TIME OFF WORK DUE TO SCAPHOID FRACTURES AND OTHER CARPAL INJURIES IN THE NETHERLANDS IN THE PERIOD 1990 TO 1993

Transcription

1 TIME OFF WORK DUE TO SCAPHOID FRACTURES AND OTHER CARPAL INJURIES IN THE NETHERLANDS IN THE PERIOD 1990 TO 1993 A. B. MINK VAN DER MOLEN, J. W. GROOTHOFF, G. J. P. VISSER, P. H. ROBINSON and W. H. EISMA From the Departments of Plastic and Reconstructive Surgery, Health Sciences and Rehabilitation, University of Groningen, Groningen, The Netherlands This study assessed the epidemiology, treatment, disability and time off work due to carpal injuries in the Netherlands in the period from 1990 to Most injuries were scaphoid fractures and carpal instabilities were rare. The time off work was considerable (mean, 155 days; median, 105 days; range, days). Patients with non-scaphoid fractures had the shortest time off work, followed by those with scaphoid fractures; patients with carpal instabilities had the longest time off work. Despite the significant time off work, the prognosis for return to work was excellent. Journal of Hand Surgery (British and European Volume, 1999) 24B: 2: Diagnosis and treatment of carpal injuries has been the subject of many publications during the last 10 to 15 years, but studies concerning the sequelae of carpal injuries, in particular the time off work and long term disability, are scarce. In order to obtain more relevant data about this subject a prospective study was conducted between 1990 and It assessed the epidemiology, the standard care, the time off work and long term disability in the working population due to carpal injuries in the Netherlands (Mink van der Molen, 1997). THE STUDY POPULATION The Joint Administrative Office (JAO) for the Dutch Sickness Insurance Act (DSIA) allowed the collection of data about the incidence of carpal injuries, their treatment and the subsequent time off work and long term disability. The DSIA covers the financial loss caused by inability to work due to sickness and disability for any person employed by a private company in the Netherlands and applies equally to work related injuries and other non-work related injuries or sickness. The Act does not cover children (<16 years), retired people (>65 years) or self-employed people. The DSIA criterion for recovery is full return to the same job the patient had at the time of injury. The maximum time off work covered by the DSIA is one continuous year. After 1 year other Dutch Welfare Acts apply and an assessment of final permanent disability is performed for those off work continuously for more than 1 year. The control system for the DSIA is in the hands of several organizations, of which the JAO, an independent non-profit organization shared by employers and employees, is the largest. The study population consisted of those of the 1.8 to 1.9 million employed people in the Netherlands covered by the DSIA who were unable to work due to a carpal injury and who were assessed by the JAO. METHODS The prospective study was conducted from 1990 until the end of Data were collected until the end of 1994, at which time the maximum period of 1 year off work covered by the DSIA was complete for the last patients entered in The JAO employed orthopaedic surgeons to assess the prospects for return to work of any injured patient off work more than 6 weeks. This limit of 6 weeks was a rule of the JAO and was not introduced by the study design. (A few exceptions applied to this rule, in particular cases with claims against the employer or another party involved in the accident. In these cases the patient was seen as soon as possible. However, this was rare, accounting for less than 2% of the cases included in the study.) Entry criteria for the study were: a carpal injury more than 6 weeks continuously off work. Carpal injuries included carpal fractures, dislocations and ligamentous injuries. Distal radial fractures were excluded, except for fractures of the radial styloid that were part of greater arc injuries or small ligamentous avulsion fractures. Data were collected by the orthopaedic surgeons of the JAO and registered on special forms. The surgeon recorded the history of the injury, performed an examination of the involved wrist (if not immobilized in plaster) and reviewed the available X-rays from the hospital where the patient was being treated. The date of injury, the date of return to previous job, diagnosis, treatment (surgical versus non-surgical, type of surgery), immobilization time, job description and whether the injury was work related were recorded. After return to work, the date of return was registered and the forms returned to the district office of the JAO in The Hague. If a patient was off work for more than one period due to the same injury, the total time off work was calculated by adding together the two periods off work. The X-rays of all patients who underwent surgery for a carpal injury, all patients who were off work for more than 1 year and all patients with either a carpal instability or carpal dislocation were reviewed by the authors (ABMvdM and GJPV) to confirm the diagnosis and to 193

2 194 THE JOURNAL OF HAND SURGERY VOL. 24B No. 2 APRIL 1999 assess the treatment. Patients were treated in any hospital in the Netherlands, usually the general hospital in their area. Statistics Data were entered in a database and analysis was done with a statistical program developed for analysis of medical data. Non-parametric tests were used for analysis and statistical significance was defined as P < 0.05 (2- sided). RESULTS A total of 560 cases were initially entered into the study, but 27 cases were excluded, either because they had no carpal injury or because data regarding time off work and diagnosis were incomplete. This left 533 patients for analysis. Based on older data about fractures collected by the JAO between 1973 and 1985 (Grond, 1979; van der Valk, 1990) this represents a response rate of approximately 50% spread over the country. No significant differences could be found for the distribution of type of carpal injury, the treatment (operative or conservative) and the time off work between the different districts of the JAO (Kruskal-Wallis test). Injuries A fracture of one or more carpal bones was seen in 490 patients (91.9%), excluding those seen in fracturedislocations. Only 29 patients (5.4%) had a fracture-dislocation of the carpus. Carpal instabilities were rare and seen in 14 (2.6%) of the patients. The scaphoid was the most frequently injured carpal bone, accounting for 89.5% of the fractures, followed by the triquetrum (4.8%) (Table 1). The majority of the scaphoid fractures were transverse (75%). The 29 fracture-dislocations consisted of 11 lesser arc injuries, 16 greater arc injuries and two radiocarpal dislocations. Ligamentous injury causing carpal instability included nine SL-dissociations Table 1 Distribution of type of carpal fractures Bone n Percentage Scaphoid % Triquetrum % Trapezium 9 1.8% Pisiform 6 1.2% Capitate 6 1.2% Hamate 5 1.0% Trapezoid 1 <1.0% Lunate 1 <1.0% Total 499* 100% *There were nine patients with more than one fracture. with a static DISI pattern, two midcarpal instabilities and three cases with either a symptomatic VISI or DISI pattern, but without a definite diagnosis (due to the lack of further diagnostic studies). Demographics The majority of the patients were male (96%) and their age distribution showed a clear peak (47%) in the age group 20 to 30 years (mean, 30 years; median, 28 years). Most patients did manual work and only a minority were employed in administrative or managerial positions (5.7%). Only 23% of the injuries occurred at work, the rest occurred during sports (26%), in leisure time (27%) and in road traffic accidents (24%). A fall of some sort was the main cause of the injury (87%). Diagnosis About one-third of the patients initially consulted their general practitioner (GP) after the injury. Two-thirds went direct to a hospital or emergency room. Seventyeight per cent of the injuries were diagnosed in the first 24 hours after injury. Delay in diagnosis was on average 13.5 days (median, 0 days) and was significantly shorter in those seen first in hospital or an emergency room (average 11.3 days compared with 15.5 days for GP consultation; Mann Whitney test, P < 0.001). Treatment Carpal fractures The treatment of choice for all carpal fractures was immobilization in a cast (98%). The average immobilization time for scaphoid fractures (mean, 11.1 weeks; median, 10 weeks) was longer than the immobilization time for non-scaphoid fractures (mean, 5.2 weeks; median, 5.0 weeks). In only six cases of the 447 (<2%) were scaphoid fractures operated upon within 2 weeks of injury. A total of 57 patients (12.8%) eventually underwent operative treatment for scaphoid fractures, mainly for delayed union and nonunion. After the operation the wrist was usually immobilized again and the mean total immobilization time of operated cases was 18.6 weeks compared with 10.0 for the nonoperated cases. Fracture-dislocations The fracture-dislocations were all reduced either open or closed (the exact distribution between open and closed procedures is unknown as operative reports are not sent to the JAO). In 11 cases the reduction was supported by K-wires. The scaphoid fracture in greater arc injuries was internally fixed with screw or bone graft in ten out of 14 cases.

3 TIME OFF WORK AFTER CARPAL INJURIES 195 Carpal instabilities Patients with instabilities were either not treated at all (two cases), treated with immobilization (seven cases) or underwent a variety of operative procedures (five cases). Time off work Most patients (497, 93.2%) were off work only once, but 35 (6.6%) were off twice due to the same carpal injury and one patient (0.2%) was off work three times. Of those 36 patients off work more than once, a significant percentage (73%) underwent surgery during the second or third period off work. This was either because surgery was delayed by waiting lists or because recurrent or persistent symptoms forced further intervention. Twenty-seven patients were off work for more than 1 year in total. The total time off work due to the different carpal injuries is given in Table 2 and Figure 1 shows the cumulative percentage of patients returning to work. The mean time off work for all patients was 155 days (median, 105 days). Influencing factors No statistically significant correlation was found between age and time off work or between injuries to the dominant hand and the non-dominant hand. In general patients in administrative work (mean time off work, 121 days; median, 89) resumed work earlier than patients in manual labour (for mechanics the mean time off work was 159 days; median, 124), but the difference was not statistically significant (only a small number worked in administrative functions). Overall there was a significant correlation between delay in diagnosis and total time off work (Spearman test, P < 0.001). There was a strong correlation between immobilization time and time off work (Spearman test, P < 0.001). The latter applied especially for scaphoid fractures and could be explained by the finding that the number of patients who resumed work with a wrist in plaster was small (<2%). Patients who underwent an operation were off work for a longer time compared with patients who were not operated upon (mean time off work 296 days compared with 123 days; Mann Whitney test, P < 0.001). This was due to the fact that severe carpal injuries, such as perilunate dislocations, were treated surgically more often than less severe injuries. Furthermore almost all scaphoid fractures that underwent surgery did so for failure of conservative treatment. Post-traumatic sympathetic reflex dystrophy developed in 25 (4.6%) patients and almost doubled the average time off work (Mann Whitney test, P < 0.001). Time interval between end of immobilization and return to work For patients with scaphoid fractures who were treated by immobilization alone and who were off work only once due to the fracture, we were able to calculate the time between the end of immobilization and the date of return to work. This period was on average 50 days (median, 37 days) and was significantly longer for patients who had physiotherapy (Mann Whitney test, P < 0.001). This correlation could not be calculated for other groups. Permanent disability Most patients (96%) were able to resume their original work (Table 3). Only 3.8% of the patients had residual Fig 1 Cumulative percentage of patients returning to work after carpal injury in the first year after injury. Table 2 Total time off work in days for each type of carpal injury Item n Mean (SD) Median Range Scaphoid fracture (129) Non-scaphoid fracture (228) Fracture-dislocations (185) Instabilities (505) Overall (165)

4 196 THE JOURNAL OF HAND SURGERY VOL. 24B No. 2 APRIL 1999 Table 3 Return to work after the different carpal injuries Injury Full return to Full return to Unemployed Not recovered (partial Total original work different work permanent disability) Scaphoid fractures Non-scaphoid fractures Fracture-dislocations Instabilities Total disabilities which prevented them from resuming their original job. Of these 10 (1.9%) were re-employed in an equivalent position without loss of income. Under the Dutch rules this group was therefore not considered for permanent disability. (Partial or full permanent disability is granted in the Netherlands not on the basis of the actual physical disability itself, but on the basis of financial loss. The difference between the income a disabled person is supposed to be able to earn compared with the previous income in the original job before disability is used to calculate the percentage of disability.) Ten other patients were not able to resume their original work and had lower paid jobs. One patient was unemployed after injury. DISCUSSION The data of the JAO gave us the unique opportunity to study a large group, representing the working population of the Netherlands, for whom the rules for assessment of disability, return to work and financial compensation during absence from work were fixed. An advantage is that in the Dutch system workers compensation claims are unlikely to influence outcome, because patients are covered by the same welfare acts and under the same conditions, regardless of whether the injury occurred at work or was not work-related at all. The patients were treated in many different hospitals in all parts of the country, giving us an understanding of the standard of care of carpal injuries in the Netherlands. A potential limitation of the study is that time off work in the Dutch welfare system may differ from other countries. Keeping this limitation in mind, we think it is worthwhile to share our results because data on this subject is limited and knowledge about final outcome is important. One-third of the patients were first seen for their injury by their GP, reflecting the normal procedure in seeking medical advice in the Netherlands. The rest went straight to the emergency room of a hospital. The delay in diagnosis was longer in the former group and it appeared that the GP tended to underestimate the injury. The fact that one-third of the patients went to their GP shows that it is important that GPs have a basic knowledge of wrist trauma. The majority of the carpal injuries were scaphoid fractures. The relative incidence of carpal fractures found in this study is consistent with other studies (Amadio and Taleisnik, 1993; Leslie and Dickson, 1981). Fracture-dislocations were rare compared to scaphoid fractures and this ratio correlated reasonably well with other studies (Kuderna, 1986). The number of ligamentous injuries causing carpal instability was very small. Because of the inclusion criteria, this study did not include patients who were off work less than 6 weeks due to a wrist sprain. Such minor ligamentous injuries do not appear to cause significant time off work, except perhaps in the rare instance when a static carpal instability pattern slowly develops. The majority of the studied population did manual work and most patients needed both hands for their job. The number of patients able to resume their job with the wrist immobilized was therefore small (<2%). The low rate of return to work in plaster may to a certain extent also reflect the policy of the JAO. The JAO usually accepted that a patient was unable to work with the arm or wrist immobilized. Treatment of carpal fractures was mainly nonoperative in the Netherlands. This applied to all non-scaphoid fractures except for a displaced intra-articular trapezium fracture, which was treated with open reduction and internal fixation (ORIF). Operative intervention for scaphoid fractures was almost exclusively reserved for delayed and nonunions. Putting the wrist in plaster is easy, cheap (medically) and carries a low risk with a high union rate (Böhler et al, 1954). The success rates of operative treatment of delayed union and nonunion of the scaphoid vary considerable. Success rates of more than 90% have been reported for inlay bone grafting (Mulder, 1968; Verdan and Narakas, 1968) and more than 70% for Herbert screw fixation with wedge bone grafting (Filan and Herbert, 1996). The likely union rate in this study (65%) seems an acceptable result, keeping in mind that the operations were done by many surgeons in different hospitals and not in specialized units. All fracture-dislocations were reduced. Good anatomical reduction was achieved in only two-thirds of the cases, proving the difficulty in restoring proper anatomical alignment in such cases. Obtaining healing of

5 TIME OFF WORK AFTER CARPAL INJURIES 197 the scaphoid fracture in greater arc injuries proved difficult, as only five of 12 fractures with adequate follow up definitely united, confirming the experience reported in other studies (Panting et al, 1984). Significant degenerative changes after perilunate fracture-dislocations developed within the 4 years of the study in three of 28, in particular in greater arc injuries when an anatomical reduction was not achieved and the scaphoid not fixed. This supports the recommendation by Garcia-Elias et al. (1986) and Herzberg et al. (1993) that the restoration of the normal anatomy is the key to success and should always be attempted. The patients with carpal instabilities were treated with a variety of procedures. There were problems with union of intercarpal arthrodeses (two out of three), as was also found in other studies (McAuliffe et al, 1993). The treatment of SL-dissociation by repositioning and temporary K-wire fixation proved to be unsatisfactory, as far as could be assessed from the X-rays as there was recurrence in all four cases. Patients with carpal fractures other than the scaphoid had the shortest time off work. The relatively good prognosis for non-scaphoid fractures is known (Höcker and Menschik, 1994; Kuderna, 1986). Data about the time off work for scaphoid fractures is limited and the most detailed source for comparison is a thesis by Wester (1947), who studied the socio-economic aspects of scaphoid fractures in Holland in a similar population to that used in this study. No statistically significant difference in the time off work was found between our data and the data of Wester (mean time off work, 144 days; median, 119 days). In both study periods the majority of scaphoid fractures were treated conservatively in the Netherlands. Only a few studies about the operative treatment of scaphoid fracture and nonunion mention the time off work (Bongers and Ponsen, 1980; Filan and Herbert, 1996; O Brien and Herbert, 1985; Parkinson et al, 1989; Verdan and Narakas, 1968). In the first three of these studies the time off work was much shorter than in our study, because internal fixation allowed early movement out of plaster. Despite significant period off work the prospects for return to work were good for scaphoid fractures, consistent with the experience of Böhler et al. (1954). The period between the end of immobilization and the return to work was on average 50 days for conservatively treated scaphoid fractures. The shorter time between end of immobilization and return to work in other studies (Morgan and Walters, 1984; Parkinson et al, 1989) might reflect the more stringent control system for financial compensation during sickness in other countries. However, in these studies it is not clear whether the patients returned to their previous job full time or obtained some other work. Carpal fracture dislocations are usually the result of high impact accidents. Because of the nature of the trauma, concurrent injuries were common (present in 14 out of 29 cases). These patients therefore underwent more operations. The result was a much longer time off work than for a simple carpal fracture. All patients in this group, however, resumed work, and therefore it seems that any residual anatomical changes were tolerated in the short term. The small group with ligamentous injuries causing carpal instability had the longest time off work. This was due to the difficulty in diagnosing and treating these injuries. The time between injury and diagnosis was clearly longer in this group than in other carpal injuries. The treatment of carpal instabilities proved difficult and operations were not always successful. The result was a significantly prolonged time off work for patients with carpal instabilities compared with those with other carpal injuries. In order to minimize these problems it seems reasonable to refer patients with a suspected ligamentous injury of the wrist to a specialized hand centre as soon as possible. References Amadio PC, Taleisnik J. Fractures of the carpal bones. In: Green DP (Ed.) Operative hand surgery, 3rd edn. New York, Churchill Livingstone, 1993, Vol 1: Böhler L, Trojan E, Jahna H (1954). Behandlungsergebnisse von 734 frischen einfachen Brüchen des Kahnbeinkörpers der hand. Wiederherstellungschirurgie und Traumatologie, 2: Bongers KJ, Ponsen RJG (1980). Operative and nonoperative management of fractures of the carpal scaphoid: five years experience. Netherlands Journal of Surgery, 32: Filan SL, Herbert TJ (1996). Herbert screw fixation of scaphoid fractures. Journal of Bone and Joint Surgery, 78B: Garcia-Elias M, Irisarri C, Henriquez A, et al. (1986). Perilunar dislocation of the carpus Annales de Chirurgie de la Main, 5: Grond J Th H. Fracture statistics (GAK Fracturen Statistiek) Amsterdam, GAK, Herzberg G, Comptet JJ, Linscheid RL, Amadio PC, Cooney WP, Stalder J (1993). Perilunate dislocations and fracture-dislocations: A multicenter study. Journal of Hand Surgery, 18A: Höcker K, Menschik A (1994). Die Triquetrumfraktur. Pathomechanik, Klassifikation, Behandlung and Ergebnisse im Rahmen einer Nachuntersuchung. Handchirugie Mikrochirurgie Plastische Chirurgie, 26: Kuderna H (1986). Frakturen and Luxationsfrakturen der Handwurzel. Orthopäde, 15: Leslie IJ, Dickson RA (1981). The fractured carpal scaphoid. Natural history and factors influencing outcome. Journal of Bone and Joint Surgery, 63B: McAuliffe JA, Dell PC, Jaffe R (1993). Complications of intercarpal arthrodesis. Journal of Hand Surgery, 18A: Mink van der Molen AB. Carpal injuries in the Netherlands (Carpale letsels; Onderzoek naar de verzuimaspecten ten gevolge van carpale letsels in Nederland ). Thesis, University of Groningen, Groningen Morgan DAF, Walters JW (1984). A prospective study of 100 consecutive scaphoid fractures. Australian and New Zealand Journal of Surgery, 54: Mulder JD (1968). The results of 100 cases of pseudarthrosis of the scaphoid bone treated with the Matti-Russe operation. Journal Bone and Joint Surgery, 50B: O Brien L, Herbert T (1985). Internal fixation of acute scaphoid fractures: a new approach to treatment. Australian and New Zealand Journal of Surgery, 55: Panting AL, Lamb DW, Noble J, Haw CS (1984). Dislocations of the lunate with and without fracture of the scaphoid. Journal of Bone and Joint Surgery, 66B: Parkinson RW, Hodgkinson JP, Hargadon EJ (1989). Symptomatic non-union of the carpal scaphoid: Matti-Russe bone grafting versus Herbert screw fixation. Injury, 20: Valk FA van der. Fracture statistics (GAK Fracturen Statistiek) Amsterdam GAK, 1990.

6 198 THE JOURNAL OF HAND SURGERY VOL. 24B No. 2 APRIL 1999 Verdan C, Narakas A (1968). Fractures and pseudarthrosis of the scaphoid. Surgical Clinics of North America, 48: Wester J. The clinical and social aspects of fractures of the carpal navicular (De klinische en sociale betekenis van de fractuur van het os naviculare manus). Thesis, University of Amsterdam, Amsterdam, Received: 27 March 1998 Accepted after revision: 21 September 1998 A. B. Mink van der Molen MD, Department of Plastic and Reconstructive Surgery, University Hospital Rotterdam, PO Box 2040, Rotterdam, NL-3000 CA, The Netherlands. minkvandermolen@plch.azr.nl 1999 The British Society for Surgery of the Hand Article no. jhsb