Richard D. Lawson

Classification of Congenital Anomalies of the Hand and Upper Limb: Development and Assessment of a New System

The Oberg, Manske, and Tonkin (OMT) classification of congenital hand and upper limb anomalies was proposed in 2010 as a replacement for the Swanson International Federation of Societies for Surgery of the Hand classification system, which has been the accepted system of classification for the international surgical community since 1976. The OMT system separates malformations from deformations and dysplasias. Malformations are subdivided according to the axis of formation and differentiation that is primarily affected and whether the anomalies involve the whole limb or the hand plate. This review outlines the development of classification systems and explores the difficulty of incorporating our current knowledge of limb embryogenesis at a molecular level into current systems. An assessment of the efficacy of the OMT classification demonstrates acceptable inter- and intraobserver reliability. A prospective review of 101 patients confirms that all diagnoses could be classified within the OMT system. Consensus expert opinion allowed classification of those conditions for which there is not a clear understanding of the mechanism of dysmorphology. A refined and expanded OMT classification is presented.

Etiology of cerebral palsy

Cerebral palsy has a complex and multifactorial etiology. Approximately 5%-10% of cases can be ascribed to perinatal hypoxia, but the vast majority of cases are caused by the interplay of several risk factors and antenatal, perinatal, and neonatal events. The strongest risk factors include prematurity and low birth weight. The prevalence of cerebral palsy has remained constant despite improvements in obstetric and neonatal care. For a long time, the only causal factors explored to account for risk for cerebral palsy were complications of labor and delivery. As other periods have been investigated, new associations have come to light. The current understanding of contributors to the risk for cerebral palsy is still incomplete. Multiple causes may interact by way of excitotoxic, oxidative, or other converging pathophysiologic pathways. A single factor, unless present to an overwhelming degree, often may be insufficient to produce cerebral damage, whereas two or three interacting pathogenic assaults may overwhelm natural defenses and produce irreversible brain injury. The low prevalence of cerebral palsy makes the formal testing of preventative strategies difficult. There is a need for such strategies to be carefully assessed in well designed, multicenter, randomized, controlled trials before becoming part of clinical practice, however, so that the balance between harm and benefit is known in advance.

Factors affecting surgical results of Wassel type IV thumb duplications.

The aim of this study is to review the outcomes of Wassel type IV thumb duplications with a minimum of one year follow-up, and to identify any factors that may compromise the quality of results. Forty one patients (42 thumbs) returned for assessment of thumb alignment, metacarpophalangeal joint and interphalangeal joint stability and motion; carpometacarpal joint motion; pinch and grip strengths; and thumb size. The subjective assessment considered thumb shape and contour, scarring, nail deformity and examiner and patient/parent satisfaction. The mean age at surgery was 16 months and the mean follow-up time was 79 months. Metacarpophalangeal joint and interphalangeal joint mal-alignment was present in 56% and 38% of cases, respectively. Interphalangeal ulnar collateral ligament laxity was significant. Metacarpophalangeal joint and interphalangeal joint motion was significantly decreased. Pinch and grip strength measurements were normal. A novel and comprehensive assessment scale is introduced, which revealed results of one (2.5%) excellent, 23 (59%) good, 14 (36%) fair and one (2.5%) poor. We consider that greater attention should be directed to the avoidance of mal-alignment and instability to improve these results.

Effect of Partial Versus Complete Circumferential Repair on Flexor Tendon Strength in Cadavers

PURPOSE This study investigated the strength of epitendinous repairs covering the palmar half of the tendon circumference only. METHODS Two hundred porcine tendons were harvested from pig feet and separated into 2 equal groups. Group 1 tendons were sutured with a 2-strand core repair and group 2 tendons were sutured with a 4-strand core repair. Each group was then divided into 5 equal subgroups (n=20). Four of the subgroups were sutured with 1 of the following epitendinous repairs: 50% simple running (50SR), complete simple running (100SR), 50% Silfverskiold (50SK), or complete Silfverskiold (100SK). One sub-group (0C) had no epitendinous repair. The core suture material was 3-0 braided polyester (Tricon; Tyco Healthcare, Dominican Republic), and the circumferential suture material was 6-0 polypropylene (Prolene, Sumerville, NJ). The tendons were mechanically strained to failure, and force data were recorded. RESULTS The 50SR and 50SK repairs significantly increased the force at 1-mm and 2-mm gap formation of both core repairs. The 50SR and 50SK repairs increased the ultimate force at failure of both core repairs by approximately 20%. Both 50% circumferential (50C) repairs increased repair strength at the points of initial gap formation more than at the point of ultimate force. The 50C repairs were approximately 50% as strong as the 100% circumferential (100C) repairs at 1-mm and 2-mm gap formation and approximately 70% as strong at the ultimate force of failure. CONCLUSIONS The 50C repairs increased the tensile strength of 2-strand and 4-strand tendon repairs in vitro. The prevention of early gapping was more significant than the increase of strength at failure.

Surgical management of the thumb in cerebral palsy.

Surgical treatment of the thumb in cerebral palsy is complex and treatment must be directed toward the specific deformities. Thumb-in-palm deformity can be treated successfully in patients with spastic CP, but caution is required in patients with other varieties of CP. The main deforming force is contracture and spasticity of the intrinsic thumb muscles. Treatment involves release of the deforming muscles and other soft tissue, augmentation of opposing muscles, and stabilization of appropriate joints.

Management of flexor tendon injuries - Part 2: current practice in Australia and guidelines for training young surgeons.

INTRODUCTION This study aims to gain a better understanding of current practice for the surgical management and rehabilitation of flexor tendon injuries in Australia, with the intent of establishing common guidelines for training of young surgeons. METHODS A survey was distributed to the membership of the Australian Hand Surgery Society to determine whether a consensus could be obtained for: suture material and gauge; core and epitenon suture techniques; sheath and pulley management; and post-operative protocols for primary flexor tendon repair. RESULTS The predominant materials used for core suture are Ticron™ Suture (Tyco Healthcare Group LP, Norwalk, Connecticut, USA) (34%) and Ethibond™ Polyester Suture (Ethicon, Somerville, New Jersey, USA) (24%). The two core suture configurations commonly used are the Adelaide (45%) and Kessler (32%) repair. The predominant materials used for epitendinous sutures are 6-0 Prolene™ Polypropylene Suture (Ethicon, Somerville, New Jersey, USA) (56%), 5-0 Prolene™ (21%) and 6-0 Ethilon™ Nylon Suture (Ethicon, Somerville, New Jersey, USA) (13%); and the majority (63%) use a running epitendinous technique. The management of critical pulleys is variable, with 89% prepared to perform some release of A2 and A4 pulleys. Rehabilitation protocols vary widely, with 24% of respondents using the same method for all patients, while 76% tailor their approach to each patient. Some component of active motion was used by most. DISCUSSION There exists some consensus on the management of flexor tendon injuries in Australia. However, the management of critical pulleys and methods of post-operative rehabilitation remain varied. For the training of young surgeons, a majority advise a 3-0 gauge braided polyester core suture of four strands, combined with a 6-0 Prolene™ simple running epitendinous suture for increased tendon repair strength and smooth glide. Trainees should attempt to retain the integrity of the A2 and A4 pulleys. Post-operative rehabilitation should include a component of active flexion.

KELOID FORMATION RESULTING IN ACQUIRED SYNDACTYLY OF AN INITIALLY NORMAL WEB SPACE FOLLOWING SYNDACTYLY RELEASE OF AN ADJACENT WEB SPACE

We present a case of acquired syndactyly secondary to keloid formation in a previously normal web space following release of syndactyly in the adjacent web space.

Stability of the Basal Joints of the New Thumb After Pollicization for Thumb Hypoplasia

PURPOSE To investigate the presence or absence of union of the new trapezium to the retained metacarpal base after pollicization and to relate this to stability of the new trapezium and the new carpometacarpal joint. METHODS Thirty-six patients (46 pollicizations) were assessed at clinical review. Mean time from surgery to review was 96 months (range, 9-260 mo). Clinical assessment measured range of motion (ROM) at the carpometacarpal joint, stability of the carpometacarpal joint, and extrinsic and intrinsic strength of both hands. Radiological review evaluated 3 parameters: bony union between the new trapezium and retained metacarpal base, stability of the new trapezium in relationship to the metacarpal base, and carpometacarpal joint stability. RESULTS There was radiographic nonunion between the new trapezium and the retained metacarpal base in 8 (1 treated) of 46 pollicizations. Relative risk of instability of the new trapezium was 39 times more likely if nonunion was present. Nine pollicizations were unstable at the carpometacarpal joint, 8 in those with union and 1 with nonunion. Relative risk of instability was 1.4 times more likely for those with union. For patients with nonunion, ROM and grip strength variables were reduced but only grip strength reached statistical significance. In patients with carpometacarpal joint instability, ROM and grip strength variables were reduced but none of the variables reached statistical significance. CONCLUSIONS This study suggests that when the surgeon is attempting to obtain union of the new trapezium to the retained metacarpal base, failure to do so results in a poorer thumb with a significantly increased risk of trapezial instability and decreased grip strength. There is a mildly increased risk of carpometacarpal joint instability with union, but significantly poorer function as a consequence of this has not been demonstrated. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

Flexor digitorum profundus avulsion injuries in Oztag players.

MJA 198 (4) · 4 March 2013 196 Flexor digitorum profundus avulsion injuries in Oztag players TO THE EDITOR: Tag rugby, known in Australia as Oztag,1 is a popular low-contact version of rugby league in which an opponent is “tackled” by pulling a velcro tag off his or her shorts. The sport has over 40 000 participants in Australia1 and is perceived to pose a low risk of serious injury. However, hand injuries occur with some frequency2,3 and are often neglected. In particular, avulsion of the flexor digitorum profundus (FDP) insertion from the base of the terminal phalanx — commonly known as rugger jersey finger — may masquerade as a simple “sprain”. Failure to make the correct diagnosis early can result in serious impairment of function of the affected finger.4 Diagnosis is based on history, an examination demonstrating loss of active flexion of the distal interphalangeal joint of the affected finger, and a radiograph to assess for avulsion fractures. Ultrasound scanning can assist diagnosis in difficult cases. From a retrospective chart review, we found that eight patients with Oztag-related FDP avulsion injuries presented to our tertiary referral hand centre over 2 years. Five patients who presented within 10 days of injury each had a primary repair with satisfactory results. The other three patients were seen 4 weeks or more after the injury. One patient seen at 4 weeks opted against a two-stage reconstruction and had excision of a painful FDP stump from the palm, with permanent loss of active distal interphalangeal joint flexion but relief of pain. The remaining two patients, seen at 6 and 8 weeks after injury, had two-stage flexor tendon reconstructions. Early diagnosis is vital with this injury, as patients presenting late may lose the chance to have a simple primary repair. By 7–10 days after injury, unopposed muscle contraction leads to proximal retraction of the tendon stump; the pulley system tends to collapse and the sheath fills with granulation tissue. At this point, advancing the tendon is difficult or impossible, and reinsertion of the stump may result in a persistent flexion contracture; thus, reconstruction of the flexor tendon with primary or twostage grafting may be offered. Twostage grafting requires removal of the damaged FDP tendon and insertion of a silicone rod into the flexor sheath at the first stage, and recreation of the FDP with a tendon graft at a second stage 3 months later. Extensive physiotherapy is required, and the procedure is not always successful in achieving a return to normal function. The treatment and ultimate function of patients with FDP avulsions is heavily influenced by the time from injury to surgery. Primary care doctors and Oztag participants should be aware that hand injuries sustained while playing the sport may be serious, and early expert evaluation is advisable.

A2 pulley integrity and the strength of flexor tendon repair: a biomechanical study in a chicken model.

PURPOSE This study assesses the influence of A2 pulley integrity on the strength of the repair. METHOD Part 1- The flexor digitorum profundus (FDP) tendons of 72 Cobb chicken feet were severed and repaired in the region of the A2 pulley using a modified Kessler core suture and an epitendinous suture. The A2 pulley was either left intact, divided for 50% of its length, or divided in its entirety. The distal interphalangeal joint was fixed at a position of 20°, 40° or 60° of joint flexion. The load to failure, integrity of the A2 pulley and the site of tendon failure were analysed. Part 2- A further 32 chicken feet were used to exclude the effects of freezing and thawing on results and to analyse differences when using a core suture only. RESULTS No difference in failure load between any of the test groups or subgroups was identified. The integrity of the A2 pulley was preserved in all specimens. The most common cause of failure was distal suture pull-out. DISCUSSION This study does not demonstrate that release of the A2 pulley provides an advantage in increasing tendon repair strength. Division of 50% of the A2 pulley does not predispose to pulley rupture. Flexor tendon repair strength did not alter with distal interphalangeal joint flexion between 20° and 60°. CLINICAL RELEVANCE The findings of this study do not support division of the A2 pulley to prevent flexor tendon repair failure if repair methods of appropriate strength are utilised.