Improved nationwide survival of sarcoma patients with a network of reference centers.

BACKGROUND: We investigated the impact of the implementation of a network of reference centers for sarcomas (NETSARC) on the care and survival of sarcoma patients in France since 2010. PATIENTS AND METHODS: NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTBs), funded by the French National Cancer Institute (INCa) since 2010. Its aims are to improve the quality of diagnosis and care of sarcoma patients. Patients' characteristics, treatments, and outcomes are collected in a nationwide database. The objective of this analysis was to compare the survival of patients in three periods: 2010-2012 (non-exhaustive), 2013-2015, and 2016-2020. RESULTS: A total of 43 975 patients with sarcomas, gastrointestinal stromal tumors (GISTs), or connective tissue tumors of intermediate malignancy were included in the NETSARC+ database since 2010 (n = 9266 before 2013, n = 12 274 between 2013 and 2015, n = 22 435 in 2016-2020). Median age was 56 years, 50.5% were women, and 13.2% had metastasis at diagnosis. Overall survival was significantly superior in the period 2016-2020 versus 2013-2015 versus 2010-2012 for the entire population, for patients >18 years of age, and for both metastatic and non-metastatic patients in univariate and multivariate analyses (P < 0.0001). Over the three periods, we observed a significantly improved compliance to clinical practice guidelines (CPGs) nationwide: the proportion of patients biopsied before surgery increased from 62.9% to 72.6%; the percentage of patients presented to NETSARC MDTBs before first surgery increased from 31.7% to 44.4% (P < 0.0001). The proportion of patients with R0 resection on first surgery increased (from 36.1% to 46.6%), while R2 resection rate decreased (from 10.9% to 7.9%), with a better compliance and improvement in NETSARC centers. CONCLUSIONS: The implementation of the national reference network for sarcoma was associated with an improvement of overall survival and compliance to guidelines nationwide in sarcoma patients. Referral to expert networks for sarcoma patients should be encouraged, though a better compliance to CPGs can still be achieved.

Arthroscopic anatomy of the middle glenohumeral ligament. A series of 300 cases.

PURPOSE: The anatomy of the middle glenohumeral ligament (MGHL) is seldomly described during arthroscopy. The aim of this study was to determine the arthroscopic variants concerning the anatomy of the MGHL. METHODS: A prospective, observational, single-center study was conducted between June 2016 and June 2017. All patients undergoing a first-time arthroscopy of the shoulder and with no history of prior surgery or trauma of the same shoulder were consecutively enrolled. The variations of the MGHLs shape and of its glenoid and distal insertions were documented during surgery. RESULTS: A total 300 patients were included. Surgeries included rotator cuff sutures, tenotomy/tenodesis of the long head of the biceps tendon (LHBT) and subacromial decompression in respectively 31%, 32.7% and 35.5% of cases. The MGHL was absent in 12% of cases, presented a flat structure in 72% of cases, a cord-like shape in 14% and a Buford complex was observed in 1%. Its glenoid insertion was located on the labrum between the superior (SGHL) and inferior (IGHL) in 43% of cases, presented a combined insertion with the LHBT in 7%, with the SGHL in 29% and with both the SGHL and LHBT in 9%. The distal insertion was located in 67% of cases on the subscapularis tendon (SCCT) or the capsule covering it, and on the humeral bone in 21%. CONCLUSION: This study confirms and details the anatomic variants of the MGHL, notably describing the lesser-known variants of its distal insertion, yet arises the question of the exact nature and function of this so-called ligament.

Surgery in reference centers improves survival of sarcoma patients: a nationwide study.

BACKGROUND: NETSARC (netsarc.org) is a network of 26 sarcoma reference centers with specialized multidisciplinary tumor boards (MDTB) aiming to improve the outcome of sarcoma patients. Since 2010, presentation to an MDTB and expert pathological review are mandatory for sarcoma patients nationwide. In the present work, the impact of surgery in a reference center on the survival of sarcoma patients investigated using this national NETSARC registry. PATIENTS AND METHODS: Patients' characteristics and follow-up are prospectively collected and data monitored. Descriptive, uni- and multivariate analysis of prognostic factors were conducted in the entire series (N = 35 784) and in the subgroup of incident patient population (N = 29 497). RESULTS: Among the 35 784 patients, 155 different histological subtypes were reported. 4310 (11.6%) patients were metastatic at diagnosis. Previous cancer, previous radiotherapy, neurofibromatosis type 1 (NF1), and Li-Fraumeni syndrome were reported in 12.5%, 3.6%, 0.7%, and 0.1% of patients respectively. Among the 29 497 incident patients, 25 851 (87.6%) patients had surgical removal of the sarcoma, including 9949 (33.7%) operated in a NETSARC center. Location, grade, age, size, depth, histotypes, gender, NF1, and surgery outside a NETSARC center all correlated to overall survival (OS), local relapse free survival (LRFS), and event-free survival (EFS) in the incident patient population. NF1 history was one of the strongest adverse prognostic factors for LRFS, EFS, and OS. Presentation to an MDTB was associated with an improved LRFS and EFS, but was an adverse prognostic factor for OS if surgery was not carried out in a reference center. In multivariate analysis, surgery in a NETSARC center was positively correlated with LRFS, EFS, and OS [P < 0.001 for all, with a hazard ratio of 0.681 (95% CI 0.618-0.749) for OS]. CONCLUSION: This nationwide registry of sarcoma patients shows that surgical treatment in a reference center reduces the risk of relapse and death.

Upper limb joint kinetic analysis during tennis serve: Assessment of competitive level on efficiency and injury risks.

The aim of this work was to compare the joint kinetics and stroke production efficiency for the shoulder, elbow, and wrist during the serve between professionals and advanced tennis players and to discuss their potential relationship with given overuse injuries. Eleven professional and seven advanced tennis players were studied with an optoelectronic motion analysis system while performing serves. Normalized peak kinetic values of the shoulder, elbow, and wrist joints were calculated using inverse dynamics. To measure serve efficiency, all normalized peak kinetic values were divided by ball velocity. t-tests were used to determine significant differences between the resultant joint kinetics and efficiency values in both groups (advanced vs professional). Shoulder inferior force, shoulder anterior force, shoulder horizontal abduction torque, and elbow medial force were significantly higher in advanced players. Professional players were more efficient than advanced players, as they maximize ball velocity with lower joint kinetics. Since advanced players are subjected to higher joint kinetics, the results suggest that they appeared more susceptible to high risk of shoulder and elbow injuries than professionals, especially during the cocking and deceleration phases of the serve.

Sclerosing Epithelioid Fibrosarcoma (SEF) versus Low Grade Fibromyxoid Sarcoma (LGFMS): Presentation and outcome in the nationwide NETSARC+ series of 330 patients over 13 years.

Sclerosing Epithelioid Fibrosarcoma (SEF) and Low Grade Fibromyxoid Sarcoma (LGFMS) are ultrarare sarcomas sharing common translocations whose natural history are not well known. We report on the nationwide exhaustive series of 330 patients with SEF or LGFMS in NETSARC+ since 2010. PATIENTS AND METHODS: NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTB). Since 2010, (i) pathological review has been mandatory for sarcoma,and (ii) tumour/patients' characteristics have been collected in the NETSARC+ nationwide database. The characteristics of patients with SEF and LGFMS and their outcome are compared. RESULTS: 35/73 (48%) and 125/257(49%) of patients with SEF and LGFMS were female. More visceral, bone and trunk primary sites were observed in SEF (p < 0.001). 30% of SEF vs 4% of LGFMS patients had metastasis at diagnosis (p < 0.0001). Median size of the primary tumor was 51 mm (range 10-90) for LGFMS vs 80 (20-320) for SEF (p < 0.001). Median age for LGFMS patients was 12 years younger than that of SEF patients (43 [range 4-98] vs 55 [range 10-91], p < 0.001). Neoadjuvant treatment was more often given to SEF (16% vs 9%, p = 0.05). More patients with LGFMS were operated first in reference centers (51% vs 26%, p < 0.001). The R0 rate on the operative specimen was 41% in LGFMS vs 16% in SEF (p < 0.001). Median event-free survival (EFS) of patients with SEF and LGFMS were 32 vs 136 months (p < 0.0001). The median overall survival (OS) was not reached. Fifty-months OS was 93% vs 81% for LGFMS vs SEF (p = 0.05). Median OS was 77 months after first relapse, similar for SEF and LGFMS. In multivariate analysis, age, tumor size, metastasis at diagnosis were independent prognostic factors for OS in LGFMS. CONCLUSIONS: Although sharing close molecular alterations, SEF and LGFMS have a different natural history, clinical presentation and outcome, with a higher risk of metastatic relapse in SEF. Survival after relapse is longer than with other sarcomas, and similar for SEF and LGFMS.

Epithelioid hemangio-endothelioma (EHE) in NETSARC: The nationwide series of 267 patients over 12 years.

EPITHELIOID HEMANGIOENDOTHELIOMA: A NATIONWIDE STUDY: Epithelioid hemangioendothelioma (EHE) is an ultrarare sarcoma whose natural history and treatment is not well defined. We report on the presentation and outcome of 267 patients with EHE in the NETSARC+ network since 2010 in France. PATIENTS AND METHODS: NETSARC (netsarc.org) is a network of 26 reference sarcoma centres with specialised multidisciplinary tumour boards (MDTB), funded by the French National Cancer Institute (NCI), Institut National du Cancer (INCA). Since 2010, presentation to an MDTB and second pathological review are mandatory for sarcoma patients. Patients' characteristics are collected in a nationwide database regularly monitored with stable incidence since 2013. The characteristics of patients with EHE at diagnosis are presented as well as progression-free survival (PFS), overall survival (OS), and outcome under treatment. RESULTS: Two hundred and sixty-seven patients with EHE were included in the NETSARC+ database since 2010. Median age in the series was 51 (range 10-90) years, 58% were women. Median tumour size was 37 mm (4-220). Forty-eight percent, 42%, and 10% were visceral, soft parts, or bone primaries. The most frequent sites were liver (28%), lung (13%). 40% were reported to have systemic (i.e. multifocal or metastatic disease) at diagnosis. With a median follow-up of 20 months, OS and PFS rates at 24 months were 82% and 67%, with 10-year projected OS and PFS of 62% and 21% respectively. Male and M+ patients at diagnosis had a significantly worse OS, but not PFS. Local treatment was associated with a favourable survival in localised but not in patients with advanced stage at diagnosis. For 23 patients receiving medical treatment, PFS and OS were 50.2% and 33.2% at 60 months were respectively. CONCLUSIONS: EHE is a frequently metastatic sarcoma at diagnosis with a unique natural history. This study shows in a nationwide series over 12 years that most patients progressed but are still alive at 10 years, both in localised and metastatic stages.

Parosteal osteosarcoma of the thumb: A case report and literature review.

Parosteal osteosarcoma (PO) is a rare malignant tumor arising from the surface of the bone. Locations in the hand are even more exceptional. This low-grade osteosarcoma shows non-specific clinical and radiological presentation, making diagnosis challenging. Moreover, histologic examination is extremely difficult and can easily lead to misdiagnosis. We report the case of a 21-year-old woman who presented PO of the right thumb, initially diagnosed as a "benign exostosis" 9 years previously. En-bloc resection followed by reconstruction using a free corticocancellous iliac crest autograft provided good esthetic and functional outcome. No recurrence occurred at 2 years' follow-up. Our literature review confirmed the rarity of PO of the hand, with only 8 cases reported in the past 60 years. Amputation was the main treatment, but some authors reported limb-sparing surgery. The present result and those in the literature review support conservative surgery when feasible, with little recurrence and better functional and esthetic results. These rare tumors should not be misdiagnosed, and should be treated in specialized centers to optimize outcome.

[Analytic study of hopes and perceptions of second-year medical school students during gross anatomy laboratory cessions]. / Enquête sur les attentes et appréhensions des étudiants de deuxième année de médecine au cours des séances de dissections.

INTRODUCTION: Using an anonymous questionnaire, this study aimed to assess hopes and perceptions of second-year medical school students faced to gross anatomy dissections and to appreciate the status of dissection within the others anatomical teaching tools. MATERIALS AND METHODS: The questionnaire was distributed among 210 second-year medical students during gross anatomy dissections. The first part of the questionnaire aimed to assess perceptions of students before dissections while the second part aimed to position dissection in their anatomical teaching cursus. RESULTS: Within the 210 students participating to the study, 70 (45%) had not seen a dead human body before the laboratory cession. The main stressful factors were technical difficulties encountered during dissection more than embarrassment in front of the cadaver. The level of stress was significantly higher in female students. Hand, neck and gluteal regions were the most stressful regions reported by students. Students considered that gross anatomy dissection was a key ritual experience crucial for their formation that should not be only proposed to senior practitioners. CONCLUSION: This study illustrates the invariable interest of medical students for gross anatomy laboratory cessions that permit a first technical experience, faced to the death.

Three concomitant locked finger metacarpophalangeal joints caused by degenerative metacarpal heads: Case report.

A locked metacarpophalangeal joint (LMCP) is a rare condition often confused with trigger finger. Its causes are numerous and typically divided into two broad categories: acquired LMCP in younger patients, and degenerative LMCP in older patients. This pathology usually affects only one MCP. Even though several external reduction techniques have been described, the main risk of non-surgical reduction treatment is recurrence. Thus, its management is most often surgical. We report the case of a 60-year-old woman with 3 simultaneous LMCP (3rd, 4th, and 5th rays of the left hand) due to degenerative metacarpal heads. Surgical treatment was performed and found that locking was due to entrapment of the radial collateral ligament on metacarpal head osteophytes. Full extension was regained at the end of the surgery. The follow-up was uneventful, no recurrence occurred. This case highlights the need for careful examination to prevent medical and surgical wandering for a rare but well-described and easy to treat condition.

[Pertrochanteric fractures in elderly subjects aged over 75]. / Les fractures du massif trochantérien chez les sujets âgés de plus de 75 ans.

Pertrochanteric fractures constitute a major public health concern. This retrospective multicentric study evaluated outcome after treatment in patients aged over 75 years hospitalized for pertrochanteric fractures over a one year period (May 2004-May 2005). Five University Hospitals in the cities of Angers, Brest, Rennes, Tours, Nantes participated in this evaluation. The quality of the reduction and the position of the osteosynthesis were the two main criteria for good outcome. The type of material implanted had little effect on outcome. The results emphasized the importance of preventing osteoporosis. Fracture prevention and treatment of osteoporosis are crucial, even after fracture.

[Aneurysmal bone cysts of the metacarpals and phalanges of the hand. A 6 case series and literature review]. / Kystes anévrismaux des phalanges et des métacarpiens. A propos de six cas et revue de la littérature.

Aneurysmal bone cysts arising from tubular bones of the hand occur very rarely and require particular diagnostic and therapeutic management techniques. The authors report the diagnostic and surgical management of a monocentric case series of six aneurysmal bone cysts involving the phalangeal and metacarpal bones. In addition to hightlighting the use of diagnostic MRI and biopsy prior to surgical intervention, the authors describe the favourable outcome of curetage with and without the use of bone graft. An aggressive treatment approach such as cryotherapy or resection with reconstruction should only be used in cases when the articular surface is involved, when full bone invasion of the phalanx or metacarpal has occurred, or in case of more than one recurrence.

Clavicle fractures.

Management of clavicle fracture has progressed over the last decade, notably with wider use of surgery in midshaft fracture, and new techniques for lateral fracture. Midshaft clavicle fracture treatment needs to be personalized and adapted to the patient's activity level. Whichever the segment involved, treatment for non-displaced fracture is functional; elbow-to-body sling immobilization seems the best tolerated. Apart from regular surgical indications (shoulder impaction, floating shoulder, open fracture or fracture with neurovascular complications), surgery is recommended in case of bone shortening exceeding 1.5cm in young active patients. The technique needs to take account of clavicle anatomy: notably periosteal vascularization in midshaft fracture and acromioclavicular ligament integrity and location in case of lateral fracture. Plate osteosynthesis should take account of bone diameter and 3D curvature; intramedullary fixation should take account of intramedullary canal morphology. Although iatrogenic vascular complications are rare, vessel relations and variants need to be known, especially in the medial end of the clavicle and midshaft. Lateral segment fractures are a particular entity. Large-scale randomized studies are needed to assess indications and results for the various possible internal fixation techniques: isolated or associated to ligament reconstruction, rigid or flexible, and open or arthroscopic.

A new approach for endoscopic neurolysis of the suprascapular nerve at the spinoglenoid notch: A preliminary cadaver study.

The suprascapular nerve (SSN) can become compressed at its 2 scapular attachments: the suprascapular and the spinoglenoid notch. The objective of this study was to describe a new arthroscopic approach for SSN neurolysis at the spinoglenoid notch. Ten cadaver shoulders were used. Two were dissected to simulate the "classical" arthroscopic approach and to help in the creation of a new "direct medial retrospinal" approach. Eight other shoulders were used to validate this new approach, with control of the whole juxta-glenoid course of the SSN as criterion of success. The retrospinal posterior approach allowed the entire juxta-glenoid segment of the SSN to be explored in 6 cases out of 8. One exploration was incomplete, another not feasible. SSN neurolysis at the spinoglenoid notch was feasible in cadavers on a retrospinal approach.

Antibiotic cements in articular prostheses: current orthopaedic concepts.

The possibilities and limits of antibiotic cements (ACs) have been assessed by many researchers. ACs are now approved by many drug agencies, including the US Food and Drug Administration (approval in 2003), with widespread use in prophylaxis and curative treatments. Laboratory experiments have achieved satisfactory antibiotic delivery without impairing the mechanical properties of ACs. Implantation in large animals (e.g. sheep) showed an antibiotic concentration in the bone cortex four times the minimal inhibitory concentration (MIC) 6 months after implantation. Human pharmacokinetics during total hip replacement (THR) show antibiotic concentrations 20 times the MIC in drainage fluids. No toxic concentrations have been detected in blood or urine, and no allergies, toxic effects, mechanical failures or selection of resistant microorganisms have been observed. Antibioprophylaxis has been assessed in prospective studies in over 1600 cases. In data from the Scandinavian arthroplasty registers, with an exhaustive follow-up of more than 240000 THRs, infection rate was reduced by ca. 50% (0.9% compared with 1.9%). In prostheses with severe infection, use of AC increases the infection control rate from 86% to 93% when using two-stage prosthetic exchanges. In moderate infection, a similar infection control rate (86%) was achieved either by two-stage exchange without local antibiotic or by one-stage exchange with AC; however, one-stage exchange achieved better functional results at lower cost and with reduced pain and hospital stay. Therefore, AC prophylaxis is widely used in countries with prostheses registers (Northern Europe), and use of ACs as treatment for infected prostheses is often considered as the gold standard in the EU and North America. However, AC is only an adjuvant treatment, and excision of infected and devascularized tissues as well as systemic antibiotic treatment managed by a multidisciplinary team remain the main factors of infection control.

The long-term results of press-fit cemented stems in total knee prostheses.

We evaluated the long-term fixation of 64 press-fit cemented stems of constrained total knee prostheses in 32 young patients with primary malignant bone tumours. Initial stable fixation, especially in rotation, was achieved by precise fit of the stem into the reamed endosteum, before cementation. Complementary fixation, especially in migration and rotation, was obtained by pressurised antibiotic-loaded cement. The mean age at operation was 33 years (13 to 61). No patient was lost to follow-up; 13 patients died and the 19 survivors were examined at a mean follow-up of 12.5 years (4 to 21). Standard revision press-fit cemented stems were used on the side of the joint which was not involved with tumour (26 tibial and six femoral), on this side there was no loosening or osteolysis and stem survival was 100%. On the reconstruction side, custom-made press-fit stems were used and the survival rate, with any cause for revision as an end point, was 88%, but 97% for loosening or osteolysis. This longevity is similar to that achieved at 20 years with the Charnley-Kerboull primary total hip replacement with press-fit cemented femoral components. We recommend this type of fixation when extensive reconstruction of the knee is required. It may also be suitable for older patients requiring revision of a total knee replacement or in difficult situations such as severe deformity and complex articular fractures.

Long-term results of tendon transfers in radial and posterior interosseous nerve paralysis.

Eighteen cases of tendon transfer for isolated radial or posterior interosseous nerve palsy have been carried out in our unit over a period of 21 years. Fifteen patients were reviewed with a mean follow-up of 9.5 years. Nine had sustained high and six low radial nerve injury. We achieved 11 excellent, two good, one fair and one bad result. The main problems were loss of power of gripping and the occurrence of radial deviation, particularly in patients with flexor carpi ulnaris transfer to the extensor digitorum communis. During this time, our technique has evolved, including changes of the tendons transferred. Our final preference is a modified Tsuge procedure, using the pronator teres to restore extension of the wrist, the flexor carpi radialis for extension of the fingers and the palmaris longus for extension of the thumb. Abduction of the thumb is restored by a tenodesis of the abductor pollicis longus to the brachioradialis. This review justifies the final policy, in particular the preservation of flexor carpi ulnaris to maintain wrist stability and flexion.

Are ligament-tensioning devices interchangeable? A study of femoral rotation.

BACKGROUND: During total knee arthroplasty (TKA), femoral rotation can be adjusted either in relation to bony landmarks or by tensioning the ligaments with the knee in 90° of flexion. The primary objective of this study was to compare femoral rotations achieved using various ligament-tensioning devices. The secondary objective was to compare these femoral rotations to that indicated by the transepicondylar axis (TEA). MATERIAL AND METHODS: We performed 13 posterior-stabilised TKA procedures using HiFit (Ceraver(®)) on cadaver knees. Before performing the posterior condyle cut, we used an original method to measure the femoral rotation induced by five different ligament-tensioning devices (2 with a ratchet mechanism, 1 with screws, 1 force-sensing device, and 1 with spacer blocks) and the central tibio-femoral distance (CTFD). RESULTS: Both ratchet tensioners provided significantly greater mean external rotation values (P=0.002), of 4.94° and 4.46°, respectively, compared to the force-sensing and spacer tensioners. Significant differences were found across devices for CTFD, with a mean difference of about 2mm between the ratchet and screw tensioners versus the force-sensing and spacer tensioners. The mean differences in rotations obtained using the tensioners versus the TEA were close to 0° but with standard deviations greater than 4°. CONCLUSION: Femoral rotation was dependent on the distraction force applied to the joint. Tensioners that did not measure the distraction force were associated with greater distraction force and external rotation values. The TEA criterion did not reliably indicate good ligament balance. LEVEL OF EVIDENCE: Experimental study.

Anatomical and morphological study of the subcoracoacromial canal.

INTRODUCTION: Many clinical anatomy studies have looked into how variations in the acromion, coracoacromial ligament (CAL) and subacromial space are associated with rotator cuff injuries. However, no study up to now had defined anatomically the fibro-osseous canal that confines the supraspinatus muscle in the subcoracoacromial space. Through an anatomical study of the scapula, we defined the bone-related parameters of this canal and its anatomical variations. MATERIALS AND METHODS: This study on dry bones involved 71 scapulas. With standardised photographs in two orthogonal views (superior and lateral), the surface area of the subcoracoacromial canal and the anatomical parameters making up this canal were defined and measured using image analysis software. The primary analysis evaluated the anatomical parameters of the canal as a function of three canal surface area groups; the secondary analysis looked into how variations in the canal surface area were related to the type of acromion according to the Bigliani classification. RESULTS: Relative to glenoid width, the group with a large canal surface area (L) had significantly less lateral overhang of the acromion than the group with a small canal surface area (S), with ratios of 0.41±0.23 and 0.58±0.3, respectively (P=0.04). The mean length of the CAL was 46±8mm in the L group and 39±9mm in the S group (P=0.003). The coracoacromial arch angle was 38°±11° in the L group and 34°±9° in the S group; the canal surface area was smaller in specimens with a smaller coracoacromial arch angle (P=0.20). CONCLUSION: Apart from acromial morphology, there could be innate anatomical features of the scapula that predispose people to extrinsic lesions to the supraspinatus tendon (lateral overhang, coracoacromial arch angle) by reducing the subcoracoacromial canal's surface area. LEVEL OF EVIDENCE: Anatomical descriptive study.

Occurrence and role of phosphoenolpyruvate carboxykinase in procyclic Trypanosoma brucei brucei glycosomes.

Phosphoenolpyruvate carboxykinase (EC 4.1.1.32) was detected in a particulate fraction of Trypanosoma brucei brucei procyclic culture form. It requires ADP rather than GDP for activity in the direction of carboxylation and is located in the glycosomes. Since phosphoenolpyruvate can serve to furnish ATP for glycolysis and can promote 3-phosphoglycerate or 1,3-bisphosphoglycerate formation without simultaneous alpha-glycerophosphate production, we suggest that the glycosomal phosphoenolpyruvate carboxykinase-malate dehydrogenase tandem contributes to ATP regeneration and NADH re-oxidation in the glycosome, and regulates alpha-glycerophosphate production.