Clinical Scenario

The anterior bundle of the ulnar collateral ligament (UCL) is the primary stabilizer against valgus forces within the functional range of 30° to 120° of elbow flexion.^1–3 During the throwing motion, substantial valgus loads placed on the elbow during the late cocking and early acceleration phases often exceed what may be required to damage the ligament.^1–3 Baseball pitchers are most often affected by UCL tears, with injury rates continuing to rise.^1,4 Reconstructive surgery is the most common treatment approach for UCL tears, but increasing evidence shows that surgical repair and conservative treatment are viable options for certain athletes. A surgical repair of the ligament will require approximately 6 months of rehabilitation before returning to competition.⁵ If reconstructive surgery is necessary, rehabilitation will last at least 12 to 18 months.^1,4,6–8 Select populations have seen positive results, including shorter return-to-play times, with conservative treatment approaches consisting of relative rest and various modalities for pain control followed by structured rehabilitation including range of motion and progressive upper-extremity strengthening exercises before beginning an interval throwing program.^3,4,7,9 More specifically, younger athletes presenting with lower grade, proximal-based, primary injuries have shown good outcomes with conservative treatment.^4,6,7,9 For most of these athletes, and athletes at all levels, the recovery time associated with surgical intervention is not feasible based on long-term goals or competition timelines. Improving outcomes for these athletes relies on reducing recovery time and increasing the likelihood of returning to competition.

Platelet-rich plasma (PRP) contains a variety of growth factors with laboratory research showing evidence of an accelerated healing process and improved tissue healing. PRP has been studied clinically in treatment of various orthopedic conditions as well.^2,6,7,10 For athletes identified as good candidates for conservative treatment, including PRP in the treatment plan may improve healing of the UCL, improve return-to-competition rates, and minimize the time necessary to return compared with rehabilitation alone.

Focused Clinical Question

Do PRP injections improve conservative treatment outcomes in overhead athletes with partial tears of the UCL compared with conservative treatment alone regarding return to participation?

Summary of Search, “Best Evidence” Appraised, and Key Findings

1. •A literature search was performed to locate all studies investigating outcomes when PRP is included in a conservative treatment program for overhead athletes with partial UCL tears. For the purposes of the literature search, conservative treatment was operationally defined as any treatment plan that did not include surgical intervention. Typical conservative approaches included, but were not limited to, rest, pain control, pharmacologic intervention, rehabilitative exercise, and throwing programs.
2. •Three studies that met inclusion and exclusion criteria were located and included in the critically appraised topic.^6,8,10 All 3 of the studies were case series.
3. •All 3 studies found reduced recovery times and improved return-to-sport rates with the use of PRP compared with rehabilitation alone. The studies also found promising results with nonprofessional athletes, the population most likely to attempt conservative treatment. No adverse effects were reported in any study. Patient selection and injury severity play a crucial role in treatment outcomes.^6,8,10

Clinical Bottom Line

Current evidence suggests that the addition of PRP to a conservative treatment program may improve outcomes in overhead athletes with partial UCL tears.^6,8,10 Athletes whose treatment included PRP show higher return-to-competition rates and shorter recovery times before returning to competition compared with athletes who performed rehabilitation only.^3,4,6–10 Additionally, athletes with grade-1 and proximal-based grade-2 injuries return to competition at rates comparable with athletes undergoing surgical intervention.^1,6,8,10 No side effects have been reported when including PRP in treatment, and its use does not preclude surgical reconstruction if conservative treatment fails.^6,8,10 The decision to use a conservative treatment approach must be made individually, and clinicians should consider many athlete- and injury-specific factors.¹ For optimal conservative management outcomes, PRP injections should be recommended for treatment of partial UCL tears.

Search Strategy

Inclusion and Exclusion Criteria

Results of Search

The literature search revealed 156 unique articles. Of these, 3 qualified for inclusion in this critically appraised topic. All 3 qualified studies were case series and represented level 4 evidence based on the 2011 Oxford Centre for Evidence-Based Medicine levels of evidence.^6,8,10 The search process is shown in Figure 1 and the search results are summarized in Table 1.

—Search strategy. PRP indicates platelet-rich plasma; UCL, ulnar collateral ligament.

Citation: Journal of Sport Rehabilitation 29, 4; 10.1123/jsr.2018-0174

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—Search strategy. PRP indicates platelet-rich plasma; UCL, ulnar collateral ligament.

Citation: Journal of Sport Rehabilitation 29, 4; 10.1123/jsr.2018-0174

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• Download figure as PowerPoint slide

—Search strategy. PRP indicates platelet-rich plasma; UCL, ulnar collateral ligament.

Citation: Journal of Sport Rehabilitation 29, 4; 10.1123/jsr.2018-0174

• Download Figure
• Download figure as PowerPoint slide

Best Evidence

The studies summarized in Table 2 represent the best evidence available based on the inclusion of PRP in a conservative treatment program for overhead athletes with partial tears of the UCL. All 3 articles were determined to be level 4 evidence based on the 2011 Oxford Centre for Evidence-Based Medicine levels of evidence.

Implications for Practice, Education, and Future Research

As the number of young athletes experiencing damage to the UCL and subsequent UCL repair or reconstruction continues to rise, efforts to develop effective conservative treatment protocols should increase.¹ The impact of surgical recovery times relative to most athletes’ career length cannot be overstated, with repair requiring approximately 6 months of recovery and reconstruction typically requiring 12 to 18 months.^1,4–8 Although complete tears of the UCL almost universally require surgical repair or reconstruction, there is a growing body of evidence suggesting that nonsurgical approaches can successfully treat partial tears in some patients.^6,8,10 This critically appraised topic sought to determine if traditional conservative treatment approaches could be improved with the addition of PRP.

Current research investigating the effects of PRP on UCL tears shows positive outcomes related to return to competition and length of time missed. These studies report 73% to 96% of athletes returned to competition with an average of 11 to 12 weeks of time missed.^6,8,10 These findings are notable increases from previously reported outcomes ranging from 42% to 84% of athletes returning to competition and a minimum average recovery time of 24.5 weeks.^3,4,7,10 Importantly, the studies also demonstrated that inclusion of PRP treatments in a conservative treatment plan does not preclude surgical reconstruction for those athletes who are unable to return to competition.^8,10

Practicing clinicians must consider several factors when considering treatment plans for an athlete based on these results. Appropriate patient selection is crucial to the success of conservative treatment, and clinicians must educate each patient to give a realistic perception of the likelihood that treatment with PRP will be successful. Patients demonstrating diffuse damage or a lower grade partial tear of the UCL on magnetic resonance imaging are more likely to respond to conservative treatment than those with a higher grade partial tear or complete tear.^4,6,7,9 Similarly, better results are seen in patients with proximal-based tears compared with those with distally based tears.^4,6,7,9 Patients who have previously undergone surgical reconstruction or repair should not be expected to respond favorably to conservative treatment.¹⁰

The patients in the reviewed studies are mostly high school and college athletes, which are 2 populations for whom avoiding surgical intervention may be most important.^6,8,10 Clinicians should be mindful of the timelines and career goals of these athletes when weighing options and should be aware that positive results have been demonstrated in these groups. The results of these studies are most applicable to baseball athletes, with the vast majority of athletes included in both the PRP groups (91%) and rehabilitation only groups (94%) being baseball players.^6,8,10 These rates are similar to those previously reported for all athletes seeking UCL reconstruction and are representative of the overall population sustaining UCL injuries.¹ Clinicians must understand that these findings may not apply to athletes in other sports and should exercise clinical judgment based on the demands that will be placed on the UCL in such cases. For baseball and softball athletes, position players demonstrate better outcomes with conservative treatment than pitchers, likely due to exposure to fewer risk factors for UCL injury upon return to participation.^1,6,10

Along with clinical judgment based on the previously discussed patient- and injury-specific factors, clinicians should also consider the role of rehabilitation specialists in a conservative treatment plan. Extensive physical rehabilitation will be necessary and should be guided by an individual who is experienced in the management of athletic injuries. Rehabilitation specialists are especially important because rehabilitation should not be limited to the affected upper-extremity, but instead should focus on whole-body exercises and address movement patterns that may contribute to UCL injury.^2,10 A typical postinjection protocol should consist of a period of relative rest and protection for the injured elbow while beginning to address strength and flexibility in other areas, followed by progressive stretching and strengthening of the upper-extremity.^2,6,8,10 Rehabilitation specialists should monitor and adjust exercises as necessary, determine the need for and duration of bracing, evaluate throwing mechanics and movement patterns, and select an appropriate progressive throwing program as an athlete prepares to return to competition.

Several limitations associated with this review should be addressed and considered when applying the results to clinical practice. None of the studies included in the review enrolled a true control group for comparison with the PRP group. Two studies required a failed trial of conservative treatment and interval throwing program as inclusion criteria, using each patient as his or her own control for comparison. This leaves the possibility for the natural time course to confound results, an issue that should be addressed in future studies by enrolling separate intervention and control groups. A second limitation is the lack of standardization and specific detail of rehabilitation plan utilized. None of the studies provide detailed explanations of their rehabilitation program, and results may be influenced by the postinjection process. Finally, all 3 studies employed different protocols for the formulation and administration of PRP injections. These studies differed on number of injections, volume of injections, inclusion or exclusion of leukocytes, and use of ultrasound guidance. These differences make direct comparison between studies difficult and negatively affect the reproducibility of the studies. Additionally, rationale for selection of a PRP protocol in these studies appears to be limited to clinical judgment and experience, manufacturer guidelines, or patient symptom reports. Future studies must include more specific characterizations and rationale for PRP formulations so work toward evaluating different formulations against one another can begin.

Future research should focus on evaluating rehabilitation and PRP protocols to allow for better comparison across studies. This should include detailed reports of rehabilitation protocols including timelines, specific rehabilitative exercises, bracing protocols, and throwing programs. PRP protocols should be evaluated to determine the effects of different formulations including volume administered, number and timing of injections, leukocyte-rich or leukocyte-poor formulations, and the use of ultrasound guidance for injections. There is also the possibility of publication bias in the literature, with positive outcomes more likely to be reported, skewing success rates. Therefore, higher level studies including case-control studies, prospective cohort studies, and randomized controlled trials must also be conducted to evaluate the efficacy of PRP. When possible, these studies should standardize patient selection, rehabilitation protocol, and PRP protocol.

In conclusion, the available research suggests that some athletes undergoing conservative treatment for partial UCL tears return to competition earlier and at higher rates when PRP is included in the treatment plan.^6,8,10 Patient selection and injury severity greatly influence treatment outcomes, so clinicians must be mindful of these factors when educating athletes and making treatment recommendations.^6,10 Athletes with proximal-based, low-grade injuries appear to be most likely to succeed in a conservative treatment plan with PRP.^4,6–10 No adverse outcomes were reported with PRP injections, allowing clinicians to safely recommend use when conservative treatment is indicated. However, high-level evidence supporting the use of PRP for partial UCL tears is limited, and recommendations should be made on a case-by-case basis until further evidence is available.