Combined Arthroscopic Wafer Procedure and Triangular Fibrocartilage Complex Debridement versus Ulnar Shortening Diaphyseal Osteotomy in Management of Ulnar Impaction Syndrome: A Randomized Clinical Trial

Abstract

Background  The literature presents great challenge in comparing the arthroscopic wafer procedure (AWP) versus ulnar shortening osteotomy (USO) in the treatment of ulnar impaction syndrome (UIS).

Purpose  We aimed primarily to compare the clinical and functional outcomes of AWP with triangular fibrocartilage complex (TFCC) debridement versus USO in the management of UIS.

Methods  The study was conducted as a randomized clinical trial including 43 patients with UIS whose ulna variance was less than 4 mm. Patients were randomly allocated to either the AWP group (21 patients) who underwent AWP and TFCC debridement or the USO group (22 patients) who underwent diaphyseal USO. Patients were followed up for at least 12 months. The primary outcome measure was the Modified Mayo Wrist (MMW) score. The Disabilities of the Arm, Shoulder, and Hand (DASH) score, the mean operative time, postoperative complications, and patient satisfaction were our secondary outcomes.

Results  Radiological correction of variance was achieved in all patients. The mean operative time was significantly shorter in the AWP group. The postoperative MMW and DASH scores were better in the AWP group than in the USO group. Fewer complications occurred in the AWP group (1 of 21 patients) compared with the USO group (3 of 22 patients).

Conclusions  AWP with TFCC debridement is a reliable and safe method for the management of UIS with a positive variance of less than 4 mm with better clinical and functional results than diaphyseal USO.

Type of study/level of evidence  Therapeutic type II.

Ulnar impaction syndrome is an abutment of the distal ulna on the lunate and sometimes the triquetrum as a result of cumulative load increases across the wrist joint. ^{1 2 3} The syndrome is a degenerative condition consisting of the triad of a triangular fibrocartilage complex (TFCC) tear, a lunotriquetral ligament tear, and an ulnar positive variance. ⁴

Small changes in ulna variance between the radius and ulna can significantly affect loads across the wrist joint. A neutral wrist joint variance has 18% of its load through the ulna, while 42% of the load crosses the ulna in a 2-mm ulnar-positive wrist and 4% in a 2-mm ulnar-negative wrist. ^{5 6}

Not only wrist trauma or its sequalae (such as radial shortening from previous Colles' fracture, lunotriquetral or scapholunate ligaments tear, nonunited fracture of ulnar styloid, or premature closure of distal radial physis) but also other factors such as occupations or sports activities that involve power-gripping, pronation, ulnar deviation, and axial loading can cause ulnar impaction syndrome. Examples include carpenters with frequent hammering, gymnasts, boxers, racquet, and stick sport athletes.

Its pathogenesis is mainly ulnar-sided wrist degeneration due to the chronic impact of the ulnar head, TFCC, lunate, and triquetrum because of cumulative overload across the wrist joint. Eventually disabling functional restrictions can result. ⁷

The conservative measures are still the first line of treatment and include immobilization, anti-inflammatory medications, corticosteroid injections and limiting aggravating movements such as pronation, gripping, and ulnar deviation. ⁸ Controversy remains about optimal surgical management if conservative measures failed. The choice of surgical treatment is based on the surgeon's preference and relatively certain indications, but basic principles should be followed. The treatment is based on mechanical decompression of the ulnocarpal articulation by decreasing ulnar variance. This could be achieved by diaphyseal shortening of the ulna or resection of its distal end that in turn significantly decreases forces across the ulnar side of the wrist joint. ^{9 10 11}

The diaphyseal/metaphyseal ulnar shortening osteotomy (USO) is an extra-articular technique that has the theoretical advantage of maintaining the distal radioulnar joint (DRUJ) and the peripheral aspect of the TFCC. The outcomes of USO were good to excellent in the literature. ^{12 13}

The arthroscopic wafer procedure (AWP) is an effective method to debride TFCC tears besides, having the ability to decompress ulnar-positive wrists by ulnar shortening. The results of this technique are equivalent to the open procedure, with fewer complications. ¹⁴ This technique avoids hardware complications and the risk of nonunion associated with USO. ¹

Therefore, our study aimed to compare the functional outcomes of combined AWP and TFCC debridement with the ulnar shortening diaphyseal osteotomy in the treatment of ulnar impaction syndrome. We hypothesized that better outcomes with fewer complications and more patients' satisfaction would be achieved in the AWP group.

Materials and Methods

Our study was performed prospectively as a randomized controlled clinical trial with two parallel groups, following Consolidated Standards of Reporting Trials (CONSORT) 2010 guidelines, ¹⁵ after being approved by our institutional research board (ORT/3459) and registered in the national clinical trials registry. A total of 43 patients attending our specialized hand and microsurgery unit for treatment of ulnar-sided wrist pain due to ulnar impaction syndrome between March 2017 and October 2021 were enrolled in the study.

Participants

Inclusion criteria were skeletally mature patients from both genders with ulnar impaction syndrome diagnosed clinically as having ulnar-sided wrist pain, tenderness on the ulnar fovea, and positive ulnocarpal stress test, and radiologically by the presence of a positive ulnar variance on true posteroanterior and lateral X-ray views, who did not respond to conservative therapy for more than 6 months. Only patients with TFCC lesions (palmer types 2C and 2D ¹⁶ ) and stable DRUJ were included. Patients with previous surgeries on the wrist or medical contraindications to surgery or who were unwilling to provide informed consent were excluded from the study. Moreover, patients with a positive ulnar variance of 5 mm or greater, reverse obliquity of sigmoid notch, lunotriquetral ligament tear or instability, advanced carpal arthritis, or fixed neurological deficit were also excluded ( Fig. 1 ).

Fig. 1.

CONSORT flow diagram of patients' recruitment. DRUJ, distal radioulnar joint; MRI, magnetic resonance imaging; TFCC, triangular fibrocartilage complex.

Patients were randomly divided into two groups. In the USO group, ulnar shortening diaphyseal osteotomy without arthroscopic examination was performed. In the AWP group, patients underwent AWP and TFCC debridement. Each participant was randomly assigned using sealed white envelopes. All participants were enrolled and randomized before surgery and no participant was recruited afterwards. All surgeries were performed by the first and senior authors.

Surgical Technique

Surgery was undertaken under regional anesthesia using a pneumatic arm tourniquet.

In the AWP group, the goal was to resect sufficient bone from the ulnar head to produce a 2 mm negative ulnar variance. Balanced vertical traction was applied to the operated upper limb and sustained dynamic traction was applied with 5 to 6 kg weight. Bony landmarks were identified as well as the commonly used portals. The arthroscopy was placed in the 4 to 5 portal. The 6R and 6U portals were used mainly for instrumentation, although it was helpful to view the completeness of ulnar head resection through the 6U portal as well. Rapid irrigation was needed to clear the debris. The edges of the TFCC tear were debrided back to stable margins. A 2.9 mm burr was then used in a back-and-forth motion to resect 2 to 3 mm of the ulnar head. The diameter of the burr was used as a gauge of the amount of bony resection, but this was checked fluoroscopically. The arm was pronated and supinated to avoid leaving a shelf of bone. Care was taken to avoid injury to the deep foveal insertion of the TFCC as well as the sigmoid notch. For complete wrist visualization and evaluation, the midcarpal joint was assessed through the ulnar and radial dorsal midcarpal portals. After the procedure was completed, the finger traps were let down and the DRUJ was tested by the shuck test for stability in full pronation, supination, and neutral. The tourniquet was deflated, and the incisions were closed. A sterile dressing and short-arm splint were applied for 2 weeks ( Fig. 2 ).

Fig. 2.

A 32-year-old male patient with ulnar impaction syndrome underwent an arthroscopic wafer procedure. ( A ) Preoperative plain radiograph with 4-mm positive ulna variance. ( B ) Coronal magnetic resonance imaging views showing cystic changes of the lunate. ( C ) Arthroscopic view of the palmar 2C triangular fibrocartilage complex lesion and exposed head of the ulna. ( D ) Arthroscopic view of the head of the ulna while resecting a bone wafer. ( E ) Postoperative plain radiograph of the wrist joint showing a neutral ulna variance after resection of the bone wafer.

In the USO group, a diaphyseal USO was performed via a 10-cm ulna subcutaneous approach (between Flexor carpi ulnaris and Extensor carpi ulnaris tendons). Free-hand transverse diaphyseal osteotomy was performed, and a segment of the diaphysis was excised according to the length of shortening planned to be achieved with a maximum of 4 mm. A volar dynamic compression plate was used to fix and compress the osteotomy site ( Fig. 3 ).

Fig. 3.

A 41-year-old female patient with ulnar impaction syndrome underwent an ulnar shortening osteotomy. ( A ) Preoperative plain radiograph with 4-mm positive ulna variance. ( B ) Coronal magnetic resonance imaging views showing cystic changes of the lunate. ( C ) Marking a bone segment with two drill holes. ( D ) Postoperative plain radiograph after resecting a 4-mm bone segment and fixation by small dynamic compression plate (note the postoperative neutral ulna variance).

Postoperative Care

All patients were protected in a below-elbow splint for 2 weeks. Supination/pronation was encouraged as tolerated. Patients received broad-spectrum prophylactic antibiotic 1 g twice daily intravenously for 3 days. All patients were on oral analgesic (nonsteroidal anti-inflammatory drugs) and oral antiedematous (α-chymotrypsin) for 2 weeks. Stitches were removed, and wrist motion was initiated after 2 weeks. Normal use and activities were encouraged 6 weeks after the procedure for both groups.

Outcome Measures

Modified Mayo wrist (MMW) score ¹⁷ (pain, range of motion [ROM], grip strength and patient satisfaction) was our primary outcome measure. Secondary outcome measures included osteotomy union in the USO group, mean operative time, grip strength, Disabilities of the Arm, Shoulder, and Hand (DASH) score, ¹⁸ and complications such as infection, nerve injury, stiffness, implant loosening, malunion and nonunion.

Radiological evaluation. Patients were evaluated immediately postoperatively for correction of variance then at 6 weeks, 3 months, and 6 months. All patients were finally evaluated at 12 months for radiographic evidence of ulnocarpal or DRUJ arthritis. Patients of the USO group were assessed for union. Delayed union is defined as the absence of radiographic progression of osteotomy healing between 4 and 6 months after surgery.

Clinical evaluation. The ulnar-sided wrist pain was assessed postoperatively using the 100 mm-visual analog scale (VAS). ¹⁹ Clinical union in the USO group was determined by the presence or absence of tenderness at the fracture site. The ROM was measured using a standard goniometer. Grip strength (in kilograms) was evaluated using a Jamar Hydraulic Hand Dynamometer. We corrected for hand dominance. For right-handed patients, the dominant hand was assumed to be 10% stronger; for left-handed persons, grip strength was considered to be equivalent in both hands. ²⁰

Preoperatively, two independent senior clinical fellows, who were blinded to the intervention groups, evaluated the radiographic, clinical, and functional parameters. At the final follow-up, other two independent observers, who were blinded to the preoperative findings, assessed the radiographic, clinical, and radiological outcomes. The average measurements of both observers were recorded.

Statistical Analysis

A sample size of 21 patients per group allowed demonstration of a difference in MMW score of 10.5 points, assuming a difference in standard deviation (SD) of 12, at an alfa level of 0.05 and a power set of 80%. ²¹ Quantitative data were expressed as median (range). Categorical data were expressed as frequency and percentage. Mann–Whitney U test was used to compare two means. The chi-squared test was used to compare proportions, but when an expected cell value was lower than 5, Fisher's exact test was applied. A difference was considered significant at p- value less than 0.05.

Results

Initially, 54 patients presented with ulnar impaction syndrome. Ten patients were excluded from the study because of age more than 50 ( n  = 5), ulnar variance more than 4mm ( n  = 3), intact TFCC in magnetic resonance imaging ( n  = 1), and previous distal radius fracture with DRUJ arthrosis ( n  = 1). Another patient was excluded from the AWP group because of unperforated TFCC under the scope. This left a total of 43 patients available for analysis ( Fig. 1 ). All patients were followed up for a minimum of 12 months (12–24 months). Baseline demographic and clinical data were similar in both groups ( Table 1 ).

Table 1. Patient's demographic and clinical characteristics.

Characteristic	AWP group	USO group
Median age, years	38 (24–51)	36 (25–53)
Gender male/female	10 / 11	10 / 12
Affected side, right/left	10 / 11	12 / 10
Affected side, dominant/nondominant	19 / 2	19 / 3
Median preoperative variance, mm	3 (3–4)	3 (2–4)
Onset of symptoms, month	15 (8–30)	18 (11–36)
Fovea sign (positive/negative)	17 / 4	16 / 6
Lunate cyst on MRI (positive/negative)	10 / 11	6 / 16
Preoperative 100 mm VAS	60 (10–80)	60 (30–80)
Preoperative grip strength, kg	55.4 (22.5–84.6)	57.2 (33.8–88.8)
Range of ulnar deviation, degree	25 (20–31)	24.5 (18–32)
Preoperative MMW score	45 (25–75)	47.5 (20–60)
Preoperative DASH score	41.7 (25–66.7)	52.5 (32.5–76.6)
Follow-up, months	18 (12–22)	17 (12–24)

Abbreviations: AWP, arthroscopic wafer procedure; DASH, Disabilities of Arm, Shoulder, and Hand; MMW, Modified Mayo wrist score; MRI, magnetic resonance imaging; USO, ulnar shortening osteotomy; VAS, visual analog scale.

Both groups showed a significant postoperative improvement compared with the preoperative data, in terms of variance correction, pain relief, grip strength improvement, regain of range of ulnar deviation, and better MMW and DASH scores ( Table 2 ).

Table 2. Pre- and postoperative outcomes of both groups ^a .

AWP	Preoperative	At final follow-up	p -Value b
Variance, mm	3 (3–4)	0 (0–1)	0.001
VAS, 100 mm	60 (10–80)	10 (0–30)	0.004
Grip strength, kg	55.4 (22.5–84.6)	86 (76–95)	0.003
Range of ulnar deviation, degree	27 (20–31)	33 (27–35)	0.003
MMS score	45 (25–75)	80 (50–85)	0.003
DASH score	41.7 (25–66.7)	15.8 (10–43.3)	0.003
USO
Variance, mm	3 (2–4)	0 ([-1]-1)	0.001
VAS, 100 mm	60 (30–80)	30 (10–50)	0.004
Grip strength, kg	57.2 (33.8–88.8)	78 (69–90)	0.024
Range of ulnar deviation, degree	26.5 (18–32)	31.5 (24–35)	0.002
MMS score	47.5 (20–60)	60 (35–75)	0.001
DASH score	52.5 (32.5–76.6)	41.6 (29.2–55.8)	0.002

Abbreviations: AWP, arthroscopic wafer procedure; DASH, Disabilities of Arm, Shoulder, and Hand; MMW, Modified Mayo Wrist score; USO, ulnar shortening osteotomy; VAS, visual analog scale.

^aValues are for median (range).

^bWilcoxon signed-rank test.

Mean operative time was significantly shorter in the AWP group than in the USO group ( p  < 0.001). Regarding the correction of the variance, both groups were similar ( p  > 0.16). The VAS score at the final follow-up was significantly better in the AWP group ( p  = 0.004). The median MMW score (including the degree of pain, grip strength, and patient satisfaction domains) was significantly better in the AWP group than in the USO group at the final follow-up ( p  < 0.002; Table 3 ). DASH score was significantly better in the AWP group at 3, 6, and 12 months ( p  < 0.01; Fig. 4 ).

Table 3. Comparison of the operative time and postoperative outcomes at the final follow-up between both groups ^a .

Outcome	AWP group	USO group	p -Value b
Variance, mm	0 (0–1)	0 ([-1]-1)	———
Operative time, minutes	50 (35–60)	82 (60–100)	< 0.001
Postoperative 100 mm VAS	10 (0–30)	30 (10–50)	0.004
Range of ulnar deviation, degree	33 (27–35)	31.5 (24–35)	0.260
Grip strength, kg	86 (76–95)	78 (69–90)	0.005
Postoperative MMW score	80 (50–85)	60 (35–75)	0.002

Abbreviations: AWP, arthroscopic wafer procedure; MMW, Modified Mayo wrist score; USO, ulnar shortening osteotomy; VAS, visual analog scale.

^aValues are for median (range).

^bMann–Whitney U test.

Fig. 4.

Pre- and postoperative DASH scores in the two groups. Preoperative ( p  > 0.05). Postoperative 3, 6, and 12 months ( p  < 0.05). AWP, arthroscopic wafer procedure; DASH, Disabilities of Arm, Shoulder, and Hand; USO, ulnar shortening osteotomy.

Fewer complications existed in the AWP group (one of 21 patients) compared with the USO group (3 of 22 patients). In the AWP group, one patient developed median nerve neuropathy. In the USO group, one patient developed delayed union in the osteotomy site, another patient developed nonunion and needed revision of the plate and bone graft, and one patient had a superficial wound infection that was managed conservatively with antibiotics and daily dressing for 10 days.

Discussion

Clinical, radiological, and functional improvements were achieved in all patients after surgery in terms of variance correction, pain relief, grip strength improvement, and regain of range of ulnar deviation. The results were superior in the AWP group than in the USO group regarding better MMW score and DASH score with shorter operative time and fewer complications.

In agreement with our study, Oh et al ²¹ compared the functional results between AWP and diaphyseal shortening osteotomy in 42 patients of idiopathic ulnar impaction syndrome with a follow-up period of 2 years and concluded that AWP produces better clinical results than USO in the management of ulnar impaction syndrome. This attributed to the better results in grip strength, MMW score and DASH score.

In contrast, Auzias et al ²² reported no statistically significant difference between the two techniques except the return-to-work time, and USO was associated with a greater number of reoperations than the AWP. Those results could be attributed to the long follow-up time (103+ 8 months) compared with our follow-up time (12+ 4 months).

A study by Bernstein et al ²³ is of great value to demonstrate the isolated value of TFCC detriment in the outcomes. Although we did not arthroscopically examine the USO group, in the study of Bernstein et al, ²³ they compared AWP with TFCC debridement versus USO with arthroscopic TFCC debridement also. Nine of 11 patients showed good-to-excellent results on MMW score after arthroscopic TFCC debridement and AWP compared with 11/16 after arthroscopic TFCC debridement and USO at a mean follow-up time of 21 and 15 months, respectively. They concluded that there is no statistically significant difference in the results between the two groups. Their results are comparable to ours and this comparability could be attributed to the significant impact of the TFCC debridement done with USO in their study which made the results similar.

Another unique study by Yamanaka et al ²⁴ highlighted the effect of variance correction on TFCC and correlated the results with clinical impaction on MMW score. A total of 79 patients with commplete data who underwent USO for TFCC injuries were included. The minimum follow-up was 24 months. The TFCC thickness and the TFCC angle on coronal magnetic resonance images before and after surgery for each patient were measured. They concluded that the reparative capacity of the TFCC is minimized in higher variance that spotlight the need for debridement in those patients and not only variance correction.

A recent study by Terzis et al ²⁵ evaluated USO in 12 patients with a mean follow-up of 9.9 (2–25) months. The mean length of the removed segment was 4.5 (3–7) mm. The postoperative evaluation, in agreement with ours, showed a significant improvement in terms of ROM, grip strength, degree of pain, and DASH score. Our results and those of Terzis et al reflect that good-to-excellent results could be achieved by USO in the management of ulnar impaction syndrome and it is still a good and viable therapeutic option.

The USO compared with AWP is still related to more postoperative complications and restrictions. Terzis et al ²⁵ reported a delayed and nonunion rate up to 18%. Moermans et al ²⁶ reported 10% nonunion. Chan et al ²⁷ reported the overall complications after 10 years of follow-up, mainly metalwork irritation (51%), nonunion (6.3%), refracture (1.6%), and chronic regional pain syndrome (1.6%). Oh et al ²¹ reported that the overall complication rate was higher in the USO group (34.8%) than in the AWP group (10.5%). In our study, the overall complications rate in the USO group was 13.6% including delayed union, nonunion, and superficial infection, compared with 4.8% in the AWP group.

In a study by Smet et al ²⁸ , 12 patients underwent AWP and TFCC debridement with a mean ulnar variance of 2.7 (3.5–5) mm. The final DASH score was excellent in 4, good in 3, and fair in 5 patients. The VAS score for pain was 4.6 (SD: 2.65). Those results were similar to ours and those reported by Gaudio and Haerle. ²⁹

The strengths of this study include the fact that no patient was lost to follow-up. Moreover, we prospectively compared two randomized groups with similar follow-up protocols and used objective outcome measures. Study limitations were the small sample, strict selection criteria, and relatively short follow-up. Also, we did not use block randomization. Patients with USO did not undergo diagnostic wrist arthroscopy as the aim of our study was to assess the ulnar diaphyseal shortening osteotomy alone (as been considered the most common mauver used) as a levelling technique and its role of decompression of the ulnocarpal articulation on the patient objectively and subjectively. Long-term radiological changes after decompression remain to be evaluated in future larger studies.

Finally, although this was a single-center study, our hand unit serves a population of more than 5 million people. We serve a broad spectrum of social and ethnic groups and believe that our data are relevant to the wider community.

Conclusions

We found that AWP of ulnar impaction syndrome is a reliable, safe method, and allows early mobilization resulting in better MMW score and DASH score with shorter operative time and fewer complications than in the USO group.

Funding Statement

Funding None of the authors received financial support for this study.