Comparison of compression screw and perpendicular clamp in ulnar shortening osteotomy

Distal Metaphyseal Ulnar Shortening Osteotomy Fixation: A Biomechanical Analysis

PURPOSE

Ulnar shortening osteotomy can be used to treat ulnar impaction syndrome and other causes of ulnar wrist pain. Distal metaphyseal ulnar shortening osteotomy (DMUSO) is one technique that has been proposed to reduce the complications seen with a diaphyseal USO or a wafer resection. However, to our knowledge, the optimal fixation construct for DMUSO has not been studied. We sought to characterize the biomechanical stiffness and rotational stability of different DMUSO constructs.

METHODS

A DMUSO was performed on 40 human cadaveric ulnas using 4 different fixation constructs (10 specimens per group): one 3.0 mm antegrade screw; two 2.2 mm antegrade screws; one 3.0 mm retrograde screw; and two 2.2 mm retrograde screws. Biaxial testing using axial load and cyclical axial torque was performed until failure, defined as 10° of rotation or 2 mm displacement. Specimens were assessed for stiffness at failure. Bone density was assessed using the second metacarpal cortical percentage.

RESULTS

Bone density was similar between all 4 testing groups. Of the 4 groups, the 2 antegrade screw group exhibited the highest rotational stiffness of 232 ± 102 Nm/deg. In paired analysis, this was significantly greater than 1 retrograde screw constructs. In multivariable analysis, 2-screw constructs were significantly stiffer than 1 screw and antegrade constructs were significantly stiffer than retrograde. Maximum failure torque did not differ with orientation, but 2 screws failed at significantly higher torques.

CONCLUSION

Using 2 screws for DMUSO fixation constructs may provide higher stiffness and maximum failure torque, and antegrade screw constructs may provide more stiffness than retrograde constructs.

CLINICAL RELEVANCE

Antegrade screw fixation using 2 screws may provide the strongest construct for DMUSO. Antegrade fixation may be preferred because it avoids violating the distal radioulnar joint capsule and articular surface of the ulna.

Successful treatment of infectious delayed union after ulnar shortening osteotomy using once-weekly teriparatide with low-intensity pulsed ultrasound

We report a 50-year-old woman who presented with infected delayed union after ulnar shortening osteotomy. She was a chronic smoker. Implants were removed and infected tissue was debrided. Sufficient bony union was obtained after 5 months of treatment with weekly teriparatide and low-intensity pulsed ultrasound during the infection-controlled waiting period.

Maintenance of Compression With a Positional Screw Versus Compression Generated With a Lag Screw

OBJECTIVE

To determine whether a position screw will maintain the interfragmentary compression force obtained by a reduction clamp across an anatomically reduced cortical bone fracture and determine whether this compressive force is equivalent to that generated by a lag screw (LS).

METHODS

Oblique fractures were created in 6 composite cortical bone models. Interfragmentary compression was measured using force sensors within the fracture after reduction with a clamp. A position screw was then placed perpendicular to the fracture, and force measurements were repeated with both the clamp and the screw. Finally, the clamp was removed, and force measurements were taken with the screw only to measure maintenance of initial compression. After these measurements, the screw was removed, and the near fragment was overdrilled to allow LS placement by technique. Compression force measurements were repeated for clamp only, clamp + screw, and screw only.

RESULTS

The mean force of clamp alone across all 12 trials was 139.77 N. Application of an LS increased the compression across the fracture (P = 0.01) which was unchanged when the clamp was removed. The position screw had the opposite effect, reducing compression, and the removal of the clamp further reduced the compression (P = 0.013).

CONCLUSIONS

A reduction clamp will initially compress a fracture to an average of 139 N. An LS will significantly increase this interfragmentary compression. A position screw will not maintain the compression created by the clamp and in fact will significantly decrease interfragmentary compression.

[Surgical treatment of ulnar impaction syndrome : Ulnar shortening osteotomy through the ulnopalmar approach using a low-profile, locking plate]

OBJECTIVE

Extra-articular shortening of the distal ulna in order to decompress the ulnocarpal joint.

INDICATIONS

Congenital or posttraumatic, symptomatic ulnar impaction syndrome.

CONTRAINDICATIONS

Osteoarthritis or deformation of the distal radioulnar joint.

SURGICAL TECHNIQUE

Exactly defined oblique osteotomy in the distal third of the ulna using the saw guide, closing of the osteotomy gap using the compression spindle, osteosynthesis with the locking plate.

POSTOPERATIVE MANAGEMENT

Palmar forearm thermoplastic cast or splint for 3 weeks, load bearing after bony union.

RESULTS

Between June 2016 and March 2018 ulnar shortening was performed in 17 patients using the new locking plate. In all, 15 patients were reevaluated with complete follow-up data. Postoperatively patients experienced significant pain reduction (Visual Analog Scale 0-10) by 65% (7 before and 2.5 after surgery; p < 0.05) and a significant improvement of function (Disabilities of Arm, Shoulder and Hand 0-100) by 49% (47 before and 24 after surgery; p < 0.05). Bony union was observed in all patients after a mean time of 4 months. Overall patient satisfaction was high.

Simultaneous Intraoperative Measurement of Cadaver Ankle and Subtalar Joint Compression During Arthrodesis With Intramedullary Nail, Screws, and Tibiotalocalcaneal Plate

BACKGROUND

Suboptimal tibiotalocalcaneal arthrodesis (TTCA) fusion rates may result from inadequate compression that increases motion and interferes with bony bridging. The aim of this study was to evaluate compressive forces at the ankle and subtalar joints with 3 contemporary TTCA constructs.

METHODS

Thirty fresh-frozen cadaveric lower extremity specimens were divided into 3 groups of 10 each: 3 partially threaded cannulated screws, hindfoot nail, and lateral plate. Specimens were mounted to a testing apparatus, and compression was independently measured at the tibiotalar and talocalcaneal interfaces. Statistical analysis included paired Student t tests, analysis of variance, and Tukey post hoc tests.

RESULTS

Mean forces at the ankle joint for the screws, nail, and plate constructs were 331 ± 86, 479 ± 137, and 548 ± 199 N, respectively, with plates providing significantly more compression than screws ( P < .01). Similarly, subtalar compressive forces demonstrated 319 ± 105 N in the screws group, 466 ± 125 N, in the nail group, and 513 ± 181 N in the plate group, with plate compression greater than that achieved with screws ( P < .01). No differences were identified in compression between ankle and subtalar joints within specimens in any group.

CONCLUSIONS

Lateral TTCA plates provided increased compressive forces at the ankle and subtalar joint compared with screws-only constructs. Hindfoot nails did not demonstrate significant differences in either of these parameters compared with plates or screws in this study.

CLINICAL RELEVANCE

Hindfoot nail and lateral plate options should be strongly considered when aiming to maximize compression in patients undergoing TTCA.

Metaphyseal Versus Diaphyseal Ulnar Shortening Osteotomy for Treatment of Ulnar Impaction Syndrome: A Comparative Study

PURPOSE

To compare the clinical and radiographic outcomes and complication rates of diaphyseal and metaphyseal ulnar shortening osteotomies for the treatment of ulnar abutment syndrome.

METHODS

We performed a retrospective study comparing 35 patients who underwent either a metaphyseal (n = 14) or diaphyseal (n = 21) osteotomy. Radiographic and clinical outcomes were compared. Complication rates including infection, hardware removal, and reoperations were also assessed.

RESULTS

There were no differences in patient characteristics, ulnar variance, or pain and functional scores between groups. Metaphyseal osteotomy surgery time was shorter (45.5 vs 71.7 minutes) and resulted in greater ulnar shortening (4.8 vs 3.4 mm) compared with diaphyseal osteotomies. At an average 19.2-month follow-up, metaphyseal osteotomies were associated with greater improvement in pain and Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire scores. The need for implant removal was the same in both groups. There were no complications in either group.

CONCLUSIONS

Results from this study suggest that metaphyseal osteotomies are a safe and effective alternative to diaphyseal osteotomies for the management of ulnar abutment syndrome. Although improved surgical time and postoperative outcomes are encouraging, further large-scale and properly powered studies with long-term outcomes will help characterize the benefit of one technique over another. Ultimately, the decision between a metaphyseal and diaphyseal osteotomy may be surgeon preference.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Influence of Plate Size and Design upon Healing of Ulna-Shortening Osteotomies

Purpose Ulna-shortening osteotomy is one of the most established and most frequent operations in hand surgery. However, bone union is not always achieved and the use of plates implies potential risks and problems. The traditional points of criticism are the duration of bone healing, the incidence of nonunion, and the necessity of hardware removal due to the soft tissue irritation by the plate or the screws. These shortcomings have been addressed by an increasing standardization of the procedure and finally specific instruments and implants. The aim of this retrospective study was to compare a new LCP (locking compression plate) Ulna Osteotomy System 2.7 mm (Synthes, Paoli, PA) with the former 3.5-mm LCDCP (limited-contact dynamic compression plate) (Synthes) regarding consolidation, complications, and rate of plate removal. Methods To investigate the effect of an implant and technique specifically designed for this purpose, we have compared the course of healing and the result in 72 patients who have undergone ulnar shortening osteotomy using general instruments and applying a standard osteosynthesis plate (Synthes, 3.5-mm LCDCP) to a consecutive cohort of 40 patients who had ulnar shortening using the new dedicated ulna-shortening osteotomy system plate (Synthes, 2.7-mm LCP). Clinical and radiologic evaluation was performed 8 weeks, 3 months, 6 months, and 1 year postoperatively in all patients. Results The latter displayed shorter bone healing time, suggesting an advantage of an oblique osteotomy. There was no significant difference in rate of plate removal. Ultimate complication and consolidation rate was not different. Conclusion Using the new LCP 2.7 implant, time to consolidation was shorter and oblique osteotomies healed faster than transverse ones. However, in spite of the smaller plate, screws, and tapered design, the plate did not cause less local problems and failed to decrease the necessity of plate removal. Furthermore, the cost of the implant is higher than the LCDPC 3.5. Type of Study Retrospective comparative study. Therapeutic evidence Level III.

Successful Bone Healing of Nonunion After Ulnar Shortening Osteotomy for Smokers Treated With Teriparatide

Ulnar shortening osteotomy is widely performed as the standard surgical treatment for ulnar impaction syndrome and has a high percentage of success for pain relief. However, delayed union and nonunion of the osteotomy site remain the most concerning complications. In particular, smokers have a higher incidence of nonunion, which amounts to 30% of cases. For the treatment of nonunion, secondary surgical interventions such as bone grafting will be necessary but are extremely challenging. Recently, teriparatide (recombinant human parathyroid hormone [PTH 1-34]) administration has been reported in several clinical studies as a noninvasive pharmacological systemic treatment for fracture healing or nonunion. The authors present 2 cases of smokers, a 62-year-old man and a 42-year-old woman, with nonunion after ulnar shortening osteotomy and fixation with 6-hole non-locking plate for ulnar impaction syndrome. For treatment of nonunion, noninvasive therapy with teriparatide (20-µg, subcutaneous injection) in addition to low-intensity pulsed ultrasound was underwent. In both cases, partial bone union began to be observed on radiographs after the first 4 weeks of teriparatide administration and successful bone healing without additional surgical interventions was achieved after 10 and 6 months of treatment with teriparatide, respectively. The current case reports showed that non-invasive combination therapy of teriparatide and low-intensity pulsed ultrasound were a possible alternative to surgical intervention. In the future, teriparatide therapy might be applied actively to patients who have risk factors for delayed union, such a heavy smoking habit, and are expected to experience nonunion after ulnar shortening osteotomy.