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Research: M. Diab, J. M. Poston, P. Huber, and A. F. Tencer The biomechanical effect of radial shortening on the radiocapitellar articulation J Bone Joint Surg Br 2005; 87-B: 879-883 [Abstract] [Full text] [PDF]

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Response to Mr Smit and Professor Stanley from the authors

Mohammad Diab, Jason Poston, Philip Huber, and Alan Tencer   (5 October 2005)

Letter from Mr Smit and Professor Stanley

A. Adriaan Smit, Professor John K. Stanley   (16 September 2005)

Response to Mr Smit and Professor Stanley from the authors 5 October 2005
Mohammad Diab, Surgeon UCSF, Jason Poston, Philip Huber, and Alan Tencer Send letter to journal: Re: Response to Mr Smit and Professor Stanley from the authors diab{at}orthosurg.ucsf.edu Mohammad Diab, et al.	Sir, Only a long term clinical trial can answer the question raised Mr Smit and Professor Stanley. Our study is the first step toward investigating alternative treatments for a condition that has variable outcomes with current treatment methods. M. DIAB, MD J. M. POSTON, BS P. HUBER, BS A. F. TENCER, PhD University of California, San Francisco San Francisco, USA.
Letter from Mr Smit and Professor Stanley 16 September 2005
A. Adriaan Smit, Orthopaedic Clinical Fellow Wrightington Hospital, Professor John K. Stanley Send letter to journal: Re: Letter from Mr Smit and Professor Stanley adriaan{at}aatsmit.fsnet.co.uk A. Adriaan Smit, et al.	Sir, We read this article with interest. We note the decrease in radiocapitellar compressive forces by using a radial shortening osteotomy in a cadaver model. Of particular importance, however, are the long-term implications on forearm biomechanics in the clinical setting. The radius undergoes progressive shortening because of cartilage thinning of the radial head,1 which predisposes to ulnar positive variance, ulnar impaction syndrome and degenerative triangular fibrocartilage complex tears. This may result in ulnocarpal chondromalacia, lunotriquetral instability and ulnocarpal osteoarthritis.2 As the radius shortens, the triangular fibrocartilage complex fails to accommodate the increased repetitive axial loading of the ulnar head and undergoes central degeneration, rather than peripheral failure because of ligaments which can accommodate physiological shear forces. While 73% of ulnar positive and neutral variance wrists and only 17% of ulnar negative variance wrists have shown degenerative triangular fibrocartilage tears,3 Werner et al4 have shown that an acute change in ulnar or radial length will dramatically change the force transmission pattern. Cadaveric studies of normal forearms have suggested that 82% of compressive wrist forces are transferred across the radiocarpal joint and 18% at the ulnocarpal unit.3,5 At the elbow 60% of compressive forces are transferred across the radiocapitellar joint and 40% across the ulnohumeral joint.6 The centre of rotation does not change much with degeneration at the highly congruent ulnohumeral joint, but the radiocapitellar joint with a smaller contact surface area and higher axial load is prone to significant joint space loss and radial shortening, seen throughout the flexion arc.1 The clinical results of radial shortening osteotomy in radiocapitellar osteochondral lesions are as yet unknown. The evidence shows that time-related elbow and wrist changes do occur and may indeed be accelerated by a radial shortening osteotomy2,4 but these changes cannot be shown in a cadaver model where quantitative and time-related changes cannot be investigated. We are therefore hesitant to accept the recommendation of radial shortening osteotomy in the management of radiocapitellar osteochondral lesions. A. A. SMIT J. K. STANLEY Wrightington Hospital, Wigan, UK. 1. Sanderson PL, Cameron IC, Holt GR, Stanley D. Ulnar variance and age. J Hand Surg [Br] 1997;22:21-4. 2. Chun S, Palmer AK. Ulnar impaction syndrome: follow-up of ulnar shortening osteotomy. J Hand Surg [Am] 1993;18:46-53. 3. Palmer AK, Glisson RR, Werner FW. Relationship between ulnar variance and triangular fibrocartilage complex thickness. J Hand Surg [Am] 1984;5:681-3. 4. Werner FW, Palmer AK, Fortino MD, Short WH. Force transmission through the distal ulna: Effect of ulnar variance, lunate fossa angulation, and radial and palmar tlit of the distal radius. J Hand Surg [Am] 1992;3:423-8. 5. Palmer AK, Werner FW. Biomechanics of the distal radioulnar joint. Clin Orthp 1984;187:26-35. 6. Halls AA, Travil A. Transmission of pressures across the elbow joint. Anat Rec 1960;150:243-8.