Background
Osgood-Schlatter disease (OSD) in children and adolescents is one of the most common causes of anterior knee pain, it is an injury resulting from a traction apophysitis of the tibial tubercle. It is self-limiting and often prevents young athletes from physical activity due to inflammation and pain. Most cases cease with skeletal maturation. Former studies have shown that it mostly occurs in boys at the age of 12-15; however, in more recent studies, no difference in sex distribution can be seen. This may be the result of the increased participation of young females in high-impact sports or the fact that more studies have been published [1].
OSD often causes short periods of pain, forcing the young athlete to take breaks in physical activity and training. In some cases, however, the condition seems to affect more and may force an end to the individual’s athletic career. In such cases, orthopedic arthroscopy is considered the golden standard for resolving Osgood-Schlatter lesions [2].
The long-term results after surgery are usually good, with only a few minor postoperative complications known and reoperations are rare [3]. Undergoing surgery is only recommended when conservative treatment has failed and is more common in younger adults [4].
This case highlights a further possible treatment option for Osgood-Schlatter disease resistant to standard treatment options or as an alternative to surgical intervention.
Case Presentation
We present the case of a 13-year-old Swedish boy with a 3-year history of chronic painful Osgood-Schlatter disease with typical ossification and swelling of the patellar tendon at the attachment point of tuberositas tibiae. The condition has made any sporting activities impossible due to severe pain and swelling both during and after physical activity.
Although most cases of OSD recover completely over time when the tibial growth plate closes, some cases have suffered such damage that the lesions and ossification make the recovery difficult. In this case, the 13-year-old boy was experiencing such difficult symptoms that all physical activity was paused for a period of 3 years. The boy was very active and competed and trained in both athletics and football but had to quit both teams due to his OSD. Surgery was discussed and the boy presented clinical symptoms of inflammation and ossification at the point of tuberositas tibiae on the right knee, the diagnosis was confirmed with ultrasound.
Materials and Method
Various types of autologous platelet concentration have been proposed to be used to treat injured tendons and deformations on their attachment. Some studies have indicated a positive effect on inflammation and tendinopathy in general; however, the effect of injected platelets on the injured tendon might require multiple injections and no standard protocols exist [5]. One way of extending the effect of the injected platelets is to heat a liquid platelet-poor plasma layer, the resorption properties of heated albumin (albumin gel) can be extended from 2 weeks to greater than 4 months heat coagulated albumin platelet rich fibrin (ALB-PRF) [6].
Preparation of platelet rich fibrin (PRF) and ALB-PRF
The injured knee of the boy was injected three times during a 1-month period with at least 1 week between the injections. 40 ml blood was collected before each of the three injections. Four 10 ml Plastic, round-bottomed vacuum tubes (Liquid PRF tubes) were used to collect the blood, after collection the tubes were spun on a horizontal swing-out bucket rotors centrifuge system. Two protocols were utilized in the treatment in this case report including a concentrated platelet rich fibrin (C-PRF) protocol of 2,000 × g for 8 minutes and a ALB-PRF protocol of 2,000 × g for 8 minutes followed by a heating and cooling down process before injection was performed. The two protocols were utilized according to previous literature following international guidelines published by Miron et al. [7].
The centrifuge utilized in all three treatments was the Bio-PRF horizontal centrifuge (Bio-PRF, USA).
The first injection was a C-PRF [8] injection of 2 ml, centrifuged at 2,000 × g for 8 minutes. While the two following injections consisted of 2.5 ml of ALB-PRF, 2,000 × g for 8 minutes on a horizontal centrifuge, the albumin layer was heated according to the ALB-PRF protocol: 75 degrees for 10 minutes [9]. In the last step, the heat-coagulated albumin was cooled down to room temperature and mixed with the remaining C-PRF to create ALB-PRF. All injections were performed with ultrasound guidance.
One week after the last treatment, the boy commenced the same rehabilitation exercises he had tried before the intervention (mainly consisting of eccentric training of the knee).
Results
The treated knee was inspected after 1, 2, and 3 months.
The boy presented a significantly lower pain level 3 months after the treatment and no longer had palpation pain when examined around the former painful area at the tuberositas tibiae.
The pain level experienced was assessed using a Verbal Rating Scale (VRS) at rest, while moving and at palpation. The change in experienced pain went from an average of 5 to below 0.33 on the VRS scale 3 months after the treatment. The changes can be seen in Figure 1.
Visually, a significant reduction of the tibial tubercle prominence was observed at the follow-up examinations after the treatment. He returned to sporting activities on an elite level already after 2 months and is still active with no relapses 2 years after the injection treatment.
Discussion
In this case, the patient presented chronic pain, swelling, and ossification of the right patellar tendon, near and at the site of tuberositas tibiae, (which can be clearly seen in Figures 2 and 3) and the diagnosis Osgood-Schlatter was made.
Ultrasound picture of ossification and inflammation of the right knee at the attachment point of the patellar tendon on the tuberositas tibiae.
Ultrasound picture of further deformations of the right knee at the attachment point of the patellar tendon on the tuberositas tibiae.
Ultrasound picture of the same right knee, 3 months after the three injections. Fewer deformations and inflammation are visible.
Ultrasound picture of the same right knee from a slightly different angle, 3 months after the three injections. Visibly less ossifications and deformations.
OSD usually resolves with age or conservative therapy (limited physical activity and mild analgesia), although it can be treatment-resistant or reoccurring. The patient in this case was physically active in both athletics and football but had to take longer breaks from his activities, eventually leading to a full stop, thereby he fits the typical profile for OSD but unfortunately also has a small percentage of not recovering after 3 years. The novel PRF and ALB-PRF treatments came after the failure of conventional conservative therapies. Two months after the treatment, he had symptom resolution and could return to sport 1 month later in elite level basketball where he is still active 4 years later. The positive structural changes can be seen in Figures 4 and 5.
In 2017, Danneberg published promising results for the injection of autologous-conditioned plasma (platelets concentrated at 300 g × 5 minutes) in the treatment of tendon injury in OSD [10], the effects, however, on ossification and deformation were absent.
Recent studies have shown that ALB-PRF has a much longer reabsorption time than PRF and other platelet concentrates, leading to the release of growth factors over an extended period of time. In dentistry, it has been used successfully in grafting processes and affects osteogenesis [11]. In animal studies, both solid PRF and Liquid PRF have been shown to hold a potent anti-inflammatory capacity in mesenchymal cells and show the ability to reduce osteoclastogenesis [12,13]. The results presented in this case highlight the possibility that the osteogenic properties of ALB-PRF may have a positive effect on ossification associated with tendon injury where ossification and osteochondrosis appear. A recent review on the subject of ALB-PRF highlighted the great biocompatibility of ALB-PRF and concluded that it has the capacity to greatly enhance fibroblast cellular activity as well as collagen production via the release of blood-derived growth factors [9].
The case presented herein describes a successful novel use of PRF and ALB-PRF for OSD, thus providing us insight into an alternative intervention for patients where the standard conservative treatment has failed or as an option to surgical intervention.
Further research on PRF and ALB-PRF for OSD in a larger patient group is indicated to optimize the treatment protocol further and test the theory in full.