to explain the clinical pattern of patellar tendonitis.

Evidence of abnormal anteroposterior patellar tilt in patients with patellar tendinitis with use of a new radiographic measurement

BACKGROUND

A number of clinical conditions of the patellofemoral joint have been correlated with abnormal patellofemoral radiographic measurements.

HYPOTHESIS

An abnormal anteroposterior patellar-tilt angle may be a contributing factor to pathologic conditions of the knee.

STUDY DESIGN

Prospective nonrandomized clinical trial.

METHODS

The anteroposterior patellar-tilt angle was measured in cadaveric knees to determine the best knee position. The radiographs of normal subjects and patients with patellar tendinitis or patellofemoral pain syndrome were examined for differences in patellar-tilt angle.

RESULTS

Cadaveric measurements demonstrated highest intertester and intratester reliability at 30 degrees of knee flexion and neutral femoral rotation. Intratester measurements on normal subjects exhibited high reliability, with a mean anteroposterior tilt angle of 30.8 degrees +/- 6.7 degrees. In the patellofemoral pain group the mean anteroposterior tilt angle was 29.1 degrees +/- 8.5 degrees; however, for patients with patellar tendinitis, it was 25.6 degrees +/- 7.0 degrees, significantly lower than in the normal population. Furthermore, there was no difference between the angles of involved and uninvolved knees of patients with unilateral patellar tendinitis.

CONCLUSION

The anteroposterior patellar-tilt angle is a clinically reliable measurement of patellar tilt in the sagittal plane that can be used to study patellofemoral tilt in a variety of clinical situations. The results of this study demonstrate that patients with patellar tendinitis have abnormal patellar tilt in the sagittal plane.

Is impingement the cause of jumper's knee? Dynamic and static magnetic resonance imaging of patellar tendinitis in an open-configuration system

BACKGROUND

Chronic overload is considered the main cause of patellar tendinitis, but it has been postulated that impingement of the inferior patellar pole against the patellar tendon during knee flexion could be responsible.

HYPOTHESIS

The role of the patellar pole in patellar tendinitis can be determined by dynamic magnetic resonance imaging.

STUDY DESIGN

Case-control study.

METHODS

We compared 19 knees with patellar tendinitis and 32 asymptomatic knees of age-matched subjects using an open-configuration magnetic resonance imaging system. Dynamic sagittal images were obtained from full extension to 100 degrees of flexion with and without activation of the quadriceps muscle. The following measurements were made from the images: tendon-patella angle, anteroposterior diameter of the tendon, signal difference-to-noise ratio, the shape of the inferior patellar pole, and the location of the patellar tendon insertion.

RESULTS

The tendon-patella angle was not significantly different between groups at any flexion angle, with or without quadriceps muscle activation. The insertion site of the patellar tendon differed significantly but not the shape of the inferior pole of the patella. The volume and the signal difference-to-noise ratio of zones of increased intratendinous signal as well as the anteroposterior diameter of the proximal patellar tendon were increased in symptomatic knees.

CONCLUSIONS

The relationship between the patella and the patellar tendon was identical in both groups; therefore, chronic overload seems to be a major cause of patellar tendinitis.

Management of Achilles tendinopathy by ultrasound-guided percutaneous tenotomy

PURPOSE

To report the middle to long-term results of ultrasound-guided percutaneous longitudinal tenotomy of the Achilles tendon

METHOD

Seventy-five athletes with unilateral Achilles tendinopathy underwent ultrasound-guided percutaneous longitudinal tenotomy under local anesthetic infiltration after failure of conservative management. Sixty-three patients were reviewed at least 36 months after the operation (51 +/- 18.2 months).

RESULTS

Thirty-five patients were rated excellent, 12 good, 9 fair, and 7 poor. Nine of the 16 patients with a fair or poor result underwent a formal exploration of the Achilles tendon 7-12 months after the index procedure. The operated tendons remained thickened and the ultrasonographic appearance of operated tendons remained abnormal even 8 yr after the operation, without interfering with physical training. Isometric maximal muscle strength and isometric endurance gradually returned to values similar to their contralateral unoperated tendon.

CONCLUSIONS

Percutaneous longitudinal ultrasound-guided internal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, does not hinder further surgery should it be unsuccessful, and, in our experience, has produced no significant complications. It should be considered in the management of chronic Achilles tendinopathy after failure of conservative management. However, patients should be advised that, if they suffer from diffuse or multinodular tendinopathy or from pantendinopathy, a formal surgical exploration with stripping of the paratenon and multiple longitudinal tenotomies may be preferable.

Intrinsic risk factors for the development of patellar tendinitis in an athletic population. A two-year prospective study

Retrospective studies have suggested various factors that might cause a disposition to develop patellar tendinitis, but no prospective data exist to determine any relationships. The purpose of this study was to determine the intrinsic risk factors for the development of patellar tendinitis in an athletic population. Before the study, 138 male and female students of physical education were evaluated for anthropometric variables, leg alignment characteristics, and muscle tightness and strength parameters. During the 2-year study, 19 of the 138 students developed patellar tendinitis. In all cases the diagnosis was confirmed by the presence of a hypoechogenic nodular lesion in the proximal region of the patellar tendon. Univariate and stepwise discriminant function analyses were performed comparing the various measurements. These analyses revealed that the only significant determining factor was muscular flexibility, with the patellar tendinitis patients being less flexible in the quadriceps and hamstring muscles (P < 0.05). The results of this study demonstrate that lower flexibility of the quadriceps and hamstring muscles may contribute to the development of patellar tendinitis in an athletic population. Therefore, the prevention of this condition in athletes should be focused on screening for and treating poor quadriceps and hamstring muscle flexibility.

Patellar tendinopathy in athletes. Outcome of nonoperative and operative management

We report the results of nonoperative and operative management of patellar tendinopathy in 42 athletes with Blazina stage 2 (26 patients) or stage 3 (16 patients) patellar tendinopathy. All patients were initially managed nonoperatively with nonsteroidal antiinflammatory drugs, physical therapy, and a progressive rehabilitation program based on isometric exercises, stretching, and eccentric exercises. After 6 months, 33 patients showed symptomatic improvement and were able to resume their sports. In nine patients with Blazina stage 3 tendinopathy, nonoperative measures failed, and surgery was performed. Operative treatment consisted of removal of the degenerated areas of the tendon, multiple longitudinal tenotomies, and drilling of the lower pole of the patella at the site of tendon attachment. Histologic examination of the excised tendon tissue showed areas of necrosis and mucoid degeneration, and alterations of the bone-tendon junction. After a mean follow-up of 4.8 years, clinical results were excellent or good in all patients. In the group treated nonoperatively, results were better in the patients who had stage 2 tendinopathy than in those with stage 3.