Treatment of Early Undifferentiated Chronic Monoarthritis of the Wrist by Arthroscopic Wrist Synovectomy Combined with Partial Denervation

Abstract

Objective

Undifferentiated chronic monosecarthritis (UCMA) is a group of inflammatory joint diseases that has the potential to progress to other diseases and can seriously affect patients' quality of life. There is yet no unified consensus regarding treatment of UCMA. This study aimed to investigate the efficacy of arthroscopic synovectomy combined with partial wrist denervation in treating Larsen 1–3 UCMA.

Methods

In this case series, we reviewed 14 patients with UCMA treated by arthroscopic synovectomy combined with partial denervation from February 2017 to June 2020. The mean duration of symptoms was 17.4 months (range, 4–60 months), and the mean follow‐up was 13.3 months (range, 6–23 months). The anterior and posterior interosseous nerves were severed at the distal forearm, and the radiocarpal, midcarpal, and distal radial ulnar joint synovial membranes were arthroscopically resected at the wrist. The clinical evaluation indices included the visual analogue scale score (VAS) for pain, grip strength, range of (active) motion of the wrist, total active motion, and Mayo wrist score. Larsen's scoring method was used as the imaging evaluation index.

Results

At the last follow‐up, significant clinical improvements were observed in the visual analogue scale (VAS) score for pain (6.0 (5.0–6.3) vs 1.0 (1.0–2.3), P = 0.001) and Mayo wrist score (42.1 ± 9.7 vs 61.8 ± 12.3, P < 0.0001). No significant changes were found in grip strength (15.9 ± 4.5 vs 16.6 ± 4.7, P = 0.230) or the flexion‐extension arc (58.9 ± 39.0 vs 64.3 ± 36.5, P = 0.317), although the mean and median did show positive changes. Among the three patients who showed progress in imaging, there was no significant difference in their pain and functional scores compared to those who did not progress. One patient underwent total wrist fusion 17 months after the operation.

Conclusion

Arthroscopic wrist synovectomy combined with partial wrist denervation can provide sustained pain relief and functional recovery for patients with Larsen 1–3 UCMA.

Arthroscopic wrist synovectomy combined with partial wrist denervation provides significant relief of wrist pain and may be an effective surgical method for the treatment of patients with Larsen 1–3 undifferentiated chronic monosecarthritis (UCMA).

Introduction

Undifferentiated chronic monoarthritis (UCMA) is a group of inflammatory joint diseases that are usually diagnosed by exclusion based on failure to meet rheumatologic classification criteria (e.g., rheumatoid arthritis [RA], psoriatic arthritis, and ankylosing spondylitis). ¹ While it frequently presents as an initial manifestation of other arthritis, UCMA can also persist or recede over time on its own. ² , ³ , ⁴ , ⁵ , ⁶ , ⁷ Spontaneous remission rates reportedly range from 26% to 76%. ⁶ , ⁸ , ⁹ , ¹⁰ , ¹¹ , ¹² While recent evidence suggests that specific biomarkers may be effective in distinguishing patients with early RA from other arthritis causes, including UCMA. ¹³ Overall, the method to determine whether or when UCMA will develop into a rheumatologic disease is still scant. While the elusive clinical course of UCMA makes the treatment choice complicated, early treatment is imperative to prevent its further progression.

Although no consensus has been established regarding the treatment of UCMA patients, previous evidence suggests that early treatment with non‐surgical approaches (e.g., medications, intra‐articular/muscular glucocorticoid injection, and radial synovectomy) might delay the development of RA. However, in the majority of these UCMA patients, the protective effect can only be maintained for 12 months. ¹⁴ Once arthritis has developed, the opportunity to improve outcomes through non‐surgical methods is lost. ¹⁵ Surgical methods can be essential for patients who do not respond to conservative treatment.

Previous research has demonstrated that removing inflamed synovial membranes can delay the progression of arthritis when antirheumatic drugs fail to control the inflammation. ¹⁶ According to Kim et al.'s study in 2012, arthroscopic synovectomy has been shown to provide significant symptom relief in the majority of patients with UCMA. However, in the subset of patients who showed radiographic progression, the pain control and Mayo score at the last follow‐up were significantly worse compared to those who did not experience recurrence. ¹⁷ On the other hand, it has been demonstrated that the partial denervation procedure has a significant pain‐relieving effect on the wrist joint. ¹⁸ , ¹⁹ The rationale behind denervation is that removing the sensory nerves reduces pain while maintaining the wrist's function and range of motion so that the outcome of denervation has a much weaker dependence on controlling the inflammatory progression of the wrist. Both arthroscopic synovectomy and partial wrist denervation are widely used in relieving pain and restoring wrist function. In terms of treatment principles, these two procedures have the potential to complement each other. Theoretically, combining the two techniques should enable better and more continuous pain relief without compromising functional recovery. However, no previous study has provided information on the effectiveness of applying arthroscopic synovectomy combined with partial denervation in UCMA patients. Clinical trials on combining these two procedures for treating other wrist disorders are also scarce.

In this case series study, we attempt to validate the following hypotheses. This combined surgery: (i) is effective in achieving satisfactory clinical outcomes in patients with UCMA; and (ii) can maintain continuous pain control and hand function in wrists which show radiographic progression.

Methods

This retrospective case series was approved by the Medical Ethics Committee of Jishuitan Hospital (code number 202106–58), and all of the procedures followed the principles of the Helsinki Declaration.

Patient Characteristics

Fourteen patients with UCMA (Larsen 1–3) were treated with arthroscopic synovectomy combined with partial wrist denervation at Beijing Jishuitan Hospital from February 2017 to June 2020. All patients were available for follow‐up.

Inclusion and Exclusion Criteria

Patients were selected using the following inclusion criteria: (i) UCMA that met the clinical diagnostic criteria (i.e., wrist pain for >3 months; laboratory tests excluding RA, ankylosing spondylitis, and osteoarthritis; and no medical reaction for >3 months); (ii) the patients who underwent the combined arthroscopic synovectomy and partial denervation procedure; (iii) an age of 18–70 years; (iv) no history of surgery on the wrist before the designated procedure; and (v) a Larsen score of 1–3. ²⁰ , ²¹ The exclusion criteria were: (i) a history of other surgeries; (ii) a previous diagnosis of other arthritic diseases; and (iii) an inability to complete regular follow‐up as required.

Fourteen patients (14 wrists) who met the criteria were enrolled.

Surgical Technique

Arthroscopic Wrist Synovectomy

The procedure was performed under general anesthesia or brachial plexus nerve block. A tourniquet was applied to the upper arm and inflated to 260 mmHg. The forearm was suspended with 6.0–7.0 kg of traction. The shoulder was abducted at 90°, and the elbow was flexed to 90°. A 2.5‐mm‐diameter, 30°‐angled arthroscope, and a 2.0‐mm synovectomy blade were used for the synovectomy.

For the synovial tissues in the radiocarpal, midcarpal radial, and midcarpal ulnar joints, the 3/4 and 4/5 portals were used as the standard portals. Other portals were also used to access all areas of the radial and midcarpal joints. In the radiocarpal joint, hypertrophied synovium was frequently observed on the ulnar side of the triangular fibrocartilage (TFC) (Fig. 1A). The synovial membrane on the ulnar and palmar sides could be removed by the 6U portal, while the 3/4 portal primarily used to remove the radial synovial membrane. If more synovium needed to be removed, an additional 1/2 portal could be created.

Fig. 1.

Arthroscopic view of the wrist. (A, B) Intraoperative photographs show synovial hyperplasia in the radiocarpal and midcarpal joints. (C) Intraoperative photograph shows a perforation in the triangular fibrocartilage that became visible after clearance of the palmar synovial tissue. The synovium in the distal radial ulnar joint could be cleared through this perforation.

In the midcarpal joint, the midcarpal radial and midcarpal ulnar portals were the standard portals and were primarily used to debride the synovium on the ulnar side. Additionally, an auxiliary portal to the scaphoid‐trapezium‐trapezoid joint was often used (Fig. 1B). To avoid tendon and nerve injuries, the exact location of these portals was determined by puncturing the joint with a needle and spreading a small hemostatic agent down through the subcutaneous tissue into the joint capsule.

When a perforation was present in the TFC, it was possible to reach the distal radial ulnar joint (DRUJ) from the radiocarpal joint through the TFC (Fig. 1C). As a secondary lesion due to chronic inflammation, this perforation has little clinical significance; however, a planer could be passed through the hole in the TFC to debride the hypertrophic synovial membrane in the DRUJ. Occasionally, the DRUJ was also accessed with a separate portal while being visualized through the hole in the TFC. Open surgery was recommended when significant synovitis or imaging evidence of severe DRUJ involvement was found.

Partial Wrist Denervation

After completion of the above procedure, the forearm was lowered and laid flat on the operating table. The wrist denervation technique used in this series was double‐incision wrist denervation, the procedure described by Berger ²² as a reference. First, a 3‐ to 4‐cm dorsal incision was made in the distal forearm; the incision was centered between the radius and ulna (Fig. 2A) and extended distally to a finger's width from the proximal end of the ulnar head. The deep forearm fascia was then incised longitudinally, and the extensor tendon was retracted to expose the dorsal surface of the interosseous membrane. The posterior branch of the anterior interosseous artery with its accompanying vein and the posterior interosseous nerve(PIN) was lying on the interosseous membrane (Fig. 2B,C). The nerve and artery were separated, and 1 cm of the nerve was excised (Fig. 2D).

Fig. 2.

The procedure of partial wrist denervation. (A) The design of the skin incision. A 3‐ to 4‐cm longitudinal incision was made, extending distally to a point approximately one finger breadth proximal to the head of the ulna, and centered between the radius and the ulna. (B, C) Intraoperative photographs show the posterior interosseous vessels and nerve (marked in Fig. 2B) after retracting the extensor pollicis longus muscle toward the ulna. (D) The posterior and anterior interosseous nerves were excised approximately 1 cm. (E, F) Intraoperative photographs show the anterior interosseous vessels and nerve (marked in Fig. 2E), which could be seen after a 3‐cm longitude incision on the interosseous membrane.

The interosseous membrane was then incised longitudinally from the distal edge of the central band of the interosseous membrane to the distal radioulnar joint capsule. The distal oblique bundle (DOB) was carefully protected during the incision to prevent post‐operative DRUJ instability. ²³ The anterior interosseous nerve (AIN) was located directly anterior to the interosseous membrane or dorsal to the pronator quadratus muscle, which was visible after the incision (Fig. 2E,F). The terminal sensory branch of the anterior interosseous nerve was separated, and 1 cm of it was resected (Fig. 2D).

Splints and a compression dressing were applied for 2 weeks postoperatively. The patients were then encouraged to begin wrist movements.

Outcome Measures

The outcomes included pre‐ and postoperative visual analogue scale (VAS) for pain, range of (active) motion (ROM), grip strength, and Mayo wrist score. Follow‐up was performed by questionnaire and physical examination. Larsen's scoring method was used as the imaging evaluation index.

Statistical Methods

All of the statistical analyses were performed using SPSS software, version 21.0 (SPSS Inc., Chicago, IL, USA). We used the Shapiro–Wilk normality test to determine the form of the distribution. Normally distributed continuous data were reported as mean and range, and non‐normally distributed continuous data were reported as the median and interquartile range (IQR). The paired t‐test was performed for numerical data that conformed to a normal distribution, and the Wilcoxon signed‐rank sum test was performed for data that did not conform to a normal distribution. A P value of <0.05 was considered statistically significant.

Results

Demographic Information

Of the 14 patients, five (35.7%) were male. The mean age was 42.0 years (range, 27–56 years). Among all 14 wrists, the mean duration of disease was 17.4 months (range, 4–60 months) and the mean follow‐up period was 13.3 months (range, 6–23 months). There were no specific postoperative complications related to the procedure. According to Larsen's scoring method, six patients had a score of 1, six patients had a score of 2, and two patients had a score of 3. Table 1 shows the demographic information of the patients.

TABLE 1.

Demographic data (14 patients)

Item	Demographic data
Age, y (range)	42.0 (27–56)
Sex (male‐to‐female)	5:9
Duration, mo (range)	17.4 (4–60)
Follow‐up, mo (range)	13.3 (6–23)

Note: Data are presented as median (range) or n.

Clinical Results

The data that fit normal distributions were the Mayo wrist score, the active extension ROM, the total active motion, and grip strength. The data that did not fit normal distributions were the VAS for pain and the active flexion ROM. At the final follow‐up, the median VAS score decreased from 6.0 (IQR, 5.0–6.3) to 1.0 (IQR, 1.0–2.3) (P = 0.001). The median active flexion ROM was 12.5° (IQR, 3.8°–35.0°) preoperatively and 20.0° (IQR, 8.8°–40.0°) at the final follow‐up (P = 0.080, nonsignificant). The mean wrist active extension ROM was 35.7° ± 16.2° preoperatively and 37.5° ± 15.0° at the final follow‐up (P = 0.466, nonsignificant). The mean flexion‐extension arc was 58.9° ± 39.0° preoperatively and 64.3° ± 36.5° at the final follow‐up (P = 0.317, nonsignificant). The mean grip strength increased from 15.9 ± 4.5 kg to 16.6 ± 4.7 kg (P = 0.230, nonsignificant). The mean Mayo wrist score improved from 42.1 ± 9.7 to 61.8 ± 12.3 (P < 0.0001). Table 2 shows the results of the comparison of the patients' clinical characteristics. Figures 3 and 4 display two cases.

TABLE 2.

Clinical Outcomes

	Pre‐operative	Final follow‐up	T value	P value
VAS for pain	6.0 (5.0–6.3)	1.00 (1.0–2.3)	– a	0.001
Flexion (°)	12.5 (3.8–35.0)	20.00 (8.8–40.0)	– a	0.080
Extension (°)	35.7 ± 16.2	37.5 ± 15.0	−0.751	0.466
Flexion‐Extension arc (°)	58.9 ± 39.0	64.3 ± 36.5	−1.041	0.317
Grip strength (kg)	15.9 ± 4.5	16.6 ± 4.7	−1.259	0.230
Mayo wrist score	42.1 ± 9.7	61.8 ± 12.3	−7.285	<0.0001

Note: Data are presented as mean ± SD for normally distributed continuous data; median (interquartile range) for non‐normally distributed continuous data.

Abbreviation: ROM, range of motion; VAS, visual analogue scale.

^a The Wilcoxon signed‐rank sum test is used for non‐normal distributed data, therefore there is no t‐value.

Fig. 3.

Case 1, a 53‐year‐old female, presented with right wrist joint swelling and pain 2 years ago, which progressively worsened over time despite pharmacological intervention, necessitating the combined procedure. Postoperatively, at an 8‐month follow‐up, the VAS score of pain improved from 4 to 1, and the grip strength of the affected side increased by 4.8 kg. The Mayo score also improved from 55 to 75. (A, B). Preoperative x‐ray images of the right wrist joint. (C, D) x‐ray images at 2‐year follow‐up after surgery.

Fig. 4.

Case 2, a 33‐year‐old male, experienced right wrist pain with a concomitant decrease in range of motion for 5 years and was diagnosed with UCMA. The pharmacological intervention failed to slow disease progression. At a 9‐month follow‐up after surgery, the VAS score of pain improved from 5 to 0, and the Mayo score increased from 55 to 75. (A, B) Preoperative x‐ray images of the right wrist joint. (C, D) X‐ray images at the latest follow‐up (9 months) after surgery.

Three patients had a 1‐point increase in the Larsen score at the last follow‐up. Table 3 presents the results of the Mann–Whitney U test comparing these patients with the remaining non‐progressing patients. Although there was a significant difference in flexion–extension arc between the two patient groups, there were no significant differences in pain, Mayo score, and grip strength. After excluding patients who showed radiographic progression, a significant difference was found in the paired t‐test for flexion–extension arc in the pre‐operative and final follow‐up of the non‐progressing patients (P = 0.004).

TABLE 3.

Comparison between patients with radiological progression and those without progression

	Non‐progressing group	Progressing group	P value a
VAS for pain
Pre‐operative	5.7 ± 1.0	6.0 ± 0	0.659
Final follow‐up	1.5 ± 1.4	2.0 ± 1.0	0.368
Mayo wrist score
Pre‐operative	42.3 ± 10.8	41.7 ± 5.8	1
Final follow‐up	65.5 ± 9.0	48.3 ± 15.3	0.088
Flexion–extension arc (°)
Pre‐operative	164.0 ± 9.2	160.0 ± 17.3	0.368
Final follow‐up	163.2 ± 8.1	161.7 ± 14.4	0.011

Abbreviation: VAS, visual analogue scale.

^a Mann–Whitney U test.

A 55‐year‐old female patient with a preoperative Larsen score of grade 2 experienced persistent progression of arthritis after surgery. Despite treatment with medication, the development of wrist arthritis could not be effectively controlled. Ultimately, 17 months after the surgery, the patient's VAS score was 3, flexion‐extension arc reduced to 20 degrees, and the Larsen score had progressed to grade 4. Due to pain and functional impairment, the patient chose to undergo total wrist arthrodesis.

Discussion

During the follow‐up period, which lasted for an average of >1 year after the surgery, significant improvements were observed in both hand function and pain level for the included 14 patients. For patients with postoperative radiographic progression, their function and pain level have not been significantly affected by such progression. Therefore, we believe that this combined procedure is beneficial for the sustained relief of wrist joint symptoms.

The Clinical Outcomes

Arthroscopic synovectomy has demonstrated good pain relief and functional recovery performance in various wrist joint inflammatory diseases. ¹⁶ , ²⁴ , ²⁵ , ²⁶ Its pain relief is mainly achieved by removing the inflammatory synovial tissue in the joint, thereby reducing inflammatory loads and preventing the progression of the disease. On the other hand, although wrist partial denervation does not affect controlling inflammation, it can achieve sustained pain relief by removing the major nerves that innervate the dorsal and palmar aspects of 2/3 of the wrist joint capsule (the AIN and PIN). ²⁷ , ²⁸ , ²⁹ , ³⁰ In the final follow‐up of this study, a significant recovery of pain and function scores was shown. Among the 14 patients, nine patients had a VAS score of 0 or 1 at the final follow‐up.

Although there was an improvement in the mean grip strength, no significant difference was found in the latest follow‐up. This is likely due to our small sample size. In previous studies, whether it was synovectomy or nerve partial resection, significant grip strength recovery has been reported. ¹⁸ , ¹⁹ , ³¹ , ³² However, considering that this procedure was first applied to UCMA in this study and there have been no literature reports on the grip strength results of synovectomy or partial denervation in UCMA, it is still inconclusive as to whether surgical treatment can help enhance the grip strength of UCMA patients based on the current results.

Regarding the range of motion, our study also failed to find a significant difference. However, in the data analysis grouped by the presence of radiographic progression, a significant difference in the flexion‐extension arc was found between patients with progression and those without. After excluding patients with progression, the remaining group showed a significant improvement in their range of motion (paired t‐test, P = 0.004). It is known that the principle behind the improvement of stiffness after synovectomy is the removal of inflamed synovial tissue, thereby ameliorating the intra‐articular environment. Conversely, partial nerve resection has limited efficacy in enhancing the range of motion. Therefore, we believe that the decline in the flexion‐extension arc is related to the progression of synovitis. For patients whose inflammation cannot be effectively controlled by synovectomy or medical treatment, the efficacy of recovering range of motion is limited for single arthroscopic synovectomy surgery.

While wrist capsule release may contribute to better ROM outcomes, we focused on the synovium incision and the denervation and did not perform capsule release in this group of patients. In our future study, the capsular release will be incorporated into the surgical protocol.

Preventing the Deterioration of Symptoms in Radiographic Progressed Patients

In Kim et al.'s study using arthroscopic synovectomy to treat UCMA patients, patients who experienced radiographic progression showed a significant decrease in VAS, wrist flexion and extension range of motion, and Mayo functional score (Wilcoxon's two‐sample test, P = 0.019, 0.001, and 0.004, respectively). This is related to the mechanism of synovectomy in wrist symptom recovery, which has been previously discussed. However, there are no reports of partial denervation being used to treat UCMA patients.

In our follow‐up, only wrist flexion and extension range of motion showed significant differences in patients with radiographic progression. No significant differences were found in VAS and Mayo scores in either group of patients. Since only three patients had radiographic progression, the Mann–Whitney U test was used to minimize the error caused by the small sample size. Based on the results obtained so far, it can be reasonably speculated that the combination of partial denervation and synovectomy enhances the pain relief and functional recovery effects of synovectomy, and has a certain resistance to symptom deterioration caused by subsequent inflammation progression.

On the other hand, the sustained symptom relief from partial denervation may lead to patients having unclear judgment about their condition, resulting in delayed treatment and other issues. However, this situation can be avoided through regular outpatient follow‐up and imaging examinations. To date, there have been no reports of partial denervation causing Charcot‐like changes. ²² Moreover, this combined procedure causes minimal damage to the wrist joint and will not interfere with any future salvage surgeries. If a patient's inflammatory progression cannot be controlled, arthrodesis or arthroplasty can be performed at any point.

The Progression of UCMA

The effectiveness of wrist arthroscopy mainly lies in controlling synovitis. However, for UCMA, the efficacy of arthroscopic synovectomy in controlling inflammation progression remains to be further evaluated. As mentioned in Kim et al.'s UCMA wrist arthroscopy synovectomy trial, among the 20 patients who underwent surgery, nine patients were able to achieve relief without medication, while the remaining 11 patients required the use of DMARDs for further assistance. Even with medical intervention, five patients eventually progressed to RA and showed radiographic progression. ¹⁷ In our study, the proportion of patients who underwent progression according to the Larsen score was 21%, similar to Kim et al.'s study (25%). ¹⁷ Overall, at the last follow‐up, four out of 14 patients required medication to control the progression of their condition. Among these four patients, only one showed radiographic progression. This female patient underwent salvage surgery due to incompletely controlled symptoms and radiographic progression. However, at the last follow‐up, there was still no clinical evidence that her arthritis had progressed to RA. Additionally, the other two patients who showed radiographic progression did not receive medication treatment. The progression condition of arthritis in our enrolled patients appears to be slightly better than that of Kim et al.'s study. However, considering that from a theoretical perspective, the addition of partial denervation may have limited contribution to arthritis control, the reason for this difference cannot yet be conclusively determined.

Strengths and Limitations

This is the first study focusing on the combination of arthroscopic synovectomy and partial wrist denervation in the treatment of UCMA. While both procedures share a similar purpose, their mechanisms for achieving the desired outcome differ. Combining these two surgical approaches can improve therapeutic efficacy without increasing the probability of complications associated with either procedure. However, this study also has some limitations. First, it is a retrospective study, which may result in biased clinical data due to certain confounding factors. Second, the number of patients enrolled in this study is relatively small. Third, the lack of a control group may affect the credibility of the conclusions.

Future Research

In the future, we will continue to follow up on the progression of joint destruction in this series of patients. Because some of these patients will be treated with antirheumatic medication, we will also pay attention to the efficacy of surgery combined with medication. Besides, capsule release will be added to the operation procedure in future studies.

Conclusion

This study showed that the combination procedure provided significant pain relief and a benign effect on preserving and improving wrist function in the UCMA patients. A combination of arthroscopic synovectomy and partial wrist denervation is recommended for early UCMA with a Larsen score of 1–3 that persists for more than 3 months and does not respond to medical therapy.

Author Contributions

All authors had full access to the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Conceptualization, Y.Y.; Methodology, Z.L, and X.H.; Investigation, Z.L, and X.H.; Formal Analysis, Y.Y.; Resources, Y.Y.; Writing‐Review & Editing, Y.Y.; Visualization, Y.Y.; Supervision, Y.Y.; Funding Acquisition, Y.Y.

Conflict of Interest Statement

No potential conflict of interest was reported by the authors. None of the authors has a financial interest in any of the products or devices mentioned in this article.

Ethics Statement

Ethical approval for this study was obtained from our Institutional Ethics Board (IRB approval number: JST20210658). Informed consent was obtained from all individual participants included in the study.