An In Vitro Study to Determine the Effect of Ulnar Shortening on Distal Forearm Loading During Wrist and Forearm Motion: Implications in the Treatment of Ulnocarpal Impaction

Is metaphyseal ulnar shortening osteotomy superior to diaphyseal ulnar shortening osteotomy in the treatment of ulnar impaction syndrome? A meta-analysis

BACKGROUND

Although metaphyseal ulnar shortening osteotomy (MUSO) is safer for the treatment of ulnar impaction syndrome (UIS) than diaphyseal ulnar shortening osteotomy (DUSO), DUSO is widely used for UIS treatment.

AIM

To evaluate the effectiveness of DUSO and MUSO for UIS treatment and determine the factors that should be considered when choosing surgical treatment for UIS.

METHODS

Articles comparing the effectiveness of DUSO and MUSO for UIS treatment were systematically retrieved from MEDLINE (Ovid), PubMed, EMBASE, and Cochrane Library. The demography, incidence of complications, secondary operation rate, postoperative DASH score, wrist pain on the visual analogue scale, and grip strength improvement were also evaluated. In addition, the correlation between the improvement of grip strength and the shortening of osteotomy length of ulna was analyzed. The outcome of the patient was discontinuous, and the odds ratio, risk ratio (RR), and 95%CI were calculated and analyzed via RevMan5.3 software.

RESULTS

Six studies, including 83 patients receiving MUSO (experimental group) and 112 patients receiving DUSO (control group), were included in the meta-analysis. The second operation rate was significantly higher after DUSO than after MUSO. The DASH scores were slightly lower in the MUSO group than in the DUSO group. The patients receiving MUSO had slightly better pain relief effect than patients receiving DUSO. However, the incidence of complications and improvement of grip strength were not significantly different between the two groups.

CONCLUSION

Although DUSO and MUSO provide similar effects for UIS, MUSO is associated with a lower secondary operation rate, slightly lower postoperative DASH scores and slightly better pain relief effect than DUSO, indicating that MUSO can effectively be used for UIS treatment.

Return to Usual Work Following an Ulnar Shortening Osteotomy: A Sample of 111 Patients

PURPOSE

The primary aim of this study was to analyze the median time until patients performed their usual work following an ulnar shortening osteotomy (USO). The secondary aim was to identify factors influencing the median time until return to their usual work.

METHODS

We used a retrospective cohort of patients with ongoing data collection from our institution in the Netherlands. Patients with paid employment who underwent USO were invited to complete a return-to-work questionnaire at 6 weeks, 3 months, 6 months, and 12 months after surgery. The probability of and median time until return to usual work were assessed using an inverted Kaplan-Meier analysis. Factors influencing the return to usual work were evaluated using multivariable Cox proportional hazard regression.

RESULTS

In total, 111 patients who underwent USO were included, with a mean age of 46 years. The probability of returning to usual work in the first year was 92%, and the median time was 12 weeks. The type of work was independently associated with a return to work, with median times of 8, 12, and 14 weeks for light, moderate, and heavy physical work, respectively. We did not find differences in return to usual work based on age, sex, duration of complaints until surgery, treatment side, smoking status, the preoperative Patient-Rated Wrist Evaluation score, or whether the osteotomy was performed freehand or with an external cutting device.

CONCLUSIONS

Half of the patients that underwent USO fully performed their usual work by 12 weeks following surgery. We found that 92% of the patients performed their usual work within 1 year after surgery. We found a large variation in the time until a return to work based on the type of work. Surgeons can use this data to inform patients on the rehabilitation phase after USO.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Radius distraction during volar plating of distal radius fractures may improve distal radioulnar joint stability at minimum 3-year follow-up: a retrospective case series study

BACKGROUND

The surgical technique of radius distraction for stabilization of distal radioulnar joint (DRUJ) if intraoperative DRUJ instability was found after the fixation of distal radius fracture has been previously described, but this surgical technique lacks clinical and radiographic effect in minimal 3 years follow-up. We therefore evaluated the clinical outcome and radiographic results of radius distraction in minimal 3 years follow-up as long-term evaluation.

METHODS

We reviewed the case series of distal radius fracture with concomitant DRUJ instability receiving radius distraction from the senior author over a 5-year period (January 1st, 2013, to June 30th, 2017) retrospectively. Radius distraction during volar plating was performed by moving the volar plate distally via compression screw loosening/fastening to achieve firm endpoint on the dorsopalmar stress test. The evaluations of radiographic, including bone union time and ulnar variance, and clinical outcomes, including grading of DRUJ instability, NRS of wrist pain, DASH score, MMWS score, and range of motion of operated wrist at final follow-up, were performed at clinic as minimum 3-year follow-up; a total 34 patients had been evaluated.

RESULTS

At minimal post-operative 36 months follow-up, all cases demonstrated acceptable wrist range of motion with stable DRUJs, low NRS of wrist pain (0.6, SD 0.7), and satisfactory DASH score (mean 9.1, SD 6.2) and MMWS score (mean 87, SD 10). There were no cases suffering from nonunion of distal radius. The mean ulnar variance of injured wrist and uninjured wrist were -1.2 mm and 0.2 mm, respectively (SD 1.0 and 0.6) with significant statistical difference.

CONCLUSIONS

Radius distraction during volar fixation of distal radius fracture should be considered if DRUJ instability was found by the dorsopalmar stress test intraoperatively, and the long-term DRUJ stability could be achieved by maintenance of normal-to-negative ulnar variance, with decreased wrist pain and satisfactory function outcome.

LEVEL OF EVIDENCE

Therapeutic Level IV.

The Effect of Forearm Position on Wrist Joint Biomechanics

PURPOSE

All active motion wrist joint simulators have been designed to simulate physiologic wrist motion; however, a main difference among them is the orientation of the forearm (horizontal or vertical with respect to gravity). Moreover, the effect of forearm orientation on experimental results has yet to be quantified, but it may be an important variable. Thus, the purpose of this study was to determine the effect of forearm orientation on wrist kinematics and contact mechanics.

METHODS

Eight cadaveric upper limbs were cycled through a flexion-extension motion using an active motion wrist simulator. Motion trials were performed in 3 forearm orientations (gravity-neutral, gravity-flexion, and gravity-extension). A computed tomography-based joint congruency technique was used to examine radiocarpal joint contact and joint contact centroid translation in the 3 tested orientations.

RESULTS

At full wrist extension and wrist flexion, radioscaphoid contact area was greatest in the gravity-extension orientation. Radiolunate contact area was similar among all 3 forearm orientations. The radioscaphoid contact centroid was consistent among the 3 tested positions with the wrist in neutral wrist position. In contrast, the radioscaphoid contact centroid translated radially in the gravity-neutral position relative to the gravity-flexion position in extreme extension. There were no differences in radiolunate centroid contact position in the 3 forearm orientations.

CONCLUSIONS

This study demonstrates that forearm orientation affects contact mechanics and end-range carpal kinematics. Future biomechanical studies should report forearm orientation and discuss the implication of the forearm orientation used on the experimental results.

CLINICAL RELEVANCE

This study provides evidence that the wrist joint is sensitive to forearm positions consistent with activities of daily living and rehabilitation protocols.

The effect of coordinate system selection on wrist kinematics

Three-dimensional motion analysis of the hand and wrist is common in in-vitro and in-vivo biomechanical research. However, all studies rely on post testing analysis, where anatomical joint coordinate systems (JCS) are created to generate clinically relevant data to describe wrist motion. The purpose of this study was to present a comparison of four JCS that have been previously described in literature. Five cadaveric upper limbs were passively cycled through a flexion-extension and radial-ulnar deviation motion pathways using a wrist motion simulator. During testing, clinical wrist angle was measured using a goniometer. Following testing, wrist angle was calculated using four previously described methods of generating wrist coordinate systems, to facilitate their comparison. For flexion-extension wrist motion, only subtle difference between JCSs were detected. When comparing the performance of each JCS to the measured wrist angle during flexion-extension wrist motion, the RMSE for all three analyzed axes were all within 6.6°. For radial-ulnar deviation wrist motion, again only subtle difference between JCSs were detected. When comparing the performance of each JCS to the measured wrist angle during radial-ulnar deviation wrist motion, the RMSE for all three analyzed axes were all within 7.1°. The results of this coordinate system comparison do not favor one JCS generation method over another, as all were found to be similar and the small differences that were found are likely not clinically significant. We support using any of the analyzed coordinate system generation methods; however, a practical advantage of using certain methods is that the required digitized points to form the coordinate systems are palpable on the skin's surface.

The Relationship Between the Tensile and the Torsional Properties of the Native Scapholunate Ligament and Carpal Kinematics

PURPOSE

The purpose of this exploratory study was to examine the relationship between the tensile and the torsional properties of the native scapholunate interosseous ligament (SLIL) and kinematics of the scaphoid and lunate of an intact wrist during passive radioulnar deviation.

METHODS

Eight fresh-frozen cadaveric specimens were transected at the elbow joint and loaded into a custom jig. Kinematic data of the scaphoid and lunate were acquired in a simulated resting condition for 3 wrist positions-neutral, 10° radial deviation, and 30° ulnar deviation-using infrared-emitting rigid body trackers. The SLIL bone-ligament-bone complex was then resected and loaded on a materials testing machine. Specimens underwent cyclic torsional and tensile testing and SLIL tensile and torsional laxity were evaluated. Correlations between scaphoid and lunate rotations and SLIL tensile and torsional properties were determined using Pearson correlation coefficients.

RESULTS

Ulnar deviation of both the scaphoid and the lunate were found to decrease as the laxity of SLIL in torsion increased. In addition, the ratio of lunate flexion-extension to radial-ulnar deviation was found to increase with increased SLIL torsional rotation.

CONCLUSIONS

Our findings support the theory that there is a relationship between scapholunate kinematics and laxity at the level of the interosseous ligaments.

CLINICAL RELEVANCE

Laxity and, specifically, the tensile and torsional properties of an individual's native SLIL should guide reconstruction using a graft material that more closely replicates the individual's native SLIL properties.

Ulnar shortening osteotomy as a treatment of symptomatic ulnar impaction syndrome after malunited distal radius fractures

A malunited distal radius fracture can lead to symptomatic ulnar impaction syndrome, which is a common cause for ulnar-sided wrist pain. If conservative treatment fails and symptoms persist after an arthroscopic ulnocarpal debridement, ulnar shortening osteotomy (USO) is the treatment of choice. Since the first USO described by Milch in 1941 after a malunited Colles fracture, many techniques have been described varying in surgical approach, type of osteotomy and osteosynthesis material used. Many studies demonstrated good to very good functional results after USO, reporting, however, a delayed union or non-union rate up to 18%. A modern, low profile, locking plate showed in our short-term study very good functional results and no implant-associated complications, in particular no non-union.