The age standardized prevalence of radiographic osteoarthritis of the proximal interphalangeal joint was 16.5 percent in women and 13.5 percent in men in the Framingham Offspring and Community cohorts.1 The frequency of symptomatic proximal interphalangeal joint osteoarthritis ranged from 0.7 to 2 percent (approximately 2.3 million cases using U.S. Standard Population data in 2000 among the same cohorts).1 Nonsurgical treatment may reduce the symptoms such as pain, swelling, stiffness, and decreased grip and pinch strength in the early stages.2,3 However, with the progression of symptoms, surgical intervention is indicated. Numerous techniques have been in practice to restore a stable, painless, and mobile finger. To achieve the most stable and powerful pinch and grip, arthrodesis has been a standard, especially for the radial finger.4,5 Successful arthroplasty for degenerative or posttraumatic proximal interphalangeal joint osteoarthritis has been an elusive goal of reconstructive hand surgery for many years. To maintain mobility of the joint, current treatment options include arthroplasty using silicone, metal, pyrocarbon, and ceramic implants with a volar, lateral, or dorsal approach. Substantial effort has been invested for more than half a century toward the development of small-joint prostheses.
After the introduction of silicone spacers to treat primary degenerative osteoarthritis, posttraumatic osteoarthritis, and inflammatory arthritis of the proximal interphalangeal joint of the finger, its surgical indications and techniques have been well established.6 Ninety-eight percent of the patients experienced good pain relief. Arc of motion increased after surgery except in patients with rheumatoid swan-neck deformities.7 Although the complications associated with silicone implants were relatively low, implant fracture necessitating revision surgery was the major complication, reported in 13 percent, with an average follow-up period of 6.5 years.8 Formerly, most studies reported the use of the dorsal approach. However, recently, favorable outcomes using the volar approach were published.9–12 The volar approach offers the advantages of maintaining the integrity of the extensor mechanism, resulting in complete restoration of extension in the arc of motion. The volar approach permits early postoperative exercise to prevent extensor tendon adhesion and joint contracture. Although the dorsal approach enables wide exposure and easy access to the joint, it risks joint contracture because of extensor tendon adhesion causing extension lag. The lateral approach needs to divide the capsule and collateral ligaments of the proximal interphalangeal joint at their proximal insertion to expose the joint; its outcome is uncertain because articles reporting on lateral approach are few.13–15
The first anatomical surface replacement arthroplasty, developed by Linscheid et al., is a novel cobalt-chrome proximal component and high-molecular-weight polyethylene distal component proximal interphalangeal joint surface replacement implant.16 Both components are designed to fit the internal contours of the medullary canal of the bone. The low profile of the implant preserves the bone stock and the integrity of the collateral ligaments.16 The complication rate after surgery is different according to the approach used. An SR PIP (Small Bone Innovations, Inc., Morrisville, Pa.) prosthesis implanted through a volar approach failed more often than those implanted through a dorsal approach.17 The PyroCarbon implant (Ascension Orthopedics, Inc., Austin, Texas), one of the latest technologies in this field, has an elastic modulus similar to bone with an assumed higher durability and wear resistance, making it a better option for younger patients.18 However, a high complication rate with implant dislocation and subsidence, and eventual poor outcomes, were observed.19–21 Although the volar approach to proximal interphalangeal joint arthroplasty was suggested recently,22 the dorsal approach to the proximal interphalangeal joint was commonly used for these surface replacement arthroplasties.23,24 Various surface replacement arthroplasty designs were introduced that have a concept of anatomical reconstruction unlike silicone spacer in which the implant acts as an internal splint, that requires the soft tissues to rebalance.25 However, there is no comparative study for outcomes of silicone spacer and nonconstrained surface replacement proximal interphalangeal arthroplasty with different approaches.
Evidence on outcomes of implant arthroplasty for proximal interphalangeal joint osteoarthritis is limited because most study designs were retrospective case series of a single implant design and had a small sample size.26–29 Only one study was a prospective, randomized, multicenter comparison of three types of proximal interphalangeal joint arthroplasty, with all using the dorsal approach.21 A systematic review is needed to summarize all the available evidence regarding the type of approach and type of implant design that will have the most favorable outcomes for reconstruction of proximal interphalangeal joint osteoarthritis. The purpose of this study was to conduct a rigorous evaluation of the available literature for silicone and various types of surface replacement arthroplasty for proximal interphalangeal joint osteoarthritis, with an emphasis on different surgical approaches. We aim to analyze the outcomes and complication rates in implant arthroplasty treatment for proximal interphalangeal joint osteoarthritis.
MATERIALS AND METHODS
Applying the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, we performed a systematic literature search of the PubMed and the EMBASE databases with the key words ((arthroplasty OR “joint replacement” OR implant) AND (finger OR digit OR hand)) AND (“proximal interphalangeal” OR PIP).30 We included articles from January 1, 1970, to December 31, 2015. The title and abstract of each article were checked according to the predetermined inclusion and exclusion criteria (Table 1). Because our target conditions for this review were primary degenerative osteoarthritis and posttraumatic osteoarthritis of the finger proximal interphalangeal joint, we excluded the studies that reported inflammatory arthritis only. However, we included articles with combined inclusion criteria for primary degenerative osteoarthritis, posttraumatic osteoarthritis, and inflammatory arthritis.
Articles were screened thoroughly for redundant articles. We included data from the latest version of articles from articles that had the same authors and came from the same institution to avoid duplication of data from the same subjects. We set postoperative arc of motion gained and revision rate as our primary outcomes in this systematic review.
Data Extraction and Analysis
For all inclusive articles, we assessed study characteristics (i.e., type of approach, year of publication, and country of origin), patient and finger demographic data (i.e., female/total ratio, mean age, osteoarthritis ratio, type of implant, type of approach, and finger distribution), number of fingers, mean follow-up period, active arc of motion, extension lag, subjective findings (i.e., pain, patient-reported outcomes, and satisfaction), and grip and pinch strength. Complications were assessed as revision rate. Data for extension lag are important for comparing the volar and dorsal approaches, because we hypothesized that the volar approach causes less extension lag than the dorsal approach. We combined the data of various types of nonconstrained surface replacement arthroplasty into one group for comparison with silicone implants because of the low number of articles with each of the different types of surface replacement arthroplasty.
Overall mean preoperative and postoperative active arc of motion, gain in arc of motion, extension lag, and number of revisions and rate were calculated for each subgroup of patients (i.e., silicone implant arthroplasty with the volar, lateral, and dorsal approaches; and surface replacement arthroplasty with the volar and dorsal approaches). Because most of the articles did not present individual patient data or standard deviation value, we could not compare subgroups statistically. Instead, we ordered the subgroups from small to large or vice versa for outcomes as appropriate.
Study Retrieval and Characteristics
Eight hundred forty-nine citations were identified though the PubMed and EMBASE databases. A flow chart diagram of our study selection is outlined in Figure 1. Of the 148 relevant titles that underwent abstract and full-text review, 40 studies were eligible for final review. Seventeen studies reported on using silicone arthroplasty, 14 studies reported on PyroCarbon arthroplasty, nine studies used SR arthroplasty, two articles reported on Moje arthroplasty (MOJE ceramic implants, Petersburg, Germany), one article used CapFlex-PIP (KLS Martin Group, Tuttlingen, Germany), and one article presented MatOrtho arthroplasty (MatOrtho Ltd., Leatherhead, Surrey, United Kingdom). Two articles contained both volar and dorsal approaches with separately extractable data.31,32 One article contained silicone, PyroCarbon, and SR arthroplasty with separately extractable data.21 Finally, we arrived at 44 studies from 40 articles according to the type of implant and surgical approach.
Study characteristics are listed in Table 2. Twenty-seven studies including silicone and surface replacement arthroplasty were reported from Europe and 13 studies were published from the United States. Most surface replacement arthroplasties were performed with the dorsal approach. Only two articles reported on surface replacement arthroplasty of the proximal interphalangeal joint with the volar approach, whereas for silicone arthroplasty, there were six articles with the volar approach, three articles mainly with the lateral approach, and eight articles with the dorsal approach. There was no article included older than 1980 because of the inclusion/exclusion criteria of this systematic review.
Patient, Implant, and Finger Characteristics
Patient, implant, and finger demographic data are listed in Table 3.4,7,9–15,19–21,23,26–29,31–53 Although the percentage of women was high in general, for posttraumatic osteoarthritis, the female-to-total patient ratio was low and ranged from 13 to 40 percent.15,33–36 Long and ring fingers were commonly operated on with not only silicone but also surface replacement arthroplasty. Mean age at surgery for patients with posttraumatic osteoarthritis only was younger (33 to 40 years) compared with patients with other types of proximal interphalangeal joint osteoarthritis (47 to 68 years).15,33–36 Twenty-three studies included more than one indication for arthroplasty, such as rheumatoid arthritis and psoriatic arthritis, except for primary degenerative or posttraumatic osteoarthritis.
Arc of Motion
The mean follow-up period of silicone arthroplasty with the volar approach and the dorsal approach, and surface replacement arthroplasty with the dorsal approach, was 41.2, 57.6, and 48.6 months, respectively. The mean postoperative arc of motion and the mean gain in arc of motion of silicone with the volar approach were 58 and 17 degrees, respectively, which were greater than silicone with the dorsal approach at 51 and 12 degrees, and also larger than surface replacement with the dorsal approach at 51 and 8 degrees, respectively. The order of the mean gain in arc of motion from large to small was silicone volar (17 degrees), silicone lateral (16 degrees), silicone dorsal (12 degrees), surface replacement volar (9 degrees), and surface replacement dorsal (8 degrees) (Table 4). 4,7,9–15,19–21,23,27–29,31–53 Because the standard deviation could not be extracted from the articles, statistical testing for significance was not possible.
Preoperative and postoperative extension lag were not reported in all included articles. The mean postoperative extension lag of silicone implant with the volar approach and surface replacement arthroplasty with the dorsal approach was 5 and 14 degrees, respectively. The order of the extension lag from small to large was silicone volar (5 degrees), silicone dorsal (8 degrees), silicone lateral (12 degrees), surface replacement dorsal (14 degrees), and surface replacement volar (17 degrees) (Table 5).4,7,9–13,23,26,27,43,33,35,36,38,39,43,44,50–53
Silicone arthroplasty with the volar approach had the lowest revision rate (all revisions including minor and salvage procedures), at 6 percent. The revision rate of surface replacement with the dorsal approach was 18 percent. The mean follow-up period of silicone arthroplasty with the volar approach and the dorsal approach and surface replacement with the dorsal approach was 41.2, 17, and 51 months, respectively. The order of revision rate from low to high was silicone volar (6 percent), silicone lateral (10 percent), silicone dorsal (11 percent), surface replacement volar (17 percent), and surface replacement dorsal (18 percent). Among those undergoing surface replacement with the dorsal approach, the most common types of revision surgery were revision to the silicone implant (23 percent), arthrodesis (14 percent), revision with or without cement to the original implant (11 percent), explantation of the implant (10 percent), amputation (4 percent), and other procedures (38 percent) (Table 6). 4,7,9–15,19–21,23,26–29,31–53
Most articles reported improvement of pain in patients after surgery. A visual analogue scale (visual analogue scale score of 0 to 10; where pain free is 0 and maximum pain is 10) was used in 23 articles. Postoperative pain was 0 to 4.0 regardless of the type of implant and surgical approach. The Disabilities of the Arm, Shoulder, and Hand (DASH) or the Quick DASH questionnaire was used in 16 articles. The postoperative mean Disabilities of the Arm, Shoulder, and Hand scores of patients with silicone implants were significantly better than those of patients with PyroCarbon implants (p = 0.006).21 The Michigan Hand Outcomes Questionnaire was used in four articles. The Patient Evaluation Measure was used in three articles, and the Canadian Occupational Performance Measure was used in two articles. Improvement of the patient-reported outcomes scores after surgery was found in all but one study.36 Sixty-six percent of articles reported on the satisfaction of patients after surgery. Most of the patients were satisfied regardless of the implant design and surgical approach. [See Appendix, Supplemental Digital Content 1, which shows the subjective findings (pain, patient-reported outcomes, and satisfaction) before and after proximal interphalangeal joint implant arthroplasty, http://links.lww.com/PRS/C129.]
Grip and Pinch Strength
Data on grip and pinch strength before and after surgery were sparse. (See Appendix, Supplemental Digital Content 2, which shows the grip and pinch strength before and after proximal interphalangeal joint implant arthroplasty, http://links.lww.com/PRS/C130.) Postoperative grip and pinch strength improved regardless of the type of implant and surgical approach13,20,33,36–41; however, one study reported a decrease in grip strength from 21 kg preoperatively to 17 kg at 10-year follow-up.42
We hypothesized that silicone arthroplasty with the volar approach has less extension lag and better gain in arc of motion compared with other approaches and implant designs. In our systematic review, silicone implant with the volar approach showed better outcomes in terms of gain in arc of motion, extension lag, and revision rate compared with a different approach and surface replacement arthroplasty.
Implant arthroplasty for the proximal interphalangeal joint is indicated when patients do not recover after nonsurgical treatment such as self-management, behavioral changes, joint supports, adjunct pharmacologic treatments and/or topical nonsteroidal antiinflammatory drugs, and intraarticular corticosteroid injections.54 However, revision rates after arthroplasty range from 6 to 18 percent at the mean follow-up ranging from 17 to 80 months.
Various types of implant design for finger proximal interphalangeal joint surface replacement have been developed so far. PyroCarbon and SR PIP are currently the most commonly used and reported implants. In addition, the use of ceramic unconstrained two-component implant (Moje), a modular prosthesis (CapFlex-PIP), and a cobalt-chromium metal-on-polyethylene mobile-bearing surface replacement arthroplasty (MatOrtho) was reported recently.51–53 The Moje ceramic implant is coated by hydroxyapatite to advance bony ingrowths and to preclude loosening of the prosthesis.51 CapFlex was designed to improve lateral stability with press fit fixation because collateral ligaments are preserved and to minimize the bone resection.52 MatOrtho is a cementless prosthesis with hydroxyapatite coating to hasten bony integration. It also preserves the collateral ligament attachments.53 These anatomical unconstrained implants have a risk of joint instability. Careful soft-tissue balance and appropriate alignment of the finger are necessary for success with surface replacement arthroplasty.25
Nearly half a century passed after Swanson first reported silicone implants for replacement of degenerated or damaged joints in the hand.6 Swanson et al. reported favorable, long-term, and rewarding results for proximal interphalangeal joint with the dorsal approach.7 Most authors favored a dorsal approach for silicone implants because of ease of joint exposure despite the use of other approaches.4,33,34 The dorsal approach uses a dorsal incision over the proximal interphalangeal joint and longitudinal division of the central slip of the extensor apparatus, or Chamay’s technique by lifting the central dorsal aponeurosis.21,41 Although the dorsal approach enables easy access to the joint and is used widely, it possess the risk of joint contracture because of extensor tendon adhesion causing extension lag. In contrast, after Schneider first reported the volar approach for proximal interphalangeal joint osteoarthritis in 1991, beneficial outcomes have been reported using this approach more recently.9,12,37 The volar approach consists of a volar zigzag incision over the proximal interphalangeal joint crease, and release of the A3 pulley, volar plate, and partial collateral ligaments. The volar approach does not always require postoperative splinting and enables range-of-motion exercises immediately after surgery.37 Therefore, we hypothesized that silicone implant arthroplasty with the volar approach has the best gain in arc of motion and less extension lag after surgery. An 8-year follow-up study of silicone arthroplasty for the proximal interphalangeal joint with the volar approach demonstrated their durability, with only one revision operation (3 percent) performed.10 Although a comparative study of dorsal and volar approaches showed no significant difference in the two groups in terms of postoperative arc of motion, the authors preferred the volar approach for silicone arthroplasty of proximal interphalangeal joints in cases for which no dorsal bony or extensor tendon correction was necessary because the volar approach enabled early active and more aggressive rehabilitation.31 Minamikawa et al. reported on the greater lateral laxity of silicone implants compared with surface replacement prosthesis in their cadaveric anatomical study.55 Silicone implant becomes encapsulated, and with appropriate surgical procedures, including reattachment of collateral ligament, stability of the joint can be restored.56 In our systematic review on finger characteristics, not only did the ulnar little and ring fingers undergo silicone arthroplasty, but silicone spacers were implanted in the index and the long fingers even though lateral stability of pinch was a concern.
A randomized study comparing silicone and two types of surface replacement arthroplasty for degenerative proximal interphalangeal joint osteoarthritis showed that implant explantations were required in 11, 27, and 39 percent of patients, respectively. Silicone arthroplasty had fewer complications among the three groups.21 In this systematic review, the subgroup of silicone arthroplasty with the volar approach had the lowest rate of revision (6 percent at the mean follow-up of 41 months) among all the subgroups. Comparing silicone volar approach with dorsal, 47 revisions (44 percent) because of stiffness or extensor tendon adhesion were reported among the silicone with dorsal approach subgroup. There was no tenolysis reported in the silicone with volar approach subgroup. This difference could be attributable to their approaches. Furthermore, surface replacement arthroplasty with the dorsal approach had the highest rate of revision, including tenolysis (18 percent at the mean follow-up of 51 months) among all the subgroups. Thirty-six revision operations (23 percent) after surface replacement arthroplasty with the dorsal approach were conversions to silicone implants. There is a clear difference in the number of revisions between silicone arthroplasty with the volar approach and silicone or surface replacement arthroplasty with the dorsal approach.
Sixty-six percent of articles reported higher satisfaction after surgery regardless of the approach and implant design. Among the articles that reported on pain status, the authors found general improvement of pain after surgery. These results suggest that there is a definite need of implant arthroplasty for degenerative or posttraumatic proximal interphalangeal joint osteoarthritis.
Postoperative grip and pinch strength improved regardless of the type of implants and surgical approach. However, most articles failed to report on grip and pinch strength. We found a tendency that recent articles published in the twenty-first century reported on grip and pinch strength more rigorously compared with previous articles. These data variables must be included in future studies because grip strength and pinch strength are among the important factors for evaluating functional status.
Our study has several limitations, as with any systematic review. The quality of the available literature influenced our review because most articles were retrospective case series, which may have selection bias. We attempted to reduce this bias with strict inclusion and exclusion criteria. We also included both English and non-English articles to collect data on more numbers of patients from 1970 on. Most articles failed to report preoperative arc of motion, pain status, patient-reported outcomes, and grip and pinch strength. Furthermore, most articles did not report standard errors or deviations. Therefore, it was difficult to analyze statistically when complete data reporting was lacking. We recommend that comprehensive reporting be performed, including clear inclusion and exclusion criteria; patients and finger characteristics; and individual data of preoperative and postoperative outcomes using subjective and objective evaluation such as arc of motion, extension lag, complication, grip and pinch strength, pain status, patient-reported outcomes, and satisfaction, with an appropriate follow-up period in future publications.
We found that silicone implant arthroplasty with the volar approach showed the best gain in arc of motion, had less extension lag, and had fewer complications after surgery among all the implant designs and surgical approaches. This volar approach using the silicone implant is the preferred technique adopted by the senior author (K.C.C.) because of the lower revision rate, ease of revision if necessary, minimal extension lag, and best arc of motion. Level I evidence using prospective, randomized, controlled trials for proximal interphalangeal joint arthroplasty with different implant designs and surgical approaches is required. Most importantly, the future for this critical joint is to develop an anatomical implant that will osteointegrate by critically evaluating current and past implants designed for continued refinement.
Research reported in this publication was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award number 2 K24-AR053120-06.
The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
1. Haugen IK, Englund M, Aliabadi P, et al. Prevalence, incidence and progression of hand osteoarthritis in the general population: The Framingham Osteoarthritis Study. Ann Rheum Dis. 2011;70:15811586.
2. Valdes K, Marik T. A systematic review of conservative interventions for osteoarthritis of the hand. J Hand Ther. 2010;23:334350; quiz 351.
3. Beasley J. Osteoarthritis and rheumatoid arthritis: Conservative therapeutic management. J Hand Ther. 2012;25:163171; quiz 172.
4. Pellegrini VD Jr, Burton RI. Osteoarthritis of the proximal interphalangeal joint of the hand: Arthroplasty or fusion? J Hand Surg Am. 1990;15:194209.
5. Vitale MA, Fruth KM, Rizzo M, Moran SL, Kakar S. Prosthetic arthroplasty versus arthrodesis for osteoarthritis and posttraumatic arthritis of the index finger proximal interphalangeal joint. J Hand Surg Am. 2015;40:19371948.
6. Swanson AB. Silicone rubber implants for replacement of arthritis or destroyed joints in the hand. Surg Clin North Am. 1968;48:11131127.
7. Swanson AB, Maupin BK, Gajjar NV, Swanson GD. Flexible implant arthroplasty in the proximal interphalangeal joint of the hand. J Hand Surg Am. 1985;10:796805.
8. Takigawa S, Meletiou S, Sauerbier M, Cooney WP. Long-term assessment of Swanson implant arthroplasty in the proximal interphalangeal joint of the hand. J Hand Surg Am. 2004;29:785795.
9. Proubasta IR, Lamas CG, Natera L, Millan A. Silicone proximal interphalangeal joint arthroplasty for primary osteoarthritis using a volar approach. J Hand Surg Am. 2014;39:10751081.
10. Lautenbach M, Kim S, Berndsen M, Eisenschenk A. The palmar approach for PIP-arthroplasty according to Simmen: Results after 8 years follow-up. J Orthop Sci. 2014;19:722728.
11. Lin HH, Wyrick JD, Stern PJ. Proximal interphalangeal joint silicone replacement arthroplasty: Clinical results using an anterior approach. J Hand Surg Am. 1995;20:123132.
12. Bouacida S, Lazerges C, Coulet B, Chammas M. Proximal interphalangeal joint arthroplasty with Neuflex implants: Relevance of the volar approach and early rehabilitation. Chir Main 2014;33:350355.
13. Merle M, Villani F, Lallemand B, Vaienti L. Proximal interphalangeal joint arthroplasty with silicone implants (NeuFlex) by a lateral approach: A series of 51 cases. J Hand Surg Eur Vol. 2012;37:5055.
14. Stahlenbrecher A, Hoch J. Proximal interphalangeal joint silicone arthroplasty: Comparison of Swanson and NeuFlex implants using a new evaluation score (in German). Handchir Mikrochir Plast Chir. 2009;41:156165.
15. Hage JJ, Yoe EP, Zevering JP, de Groot PJ. Proximal interphalangeal joint silicone arthroplasty for posttraumatic arthritis. J Hand Surg Am. 1999;24:7377.
16. Linscheid RL, Dobyns JH, Beckenbaugh RD, Cooney WP III. Proximal interphalangeal joint arthroplasty with a total joint design. Mayo Clin Proc. 1979;54:227240.
17. Murray PM, Linscheid RL, Cooney WP III, Baker V, Heckman MG. Long-term outcomes of proximal interphalangeal joint surface replacement arthroplasty. J Bone Joint Surg Am. 2012;94:11201128.
18. Cook SD, Beckenbaugh RD, Redondo J, Popich LS, Klawitter JJ, Linscheid RL. Long-term follow-up of pyrolytic carbon metacarpophalangeal implants. J Bone Joint Surg Am. 1999;81:635648.
19. Sweets TM, Stern PJ. Pyrolytic carbon resurfacing arthroplasty for osteoarthritis of the proximal interphalangeal joint of the finger. J Bone Joint Surg Am. 2011;93:14171425.
20. Ono S, Shauver MJ, Chang KW, Chung KC. Outcomes of pyrolytic carbon arthroplasty for the proximal interphalangeal joint at 44 months’ mean follow-up. Plast Reconstr Surg. 2012;129:11391150.
21. Daecke W, Kaszap B, Martini AK, Hagena FW, Rieck B, Jung M. A prospective, randomized comparison of 3 types of proximal interphalangeal joint arthroplasty. J Hand Surg Am. 2012;37:17701779.e1.
22. Duncan SF, Merritt MV, Kakinoki R. The volar approach to proximal interphalangeal joint arthroplasty. Tech Hand Up Extrem Surg. 2009;13:4753.
23. Dickson DR, Nuttall D, Watts AC, Talwalkar SC, Hayton M, Trail IA. Pyrocarbon proximal interphalangeal joint arthroplasty: Minimum five-year follow-up. J Hand Surg Am. 2015;40:21422148.e4.
24. Storey PA, Goddard M, Clegg C, Birks ME, Bostock SH. Pyrocarbon proximal interphalangeal joint arthroplasty: A medium to long term follow-up of a single surgeon series. J Hand Surg Eur Vol. 2015;40:952956.
25. Watts A, Trail I. Anatomical small joint replacement in the hand. J Bone Joint Surg Br. 2011;1:16.
26. Stoecklein HH, Garg R, Wolfe SW. Surface replacement arthroplasty of the proximal interphalangeal joint using a volar approach: Case series. J Hand Surg Am. 2011;36:10151021.
27. Amirtharajah M, Fufa D, Lightdale N, Weiland A. Conical, radiographic, and patient-reported results of surface replacing proximal interphalangeal joint arthroplasty of the hand. Iowa Orthop J. 2011;31:140144.
28. Heers G, Springorum HR, Baier C, Götz J, Grifka J, Renkawitz T. Proximal interphalangeal joint replacement with an unconstrained pyrocarbon prosthesis (Ascension): A long-term follow-up. J Hand Surg Eur Vol. 2013;38:680685.
29. Hutt JR, Gilleard O, Hacker A, Citron N. Medium-term outcomes of pyrocarbon arthroplasty of the proximal interphalangeal joint. J Hand Surg Eur Vol. 2012;37:497500.
30. Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. J Clin Epidemiol. 2009;62:10061012.
31. Herren DB, Simmen BR. Palmar approach in flexible implant arthroplasty of the proximal interphalangeal joint. Clin Orthop Relat Res. 2000;371:131135.
32. Jennings CD, Livingstone DP. Surface replacement arthroplasty of the proximal interphalangeal joint using the SR PIP implant: Long-term results. J Hand Surg Am. 2015;40:469473.e6.
33. Mathoulin C, Gilbert A. Arthroplasty of the proximal interphalangeal joint using the Sutter implant for traumatic joint destruction. J Hand Surg Br. 1999;24:565569.
34. Silva JB, Schwanke RL, Vicente MG, Fridman M. Arthroplasty with silicone implant in post traumatic lesions of the proximal interphalangeal joint (in Portuguese). Rev Bras Ortop. 1998;33:7982.
35. Cesari B, Alnot JY. Proximal interphalangeal joint implant arthroplasty for degenerative or post-traumatic arthritis (in French). Main 1997;2:8596.
36. Nunley RM, Boyer MI, Goldfarb CA. Pyrolytic carbon arthroplasty for posttraumatic arthritis of the proximal interphalangeal joint. J Hand Surg Am. 2006;31:14681474.
37. Schneider LH. Proximal interphalangeal joint arthroplasty: The volar approach. Semin Arthroplasty 1991;2:139147.
38. Namdari S, Weiss AP. Anatomically neutral silicone small joint arthroplasty for osteoarthritis. J Hand Surg Am. 2009;34:292300.
39. Lawson-Smith M, Policinski I, Smith J, Roberts C. Results of surface replacement proximal interphalangeal joint arthroplasty. J Arthrosc Joint Surg. 2014;1:8286.
40. Vogt R, Aerni M, Ampofo C, Schmelzer-Schmied N. Proximal interphalangeal (PIP) finger prosthesis—What have we learnt? Experiences over 10 years (in German). Handchir Mikrochir Plast Chir. 2012;44:293299.
41. Luther C, Germann G, Sauerbier M. Proximal interphalangeal joint replacement with surface replacement arthroplasty (SR-PIP): Functional results and complications. Hand (N Y) 2010;5:233240.
42. Johnstone BR, Fitzgerald M, Smith KR, Currie LJ. Cemented versus uncemented surface replacement arthroplasty of the proximal interphalangeal joint with a mean 5-year follow-up. J Hand Surg Am. 2008;33:726732.
43. Tägil M, Geijer M, Abramo A, Kopylov P. Ten years’ experience with a pyrocarbon prosthesis replacing the proximal interphalangeal joint: A prospective clinical and radiographic follow-up. J Hand Surg Eur Vol. 2014;39:587595.
44. Reissner L, Schindele S, Hensler S, Marks M, Herren DB. Ten year follow-up of pyrocarbon implants for proximal interphalangeal joint replacement. J Hand Surg Eur Vol. 2014;39:582586.
45. Desai A, Gould FJ, Mackay DC. Outcome of pyrocarbon proximal interphalangeal joint replacement. Hand Surg. 2014;19:7783.
46. McGuire DT, White CD, Carter SL, Solomons MW. Pyrocarbon proximal interphalangeal joint arthroplasty: Outcomes of a cohort study. J Hand Surg Eur Vol. 2012;37:490496.
47. Mashhadi SA, Chandrasekharan L, Pickford MA. Pyrolytic carbon arthroplasty for the proximal interphalangeal joint: Results after minimum 3 years of follow-up. J Hand Surg Eur Vol. 2012;37:501505.
48. Meier R, Schulz M, Krimmer H, Stütz N, Lanz U. Proximal interphalangeal joint replacement with pyrolytic carbon prostheses. Oper Orthop Traumatol. 2007;19:115.
49. Bravo CJ, Rizzo M, Hormel KB, Beckenbaugh RD. Pyrolytic carbon proximal interphalangeal joint arthroplasty: Results with minimum two-year follow-up evaluation. J Hand Surg Am. 2007;32:111.
50. Wesemann A, Flügel M, Mamarvar M. Moje prosthesis for the proximal interphalangeal joint (in German). Handchir Mikrochir Plast Chir. 2008;40:189196.
51. Pettersson K, Wagnsjö P, Hulin E. Replacement of proximal interphalangeal joints with new ceramic arthroplasty: A prospective series of 20 proximal interphalangeal joint replacements. Scand J Plast Reconstr Surg Hand Surg. 2006;40:291296.
52. Schindele SF, Hensler S, Audigé L, Marks M, Herren DB. A modular surface gliding implant (CapFlex-PIP) for proximal interphalangeal joint osteoarthritis: A prospective case series. J Hand Surg Am. 2015;40:334340.
53. Flannery O, Harley O, Badge R, Birch A, Nuttall D, Trail IA. MatOrtho proximal interphalangeal joint arthroplasty: Minimum 2-year follow-up. J Hand Surg Eur. 2015;41:910916
54. Conaghan PG, Dickson J, Grant RL; Guideline Development Group. Care and management of osteoarthritis in adults: Summary of NICE guidance. BMJ 2008;336:502503.
55. Minamikawa Y, Imaeda T, Amadio PC, Linscheid RL, Cooney WP, An KN. Lateral stability of proximal interphalangeal joint replacement. J Hand Surg Am. 1994;19:10501054.
56. Swanson AB. Lateral stability of proximal interphalangeal joint replacement. J Hand Surg Am. 1995;20:701702.