Biomedical subjects

J-F Kempf

Publications and source records attributed to J-F Kempf.

7 recordsLinked to original sources

PubMed2005

[Transverse radioulnar branch of the dorsal ulnar nerve: anatomic description and arthroscopic implications from 45 cadaveric dissections].

PURPOSE OF THE STUDY: We conducted an anatomic study of the transverse branch of the dorsal ulnar nerve to describe its morphology and position in relation to arthroscopic exploration portals. MATERIAL AND METHODS: Forty-five non-side-matched anatomic specimens of unknown age and gender were preserved in formol. The dorsal branch of the ulnar nerve was identified and dissected proximally to distally in order to reveal the different terminal branches. The morphometric analysis included measurement of the length and diameter of the transverse branch and measurement of wrist width. We also measured the smallest distance between the transverse branch and the ulnar styloid process, and between the branch and usual arthroscopic portals (4-5, 6R, 6U) in the axis of the forearm. RESULTS: The transverse branch was inconstant. It was found in 12 of the 45 dissection specimens (27%). In two-thirds of the specimens, the branch ran over less than 50% of the wrist width, tangentially to the radiocarpal joint. Mean nerve diameter was 1 mm. It was found 5-6 mm from the ulnar styloid process and was distal to it in 83% of the specimens. The dissections demonstrated two anatomic variants. Type A corresponded to a branch running distally to the ulnar styloid process, parallel to the joint line (10/12 specimens). Type B exhibited a trajectory proximal to the ulnar styloid process, crossing the ulnar head (2/12 specimens). The relations with the arthroscopic portals (4-5, 6R, 6U) showed that the mean distance from the branch to the portal was 3.75 mm for the 4-5 portal (distally in 11/12 specimens), 3.68 mm for the 6R portal (distally in 10/12 specimens), and 4.83 mm for the 6U portal (distally in 7 specimens and proximally in 5). DISCUSSION: To our knowledge, there has been only one report specifically devoted to this transverse branch. Two other reports simply mention its existence. According to the literature, the transverse branch of the dorsal ulnar nerve occurs in 60-80% of the cases. We found two anatomic variations different than those described in the literature. Based on our findings and data reported previously, we propose a new classification, describing two main types. In Type 1, the transverse branch arises proximally to the ulnar styloid process;type 1A and type IB are described in relation to the direction of the branch. In Type II, the branch arises distally to the ulnar styloid process;type IIA and type IIB again being described in relation to the direction of the branch. On the tangential trajectory over the radiocarpal joint, the morphometric data show a zone of risk described by a rectangle measuring 10 mm wide (6 mm distal and 4 mm proximal to the ulnar styloid process) and covering 50% of the wrist width. The relations with arthroscopic portals describe a zone of risk corresponding to a 5-7 mm radius circle centered on the portals (4-5, 6R, 6U), which includes 83% of the transverse branches.

Arm↗

PubMed2005

[Arthroscopic repair of full-thickness cuff tears: a multicentric retrospective study of 576 cases with anatomical assessment].

PURPOSE OF THE STUDY: Totally arthroscopic repair of rotator cuff tears is now common practice. The techniques used were evaluated by a retrospective multicentric analysis conducted by the French Society of Arthroscopy. MATERIAL AND METHODS: The series was limited to arthroscopic repair of full thickness tears of the supraspinatus or infraspinatus evaluated using the Constant score and arthro-MRI or arthroscan performed with at least one year follow-up. Data were processed with SPSS 10. The series included 576 patients who underwent surgery between January 2001 and June 2003. Mean patient age was 57.7 years; 52% were men and 60% were manual laborers. The mean preoperative Constant score was 46.4 +/- 13.4/100. The tear was limited to the supraspinatus in 69% of shoulders, with extension to the upper third of the infraspinatus in 23.5% and the entire infraspinatus in 7.5%. The supraspinatus tear was distal in 41.7% of shoulders, intermediary in 44% and retracted in 14.3%. Fatty degeneration of the supraspinatus was noted grade 0 in 60%, 1 in 27%, 2 in 11% and 3 in 2%. Arthroscopic repair was performed in all cases, with locoregional anesthesia in 60.9%. Bioresorbable implants were used in 33% and metallic implants in 62.1%. Acromioplasty was performed in 92.7% and capsulotomy in 14.9%. RESULTS: On average, the subjective outcome was scored 8.89/10. The Constant score improved from 46.3 +/- 13.4 to 82.7 +/- 10.3 with 62% having a strictly pain free shoulder. Muscle force improved from 5.8 +/- 3.7 to 13.6 +/- 5.4. Outcome was excellent in 94% of shoulders at 18.5 months mean follow-up. The complication rate in this series was 6.2% with 3.1% prolonged stiffness, 2.7% reflex dystrophy, 0.2% infection, and 0.2% anchor migration. The cuff was considered normal in 55.7% of shoulders with an intratendon addition image in 19%, i.e. 74.7% of non-ruptured cuffs. Minimal loss of integrity was noted in 9.5% and was marked in 15.7%, i.e. 25.2% iterative tears.ANATOMOCLINICAL CORRELATIONS: The Constant score was strongly correlated with rotator cuff integrity (p<0001). This correlation was also found for force (p<0001), motion (0.01) and activity (0.04), but not for pain. The clinical outcome was correlated with extension, retraction, intrasubstance tear, and fatty degeneration of the lesion preoperatively. Anatomic results were statistically less favorable for tears which were older, extensive, retracted or associated with fatty degeneration. Age was correlated with extent of the initial tear and also with less favorable anatomic and clinical outcome. Occupational accidents were correlated with less favorable clinical outcome. CONCLUSION: Functional improvement after healing is a strong argument for repair. Arthroscopy has the advantage of combining a low complication rate with good clinical and anatomic results. Age is correlated with functional outcome and healing, but is not a contraindication.

English Abstract↗

PubMed2005

[Not Available].

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Journal Article↗

PubMed2005

[Not Available].

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Journal Article↗

PubMed2005

[Not Available].

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Journal Article↗

PubMed2004

[A new implant for proximal humeral fracture: experimental study of the basket plate].

PURPOSE OF THE STUDY: We conducted a comparative study of three ostheosynthesis systems for proximal humeral fractures. The conclusions led to the elaboration of a rigid extramedullary osteosynthesis implant. This novel implant allows specific fixation of the tuberosities via six adjustable and removable hooks organized like a basket. There are two versions, with and without a central cephalic locking screw. We report two static biomechanical studies conducted to analyze this material. MATERIAL AND METHODS: The two studies were performed on fresh frozen cadaver specimens with known bone density and with an experimental model of a four-fragment fracture of the proximal humerus. The first tests were designed to measure axial pressure reproducing the physiological movement applying the most stress on the head of the humerus. This allowed a global analysis of the mechanical behavior of the implant and an assessment of the contribution of the central cephalic locking screw. The second series of tests were traction tests used to analyze the behavior of the tuberosities fixed with the hooks. We assess the assemblies by measuring the mechanical resistance: rigidity of the fixation was recorded in mm/100N. Pre- and post-procedure x-rays and photographs were obtained to allow a subjective assessment of fragment displacement. RESULTS: The first series of tests demonstrated that the implant, with the central cephalic locking screw, presented good overall mechanical properties. The notion of better stability of the tuberosities obtained with the hooks, as seen during the first tests, was reinforced by the data from the second tests, although no statistically significant difference was demonstrated. We also noted that there was no statistically significant correlation between bone density and the slopes of the force-resistance curves. DISCUSSION: This prototype implant has an overall mechanical resistance equivalent to the reference implant, with at least equivalent performance. Proof of the usefulness of the central locking screw was not established, even though improved tolerance to loading by better force distribution seemed apparent. The contribution of the hook basket was not demonstrated. Data from the observations do however suggest the expectations of the implant will be fulfilled. Tests conducted on a larger scale would probably demonstrate a difference. It is clear that the small number of implants used here limited the study. Comparison with data in the literature show that this new prototype is adapted to the mechanics of the proximal humerus. Resistant to physiological stress, the implant allows pendular movement and passive physical therapy during the early post-operative period.

Biomechanical Phenomena↗

PubMed2003

[Arthroscopy-guided treatment of fractures of the distal radius: 16 wrists].

PURPOSE OF THE STUDY: We report our experience with arthroscopy-guided treatment of fractures of the distal radius. MATERIAL AND METHODS: Between November 2001 and June 2002, 16 patients (10 men, 6 women, mean age 51 years, age range 24-75 years) underwent arthroscopy-guided treatment of articular fractures of the distal radius. Patients were installed with the arm held in a horizontal position with a brace, the wrist under traction. The same procedure was used in all cases: introduction of the arthroscope, joint cleaning and shaving, search for lesions, arthroscopy-guided treatment. Kirschner 2-mm pins were used for fixation in all cases, combined with 1.2-mm pins in the event of ligament injury. RESULTS: Arthroscopic exploration revealed cartilage impaction in 25% of the wrists and ligament injuries in 30%. One fixation disassembled and was not remounted. There were two cases of reflex dystrophy. There were no arthroscopy-related complications. Bone healing was achieved in eight weeks in all cases. The mean DASH score was 22.5 at six months follow-up (range 3-10). DISCUSSION CONCLUSION: Arthroscopy-guided treatment of fractures of the distal radius was attempted for the first time in the early 90s. Per-operative arthroscopy enables a good view of the fracture and associated lesions (cartilage impaction, scapholunate, lunotriquetral ligament injury) and facilitates control of the reduction. Arthroscopy is technically simple and is the technique of choice due to the lack of morbidity. Several authors have reported their experience in more or less extensive series. Two notions should be emphasized. First, defective intra-articular reduction greater than 1 mm may lead to osteoarthritis of the wrist in 90% of the cases. Secondly, intra-operative imaging (fluoroscopy) does not provide sufficient precision to visualize a 1-mm stairstep in the articular surface, raising the risk of radiocarpal degeneration at mid term despite often satisfactory postoperative x-rays. We thus propose intra-operative arthroscopy to control the treatment of all articular wrist fractures, with or without displacement, in order to ensure satisfactory reduction with less than 1-mm defect in the articular surface and to search for and treat any associated bone or ligament injuries not diagnosed before surgery.

Adult↗