Safety and efficacy of platelet-rich plasma injections in basal thumb osteoarthritis; should we offer it or not?

Abstract

Nonsurgical therapeutic approaches for thumb carpometacarpal (CMC) osteoarthritis (OA) often offer only inconsistent symptom relief and fail to restore hand function. Intra-articular platelet-rich plasma (PRP) injections have recently emerged as a promising alternative, with encouraging outcomes in knees and hips. This systematic review and meta-analysis aims to highlight the safety and efficacy of PRP injections in thumb CMC OA. A systematic review was completed using Medline, Embase, and Cochrane. Primary outcomes focused on patients with basal thumb osteoarthritis treated with intra-articular PRP injections. Patient characteristics, product administration, functional outcomes and complications were analyzed as means of central tendency. A meta-analysis was performed focusing on pain relief and improvement in hand function. Seven articles were included, comprising 115 patients with an average age of 62.6 years, predominantly female (67.0 %). Patients received an average of 1.4 PRP injections per joint, with an average follow-up of 14.1 months. Control groups were administered corticosteroids, normal saline, and hyaluronic acid. All PRP-treated patients resumed their prior activities of daily living with a satisfaction rate at 73.7 % (n = 76). Statistically significant pain reduction (n = 98) and improvement in pinch strength were reported, while no statistically significant improvement in grip strength was observed (n = 39). No adverse events occurred, with only one complication (a palmar wrist ganglion) reported. Intra-articular PRP injections in thumb CMC OA yields favorable outcomes for pain relief and hand function without major complications. However, procedural and data heterogeneity affect reliability. Further randomized controlled trials comparing PRP and cortisone injections are needed.

1. Introduction

Osteoarthritis (OA) is a common degenerative medical condition that affects the joints of older adults.^1,2 Secondary to an alteration in the joint microenvironment, OA results in the degradation of articular cartilage and the proliferation of chondrocytes within the joint space.^3,4 Ultimately, the disruption of the synovial fluid produces changes within the joint margins, subchondral bone, and periarticular structures, causing severe pain and drastically impacting patients' quality of life¹ (see Table 1, Table 2).

Table 1.

Study characteristics.

Title	Study	Year	Study Type	Comparative Study	Funding	Country
Platelet-Rich Plasma Injection for Thumb Carpometacarpal Joint Osteoarthritis	Hasley et al.	2023	Retrospective Case Series	No	None	USA
Leukocyte-reduced platelet-rich plasma treatment of basal Thumb arthritis: A Pilot Study	Loibl et al.	2016	Prospective Cohort	No	Yes	Germany
Platelet-Rich Plasma versus corticosteroid intra-articular injections for the treatment of trapeziometacarpal arthritis: A Prospective Randomized Controlled Clinical Trial	Malahias et al.	2021	RCT	Yes	None	Greece
Intra-Articular laser treatment plus Platelet Rich Plasma (PRP) significantly reduces pain in many patients who had failed prior PRP treatment	Prodromos et al.	2019	Case Series	No	None	USA
A comparative study for different types of thumb base osteoarthritis injections: a randomized controlled interventional study	Sabaah et al.	2020	RCT	Yes	None	Egypt
Effects of intra-articular Platelet-Rich Plasma (PRP) injections on osteoarthritis in the thumb basal joint and scaphoidtrapeziotrapezoidal joint	Sward and Wilcke	2022	Retrospective Case Series	No	None	Sweden
Minimal invasive treatment of trapeziometacarpal osteoarthritis: Results of a blinded, randomized controlled trial	Winter et al.	2023	RCT	Yes	None	Austria

PRP: Platelet Rich Plasma, RCT: Randomized controlled trials, USA: United States of America.

Table 2.

Patient characteristics.

Study	N	Sex	Mean Age, years (range)	Controls	Control Type	Injection Guidance	PRP Preparation
Hasley et al. (2023)	19 (33 joints)	M:10	65 (40–74)	None	None	Ultrasound	Mean volume of blood drawn was 116.3 mL. Volume of PRP produced varied between 0.8 and 7.3 mL, averaging 3.6 mL. All samples were processed using the Arthrex Angel System, following manufacturer guidelines, with a 1 % hematocrit setting. No platelet activators were employed.
		F:9
Loibl et al. (2016)	10	M:2	56.1 ± 9.9	None	None	Fluoroscopy	15 mL venous blood drawn into the Arthrex Double Syringe for autologous conditioned plasma production and centrifuged at 1500 rpm for 4 min, allowing the blood to be separated into two distinct layers. The upper layer of plasma containing PRP was isolated by drawing the inner syringe.
		F:8
Malahias et al. (2021)	16	M:3	62.8 ± 10.6	17	US-guided intra-articular methylprednisolone and lidocaine	Ultrasound	20 mL autologous venous blood drawn and centrifuged 2 consecutive times. After the 1st centrifugation, the RBCs were removed, and after the 2nd centrifugation, 2 mL of autologous, leukocyte-poor nonactivated PRP were separated from platelet-poor plasma.
		F: 13
Prodromos et al. (2019)	2	M:1	60	None	None	Ultrasound	45 mL blood drawn and double-spined to create one 4 mL dose of PRP. Ultrasound guidance was used in the placement of all needles.
		F:1
Sabaah et al. (2020)	15	M:6∗	52.45 ± 8.25∗	1) 15	1) Hyaluronic acid	NR	Using a PRP device, 20 mL whole blood drawn and centrifuged at 1500 rpm for 15 min. Plasma was separated and centrifuged at 3500 rpm for 10 min. PRP was then drawn.
		F:38∗		2) 15	2) Corticosteroids
Sward and Wilcke (2022)	33	M:12	63 (34–86)	None	None	Fluoroscopy	Using the Arthrex ACP double-syringe system, 15 mL of venous blood was drawn and centrifuged at 1500 rpm for 5 min.
		F:17
Winter et al. (2023)	24	M:5	63	21	0.9 % saline	Dual-plane image-converter X-ray	Venous blood (28 ml) was drawn and centrifuged using Endoret kit (BTI Deutschland GmbH) to produce PRP. Additionally, 5 ml of fat was obtained using Tulip Sorenson Harvester™. Two 9 mL blood samples were then centrifuged at 580 G for 9 min to yield leukocyte- and erythrocyte-free PRP. 1.5 ml of this PRP was prepared in a 2 ml syringe and activated with 3 units of calcium chloride before use.
		F:19
Total:	117	M:35	54.6	68	N/A	N/A	N/A
		F:67
F: Female; M: Male; NR: Not Reported; N/A: Not applicable; N: number of participants; PRP: Platelet-Rich Plasma; RBCs: red blood cells; ∗ Not included in pooled analysis

Study	Dominant Hand	Time from Symptoms, month	OA Classification	Number of injections	Time between injections, weeks	Volume per injection, mL	Follow-up, months	Injection Guidance
Hasley et al. (2023)	NR	NR	I: 0	1	NR	1.1 ± 0.4 ml (0.25–2.0)		Ultrasound
			II: 7				1st: 12
			III: 18				2nd: 32.4
			IV: 8
Loibl et al. (2016)	3	NR	I:0	2	4	1st: 1.47 ± 0.25 2nd: 1.5 ± 0.41		Fluoroscopic
			II:2				1st: 3
			III:3				2nd: 6
			IV:5
Malahias et al. (2021)	NR	NR	I: NR	2	2.14	NR		Ultrasound
			II: NR				1st: 3
			III: NR				2nd: 12
			IV: 0
Prodromos et al. (2019)	NR	NR	NR	2	NR	4	24	Ultrasound
Sabaah et al. (2020)	NR	NR	NR	1	N/A	1	1st: 1	NR
							2nd: 3
Sward and Wilcke (2022)	NR	NR	I: 2	2	3.5	0.5–2	3	Fluoroscopic
			II: 4
			III: 12
			IV: 3
Winter et al. (2023)	NR	NR	I: 0	1	NR	1.5	1st: 0.5	Dual-plane image-converter X-ray
			II: 5				2nd: 1
			III: 14				3rd: 2
			IV: 5				4th: 3
							5th: 24
mL: milliliter; NR: Not Reported; OA: Osteoarthritis

The hand is the most affected anatomical area of the human body.3, 4, 5 Specifically, within the hand, OA affects the thumb carpometacarpal (CMC) joint.⁶ It is estimated that thumb CMC OA impacts between eight to twelve percent of the general population.⁷ Moreover, the prevalence of this disease increases with factors such as obesity, mechanical strain, trauma, hypermobility, age, and female gender.8, 9, 10, 11, 12 In fact, one in three post-menopausal women are diagnosed with thumb CMC OA due to both anatomical and hormonal differences compared to older men.^13,14

As the disease slowly evolves, patients face increasing thumb pain, digit deformity, joint instability, and decreased range of motion.^6,12 While the condition is centered around the base of the thumb, it carries much larger implications on individuals' quality of life and restricts them in their activities of daily living (ADL). Simple movements that require substantial dexterity, such as turning keys, opening jars, and unboxing packages, can be extremely challenging for patients with thumb CMC OA.¹²

While no intervention is currently available to mitigate thumb CMC OA progression, several conservative and surgical treatment options exist to provide symptomatic relief and improve patients' quality of life.¹⁵ Treatment selection is typically guided by the clinical presentation and Eaton-Littler classification for thumb CMC OA.^16,17 Operative interventions are typically reserved for Eaton-Littler stages II-IV and select stage I cases.¹⁷ However, nonoperative modalities, such as exercise plans, orthoses, analgesics, and corticosteroid injections, remain the standard of care for Eaton-Littler stage I individuals and those who wish to avoid or to delay surgical management.^16,18, 19, 20 Yet, the literature remains scarce in terms of the clinical efficacy of these conservation interventions.⁶

Intra-articular platelet-rich plasma (PRP) injections have recently gained traction as a novel alternative to standard conservative OA treatment options with emerging evidence demonstrating its efficacy in the management of knee and hip OA.^12,21, 22, 23, 24 PRP is an autologous blood product of a highly concentrated platelet solution produced via centrifugation.²⁵ Following its injection into the targeted joint, platelets are activated through the degranulation of ɑ-granules, which subsequently release several inflammatory mediators and growth factors including transforming growth factor beta (TGF-β), platelet-derived growth factor (PDGF), fibroblastic growth factor, vascular endothelial factor (VEF), and insulin-like growth factor (IGF).^26,27 These mediators subsequently interact with immune cells, the synovial membrane, subchondral bone, and cartilage to alter the pro-inflammatory and catabolic OA microenvironment. Ultimately, PRP serves the fundamental purpose to assist with tissue repair and re-establish joint homeostasis.^28,29

While PRP injections have increasingly been utilized for OA treatment within larger joint spaces, very little has been reported on their use within the smaller joints of the hand. Given the lack of a consensus surrounding the efficacy of current conservative interventions, PRP injections may serve as a valuable option for the treatment of thumb CMC OA. Hence, the following systematic review and meta-analysis aims to describe the outcomes and complications of intra-articular PRP injections in the context of thumb CMC OA.

2. Materials and methods

The following systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.³⁰ A protocol for this study (https://doi.org/10.17605/OSF.IO/EYUQR) was registered on Open Science Framework.

2.1. Search strategy

A comprehensive search of MEDLINE (via Ovid), EMBASE (via Ovid), and Cochrane Library was performed. No limits (language, publication type, etc.) were placed. Search strategies are provided in Supplementary Data: Table S1. Terms were joined using the Boolean operators “AND” and “OR”. Once citations were retrieved, they were uploaded into EndNote™ X9 and deduplication was performed. The reference lists of relevant studies were screened to identify additional papers not identified in the search.

2.2. Study selection

Following deduplication, references were uploaded in Rayyan (an online systematic review software). Both title and abstract screening as well as full text review were performed by two independent reviewers (OE and JL). Any disagreements between reviewers were resolved through consensus and when necessary, through discussion with a third reviewer (SD). Supplementary data Table S2 provides the reasons for exclusion for studies at the full-text stage.

2.3. Study eligibility

Strict inclusion and exclusion criteria were used to identify relevant studies for inclusion. English prospective and retrospective studies, randomized controlled trials, case-series, and case-control studies were eligible for inclusion. Systematic reviews, meta-analyses, case reports, letters to the editor, viewpoints, commentaries, cadaveric studies, abstracts not traced to full-text and protocols not traced to full text were excluded. Studies with and without a comparator group were eligible for inclusion. Adult patients (≥18 years old) that underwent PRP injections at the base of the thumb for arthritis were eligible for inclusion. Finally, any form or derivative of PRP injections (i.e., leukocyte reduced PRP) used at the thumb base were eligible for inclusion along with guidance tools required for proper injection.

2.4. Data extraction & synthesis

Data extraction was performed by a single reviewer with a second reviewer validating the extracted information. Any disagreements were resolved through consensus and when necessary, through discussion with a third reviewer. Data points extracted are provided in Supplementary data Table S3. Extracted data was provided in summary tables and where applicable descriptive statistics were performed (i.e., outcomes, complication rates and overall means).

2.5. Meta-analysis

A meta-analysis assessed the effectiveness of PRP therapy in patients with CMC OA, focusing on both pain reduction and functional outcomes. For pain, five studies (Loibl et al., 2016³¹; Malahias et al., 2021³²; Sabaah et al., 2020³³; Sward and Wilcke 2022³⁴; Winter et al., 2023³⁵) involving 98 patients, and for functional outcomes, four studies (Hasley et al., 2023³⁶; Loibl et al., 2016; Malahias et al., 2021; Winter et al., 2023) with 64 patients, reporting DASH scores across different scales (e.g., Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire vs. Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire) were included. Outcome measures were standardized to Standardized Mean Differences (SMDs). Both fixed-effect and random-effects meta-analyses were conducted using Python package statsmodels (v. 0.13.2). We assessed heterogeneity via the I² statistic and tau-squared (τ²). Grip and pinch strength were pooled only from Loibl et al., 2016 and Sward and Wilcke 2022. This was due to Winter et al., 2023 not providing variance estimates, as well as Prodromos et al., 2019³⁷ lacking baseline strength reports. Forest plots were generated to visualize SMDs and 95 % confidence intervals for individual studies and the overall effect sizes using Python package matplotlib (v. 3.5.1).

3. Results

The initial search yielded a total of 366 articles. 38 records were duplicates and removed prior to screening, while the remaining 328 studies underwent title and abstract screening. A total of 22 reports were assessed for eligibility and screened via full-text review. In the end, a total of seven articles satisfied this study’s inclusion criteria (Fig. 1).

Fig. 1.

Preferred reported items for systematic reviews and meta-analyses (PRISMA flow diagram of study selection).

The studies included three randomized control trials, one prospective cohort, and three case series. All studies were published between 2016 and 2023. In total, the reports comprised 129 affected joints in 115 thumb CMC OA patients receiving PRP injections. Among the pooled population, the majority were female at 67.0 % (n = 67 patients), and the mean age was 62.6 years (n = 100 patients, range:34–86). Dominant hand thumb CMC OA was diagnosed in 30.0 % of patients (n = 3 patients). Four studies reported on patients' Eaton-Littler classification with Eaton-Littler grade III being the most common (n = 47 joints, 53.4 %). This was followed by Eaton-Littler grade IV (n = 21 joints, 23.9 %) and Eaton-Littler grade II (n = 18 joints, 20.5 %). The remaining 2.3 % of subjects (n = 2 joints) were categorized as Eaton-Littler grade I. Amongst the controls, 47.1 % patients received corticosteroids (n = 32 patients), 30.9 % received normal saline (n = 21 patients), and 22.1 % received hyaluronic acid (n = 15 patients).

Seven articles described their unique PRP preparation methods, and an average of 1.3 mL were used per injection (n = 129 injections). Among the six articles reporting on the type of injection guidance, 50 % utilized ultrasound (N = 3) and 33.3 % used fluoroscopy (N = 2). One study implemented dual-plane image-converter x-ray-guided injections (16.7 %). The overall mean number of injections per joint was 1.4 injections per joint (range: 1–2), and the mean time between injections was 3.2 weeks (range 2–4, N = 3) (see Table 3).

Table 3.

Pooled analysis of patient characteristics.

Injection Type	Last Follow Up Time, months	Dominant Hand	Average # Injections	Time between injections, weeks	Volume per injection, mL	Patient Satisfaction	OA Class I	OA Class II	OA Class III	OA Class IV
PRP injection	14.1	3/10 (30.0 %)	1.4	3.2	1.3	56/76 (73.7 %)	2	18	47	21
Range	3–32.4	NA	1–2	2–4	0.25–4	NA	0–2	1–4	0–18	0–8

mL: milliliter; OA: Osteoarthritis; #: number.

The mean follow-up time was 14.1 months. In terms of post-interventional outcomes, one article reported on joint tenderness (n = 15 joints), one reported Australian Canadian Osteoarthritis Hand Index (AUSCAN) scores (n = 15 joints), and one reported Kapandji opposition scores (n = 24 joints), one reported Mayo wrist scores (n = 10 joints) (Table 4). Across five studies, only one minor complication (1.0 %), a palmar wrist ganglion, was observed, whereas no major adverse events occurred (n = 98 joints). Furthermore, a patient satisfaction rate of 73.7 % was calculated amongst four reports (n = 76 joints).

Table 4.

Postoperative outcomes.

Study	VAS score (IQR)	NRS (1–10) (IQR)	PRWHE score (0–100) (IQR)	Tenderness	DASH scores	Patient satisfaction
Hasley et al. (2023)	Pre-injection: 4.3 (rest) and 5.6 (activity) pre-injection (7 responses); 12 months post: 3.3 (rest) and 2.3 (activity) (4 responses)	NR	NR	NR	Quick DASH	Very satisfied: 13 (40.6 %)
					Pre-injection: 28.6 pre-injection (5 responses)	Mostly satisfied: 9 (28.1 %)
					12 months post: 52.3 (2 responses).	Neutral: 4 (12.5 %)
						Mostly unsatisfied: 0
						Very unsatisfied: 6 (18.8 %)
Loibl et al. (2016)	Pre: 6.2 ± 1.6	NR	NR	NR	Dash	Very satisfied: 2
	3 months: 4.0 ± 2.4 †				Pre: 32.9 ± 11.9 (24.4–41.5)	Satisfied: 5
	6 months: 5.4 ± 2.2 †				3 months: 20.4 ± 14.7 (10.0–30.1)	Neither: 3
					6 months: 26.8. ± 18.9 (13.3–40.3)	Dissatisfied: 0
Malahias et al. (2021)	Pre: 75 (57.5–80.0)	NR	NR	NR	Quick Dash	3 months:
	3 months: 40 (17.5–70.0) †				Preop: 50.4 ± 21.6,	Satisfied: 7 (44 %)
	12 months: 20 (10.0–52.5) †				3 months: 32.8 ± 29.2 †	Dissatisfied: 9 (56 %)
					12 months: 20.4 ± 27.7 †	12 months:
						Satisfied: 11 (69 %)
						Dissatisfied: 5 (31 %)
Prodromos et al. (2019)	NR	NR	NR	NR	NR	NR
Sabaah et al. (2020)	Pre: 8 (6–8), [6–9]	NR	NR	Pre: Grade 1: 5 (33.3 %) Grade 2: 7 (46.7 %) Grade 3: 3 (20.0 %)	NR	NR
	4weeks: 4 (3–5), [3–5]			4 weeks: Grade 0: 10 (66.7 %) Grade 1: 4 (26.7 %) Grade 2: 1 (6.7 %)
	12weeks: 5 (4–6), [3–7] †			12 weeks: Grade 0: 0 (0.0 %), Grade 1: 6 (40.0 %), Grade 2: 9 (60.0 %), Grade 3: 0 (0.0 %) †
Sward and Wilcke (2022)	NR	Pain at rest: - Pre: 2 (1–5) - 2nd inj.: 0 (0–4) −3 months: 1 (0–3) Pain on load: - Pre:8 (6–9) - 2nd inj:7 (4–10) - 3mth:6 (4–9)	Pre: 65 (55–77) 2nd inj: 60 (43–77) 3 months: 54 (40–81)	NR	NR	Satisfied: 16 Unsure: 3 Dissatisfied: 9 No answer: 1
Winter et al. (2023)	NR	Overall: 0mth: 4.94 (SD 0.38), 24 mth: 3.95 (0.48)	NR	NR	Mean reduction by PRP: −9.1 points Relative DASH: 0 mth: 1; 0.5mth: 0.96, 1 mth: 0.82; 2 mth: 0.76; 3mth: 0.80	NR
		Rest: 0 mth: 3.12 (SD 0.48), 24 mth: 2.73 (0.65)
		Motion: 0 mth: 6.75 (SD 0.28), 24 mth: 5.18 (0.62)
DASH: Disabilities of the Arm, Shoulder and Hand; IQR: Interquartile range; NR: not reported; NRS: numerical rating scale; PRWHE: Patient-rated wrist and hand evaluation; ROM: Range of motion; †: Statistically significant; VAS: Visual analogue scale

Study	Mayo Wrist Score	Grip Strength (kg)	Pinch test (kg)	Kapandji Opposition Score	AUSCAN score (IQR)	Patient Reported Outcomes	Adverse events
Hasley et al. (2023)	NR	NR	NR	NR	NR	Patient reported symptom relief:	0
						Of the 32 joints
						7 no improvement (21.9 %),
						3 mild (9.4 %),
						11 moderate (34.4 %),
						11 excellent (34.4 %)
Loibl et al. (2016)	Preop: 46.5 ± 18.6 3 mth: 68.3 ± 18.5† 6 mth: 67.5 ± 19.0†	Preop: 16.4 ± 9.9 3 mth: 16.8 ± 10.2 6 mth 16.7 ± 10.4	Preop: 6.0 ± 3.0 3 mth: 4.6 ± 2.1 6 mth: 4.9 ± 1.8†	NR	NR	NR	1: Palmar wrist ganglion
Malahias et al. (2021)	NR	NR	NR	NR	NR	NR	NR
Prodromos et al. (2019)	NR	NR	NR	NR	NR	Normal	0
Sabaah et al. (2020)	NR	NR	NR	NR	Functional	NR	NR
					Pre: 24 (22–25)
					4 wk: 20 (18–20) †
					12 wk: 21 (18–22)
					Total:
					Pre: 35 (32–37)
					4 wk: 28 (26–30)
					12 wk: NR
Sward and Wilcke (2022)	NR	Pre: 23 (SD:13)	Prep: 5.5 ± 2.5	NR	NR	NR	0
		2nd inj: 22 (SD:13)	2nd inj: 5.8 ± 2.9
		3mth: 23 (SD:14)	3mth: 6.0 ± 2.9
Winter et al. (2023)	NR	0mth: 22.87	0mth: 1.576	0mth: 9.833 0.5mth: 9.625 1mth: 9.708 2mth: 9.917 3mth: 9.875	NR	NR	0
		0.5mth: 20.29	0.5mth: 1.461
		1mth: 21.72	1mth: 1.463
		2mth:21.25	2mth: 1.538
		3mth: 21.32	3mth: 1.782

AUSCAN: Australian Canadian Osteoarthritis Hand Index; kg: kilograms; NR: Not reported; ROM: range of motion; SD: Standard deviation; mth: months; †: Statistically significant; IQR: Interquartile range; wk: weeks.

Six different articles reported on pain reduction following PRP injections either via visual analogue scale (VAS) scores (n = 4), numerical rating scale (NRS) scores (n = 2), and/or patient-rated wrist and hand evaluation (PRWHE) scores (n = 1). A meta-analysis was performed on five of these reports, in 98 patients, there was a statistically significant reduction in pain using a random-effects model (SMD = 2.2, 95 % CI 2.0 to 2.3) (Fig. 2). Moreover, DASH score variations, either DASH or QuickDASH, were reported in four separate articles (n = 64). Following a meta-analysis via a random-effects model, a statistically significant decrease in DASH scores was demonstrated (SMD = 0.7, 95 % CI 0.1 to 1.2) (Fig. 2).

Fig. 2.

Forest plots for impact of PRP on patient outcomes.

Quantitative data in terms of grip strength was reported in three studies. Yet, one article was excluded from the meta-analysis. Winter et al. did not incorporate variance estimates. Data was also collected for pinch strength in three studies. However, Winter et al.³⁵ was excluded from the meta-analysis for the aforementioned reason. Hence, a meta-analysis using a random-effects model was performed on a total of 39 patients for both grip and pinch strength. While no statistically significant improvement in grip strength (SMD = 0.1, 95 % CI -1.1 to 1.2) was determined, a statistically significant improvement in pinch strength (SMD = 0.3, 95 % CI 0.1 to 0.5) was found.

The one-way ANOVA indicated no statistically significant difference in patient satisfaction rates across the four osteoarthritis classes (Class I-IV), F (3, 56) = 2.05, p = 0.117 (Total Mean = 75.0 %, 95 % CI 63.95 to 86.05). The mean satisfaction rates for Class I (M = 64 %, SD = 0), Class II (M = 74.29 %, SD = 10.87), Class III (M = 73.37 %, SD = 10.09), and Class IV (M = 80.4 %, SD = 13.72) showed no significant variations. Additionally, post-hoc analysis using Tukey’s HSD test confirmed that no pairwise comparisons reached statistical significance.

4. Discussion

4.1. Summary of the findings

This systematic review and meta-analysis aimed to assess the efficacy of intra-articular platelet-rich plasma (PRP) injections as a treatment option in the management carpometacarpal osteoarthritis of the thumb. Seven papers amounting to 115 patients with thumb CMC OA treated with PRP injections were included and analyzed. Most joints were categorized as Eaton-Littler grade III. Mean follow-up time was 14.1 months. Approximately 1.3 mL were used per injection, with a mean of 1.4 injections per joint administered at 3.2 weeks interval on average. The overall patient satisfaction rate was 73.7 %. Patient satisfaction rates do not differ significantly across osteoarthritis severity levels. Statistically significant pain reduction was reported. While no statistically significant improvement was observed in grip strength, there was a statistically significant improvement in pinch strength. Only one complication, a palmar wrist ganglion, was reported. In summary, these findings demonstrate that PRP injections are a safe and effective option for the management of thumb carpometacarpal osteoarthritis.

4.2. Background on PRP injections

Carpometacarpal osteoarthritis of the thumb encompasses a variety of pathologies, classified according to the affected carpal bones. Basal joint arthritis and rhizarthrosis are among the nomenclatures used when referring to arthritis involving the trapezium at the base of the thumb.³⁸ This range of pathologies can cause significant morbidity for patients, since osteoarthritis affecting the CMC of the first digit is known to be more painful than any other joints in the hand.³⁹

PRP injections have shown to provide clinically significant improvements in function and pain relief compared to hyaluronic acid, corticosteroids, or saline injections in knee osteoarthritis.^24,40, 41, 42, 43 Several prospective therapeutic cohorts have shown benefits of PRP injections in treating patients with arthritic hip and knee joints.^24,44, 45, 46, 47 Although its protective and healing action on cartilage defects have been demonstrated, the use of PRP is still controversial in the management of pain and functional outcomes of OA patients.^45,47, 48, 49, 50 More recently, attention has been brought towards its efficacy in treating smaller joints. Pain reduction and improvement in mandibular motion has been observed in temporomandibular joint (TMJ) OA.⁵¹ OA of the wrist’s sister, the ankle, was subject to PRP injection in a randomized clinical trial were no significant improvement in pain or function was shown in comparison to saline.⁵² Overall, evidence for PRP injections in larger joints like the knee and hip is more reliable than for smaller joints.⁵³

4.3. Procedural heterogeneity

Several studies are ongoing observing PRP injections as a treatment for thumb CMC OA seeking to elucidate its clinical significance. A lack of standardization exists as cell composition within the injection varies between studies and are often not reported. The heterogeneity in clinical efficacy could be a reflection of varying platelet concentration, as well as the presence and abundance of leukocytes.^36,54

Radiological guidance for the injection process is surgeon and centre dependent. Among the studies included in this review, fluoroscopy, palpation, radiograph, and ultrasound were used, with the latter being most adopted. While palpation, also known as the blind technique, is quicker and inexpensive, it puts the injector at a disadvantage when working with small joints. Imaging modalities such as ultrasound and fluoroscopy result in longer procedure times but allow confirmation of the placement in the joint. Ultrasound tends to be chosen over other modalities since it is inexpensive and radiation-free. However, it appears to be operator dependent.⁵⁵ Thus, intraarticular injection of PRP demonstrates heterogeneity in the procedural protocol in terms of product quantity, concentration, components, and method of administration.

4.4. Nonsurgical management of thumb CMC OA

Several factors influence the management plan in thumb CMC OA. Optimal treatment needs to align age, clinical demands, and disease staging. Classification systems often used are the Dell and Eaton-Littler, both specific to the trapeziometacarpal (TMC) joint.³⁸ The Eaton-Littler classification is based on radiographic findings only, resulting in several limitations in guiding treatment. Its reliability is often described as weak to moderate due to the difficulty of evaluating the thumb via solely radiographs since there are differences between radiological and intraoperative findings, and clinical symptoms. A poor correlation exists between this classification, symptom severity and treatment choices.56, 57, 58 In their randomized controlled trial, Winter et al.³⁵ used the Eaton-Littler classification for patients with thumb CMC OA and World Health Organization (WHO) for STT OA patients. Pain reduction after PRP injection was significantly higher in patients with stage III than stage II (p = 0.009) while stage IV experienced the smallest pain relief. As for STT OA, the efficacy of PRP injections improved with higher stages.

In our review, three randomized controlled trials were included comparing PRP injection to other products injected in the treatment of thumb CMC OA. Malahias et al.³² described significantly better results when using PRP compared to corticosteroids in terms of VAS score (p = 0.015) and Q-DASH score (p = 0.025). Patients receiving two injections of PRP showed significant pain reduction. This could potentially lead to a recommendation that more than one injection should be used for optimal results. Satisfaction rates were significantly higher in patient treated with PRP compared to the alternative option at 12 months (69 % vs. 12.5 %, p = 0.002). This is comparable to the 73.7 % rate found in our review. These satisfaction rates can be compared to other treatment modalities, a prospective review performed by Maarse et al.⁵⁹ reported a satisfaction rate at 36 months of 59 % following the use of intra-articular corticosteroid injection using fluoroscopy. By looking at long term outcomes, Esteban Lopez et al.⁶⁰ portrayed satisfaction rates following five years of conservative management of thumb CMC OA with orthosis, hand therapy, patient education, and daily exercises were 55 % of the patients rated their satisfaction as “good” or “excellent”. Thus, our study shows a higher satisfaction rate in comparison to alternative conservative treatment measures. Regarding post operative outcomes, Sabaah et al.³³ demonstrated through their study a significant decrease in pain and improvement in hand function after four weeks. While these positive results were sustained in the hyaluronic acid (HA) control group, they were not sustained in both the PRP and the corticosteroids control groups after twelve weeks. Winter et al.³⁵ compared outcomes for 95 patients divided in four groups: 0.9 % saline solution, autologous fat, PRP and a combination of fat and PRP. The latter showed the most significant pain relief compared to the saline group (p = 0.003). While fat alone reduced pain in similar rates to the control group, PRP yielded less effective results compared to saline. The highest median reduction in Q-Dash score was observed in the combined fat and PRP group. Throughout all groups, no significant improvements were demonstrated in pinch and power grip. After collecting patient questionnaires, only patients treated with fat and PRP, compared to saline, had significantly higher scores in the physical component of the survey (p = 0.016). No adverse events or complications were observed. Thus, Winter et al.³⁵ opened the door to exploring more autologous fat and PRP infiltration as a combination in the treatment of thumb CMC OA. In our review, a satisfaction rate of 73.7 % was found for all patients treated with PRP.

4.5. Limitations

Our systematic review was not without limitations. The low number of patients included in this systematic review, and the heterogeneity of reported outcomes, prevents any subgroup analysis for factors such as age, dominance, type of work/activity level and, symptom resolution as a function of Eaton-Littler stages. Despite a mean follow-up of 14.1 months, this study does not provide long-term recommendations on the efficacy of PRP injection for small joints. Furthermore, the main hurdle to overcome are the lack of standardized protocols for harvesting and preparing the PRP injection and an absence of procedural roadmaps amongst multiple studies. Radiological guidance also varies depending on the surgeon and the center amplifying the need for uniform protocols.

5. Conclusions

Herein, we report that thumb carpometacarpal osteoarthritis can be treated with intra-articular platelet-rich plasma injections. Despite the lack of standardized protocols, PRP injections consistently demonstrated significant pain reduction and improvement in hand function. These findings warrant further investigation and refinement of treatment protocols to optimize the efficacy and safety of PRP injections, ultimately enhancing patient outcomes and quality of life in those suffering from thumb CMC OA. Moving forward, efforts should be to compare the results of PRP versus other products (cortisone, saline, hyaluronic acid, fat graft) injected through randomized control trials as well as studies that combine PRP injections with fat grafting given the current promising results.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

The following are the Supplementary data to this article: