Management of chronic mallet finger: Indications and long-term results of Fowler central slip tenotomy and distal interphalangeal joint arthrodesis.

INTRODUCTION: Many surgical techniques have been described to correct the sequelae of chronic mallet fingers (MF), but no clear therapeutic strategy has been defined. We have reported the choice of their management according to the severity of the deformities. Two procedures were compared: Fowler's central slip tenotomy (CST) and arthrodesis of the distal interphalangeal joint (DIP). HYPOTHESIS: The use of our decision tree, based on the severity of deformity (flexion deformity at the DIP and recurvatum at the proximal interphalangeal joint), allows good long-term clinical results to be obtained. MATERIAL AND METHODS: Thirty-three patients (34 fingers) were operated on for sequelae of chronic MF either by CST or by DIP arthrodesis. Patients with ≤35° DIP flexion deformity and <25° proximal interphalangeal (PIP) recurvatum, without DIP joint involvement (osteoarthritis, subluxation, stiffness), were treated with CST. For the others, arthrodesis of the DIP joint was performed. RESULTS: Thirteen patients (13 fingers) were evaluated in the CST group with a mean follow-up of 13 years. There were no postoperative complications and no failures. The mean DIP residual extension lag was 4.23° with complete correction of the PIP recurvatum. All patients would redo the intervention in hindsight. The improvement in Quick-DASH was statistically significant (p=0.01). Twenty patients (21 fingers) were included in the DIP arthrodesis group with a mean follow-up of 10 years. Two failures (9.5%) occurred due to failed correction of the PIP recurvatum. No worsening of the deformities was reported, and they were corrected in 90% of cases. The absence of correction of the PIP recurvatum was more frequent in MF bone (p=0.01). All except 1 (95%) patient, who reported a lack of mobility of the DIP joint, would repeat the procedure. Quick-DASH was improved for all patients. DISCUSSION: CST is effective in correcting deformities in chronic MFs for ≤35° DIP flexion deformity and <25° PIP recurvatum without DIP joint involvement. In other cases, it is preferable to perform a DIP arthrodesis by combining, if necessary, a complementary procedure to correct the PIP recurvatum. LEVEL OF EVIDENCE: IV, retrospective study.

Scapular winging due to rhomboid muscle paralysis: clinical assessment of 4 cases and anatomic study of the dorsal scapular nerve.

BACKGROUND: A rare cause of scapular winging is rhomboid muscle paralysis secondary to dorsal scapular nerve (DSN) neuropathy. This paralysis causes winging of the medial border of the scapula with lateral rotation of its inferior angle. We report a series of 4 clinical cases of isolated DSN compression and the results of a specific rehabilitation protocol. METHODS: A continuous clinical series of 4 patients with isolated rhomboid muscle deficiency was analyzed. Two patients were men and 2 were women, with a mean age of 40 years (range, 33-51 years). Three patients were right-handed and 1 was left-handed. Scapular winging always affected the dominant side. Two patients had occupations involving heavy physical work. The sports practiced involved exertion of the arms (dancing, boxing, gymnastics, muscle strengthening). A specific rehabilitation protocol was offered to the patients. In addition, 6 fresh cadaver dissections were performed to reveal possible DSN compression. Potential areas of compression were identified, in particular when the arm was raised. RESULTS: The 4 patients presented with isolated DSN neuropathy were confirmed by electroneuromyographic testing. Total correction of scapular winging was not obtained in any patient. Three patients experienced residual pain with a neuropathic pain by the questionnaire for a Diagnosis of Neuropathic Pain (DN4) score of 2. The mean Quick-Disabilities of the Arm, Shoulder and Hand (DASH) score after treatment was 31.8 of 100. The mean ASES score was 56.2. Only 1 patient agreed to rehabilitation in a specialized center and underwent follow-up electroneuromyography. Signs of rhomboid muscle denervation were no longer present and distal motor latencies had become normal. In all cadaver dissections, the DSN originated from the C5 nerve root and did not pass through the middle scalene muscle. We identified a site of dynamic compression of the DSN by the upper part of the medial border of the scapula when the arm was raised. DISCUSSION: DSN compression is conventionally attributed to the middle scalene muscle, but it is noteworthy that our study reveals the possibility of dynamic compression of the nerve by the proximal part of the medial border of the scapula, which occurs when the arm elevation is above 90°. CONCLUSION: Our study reveals the possibility of dynamic compression of the DSN by the proximal part of the medial border of the scapula, which occurs when the arm is raised above 90°. In the absence of a surgical solution, conservative treatment is fundamental and requires management in a rehabilitation center with intervention by a multidisciplinary team.