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Silastic metatarsophalangeal arthroplasty
The Foot 13 (2003) 146–150
Silastic metatarsophalangeal arthroplasty Very long-term results of single-stem implants in degenerative joint disease W. James Harrison, Jonathan M. Loughead∗ North Tyneside General Hospital, North Shields, Tyne and Wear, UK Received 20 March 2003; accepted 24 March 2003
Abstract Concern over long-term outcomes in patients with silastic metatarsophalangeal (MTP) implants prompted an assessment of such patients. We reviewed 21 single-stemmed silastic metatarsophalangeal arthroplasties in 18 patients with a mean follow-up of 18 years 9 months. Eight operations were performed for hallux valgus (HV) and 13 for hallux rigidus (HR). Patients were assessed by clinical scoring, patient satisfaction and radiographic grading. Patients treated for HR achieved higher clinical scores than those treated for HV. This difference was statistically significant. There was no correlation between radiographic appearance and clinical score, patient satisfaction or time since implantation. Long-term changes to the bone stock did not cause clinical detriment, and in no case was late revision surgery necessary. Very long-term results have not previously been reported and in our review outcomes were surprisingly good particularly in the surgical treatment of HR in the over 50 age group. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Silastic; Hallux rigidus; Hallux valgus
1. Introduction Silastic interposition arthroplasty for hallux rigidus (HR) offers good pain relief whilst retaining movement. Nevertheless, many surgeons have disregarded the procedure. This may be attributed to concern regarding silicone synovitis associated with early clinical detriment. Furthermore, uncertainties regarding the long-term effect on bone stock have added to the concern. It is conceivable that progressive erosive bony changes could require difficult late reconstruction. The question about the long-term clinical results has not been adequately addressed. When Swanson introduced these implants in 1967, the silicone was thought to be inert producing no biological reaction. Several subsequent reports described silicone synovitis and bony reactions [1–4]; whilst case reports linking these implants with lymphadenopathy [5,6], and even lymphoma [7–9], have raised alarm. Recent public attention has focused more on the safety of silicone breast implants than small joint arthroplasties and concern continues in both areas. Several short- and medium-term follow-up studies have ∗ Corresponding author. Present address: 20 Delaval Terrace, Gosforth, Newcastle upon Tyne, NE3 4RT, UK. Tel.: +44-191-284-4357. E-mail address: [email protected] (J.M. Loughead).
been published and fragmentation of the silastic implants has been widely reported [1,4,10]. The long-term clinical effect of this complication has not been reported, nor the long-term functional outcome assessed. 2. Methods During the period 1972–1983, 82 patients underwent silastic MTP implants at the authors’ hospital. The implants used were those designed by Swanson and manufactured by the DOW Corning Corporation. Early results of some of these patients were previously published [11] and were encouraging, particularly in the treatment of HR. In the current study an attempt was made to trace all 82 patients. Of these patients, 20 were deceased, 38 were untraceable and 2 declined to attend for review; 22 patients attended for long-term review. For the 20 patients who were deceased, the death certificate records were traced where possible to identify cause of death. The 22 patients who attended for clinical review had 27 silastic MTP implants. Of those reviewed, the diagnosis was hallux valgus (HV) or HR in all except one patient, who suffered from rheumatoid arthritis; this latter patient was excluded from the main analysis. In those patients who
0958-2592/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0958-2592(03)00037-3
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
underwent surgery for correction of HV soft tissue balancing was also performed but without a metatarsal osteotomy. Silastic arthroplasty was performed in HV patients who had associated degenerative change in the first MTP joint. In 18 patients the implant used was a single-stemmed hemiarthroplasty, whilst in 3 patients a double-stem hinged implant was selected; hinged implants were excluded from the main analysis. Thus, the main group consisted of 21 single-stem silastic arthroplasties in 18 patients; 8 implants were used to treat HV and 13 to treat HR. The mean age at implantation was 49 and 52 for the HV and HR groups, respectively. Mean follow-up was 18 years 6 months (range 14 years 4 months to 24 years 10 months) for HV, and 17 years 8 months (range 13 years 10 months to 23 years 5 months) for HR. There were 19 females and 3 males. The three males had all suffered from HR. Two patients, both in the HR group, had their silastic implants removed at between 2 and 3 years postoperatively, one because of swelling from either silicone synovitis or infection; in the other case, the indication for revision was uncertain. Results from these patients were retained in the analysis. No other implants had been revised. Assessment of the patients involved clinical scoring using the hallux metatarsophalangeal-interphalangeal (MTP-IP) scale of Kitaoka [12] (Table 1). In this scale, 40 points were assigned to pain, 45 to function and 15 to alignment. Furthermore patients were asked to self-allocate to one of the following four subjective satisfaction ratings: A B C D
Much improved, all that was expected Improved, but not all that was expected Satisfactory, unchanged Worse
147
Table 1 Hallux metatarsophalangeal-interphalangeal scale (100 points total) (from Kitaoka et al. [12]) Pain (40 points) None Mild, occasional Moderate, daily Severe, almost always present Function (45 points) Activity limitations No limitations No limitation of daily activities, such as employment responsibilities, limitation of recreational activities Limited daily and recreational activities Severe limitation of daily and recreational activities
40 30 20 0
10 7 4 0
Footwear requirements Fashionable, conventional shoes, no insert required Comfort footwear, shoe insert Modified shoes or brace
10 5 0
MTP joint motion (dorsiflexion plus plantarflexion) Normal or mild restriction (75◦ or more) Moderate restriction (30–74◦ ) Severe restriction (less than 30◦ )
10 5 0
IP joint motion (plantarflexion) No restriction Severe restriction
5 0
MTP-IP stability (all directions) Stable Definitely unstable or able to dislocate
5 0
Callus related to hallux MTP-IP No callous or asymptomatic callus Callous, symptomatic
5 0
Alignment (15 points) Good, hallux well aligned Fair, some degree of hallux malalignment observed, no symptoms Poor, obvious symptomatic malignment
Fig. 1. Cysts in the metatarsal head and proximal phalanx.
15 8 0
148
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150 Table 2 Clinical score against diagnosis
Fig. 2. Lucency of greater than 1 mm around implant stem.
Radiographs were taken of all forefeet. Bony cystic changes may be present secondary to small particle synovitis (Fig. 1); sometimes cysts appear to coalesce to form a lucency around the silastic stem (Fig. 2). In order to evaluate for correlation between radiographic changes and clinical outcome, a simple, if rather crude, radiographic scoring system was developed. The radiographs were analysed for four features, namely: • Lucency around the implant of greater than 1 mm; • Two or more cysts in the proximal phalanx of greater than 1 mm diameter; • Two or more cysts in the metatarsal head of greater than 1 mm diameter; and • Obvious fracture of the implant. Each case was assessed allocating one grading point for each of these features, giving a grading from 0, where none of these changes are present, through to IV, where all these features are present. Thus, a grading of IV represents very marked radiographic change.
ered excellent; 5 (25%) patients scored 81–90 which was considered very good; 7 (35%) patients scored 71–80 which was considered good; and 5 (25%) patients scored 61–70 which was considered fair. When analysed by preoperative diagnosis, the mean score for patients with HV was 73 (range 62–88), while that for patients with HR was 84 (range 70–95) (Table 2). This difference in score for different diagnosis was statistically significant with a confidence level of 98% using a two-sided t-test. The two patients with excision arthroplasties (both HR) scored 90 and 95. If the pain component of the clinical score is analysed separately, the mean pain score was 37 (range 30–40). There was no difference in mean pain scores for the HV group (mean 38) compared to the HR group (mean 36). Thus, the significant difference in clinical score between HV and HR groups was entirely attributable to the function and alignment components of the scoring system. As the scoring system gives little weight to alignment of the toe, patients with HV who have good function and pain relief score well, which may explain the surprisingly good results obtained in this group. 3.2. Satisfaction 14 (70%) (5 HV, 9 HR) implants gave grade A satisfaction—much improved 4 (20%) (2 HV, 2 HR) implants gave grade B satisfaction—improved 1 (5%) (0 HV, 1 HR) implant gave grade C satisfaction—unchanged 1 (5%)(1 HV, 0 HR) implant gave grade D satisfaction—worse There was no statistical correlation between subjective patient satisfaction and preoperative diagnosis, clinical score or radiographic grading. Its contribution to outcome assessment is questionable in such a long-term review. 3.3. Radiographic grading Patients were graded as follows:
3. Results 3.1. Clinical scores The mean score for the whole group was 79 (range 62–95). Three (15%) patients scored 91 or more which was consid-
1 5 6 5 4
(5%) (1 HR, 0 HV) implant was grade 0 (24%) (4 HV, 1 HR) implants were grade I (28%) (2 HV, 4 HR) implants were grade II (24%) (2 HV, 3 HR) implants were grade III (19%) (0 HV, 4HR) implants were grade IV
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
149
There was no statistical correlation between radiographic grading and preoperative diagnosis, clinical score or duration of implantation. Thus, erosive bone changes and subsequent loss of bone stock did not appear to cause clinical detriment. Bony changes did not necessitate late reconstruction, even in the very long term.
4. Discussion In reviewing 21 implants at a mean follow-up of nearly 20 years, meaningful numbers are presented in a patient group that, to the knowledge of the authors, has not previously been reported on. Nonetheless, the authors concede that only a quarter of all the patients originally operated on could be reviewed and this raises the possibility of an inadvertent selection bias. The overwhelming reasons for failure to review were: untraceable patients (46%) and death (24%). It would seem likely that this sample is representative of the whole group. No deaths were identified that were related to silicone or lymphoma. A longitudinal study would give more information on long-term implant function and safety. The outcome, as measured by clinical score, in the patients reviewed was very good in the HR group and good in the HV group. These groups were small but well-matched. No control group undergoing an alternative method of treatment was available, making comparison with other forms of treatment for HR difficult. However, the results presented are comparable to those reported for arthrodesis or Keller’s excision arthroplasty [13,14]. The authors are unaware of any prospective trials comparing silastic replacement with arthrodesis or Keller’s excision arthroplasty in treatment of HR. No correlation was found between radiographic changes and clinical score suggesting that rejection of silastic interposition arthroplasty on account of small particle synovitis and consequent erosive bony changes would not appear to be justified. It is possible that correlation between radiographic changes and clinical scoring may be present in the early years following implantation, but disappear in the longer term as a steady state is achieved; what is clear is that no revision surgery was required on account of bony changes, even in the very long term. In this series, two patients had implants removed within 2 years of implantation, one because of presumed synovitis, but both achieved excellent long-term outcomes. In one of the study group, a bony ankylosis had developed across the implant. Since the ankylosis abolished movement which is the source of wear particles, which are in turn responsible for granulomatous reaction, it is interesting to confirm that this patient did not undergo any radiographic erosive changes (Fig. 3). Grommets may also reduce debris production [15]. This review relates to single-stemmed silastic MTP arthroplasties, which have now been superseded by hinged arthroplasties. This modification is likely to affect long-term
Fig. 3. MTP ankylosis. The resultant failure of movement appears to have prevented debris formation and there is no bony reaction.
results; the hinge implant provides interposition, but has some intrinsic stability against displacement and angulation. The hinge also abolishes the articulation between silicone and the articular surface of the metatarsal head, which may become a potent source of small particle debris in the button silastic arthroplasty since subchondral bone is harder than silicone. One might therefore expect the long-term outcome with hinge silastic arthroplasties to surpass that with buttons, and indeed the medium-term results are encouraging [10,16,17]. Until long-term results with hinged implants are available, information gained from study of the long-term impact of silicone on bone must be derived from a series of silastic hemiarthroplasties such as this.
5. Conclusion Silastic hemiarthroplasty has been superseded by hinged implants and in many centres abandoned because of short-term complications. However, in our series, patients treated with silastic hemiarthroplasties for HR achieved very good results in the long term. No correlation was found between time since implantation or bony changes and clinical score; these results should be reassuring to those involved in the management of a very large cohort of patients who have previously undergone this procedure.
150
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
Acknowledgements We thank Mr. D.J. Campbell of the University of Northumbria for his help with the statistical analysis and Mr. D.C. D’Netto for allowing us to review his patients. References [1] Gordon M, Bullough PG. Synovial and osseous inflammation in failed silicone-rubber prostheses. J Bone Joint Surg (Am) 1982;64A:574–80. [2] Nalbandian RM, Swanson AB, Maupin BK. Long-term silicone implant arthroplasty. Implications of animal and human autopsy findings. JAMA 1983;250:1195–8. [3] Rahman H, Fagg PS. Silicone granulomatous reactions after first metatarsophalangeal hemiarthroplasty. J Bone Joint Surg (Br) 1993; 75-B:637–9. [4] Verhaar J, Vermeulen A, Bulshra S, Walenkamp G. Bone reaction to silicone metatarsophalangeal joint hemiprosthesis. Clin Orthop 1989;245:228–32. [5] Jasim KA, Weerasinghe BD. Silicone lymphadenopathy, synovitis and osteitis complicating big toe silastic prostheses. J R Coll Surg Edinb 1987;32:29–33. [6] Shiel Jr WC, Jason M. Granulomatous inguinal lymphadenopathy after bilateral metatarsophalangeal joint silicone arthroplasty. Foot Ankle 1986;6:216–8. [7] Benjamin E, Ahmed A, Rashid AT, Wright DH. Silicone lymphadenopathy: a report of two cases, one with concomitant malignant lymphoma. Diagn Histopathol 1982;5:133–41.
[8] Digby JM. Malignant lymphoma with intranodal silicone rubber particles following metacarpophalangeal joint replacements. Hand 1982;14(3):326–8. [9] Murakata LA, Rangwala AF. Silicone lymphadenopathy with concomitant malignant lymphoma. J Rheumatol 1989;16:1480–3. [10] Cracchiolo A, Weltmer JB, Liam G, Dalseth T, Dorey F. Arthroplasty of the first metatarsophalangeal joint with a double-stem silicone implant. Results in patients who have degenerative joint disease failure of previous operations, or rheumatoid arthritis. J Bone Joint Surg (Am) 1992;74-A:552–63. [11] Sethu A, D’Netto DC, Ramakrishna B. Swanson’s silastic implants in great toes. J Bone Joint Surg (Br) 1980;62-B:83–5. [12] Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int 1994;15:349– 53. [13] O’Doherty DP, Lowrie IG, Magnussen PA, Gregg PJ. The management of the painful first metatarsophalangeal joint in the older patient. Arthrodesis or Keller’s arthroplasty? J Bone Joint Surg (Br) 1990;72-B:839–42. [14] Wrighton JD. A ten-year review of Keller’s operation. Review of Keller’s operation at the Princess Elizabeth Orthopaedic Hospital, Exeter. Clin Orthop 1972;89:207–14. [15] Ishikawa H, Hanyu T, Murasawa A. The use of grommets for flexible hinge toe implants, a case report. Clin Orthop 1995;316: 173–9. [16] Laird L. Silastic joint arthroplasty of the great toe. A review of 228 implants using the double-stemmed implant. Clin Orthop 1990;255: 268–72. [17] Shankar NS, Asaad SS, Craxford AD. Hinged silastic implants of the great toe. Clin Orthop 1991;272:227–34.
Silastic metatarsophalangeal arthroplasty Very long-term results of single-stem implants in degenerative joint disease W. James Harrison, Jonathan M. Loughead∗ North Tyneside General Hospital, North Shields, Tyne and Wear, UK Received 20 March 2003; accepted 24 March 2003
Abstract Concern over long-term outcomes in patients with silastic metatarsophalangeal (MTP) implants prompted an assessment of such patients. We reviewed 21 single-stemmed silastic metatarsophalangeal arthroplasties in 18 patients with a mean follow-up of 18 years 9 months. Eight operations were performed for hallux valgus (HV) and 13 for hallux rigidus (HR). Patients were assessed by clinical scoring, patient satisfaction and radiographic grading. Patients treated for HR achieved higher clinical scores than those treated for HV. This difference was statistically significant. There was no correlation between radiographic appearance and clinical score, patient satisfaction or time since implantation. Long-term changes to the bone stock did not cause clinical detriment, and in no case was late revision surgery necessary. Very long-term results have not previously been reported and in our review outcomes were surprisingly good particularly in the surgical treatment of HR in the over 50 age group. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Silastic; Hallux rigidus; Hallux valgus
1. Introduction Silastic interposition arthroplasty for hallux rigidus (HR) offers good pain relief whilst retaining movement. Nevertheless, many surgeons have disregarded the procedure. This may be attributed to concern regarding silicone synovitis associated with early clinical detriment. Furthermore, uncertainties regarding the long-term effect on bone stock have added to the concern. It is conceivable that progressive erosive bony changes could require difficult late reconstruction. The question about the long-term clinical results has not been adequately addressed. When Swanson introduced these implants in 1967, the silicone was thought to be inert producing no biological reaction. Several subsequent reports described silicone synovitis and bony reactions [1–4]; whilst case reports linking these implants with lymphadenopathy [5,6], and even lymphoma [7–9], have raised alarm. Recent public attention has focused more on the safety of silicone breast implants than small joint arthroplasties and concern continues in both areas. Several short- and medium-term follow-up studies have ∗ Corresponding author. Present address: 20 Delaval Terrace, Gosforth, Newcastle upon Tyne, NE3 4RT, UK. Tel.: +44-191-284-4357. E-mail address: [email protected] (J.M. Loughead).
been published and fragmentation of the silastic implants has been widely reported [1,4,10]. The long-term clinical effect of this complication has not been reported, nor the long-term functional outcome assessed. 2. Methods During the period 1972–1983, 82 patients underwent silastic MTP implants at the authors’ hospital. The implants used were those designed by Swanson and manufactured by the DOW Corning Corporation. Early results of some of these patients were previously published [11] and were encouraging, particularly in the treatment of HR. In the current study an attempt was made to trace all 82 patients. Of these patients, 20 were deceased, 38 were untraceable and 2 declined to attend for review; 22 patients attended for long-term review. For the 20 patients who were deceased, the death certificate records were traced where possible to identify cause of death. The 22 patients who attended for clinical review had 27 silastic MTP implants. Of those reviewed, the diagnosis was hallux valgus (HV) or HR in all except one patient, who suffered from rheumatoid arthritis; this latter patient was excluded from the main analysis. In those patients who
0958-2592/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0958-2592(03)00037-3
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
underwent surgery for correction of HV soft tissue balancing was also performed but without a metatarsal osteotomy. Silastic arthroplasty was performed in HV patients who had associated degenerative change in the first MTP joint. In 18 patients the implant used was a single-stemmed hemiarthroplasty, whilst in 3 patients a double-stem hinged implant was selected; hinged implants were excluded from the main analysis. Thus, the main group consisted of 21 single-stem silastic arthroplasties in 18 patients; 8 implants were used to treat HV and 13 to treat HR. The mean age at implantation was 49 and 52 for the HV and HR groups, respectively. Mean follow-up was 18 years 6 months (range 14 years 4 months to 24 years 10 months) for HV, and 17 years 8 months (range 13 years 10 months to 23 years 5 months) for HR. There were 19 females and 3 males. The three males had all suffered from HR. Two patients, both in the HR group, had their silastic implants removed at between 2 and 3 years postoperatively, one because of swelling from either silicone synovitis or infection; in the other case, the indication for revision was uncertain. Results from these patients were retained in the analysis. No other implants had been revised. Assessment of the patients involved clinical scoring using the hallux metatarsophalangeal-interphalangeal (MTP-IP) scale of Kitaoka [12] (Table 1). In this scale, 40 points were assigned to pain, 45 to function and 15 to alignment. Furthermore patients were asked to self-allocate to one of the following four subjective satisfaction ratings: A B C D
Much improved, all that was expected Improved, but not all that was expected Satisfactory, unchanged Worse
147
Table 1 Hallux metatarsophalangeal-interphalangeal scale (100 points total) (from Kitaoka et al. [12]) Pain (40 points) None Mild, occasional Moderate, daily Severe, almost always present Function (45 points) Activity limitations No limitations No limitation of daily activities, such as employment responsibilities, limitation of recreational activities Limited daily and recreational activities Severe limitation of daily and recreational activities
40 30 20 0
10 7 4 0
Footwear requirements Fashionable, conventional shoes, no insert required Comfort footwear, shoe insert Modified shoes or brace
10 5 0
MTP joint motion (dorsiflexion plus plantarflexion) Normal or mild restriction (75◦ or more) Moderate restriction (30–74◦ ) Severe restriction (less than 30◦ )
10 5 0
IP joint motion (plantarflexion) No restriction Severe restriction
5 0
MTP-IP stability (all directions) Stable Definitely unstable or able to dislocate
5 0
Callus related to hallux MTP-IP No callous or asymptomatic callus Callous, symptomatic
5 0
Alignment (15 points) Good, hallux well aligned Fair, some degree of hallux malalignment observed, no symptoms Poor, obvious symptomatic malignment
Fig. 1. Cysts in the metatarsal head and proximal phalanx.
15 8 0
148
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150 Table 2 Clinical score against diagnosis
Fig. 2. Lucency of greater than 1 mm around implant stem.
Radiographs were taken of all forefeet. Bony cystic changes may be present secondary to small particle synovitis (Fig. 1); sometimes cysts appear to coalesce to form a lucency around the silastic stem (Fig. 2). In order to evaluate for correlation between radiographic changes and clinical outcome, a simple, if rather crude, radiographic scoring system was developed. The radiographs were analysed for four features, namely: • Lucency around the implant of greater than 1 mm; • Two or more cysts in the proximal phalanx of greater than 1 mm diameter; • Two or more cysts in the metatarsal head of greater than 1 mm diameter; and • Obvious fracture of the implant. Each case was assessed allocating one grading point for each of these features, giving a grading from 0, where none of these changes are present, through to IV, where all these features are present. Thus, a grading of IV represents very marked radiographic change.
ered excellent; 5 (25%) patients scored 81–90 which was considered very good; 7 (35%) patients scored 71–80 which was considered good; and 5 (25%) patients scored 61–70 which was considered fair. When analysed by preoperative diagnosis, the mean score for patients with HV was 73 (range 62–88), while that for patients with HR was 84 (range 70–95) (Table 2). This difference in score for different diagnosis was statistically significant with a confidence level of 98% using a two-sided t-test. The two patients with excision arthroplasties (both HR) scored 90 and 95. If the pain component of the clinical score is analysed separately, the mean pain score was 37 (range 30–40). There was no difference in mean pain scores for the HV group (mean 38) compared to the HR group (mean 36). Thus, the significant difference in clinical score between HV and HR groups was entirely attributable to the function and alignment components of the scoring system. As the scoring system gives little weight to alignment of the toe, patients with HV who have good function and pain relief score well, which may explain the surprisingly good results obtained in this group. 3.2. Satisfaction 14 (70%) (5 HV, 9 HR) implants gave grade A satisfaction—much improved 4 (20%) (2 HV, 2 HR) implants gave grade B satisfaction—improved 1 (5%) (0 HV, 1 HR) implant gave grade C satisfaction—unchanged 1 (5%)(1 HV, 0 HR) implant gave grade D satisfaction—worse There was no statistical correlation between subjective patient satisfaction and preoperative diagnosis, clinical score or radiographic grading. Its contribution to outcome assessment is questionable in such a long-term review. 3.3. Radiographic grading Patients were graded as follows:
3. Results 3.1. Clinical scores The mean score for the whole group was 79 (range 62–95). Three (15%) patients scored 91 or more which was consid-
1 5 6 5 4
(5%) (1 HR, 0 HV) implant was grade 0 (24%) (4 HV, 1 HR) implants were grade I (28%) (2 HV, 4 HR) implants were grade II (24%) (2 HV, 3 HR) implants were grade III (19%) (0 HV, 4HR) implants were grade IV
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
149
There was no statistical correlation between radiographic grading and preoperative diagnosis, clinical score or duration of implantation. Thus, erosive bone changes and subsequent loss of bone stock did not appear to cause clinical detriment. Bony changes did not necessitate late reconstruction, even in the very long term.
4. Discussion In reviewing 21 implants at a mean follow-up of nearly 20 years, meaningful numbers are presented in a patient group that, to the knowledge of the authors, has not previously been reported on. Nonetheless, the authors concede that only a quarter of all the patients originally operated on could be reviewed and this raises the possibility of an inadvertent selection bias. The overwhelming reasons for failure to review were: untraceable patients (46%) and death (24%). It would seem likely that this sample is representative of the whole group. No deaths were identified that were related to silicone or lymphoma. A longitudinal study would give more information on long-term implant function and safety. The outcome, as measured by clinical score, in the patients reviewed was very good in the HR group and good in the HV group. These groups were small but well-matched. No control group undergoing an alternative method of treatment was available, making comparison with other forms of treatment for HR difficult. However, the results presented are comparable to those reported for arthrodesis or Keller’s excision arthroplasty [13,14]. The authors are unaware of any prospective trials comparing silastic replacement with arthrodesis or Keller’s excision arthroplasty in treatment of HR. No correlation was found between radiographic changes and clinical score suggesting that rejection of silastic interposition arthroplasty on account of small particle synovitis and consequent erosive bony changes would not appear to be justified. It is possible that correlation between radiographic changes and clinical scoring may be present in the early years following implantation, but disappear in the longer term as a steady state is achieved; what is clear is that no revision surgery was required on account of bony changes, even in the very long term. In this series, two patients had implants removed within 2 years of implantation, one because of presumed synovitis, but both achieved excellent long-term outcomes. In one of the study group, a bony ankylosis had developed across the implant. Since the ankylosis abolished movement which is the source of wear particles, which are in turn responsible for granulomatous reaction, it is interesting to confirm that this patient did not undergo any radiographic erosive changes (Fig. 3). Grommets may also reduce debris production [15]. This review relates to single-stemmed silastic MTP arthroplasties, which have now been superseded by hinged arthroplasties. This modification is likely to affect long-term
Fig. 3. MTP ankylosis. The resultant failure of movement appears to have prevented debris formation and there is no bony reaction.
results; the hinge implant provides interposition, but has some intrinsic stability against displacement and angulation. The hinge also abolishes the articulation between silicone and the articular surface of the metatarsal head, which may become a potent source of small particle debris in the button silastic arthroplasty since subchondral bone is harder than silicone. One might therefore expect the long-term outcome with hinge silastic arthroplasties to surpass that with buttons, and indeed the medium-term results are encouraging [10,16,17]. Until long-term results with hinged implants are available, information gained from study of the long-term impact of silicone on bone must be derived from a series of silastic hemiarthroplasties such as this.
5. Conclusion Silastic hemiarthroplasty has been superseded by hinged implants and in many centres abandoned because of short-term complications. However, in our series, patients treated with silastic hemiarthroplasties for HR achieved very good results in the long term. No correlation was found between time since implantation or bony changes and clinical score; these results should be reassuring to those involved in the management of a very large cohort of patients who have previously undergone this procedure.
150
W.J. Harrison, J.M. Loughead / The Foot 13 (2003) 146–150
Acknowledgements We thank Mr. D.J. Campbell of the University of Northumbria for his help with the statistical analysis and Mr. D.C. D’Netto for allowing us to review his patients. References [1] Gordon M, Bullough PG. Synovial and osseous inflammation in failed silicone-rubber prostheses. J Bone Joint Surg (Am) 1982;64A:574–80. [2] Nalbandian RM, Swanson AB, Maupin BK. Long-term silicone implant arthroplasty. Implications of animal and human autopsy findings. JAMA 1983;250:1195–8. [3] Rahman H, Fagg PS. Silicone granulomatous reactions after first metatarsophalangeal hemiarthroplasty. J Bone Joint Surg (Br) 1993; 75-B:637–9. [4] Verhaar J, Vermeulen A, Bulshra S, Walenkamp G. Bone reaction to silicone metatarsophalangeal joint hemiprosthesis. Clin Orthop 1989;245:228–32. [5] Jasim KA, Weerasinghe BD. Silicone lymphadenopathy, synovitis and osteitis complicating big toe silastic prostheses. J R Coll Surg Edinb 1987;32:29–33. [6] Shiel Jr WC, Jason M. Granulomatous inguinal lymphadenopathy after bilateral metatarsophalangeal joint silicone arthroplasty. Foot Ankle 1986;6:216–8. [7] Benjamin E, Ahmed A, Rashid AT, Wright DH. Silicone lymphadenopathy: a report of two cases, one with concomitant malignant lymphoma. Diagn Histopathol 1982;5:133–41.
[8] Digby JM. Malignant lymphoma with intranodal silicone rubber particles following metacarpophalangeal joint replacements. Hand 1982;14(3):326–8. [9] Murakata LA, Rangwala AF. Silicone lymphadenopathy with concomitant malignant lymphoma. J Rheumatol 1989;16:1480–3. [10] Cracchiolo A, Weltmer JB, Liam G, Dalseth T, Dorey F. Arthroplasty of the first metatarsophalangeal joint with a double-stem silicone implant. Results in patients who have degenerative joint disease failure of previous operations, or rheumatoid arthritis. J Bone Joint Surg (Am) 1992;74-A:552–63. [11] Sethu A, D’Netto DC, Ramakrishna B. Swanson’s silastic implants in great toes. J Bone Joint Surg (Br) 1980;62-B:83–5. [12] Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int 1994;15:349– 53. [13] O’Doherty DP, Lowrie IG, Magnussen PA, Gregg PJ. The management of the painful first metatarsophalangeal joint in the older patient. Arthrodesis or Keller’s arthroplasty? J Bone Joint Surg (Br) 1990;72-B:839–42. [14] Wrighton JD. A ten-year review of Keller’s operation. Review of Keller’s operation at the Princess Elizabeth Orthopaedic Hospital, Exeter. Clin Orthop 1972;89:207–14. [15] Ishikawa H, Hanyu T, Murasawa A. The use of grommets for flexible hinge toe implants, a case report. Clin Orthop 1995;316: 173–9. [16] Laird L. Silastic joint arthroplasty of the great toe. A review of 228 implants using the double-stemmed implant. Clin Orthop 1990;255: 268–72. [17] Shankar NS, Asaad SS, Craxford AD. Hinged silastic implants of the great toe. Clin Orthop 1991;272:227–34.