Biopsy of the anterior interosseous motor branch for the pronator quadratus muscle: a safe and minimally invasive diagnostic tool for peripheral neuropathies. Anatomical surgery and surgical technique.

BACKGROUND AND OBJECTIVES: Choosing the correct site for a nerve biopsy remains a challenge due to nerve sacrifice and major donor site complications, such as neuroma, as seen in sural nerve biopsy. Selecting a deeper donor nerve can help in burying nerve stumps in deep soft tissues, preventing neuroma. Moreover, using an expendable, deeply situated motor nerve can aid indiagnosis when a motor neuropathy is suspected. The authors propose using the pronator quadratus (PQ) branch for this purpose, as it is located deep between the bellies of the flexor muscles and the interosseous membrane in the forearm. This branch is expendable since the denervation of the PQ has a negligible effect on forearm pronation, which is primarily sustained by the pronator teres. METHODS: The surgical approach is the same as the approach for anterior interosseous nerve transfer to the motor component of the ulnar nerve in the distal forearm: access is in the midline in the middle third of the forearm under local anesthesia Blunt dissection is performed, separating and retracting the flexor musculotendinous junction to reach the interosseous membrane where the PQ branch is identified. A careful dissection of the nerve branch is performed, allowing a 2 cm long segment to be cut and removed. The proximal stump is then buried into an adjacent muscle belly and the surgical site is closed. RESULTS: The technique is safe and reproducible in experienced hands. CONCLUSION: This technique may be especially applicable in cases where neurologists need to study motor neuropathies. Contraindications of the technique include wrist instability and high median nerve palsies.

Impact of Pronator Quadratus Muscle Tear in Distal Radius Fractures on Patient Outcomes: Analyses of 55 Patients in a Volar Locking Plate Arm of a Randomized Clinical Trial.

Background The advantage of pronator quadratus (PQ) repair following internal fixation via the volar approach in distal radius fracture (DRF) surgery remains unconfirmed in the literature. The aim of this study was to compare grip strength, patient-reported outcomes, and functional results between patients with an intact PQ and those with a ruptured PQ before undergoing surgery with a volar locking plate for dorsally displaced unstable extra-articular DRFs. Methods A total of 120 patients aged 55 years and older were included in a randomized controlled trial comparing a volar locking plate with a dorsal nail plate. Of the 60 patients randomized to the volar plate group, the integrity of the PQ muscle was recorded during surgery for 55 patients, who were included in this study. The outcomes measured were the Quick Disabilities of the Arm, Shoulder, and Hand Outcome Measure (QuickDASH) score, the Patient-Rated Wrist Evaluation (PRWE) score, the EQ-5D index, the visual analog scale (VAS) score, grip strength, and range of motion (ROM). Results The median age was 67 years (range 55 to 88), and the one-year follow-up rate was 98%. Patients with an identified intact PQ (28/55) before surgical release had better QuickDASH scores after one year (2.5 vs 8.0, mean difference 5.5, 95% CI: 1.3 to 9.8, p=0.028). Patients in the intact group also had better EQ-5D Index scores after one year (0.94 vs 0.85, mean difference 0.089, 95% CI: 0.004 to 0.174, p=0.031), and demonstrated better grip strength throughout the trial; after one year: 24 kg vs 20 kg (mean difference 3.9; 95% CI: 0.3 to 7.6, p=0.016). After one year, the intact group had regained 96% of their grip strength and the nonintact group had regained 93% of their grip strength compared to the uninjured side. The observed differences may be of questionable clinical importance, as they were lower than those of previously proposed minimal clinically important differences (MCIDs). Conclusions Patients with a DRF and a ruptured PQ prior to surgery exhibited higher QuickDASH scores and lower EQ-5D index scores after one year. The integrity of the PQ should be reported in future studies.

Pronator quadratus preserving versus pronator quadratus dissecting approaches in volar plate fixation of distal radius fractures: a systematic review of comparative studies.

PURPOSE: To compare pronator quadratus preserving (PQ-P) approaches with PQ dissecting (PQ-D) approaches in volar plate fixation of distal radius fractures (DRFs). METHODS: Three databases were searched on March 10th, 2024. The authors adhered to the PRISMA and R-AMSTAR guidelines and Cochrane Handbook for Systematic Reviews. Data on demographics, fracture classifications, patient reported outcome measures (PROMs), range of motion, radiographic parameters, and complications were extracted. RESULTS: Thirteen studies with a total of 1007 fractures were included. Two of three studies reported lower DASH scores in the PQ-P group between 6 weeks and 3 months postoperative, however no studies reported lower scores in the PQ-P group after 3 months. Three of three studies reported significantly lower VAS scores at 6 weeks postoperative, however no studies reported significant differences after 6 months. Only one of six studies reported significantly greater flexion, extension, and pronation in the PQ-P group. One of four studies reported greater radial deviation in the PQ-P group, while there were no differences in supination or ulnar deviation. One of ten and one of six studies reported greater volar tilt and ulnar variance or radial length, respectively, in the PQ-P group. CONCLUSION: There is not sufficient evidence supporting the utility of PQ-P approaches over conventional PQ-D approaches for volar plate fixation of DRFs, especially at long-term follow-ups (3+ months). There may be short term benefits with PQ-P approaches, specifically with regards to PROMs in the short-term (< 6 weeks), however there is limited high-quality evidence supporting these findings. LEVEL OF EVIDENCE: Level III.

Ultrasound Secondary Signs for the Diagnosis of Pediatric Distal Forearm Fractures: A Diagnostic Study.

OBJECTIVE: To evaluate the diagnostic accuracy of ultrasound secondary signs of fractures in pediatric patients aged 5-15 y presenting to the emergency department with a clinically non-deformed distal forearm injury. METHODS: This diagnostic study was conducted in South East Queensland, Australia. Emergency clinicians performed point-of-care ultrasound on eligible patients and recorded secondary signs of fractures (pronator quadratus hematoma [PQH] sign, periosteal hematoma, visible angulation) or physeal fractures (fracture-to-physis distance [FPD], physis alteration). The reference standard was the final fracture diagnosis determined by expert panel. The primary outcome was the diagnostic accuracy of secondary signs for cortical breach and physeal fractures. Diagnostic statistics were reported for each relevant secondary sign. RESULTS: A total of 135 participants were enrolled. The expert panel diagnosed 48 "no" fracture, 52 "buckle" fracture and 35 "other" fracture. All "other" fractures were cortical breach fractures and included 15 Salter-Harris II fractures. The PQH sign demonstrated high sensitivity and moderate specificity to diagnose cortical breach fractures (91%, 95% Confidence Interval [CI] 78%-97% and 82%, 73%-88%). Poor sensitivity but high specificity was observed for the visible angulation and periosteal hematoma secondary signs. FPD <1cm showed perfect sensitivity and moderate specificity (100%, 80%-100% and 85%, 78%-90%) for diagnosis of Salter-Harris II fracture. Conversely, physis alteration showed poor sensitivity but excellent specificity (40%, 20%-64% and 99%, 95%-100%) for the diagnosis of Salter-Harris II fractures. CONCLUSION: Ultrasound secondary signs showed good diagnostic accuracy for both cortical breach fractures and Salter-Harris II fractures. Future research should consider optimal use of secondary signs to improve diagnostic accuracy.

Is pronator quadratus muscle repair required after anterior plate fixation for distal radial fractures? A prospective randomized comparative study.

In this prospective, randomized comparative study in patients with distal radial fractures, we aimed to determine whether surgical repair of the superficial head after anterior locking plate fixation of the radius improves clinical or functional outcomes or both, and distal radioulnar joint stability. One hundred patients were randomized to undergo distal radial fixation with or without repair of the superficial head. Twenty-one patients were lost to follow-up, leaving a final sample of 79 patients. No differences were observed between the groups in functional scores or complication after operation. Surgical repair of the superficial head of the pronator quadratus muscle after osteosynthesis with an anterior locking plate for distal radial fractures does not appear to substantially contribute to preserving distal radioulnar joint stability or improving the consolidation process.Level of evidence: II.

Comparison of three kinds of palmar approach plate implantation for treatment of unstable distal radius fractures / 中国组织工程研究

BACKGROUND:In the past,it was necessary to cut off the pronator quadratus muscle in the treatment of distal radius fractures.Failure to repair the pronator quadratus muscle can lead to a series of complications. OBJECTIVE:To explore the clinical efficacy of different methods of preserving the pronator quadratus muscle combined with a palmar steel plate in the treatment of distal radius fractures. METHODS:Clinical data of 66 patients with distal radius fractures were retrospectively included,divided into the traditional Henry approach group(group A),the split brachioradialis tendon approach group(group B),and the posterior pronator quadratus muscle approach group(group C),with 22 patients in each group.Postoperative internal fixation,fracture healing,and postoperative complications were observed in the three groups.The visual analog scale score of postoperative wrist pain and forearm rotation angle were compared among the three groups.The Dienst Joint Scale was used to evaluate the wrist function of patients. RESULTS AND CONCLUSION:(1)The surgical time,intraoperative blood loss,and fracture healing time of groups B and C were significantly lower than those of group A(P<0.01).There was no significant difference in intraoperative blood loss and fracture healing time between groups B and C,but the surgical time was shorter in group B.(2)The anteroposterior and lateral wrist X-ray examination 3 days and 1 and 3 months after surgery exhibited that there were no significant differences in radial height,palm angle,and ulnar deviation angle among the three groups(P>0.05).No significant difference was detected in various indicators during the same phase among the three groups(P>0.05).(3)At a follow-up of 12 months after surgery,there were no significant differences in visual analog scale scores and forearm rotation angle among the three groups.However,the evaluation results at 1 and 3 months after surgery demonstrated significant differences in visual analog scale scores and forearm rotation angle among the three groups(P<0.05).Among them,group C had a lower visual analog scale score and a larger forearm rotation angle.(4)According to the Dienst joint scoring standard,the excellent and good rate of wrist joint function evaluation was 86%(19/22),91%(20/22),and 95%(21/22)in groups A,B,and C,respectively 12 months after surgery.(5)All patients did not experience any postoperative vascular or neurological damage or surgical site infection.Group A had three cases of tendon irritation,two cases of traumatic arthritis,and two cases of carpal tunnel syndrome.In group B,tendon irritation occurred in 1 case and joint stiffness in 1 case.There was 1 case of traumatic arthritis and 1 case of carpal tunnel syndrome in group C.(6)It is suggested that different surgical methods for treating distal radius fractures have achieved good clinical results.Placing a steel plate under the pronator muscle can alleviate early postoperative pain,promote early activity,and restore normal life.The brachioradialis tendon approach has more advantages in exposing intraoperative fractures and can shorten the surgical time.

Surgical Treatment of Distal Radius Fractures Complicated by Concomitant Flexor Carpi Radialis Brevis: A Case Series and Surgical Techniques.

Introduction: The flexor carpi radialis brevis (FCRB) is a rare anatomical variation, with a reported prevalence ranging from 0.9% to 8.7%. Our previous report showed three cases of FCRB in distal radius fracture (DRF) and found that hypoplastic pronator quadratus (PQ) adjacent to the FCRB muscle made it difficult to cover a volar locking plate (VLP). As we subsequently experienced additional six FCRBs, we report on new findings and surgical tips. Case Report: VLP fixation was performed on DRF with FCRB in nine limbs of eight patients. The prevalence was 2.9% (9 of 310 limbs). Of the seven patients that underwent unilateral surgery, six were muscle type and one was tendon type. One patient who underwent bilateral surgery had a muscle type on the left and a tendon type on the right. In three muscle types, as the FCRB muscle belly was widely attached to the radial side of the radius and the radial side of the PQ was hypoplastic, postoperative covering of the plate by repair of the PQ was impossible. Then, in two of those cases, the PQ and FCRB were sutured and the plate was covered. FCRB muscle could be retracted to the radial side in all cases. One patient with a tendon type had a ruptured tendon, which was left unrepaired. All patients had no postoperative problems. Conclusion: In the muscle-type FCRB, the muscle should be retracted to the radial side for VLP fixation. The muscle belly might occupy the radial side of the radius, and the PQ might be hypoplastic and unrepairable. However, the plate can be covered by suturing the PQ and FCRB.

A New Repair Technique in Pronator Quadratus in Management of Distal Radius Fracture: Comparison with Primary Repair and Unrepaired Techniques.

Objective We aimed to compare the functional and clinical results between our new repair technique in the groups with and without pronator quadratus (PQ) repair in distal radius fractures treated with plate fixation using the volar approach. Methods The medical records of patients who underwent open reduction and volar plate fixation due to distal radius fracture between 2018 and 2020 were studied. In group A, PQ cannot be sutured or tension may occur, the intact radial fascia of the deep anterior fascia (DAF) was placed under the flexors toward the PQ and it was sutured with a 3-0 slow-absorbable monofilament suture to DAF. In group B, no repair was performed. In group C, PQ was sutured with traditional method. Range of motion (ROM) of wrist and handgrip strengths were measured at final examination. Pain was assessed with Visual Analogue Score (VAS), and functional status was evaluated with Quick - Disabilities of the Arm, Shoulder, and Hand (DASH). Complications which included tendinopathy, neuritis, tendon rupture due to plate irritation, implant failure, and malunion were also compared. Results Seventy-seven patients (group A, 21, group B, 24, group C, 32 patients) were included in the final follow-up examination who met our inclusion criteria. Among the clinical, functional, and radiological results such as ROM, VAS, DASH, grip strength, and complications in the all group at a mean postoperative of 16.6 months no significant difference was observed. Conclusion Although there was no significant difference between the groups in this study, we think that covering the plate may prevent long-term complications.

Evaluation of the treatment of distal radial volar fracture by different methods sparing the pronator quadratus.

OBJECTIVE: The traditional volar approach requires the release of the pronator quadratus (PQ) muscle in the treatment of distal radius fractures. However, intraoperative repair of the PQ muscle often fails due to tissue injury and unstable muscle repair. This study compared the outcomes of different methods of sparing the PQ muscle combined with the volar plate in treating distal radius fractures. METHODS: A total of 95 patients with distal radius fractures sparing the PQ muscle were enrolled with the brachioradialis (BR) splitting approach (group A, 33 people), the volar plating insertion PQ muscle approach (group B, 35 people) and traditional Henry approach without sparing PQ muscle (group C, 27 people). Postoperative internal fixation, fracture healing and postoperative complications were observed in the three groups. The visual analog scale (VAS) of postoperative wrist pain was compared between three groups. The Dienst joint scale was used to evaluate the wrist function of patients, and imaging indexes were used to evaluate the surgical efficacy. RESULTS: A total of 95 patients with distal radius fractures were followed up for more than one year after surgery. All fractures obtained good union, with no vascular injury, nerve injury or wound infection. Outcomes at three days, one month and three months all showed no significant differences in postoperative imaging indexes among three groups and no significant differences in various indexes among three groups during the same period. The mean operative time in group C was significantly lower than that in groups A and B. There was significant difference in the mean operation time between group A and group B. The amount of mean operative blood loss or mean bone union time in groups A and B was significantly lower than those in group C. No significant difference was shown in mean operative blood loss or mean bone union time between group A and group B. No significant differences in limb function scores, VAS scores and the mean range of motion existed among three groups at the 12-month postoperative follow-up. However, outcomes assessed one week, one month and three months after surgery demonstrated significant differences in the VAS scores and the mean range of motion among three groups, and the group B had lower VAS score and greater the mean range of motion. According to Dienst score, the excellent rate in groups A, B and C was 91.0% (30/33), 94.2% (33/35) and 85.2% (23/27), respectively, at 12 months after surgery. Tendon irritation occurred in 2 cases and joint stiffness in 1 case in group A. In group B, there were 2 cases traumatic arthritis and 2 cases delayed carpal tunnel syndrome and 1 case tendon irritation. In group C, tendon irritation and delayed carpal tunnel syndrome occurred, respectively, in 3 cases. CONCLUSION: Our results demonstrated that these two different surgical approaches were effective ways to reserve PQ and had good clinical outcomes. The volar plating insertion PQ muscle approach could reduce early postoperative pain, promote early activity and return to normal life, while the BR splitting approach was more advantageous in intraoperative fracture exposure and could shorten the operative time. However, some defects also existed. At 12 months of follow-up, no significant advantage was seen in sparing the PQ muscle. Therefore, surgeons should be aware of their individual characteristics and choose patients carefully.

Location of distal pronator quadratus repair in distal radius fractures: A cadaveric biomechanical study.

BACKGROUND: We aimed to biomechanically evaluate the distal pronator quadratus and compare two locations of distal transection on the strength of the subsequent repair. METHODS: Eighteen fresh-frozen cadaveric specimens were dissected to the pronator quadratus muscle. Specimens were randomly allocated for transection of the pronator quadratus at the myotendinous junction (red group) or parallel to the myotendinous junction at the midsection of the distal tendinous zone (white group). For both groups, repair of the muscle was performed using two figure-of-8 sutures. The radius and ulna were positioned in 90° of wrist extension. The proximal muscular pronator quadratus was fixed in a cryo-clamp. Load-to-failure testing of the repair was performed at 1 mm/s with maximum amount of force applied to the pronator quadratus recorded for each specimen. FINDINGS: The pronator quadratus had a mean width, height, and area of 31.41 ± 5.74 mm, 53.79 ± 7.46 mm, and 1604.27 ± 429.20 mm2 respectively. The pronator quadratus distal tendinous zone had a mean width, height, and area of 29.71 ± 5.83 mm, 12.22 ± 2.79 mm, 282.94 ± 148.30 mm2 respectively. There was no significant difference between the two groups for pronator quadratus height, width, total area, or tendinous zone height, width, or total area. The average load to failure for the white group was significantly higher than that of the red group (29.46 ± 4.24 N vs. 13.78 N ± 6.66 N). INTERPRETATION: Incision and repair of the pronator quadratus in the distal tendinous region is stronger than incision and repair at the red myotendinous junction of the distal PQ.

Pronator quadratus musculo-osseous free flap for wide hard palatal defect reconstruction: An anatomical study.

Wide hard palate defects include congenital and acquired defects that are six square centimeters or larger in size. Obturator prostheses and autologous soft tissue transfers have been used to reconstruct palatal defects. This study aims to repair wide, hard palatal defects by using a pronator quadratus musculo-osseous free flap to achieve subtotal reconstruction. Seventeen formalin-fixed cadavers were dissected. Free musculo-osseous pronator quadratus flaps were prepared after a 12 cm curvilinear volar skin incision. Standard 30 × 23 mm (690 ± 52.12 mm2) hard palate defects were made by chisels and saws. A subcutaneous tunnel was created between the mandibular edge cross point of the facial vessels and the retromolar trigone through the subcutaneous to the superficial musculoaponeurotic system by dissection. Area measurements of the pedicle and palate defects were performed by the ImageJ program (National Institutes of Health, Bethesda, MD, USA) on drawings over an acetate layer of materials. Mandibular distances of gonion-facial vessel cross point (a), gonion-gnathion (m), and facial vessels' cross point-retromolar entrance point (h) were measured. Ratios of h/m and a/m were calculated. The mean pronator quadratus area was 2349.39 ± 444.05 mm2, and the arterial pedicle pronator quadratus diameter was 2.32 ± 0.34 mm. The mean pedicle length of the pronator quadratus was 117.13 ± 8.10 mm. Study results showed that musculo-osseous pronator quadratus flaps' bone and muscle parts perfectly fit on the defects in all cadavers. Pronator quadratus musculo-osseous flap is a feasible surgical option for wide, hard palatal defect reconstruction strategies.

Does the pronator-sparing approach improve functional outcome, compared to a standard volar approach, in volar plating of distal radius fractures? A prospective, randomized controlled trial.

BACKGROUND: This study aimed to compare functional outcomes of a volar plate osteosynthesis for distal radius fractures (DRF) performed with either a standard volar approach (SVA), which required detachment of the pronator quadratus muscle, or a pronator-sparing approach (PqSA). MATERIALS AND METHODS: This prospective randomized controlled study included 106 patients scheduled for volar plate osteosyntheses. Patients were allocated to either the SVA group (n = 53) or the PqSA group (n = 53). Patients were blinded to treatment until completion of the study. The primary outcome measure was the Patient-Rated Wrist Evaluation (PRWE). Secondary outcome parameters were the Disabilities of the Arm, Shoulder, and Hand (DASH) score and the Modified Mayo Wrist Score (MMWS). Follow-up examinations were performed at 8 weeks and 3, 6, and 12 months postoperatively. RESULTS: Overall, 91 patients were included in the final analysis: 48 in the SVA group and 43 in the PqSA group. The two cohorts were not significantly different in demographic characteristics, including age, sex, injuries on the dominant side, type of injury, and fracture classification. We found significant differences between groups at 6 months in the mean PRWE (SVA: 12.3 ± 10.4, PqSA: 18.9 ± 14.11 points) and in the mean DASH score (SVA: 12.3 ± 11.9, PqSA: 19.3 ± 16.7 points), which favoured the SVA. We found no significant differences between groups in the MMWS or in the PRWE and DASH scores at any other time points. CONCLUSIONS: This randomized comparative clinical trial failed to demonstrate that a volar plate osteosynthesis performed with a PqSA could improve the outcome, compared to the SVA, in patients with DRF. LEVEL OF EVIDENCE: II Trial registration Comparison of Two Volar Plating Systems for Distal Radius Fractures, ClinicalTrials.gov (NCT03474445), registered 22 March 2018, retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03474445?cond=radius&cntry=AT&draw=2&rank=1.

Does pronator quadratus repair affect functional outcome following volar plate fixation of distal radius fractures? A systematic review and meta-analysis.

Introduction: The study aimed to evaluate the efficacy of pronator quadratus (PQ) repair versus no repair following volar plate fixation of distal radius fractures. Methods: A comprehensive search was performed in PubMed, CNKI, EMBASE, Web of Science, Ovid, and Cochrane Library databases. All randomized controlled trials comparing PQ repair with no repair in distal radius fractures before January 2023 were included. Two investigators independently screened eligible articles, assessed the study quality, and extracted data from included studies. Continuous variables used standardized mean difference and 95% confidence interval as efficacy statistics. The meta-analysis was performed using the Revman 5.4 software. Results: A total of 430 patients in 7 RCT studies were included in this meta-analysis, of which 218 underwent PQ repair, while 212 patients underwent no repair. The results of the meta-analysis displayed statistically significant differences in grip strength (short-term), pronation angle (short-term), and pronation strength (short- and long-term) between the two groups. No significant difference in other outcomes was found between the two treatment arms. Discussion: The repair of PQ may further increase grip strength and pronation function in the short-term and enhance long-term pronator muscle strength compared to no repair. However, due to the small number of articles included in the study, the above conclusions need to be verified by a larger sample and multi-center clinical study.

Dorsal dry needling to the pronator quadratus muscle is a safe and valid technique: A cadaveric study.

BACKGROUND: The pronator quadratus (PQ) muscle is an important stabilizer of the distal radio-ulnar joint and its pain referral pattern can mimic median or ulnar neuropathy. Research on treatment safety and efficacy with dry needling is scarce. OBJECTIVE: To determine if a solid filiform needle accurately and safely penetrates the PQ during simulated clinical application of dry needling. METHODS: A cadaveric descriptive study was conducted. Needling insertion of PQ was performed in 10 cryopreserved forearms with a 30*0.32 mm solid filiform needle. With the forearm pronated, the needle was inserted 3 cm proximal to the ulnar styloid in an anterior direction toward the muscle. The needle was advanced into the PQ based upon clinician judgment. Safety was assessed by calculating the distance from the needle to the surrounding neurovascular bundles. RESULTS: Accurate needle penetration of the PQ was observed in 90% of the cadavers (needle penetration: 19.8 ± 4.0 mm, 95%CI 17.0 to 22.6 mm). No neurovascular bundle was pierced during needling in any specimen forearms. The distance from the tip of the needle was 15.1 ± 4.8 mm (95%CI 11.7 to 18.5 mm) to the ulnar nerve, 15.6 ± 7.6 mm (95%CI 10.0 to 21 mm) to the ulnar artery, 11.2 ± 3.3 mm (95%CI 8.8 to 13.6 mm) to the median nerve, and 4.9 ± 1.4 mm (95%CI 3.9 to 5.9 mm) to the anterior interosseous neurovascular bundle. CONCLUSION: The results from this cadaveric study support the assumption that needling of the PQ by the dorsal aspect of the forearm can be accurately and safely conducted by an experienced clinician. Studies investigating the clinical safety and effectiveness of this interventions are needed.

Ultrasonographic appearance of the pronator quadratus muscle in high school baseball pitchers with and without elbow symptoms: a pilot study.

PURPOSE: Earlier reports have described forearm flexor muscles as active stabilizers of the elbow to valgus stress during throwing motion. The pronator quadratus (PQ) muscle acts in coordination with the pronator teres muscle for forearm pronation. This study of high school pitchers was conducted to assess the association between sonographic appearance and a history of elbow symptoms. METHODS: We examined 123 high school baseball pitchers, all of whom had completed a self-administered questionnaire, including items related to throwing-related elbow joint pain sustained during the prior year. Ultrasound examination was made of the pitchers with and without valgus stress of the medial aspect of the bilateral elbows. The sonographic appearance of the PQ was assessed on sagittal and axial images on the bilateral side. For participants with and without a history of elbow symptoms, we compared the maximum thickness of the PQ on sagittal and axial images of the throwing side. RESULTS: Regarding maximum thickness of the PQ on the sagittal and axial images, a significant difference was found between the throwing and non-throwing sides (throwing side vs non-throwing side mean: sagittal 6.3 mm vs 5.7 mm, axial 8.2 mm vs 7.5 mm, 95% confidence interval: sagittal 0.41-0.70, p < 0.001, axial 0.53-0.82, p < 0.001). The maximum thickness of the PQ on axial images with elbow symptoms was significantly greater than the PQ thickness of those without elbow symptoms. Nevertheless, no association was found between elbow valgus instability and the maximum thickness of the PQ on sagittal and axial images of the throwing side. CONCLUSION: Sonographic appearance of the PQ might be associated with elbow joint conditions in high school baseball players.

Clinical applications of internal fixation via the volar approach with pronator quadratus preservation for distal radius fractures.

BACKGROUND: The purpose of this study is to investigate the success rate of volar plate treatment of distal radius fractures with preservation of the pronator anterior muscle; the incidence of complications, such as infection, vascular nerve injury, and tendon injury; fracture healing rate; and changes in muscle anatomy. METHODS: The Henry approach was adopted to treat distal radius fractures with pronator quadratus (PQ) preservation on a trial basis. Between June 2015 and January 2017, 46 cases of distal radius fractures were considered according to the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification. The PQ was preserved, the distal margin was exposed, and a fracture reset was completed by pulling the muscles toward the near side. The K-wires were temporarily fixed, and the plate was placed by a plate channel. The mean operation duration was 52 min and the average blood loss was approximately 30 mL. There were no implant failures, adhesions requiring tenolysis, and tendon rupture. No patient developed carpal tunnel syndrome. All fractures healed without infection, radial artery injury, nerve damage, tendon rupture, and nonunion. A guider was applied to implant a screw under the muscle. RESULTS: In total, 46 patients with PQ preservation between ages 29 to 52 were performed distal radius fracture surgery. AO classification revealed that there were four cases of type A, seven cases of type B3, 10 cases of type C1, 13 cases of type C2, and 12 cases of type C3. For most fractures, such as Types A, B3, C1, C2, and C3, the fracture sites were located around the muscle distal margin. Thus, slight pulling of the muscles to the near side can reveal the fracture, and surgery with PQ preservation can be implemented. The postoperative muscle structures found during hardware removal procedures were similar to the muscle structures before the first operation. The radiographic outcome of fracture fixation was satisfactory. DISCUSSION: Surgery with PQ preservation is suitable for most distal radius fractures other than Types B1 and B2. For a small part of fractures involving the shaft of the radius, the PQ needed to be partially cut off to complete the operation. The postoperative muscle structures were close to normal.

Use of free radial forearm and pronator quadratus muscle flap: Anatomical study and clinical application.

The authors present an anatomical study and clinical experience with radial forearm flap (RFF) and pronator quadratus muscle (PQM) application in the reconstruction of various body areas. The aim was to describe the anatomical placement and proportions of the PQM, the anatomical location of the major arterial branch of the radial artery supplying the PQM, and the application of this knowledge in clinical practice. The anatomical study was based upon an analysis of 13 fresh adult cadaver upper extremities, of which nine were female and four male; both arms from the same donors were used in four cases. The study of the PQM was performed using a dye-containing intraarterial injection, standard macro- and micro-preparation techniques, and chemical digestion. The data on the PQM size in males and females, thickness of the radial artery branch (the principal artery nourishing the muscle), and its position were analysed. The radial artery branch nourishing the PQM was identified in all cadaveric specimens of the anatomical study. In addition, 12 patients underwent reconstructions of soft and bony tissue defects using a RFF + PQM (pedicled or free flap). The radial artery branch perfusing the PQM was identified in all cases. The flap was used for the management of defects of the head (seven cases), arm (three cases) and lower leg (two cases). The harvest site healed well in all cases and, with the exception of one case in which a partial necrosis of the flap was observed, all flaps remained viable, which demonstrated the safety of the method.

Calcific tendinopathy of the pronator quadratus muscle: A rare site and cause of ulnar sided wrist pain.

Ulnar -sided wrist pain is a common complaint and can present a diagnostic challenge for a musculoskeletal clinician. Calcific tendinopathy is a well-recognised disorder related to the deposition of calcium hydroxyapatite crystals within tendons. Classically, tendons around the shoulder and the hip joints are the most commonly affected sites. We report a rare site of calcific tendinopathy of the Pronator Quadratus muscle presenting with ulnar-sided wrist pain in a 36-year-old male posing a diagnostic dilemma. This case-report highlights the importance of a thorough clinical evaluation and crucial role of cross-sectional imaging in reaching a diagnosis of calcific tendinopathy of the Pronator Quadratus muscle as unusual cause of ulnar-sided wrist pain. This is the first reported case of calcific tendinopathy in pronator quadratus in the literature we could review.

[Transfer of the pronator quadratus to restore opposition of the thumb: An anatomic study and a clinical report]. / Étude anatomique sur le lambeau de carré pronateur pédiculé réinnervé pour réanimer l'opposition du pouce et application clinique.

OBJECTIVE: The purpose of this study is to explore the feasibility of reconstructing the APB with a pedicled PQ flap, and to report results in a child presenting with bilateral radial deficiency. METHODS: Twenty-one injected cadaver upper extremities were dissected. The muscle was pedicled distally on the transverse carpal artery, and reinnervated with the flexor digiti minimi (FDM) motor branch. The transfer was evaluated on 3 parameters: surgical feasibility, length of the distal pedicle and distance from the coaptation site to the muscle entry of recipient nerve. A bilateral PQ pedicled transfer was accomplished in a 17-month old child with bilateral radial deficiency. RESULTS: In the cadaver study, transfer of PQ to the APB was feasible and the distal end of the PQ transfer was reaching the radial side of the first metacarpophalangeal joint in all cases. The length of the distal pedicle on the transverse carpal artery was 38.5±0.20mm. The distance from coaptation of the FDM to the PQ muscle entry was 43.0±3.77mm. At 7 months, there was a cosmetic improvement of the thenar eminence, a bilateral M3 abduction of the thumb and a functional improvement from bilateral PQ pedicled transfer. CONCLUSIONS: Reconstruction of the APB may be achieved with a PQ pedicled transfer reinnervated, improving the function and the cosmetic aspect of the thenar eminence without sacrificing any function of the hand.

Evaluation of sparing the pronator quadratus for volar plating of distal radius fractures: a retrospective clinical study.

BACKGROUND: The most commonly used approach for distal radius fractures is the traditional Henry approach. However, it requires an intraoperative incision of the pronator quadratus (PQ) muscle, which results in a series of complications if the repair of the PQ fails. AIM: The objective of this study was to investigate the efficacy of sparing the pronator quadratus for volar plating of the distal radius fractures. METHODS: Seventy-six patients who suffered from distal radius fractures of types 23-B, 23-C1, and 23-C2 as per the AO Foundation and Orthopaedic Trauma Association (AO/OTA) classification were treated with volar locking plate fixation using either the PQ muscle incision and repair (group A, n = 39) or the PQ muscle preservation approach (group B, n = 37). Intraoperative index, postoperative efficacy and complications of patients were recorded and evaluated. RESULTS: All patients were followed up for more than one year after surgery. All fractures achieved union. There were significant differences in mean operative time, mean intraoperative blood loss, and mean fracture healing time between the two groups. Still, there were no significant differences in limb function scores between the two groups at the 12-month postoperative follow-up. Outcomes assessed at 1 week, 1 month, and 3 months after surgery demonstrated significant differences in the mean range of motion and pain-related visual analog scale (VAS) between the two groups. As the range of motion and grip strength increased, the VAS scores decreased, and there was no significant difference between the two groups at 12 months postoperatively. Although tendon irritation and delayed carpal tunnel syndrome were more common in group A than in group B (7.6% vs. 0% and 5.1% vs. 0%, respectively), the differences were not statistically significant. CONCLUSION: The modified Henry approach with sparing pronator quadratus muscle has no significant advantage in the range of wrist motion and upper limb function in the late stage. Nevertheless, the intraoperative placement of the plate under the pronator quadratus muscle can shorten the operation time, reduce intraoperative bleeding, reduce early postoperative pain, promote early activity, and improve the patient's quality of life. It is recommended that the pronator be preserved at the time of surgery.