Ulnar Resection Length: A Risk Factor for Nonunion in Ulnar Shortening Osteotomy

BACKGROUND

Nonunion rates following ulnar shortening osteotomy (USO) are reported up to 18% with few known risk factors. While resection length is variable in practice, little is known about the prognostic implications on healing. The purpose of this study was to evaluate whether longer resection lengths increased the odds of nonunion.

METHODS

A retrospective review was performed on patients who underwent an elective USO at a single institution over a 6-year period. Demographic, social, comorbidity, and surgical data were reviewed. Ulnar resection length was obtained from operative notes and dichotomized into smaller (<5.5 mm) and larger (≥5.5 mm) groups. The primary outcome was the rate of nonunion. Univariate analyses and a multivariable logistic regression model were used to assess for significant predictors of nonunion.

RESULTS

A total of 87 patients were included with a mean age of 45 years. Patient comorbidities included 12.6% with diabetes, 29.9% with an American Society of Anesthesiologists score of ≥ 3, 5.8% reporting current tobacco use, and 29.9% reporting former tobacco use. There were 55 patients (63.2%) with resection lengths < 5.5 mm and 32 patients (36.8%) with ≥ 5.5 mm resections. Multivariable analysis identified longer resection length (≥5.5 mm) and current tobacco use as independent risk factors for nonunion. Patients with a resection length of ≥ 5.5 mm had 20.2 times greater odds of nonunion compared with patients with smaller resections, and current smokers had 72.2 times greater odds of nonunion compared with nonsmokers.

CONCLUSION

Longer ulnar resection length (≥5.5 mm) significantly increases the risk of nonunion following USO.

Minimial clinically important difference values in distal metaphyseal ulnar shortening for ulnar impaction syndrome and assessment of the relationship between level of the osteotomy and bone union time

OBJECTIVE

We aimed to define minimal clinically important difference (MCID) values of patient-reported outcome measures (PROMs) for distal metaphyseal ulnar shortening and to assess the relationship between level of the osteotomy and time to bone union.

METHODS

20 patients who had distal metaphyseal ulnar shortening osteotomies due to ulnar impaction syndrome and had at least 6 months of follow-ups were included in this study. The mean follow-up period was 12.3 ± 7.01 months. The PROMs which consisted of patient-rated wrist evaluation (PRWE) and quick disabilities of arm, shoulder, and hand (QDASH) were recorded on the day before the surgery and at follow-up assessments. Grip strength and range of motion were recorded for operated and contralateral wrists at postoperative assessments. Postoperative radiological evaluations of distance of the osteotomy from the distal ulnar articular surface (osteotomy level), the union of osteotomy site; preoperative and postoperative evaluations of styloid-triquetral distance, and ulnar variance were performed using AP wrist x-rays. The MCID values for PRWE and QDASH were calculated using ROC curve analysis.

RESULTS

Mean PRWE and QDASH scores decreased statistically significantly. The mean grip strength of contralateral wrists was higher. Mean ulnar variance decreased, whereas styloid-triquetral distance increased postoperatively. Patients with osteotomy levels of greater than 13.7 mm had a longer time from surgery to bone union. Furthermore, patients with time from surgery to bone union shorter than 7 weeks had an osteotomy closer to the ulnar articular surface. The MCID values for PRWE and QDASH were analyzed and calculated through the ROC curve as 22.25 and 20.45, respectively.

CONCLUSION

This study has shown us that the osteotomy level affects the time to bone union and an osteotomy closer than 13.7 mm to the ulnar articular surface seems to result in shorter union time. Furthermore, MCID values were defined for PRWE and QDASH as 22.25 and 20.45, respectively.

LEVEL OF EVIDENCE

Level IV, Therapeutic Study.

Radiographic Assessment of Bilateral Asymmetry in the Upper Extremities of Living Humans

Objective Injuries resulting from trauma or tumor resection may cause length alterations in the bones of the upper extremities (UE) requiring reconstruction. Direct contralateral bone is often used to determine the appropriate length for reconstruction but fails to account for potential asymmetry. Given the paucity of data assessing asymmetry in living populations and the need for accurate length approximation, we developed a study evaluating UE long bone asymmetry using radiographic imaging in living subjects. Methods Bilateral X-ray images previously obtained for traumatic injury or chronic osseous conditions were retrospectively collected for adult subjects (ages 18-81). After screening, 61 patients met the inclusion criteria: 28 radii, 29 ulnae, and 19 humeri. Three serial measurements were taken, and the median was used for subsequent analysis. Wilcoxon signed-rank tests were performed to assess differences in contralateral bone lengths. Bootstrapping was utilized to obtain sample sizes of 200, 500, and 1000 for each bone. Results The difference in mean absolute length was 27.0 mm for the humerus, 8.6 mm for the radius, and 7.5 mm for the ulna. Neither the left side nor the right side was significantly longer for any bone. In 57.9% (11/19) of patients, the right humerus was longer than the left; in 60.7% (17/28), the right radius was longer than the left; and in 48.3% (14/29), the right ulna was longer than the left. All other measurements showed the left was longer than the right. Wilcoxon signed-rank tests did not find significant differences between contralateral pairs in any direct measurement group. In bootstrap samples, significant differences in length (p ≤ 0.05) were seen in all samples (n = 200, 500, and 1000) for both humerus and radius but only the 1000 sample group for the ulna. Conclusions Direct contralateral measure may be an appropriate method of length estimation for the humerus, radius, and ulna in post-industrial humans.

Arthroscopic Wafer Procedure Versus Ulnar Shortening Osteotomy for Treatment of Idiopathic Ulnar Impaction Syndrome: A Randomized Controlled Trial

PURPOSE

We compared the arthroscopic wafer procedure (AWP) and ulnar shortening osteotomy (USO) for treatment of idiopathic ulnar impaction syndrome in terms of clinical, functional improvement and time of return to work.

METHODS

This single-center study was conducted at an academic level 1 referral center between 2014 and 2020. Sixty patients with idiopathic ulnar impaction syndrome were prospectively randomized to treatment with either AWP or USO. At the final follow-up, patients were evaluated by the Disabilities of the Arm, Shoulder, and Hand; the Modified Mayo Wrist Score; the visual analog scale for pain; wrist range of motion; and grip strength. Also, the time of return to work and complications were reported.

RESULTS

The mean follow-up periods were 22 ± 5.7 months in the AWP group and 21.1 ± 5.3 months in the USO group. All patients in the USO group achieved union by 12 weeks. At the final follow-up, there were no statistically significant differences in the outcome measures (Disabilities of the Arm, Shoulder, and Hand score; Modified Mayo Wrist Score; visual analog scale score; range of motion; and grip strength) in either group. Fewer complications and an earlier return to work were observed in the AWP group.

CONCLUSIONS

Both techniques yielded comparable outcomes, with earlier return to work, a lower incidence of complications, and fewer secondary procedures in the AWP group.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Distal Ulnar Metaphyseal Wedge Osteotomy for Ulnar Abutment Syndrome

Background  Ulnar shortening osteotomy of the diaphysis is a common and effective surgical procedure for ulnar abutment syndrome. However, this procedure has some disadvantages, such as a long period until union and a relatively high nonunion rate. To overcome these disadvantages, we have developed distal ulnar metaphyseal wedge osteotomy. The purpose of this article is to describe the technique and to report its clinical results. Patients and Methods  Distal ulnar metaphyseal wedge osteotomy consists of resection of the wedge fragment at the distal ulnar metaphysis, compressing the distal fragment of the ulna toward the radial-proximal direction and fixation with a Herbert type headless screw. We performed this procedure for 58 patients with ulnar abutment syndrome, and the clinical data of 43 patients who were followed for > 6 months were analyzed. We evaluated range of motion, grip strength, and HAND20 which is a validated subjective scoring system in Japan. Results  All patients experienced relief from their ulnar wrist pain, and bone union was achieved within an average of 2.6 months. The range of dorsiflexion improved from 63° preoperatively to 69° postoperatively, grip strength compared with the contralateral hand improved from 77% preoperatively to 87% postoperatively, and HAND20 improved from 41.3 points preoperatively to 22.4 points postoperatively. Discussion  This procedure has advantages especially in early bone union. This procedure should be taken into consideration as one of the options to treat ulnar abutment syndrome.

The Oblique Metaphyseal Shortening Osteotomy of the Distal Ulna: Surgical Technique and Results of Ten Patients

Background Ulnocarpal abutment is a common condition following distal radius fractures. There are different surgical methods of treatment for this pathology: open and arthroscopic wafer procedure or an ulnar shortening osteotomy. We describe an oblique metaphyseal shortening osteotomy of the distal ulna using two cannulated headless compression screws. We report the results of 10 patients treated with this method. Materials and Methods Out of 17 patients, 10 could be reviewed retrospectively for this study. Patient-rated outcomes were measured using the VAS (visual analogue scale) for pain, PRWHE (patient-rated wrist and hand evaluation) survey, and Quick-DASH (disability of arm, shoulder and hand) survey for functional outcomes. At the review we measured the range of motion (ROM) of the wrist (extension and flexion, ulnar and radial deviation, pronation and supination). Grip strength, pronation, and supination strength of the forearm was measured using a calibrated hydraulic dynamometer. ROM and strength of the affected wrist was compared with ROM and strength of the unaffected wrist. Surgical Procedure Oblique long metaphyseal osteotomy of the distal ulna (from proximal-ulnar to distal-radial), fixed with two cannulated headless compression screws. Results The average postoperative VAS score for pain was 23.71 (standard deviation [SD] of 30.41). The average postoperative PRWHE score was 32.55 (SD of 26.28). The average postoperative Quick-DASH score was 28.65 (SD of 27.21). The majority of patients had a comparable ROM and strength between the operated side and the non-operated side. Conclusion This surgical technique has the advantage of reducing the amount of hardware and to decrease the potential hinder caused by it on medium term. Moreover, the incision remains smaller, and the anatomic metaphyseal localization of the osteotomy potentially allows a better and rapid healing.

Wafer Resection of the Distal Ulna

The wafer procedure is an effective treatment for ulnar impaction syndrome, which decompresses the ulnocarpal junction through a limited open or arthroscopic approach. In comparison with other common decompressive procedures, the wafer procedure does not require bone healing or internal fixation and also provides excellent exposure of the proximal surface of the triangular fibrocartilage complex. Results of the wafer procedure have been good and few complications have been reported.

The AO Ulnar Shortening Osteotomy System Indications and Surgical Technique

Ulnar shortening osteotomy is an established and frequently performed surgical procedure in wrist surgery. The technical aspects of the procedure have continued to develop in recent years, with instruments and implants being developed specifically for this purpose. Ulnar shortening osteotomy is required for different clinical indications and situations. These varying indications demand different amounts of shortening, but all must be precise and accurate. Controversy exists as to how this can best be achieved in terms of the location for osteotomy, the surgical approach and geometry of the osteotomy, as well as which implant to use to provide optimal stability. The goal of all techniques (besides successfully resolving the underlying problem) is to achieve reliable and rapid bone union without compromising early functional rehabilitation and also to avoid hardware complications. The AO Hand Expert Group has developed a specialized instrumentation system with dedicated and specifically designed implants to ensure exact and accurate cutting with precise and rigid stabilization of the ulna. The matched drill guides and double-blade saws allow accurate completion of the planned amount of shortening together with precise coaptation of the osteotomy fragments. The specific ulnar osteotomy LCP (locking compression plate) combines maximum stability with minimum bulk and soft tissue irritation. The features of the implant, its surgical technique, and early results are described.