Union Rates and Complications After Thumb Metacarpophalangeal Fusion

Comparison of Fusion Rates/Complications Between Different Types of Thumb Metacarpophalangeal Fusion Techniques

BACKGROUND

Thumb metacarpophalangeal (MP) fusion is generally successful; however, complications have been reported to occur in 0% to 30% of cases, whereas nonunion rates vary by method but, overall, are reported to occur in 0% to 15% of cases. Many fixation techniques have been described, but there is no consensus on the optimal fusion technique. Our goal was to compare complication and union rates of different thumb MP arthrodesis techniques.

METHODS

We performed a retrospective review of patients who underwent primary thumb MP fusion between 2000 and 2022. Patients who underwent revision fusion, fusion for infection, or amputation were excluded. Fusions of MP joints of other fingers were also excluded. Data collection consisted of demographic data, complications, time to fusion, rate of delayed union and rate of nonunion. Five different fusion constructs were evaluated during our study period: staples, Kirschner wires (K-wires), cerclage, K-wires with cerclage, and intramedullary screw.

RESULTS

Forty-seven patients underwent fusion with staples, 16 with K-wires, 14 with cerclage, 9 with K-wires and cerclage, and 6 with an intramedullary screw. The individual complication and nonunion rates differed significantly among the groups with the intramedullary screw group having a statistically higher rate of nonunion (P = .004). Furthermore, smoking, diabetes, and being overweight were associated with nonunions.

CONCLUSION

Union rates were significantly lower in patients treated with an intramedullary screw and those who are smokers, diabetics, and/or overweight. Caution should be exercised when using intramedullary screw fixation for MP fusion, especially in patients with these comorbidities.

Complications and Unplanned Reoperation After Thumb Metacarpophalangeal Arthrodesis

PURPOSE

Arthrodesis of the metacarpophalangeal (MCP) joint of the thumb is a common procedure to treat arthritis or instability. Studies reporting hardware complications and nonunion rates after thumb MCP joint arthrodesis report on small sample sizes. We aimed to describe the hardware complication rate, the nonunion rate, and the number of thumbs that achieve union among patients undergoing thumb MCP joint arthrodesis.

METHODS

A database spanning 5 urban hospitals in a single metropolitan region in the United States was searched for patients who underwent thumb MCP joint arthrodesis between January 1, 2004 and January 1, 2020. After reviewing patient records, we identified 122 thumbs that underwent MCP joint arthrodesis and had a minimum follow-up of 90 days. The primary outcome was unplanned reoperation after hardware complications and nonunion. Second, the number of thumbs that achieved radiographic union was reported for the tension band and screw fixation arthrodesis group.

RESULTS

Twenty-two (18%) out of 122 thumbs had hardware complications after thumb MCP joint arthrodesis, and 11 (9%) out of 122 thumbs developed a nonunion. Patients who underwent screw fixation arthrodesis had no events of hardware complications and subsequent hardware removal. The nonunion rate was 9/65 (14%) in the tension band arthrodesis group and 2 (4%) of 45 in the screw fixation arthrodesis group. Of the thumbs that had available radiographs to assess the healing of the arthrodesis, 34 (81%) of 42 were radiographically united in the tension band arthrodesis group and 29 (91%) of 32 in the screw fixation group.

CONCLUSIONS

Our data suggest that screw fixation has fewer hardware complications and a lower reoperation rate than tension band arthrodesis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognosis IV.

Long-Term Outcomes in Female Patients With Carpometacarpal Arthroplasty and Metacarpophalangeal Fusion Compared With the Unoperated Side or Carpometacarpal Arthroplasty

PURPOSE

Patients with carpometacarpal (CMC) osteoarthritis (OA) often present with metacarpophalangeal (MP) hyperextension and/or thenar atrophy. This study hypothesizes that MP fusion (MPF) performed at the time of CMC arthroplasty (CMCA) for patients who have moderate-to-severe thenar atrophy, MP hyperextension >30°, or MP arthritis will have greater long-term pinch strength and improvements in the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score from preoperative values when compared with the unoperated side or those who had CMCA only.

METHODS

This study involved a retrospective review of long-term results from patients who underwent either CMCA or CMCA/MPF. The QuickDASH score, the pain visual analog scale (VAS), and an average of three pinch readings from each thumb were measured on the Baseline pinch gauge and recorded with a correction for hand dominance in right-handed patients.

RESULTS

Fifty-three female patients with 70 operated thumbs were included in the study. The mean age was 67.2 years. There were 29 CMCAs and 41CMCA/MPFs. The mean follow-up was 6.3 years (range 2-16.9 years). At the latest follow-up, the mean CMCA/MPF pinch strength (11.3 lbs) was significantly stronger than that of CMCA (8.0 lbs) and carpometacarpal osteoarthritis thumbs (8.9 lbs). There was no significant difference in pinch strength between patients who underwent a CMCA and CMCOA thumbs (8.0 lbs vs 8.9 lbs, respectively). Preoperative QuickDASH demonstrated worse function in the CMCA/MPF group (55.8 vs 36.5). At the latest follow-up, QuickDASH and VAS revealed similar values in both the CMCA/MPF (10.5 and 0.66) and CMCA (18.5 and 0.52) groups.

CONCLUSION

Long-term results demonstrate stronger pinch and greater improvement in QuickDASH scores in patients who underwent CMCA/MPF compared with those who underwent a CMCA or untreated carpometacarpal osteoarthritis thumbs.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.