Surgical Management of Enchondromas of the Hand: A 12-Year Experience

Abstract

Objective  Enchondromas are benign tumours of hyaline cartilage most frequently arising in the bones of the hand and the optimum surgical management strategy for these is debated. We present an audit of the surgical management of 57 enchondromas referred to our tertiary hand surgery department over a period of 12 years (2008–2020) and describe our surgical technique for this procedure as well as a comparison with other studies in the literature.

Materials and Methods  Retrospective audit of our practice. Data were extracted from our institutional operative database to identify all patients undergoing surgical management of enchondromas during the time period. The individual electronic patient records were then evaluated to extract demographics and outcome data.

Results  Our results demonstrate excellent clearance of enchondroma (74% Tordai group 1 radiological resolution) with very low complication rates and no recurrence. Our results also emphasize the importance of surgical management of enchondromas to allow diagnosis of rare chondrosarcoma (3.5% in this study).

Conclusion  A larger randomized controlled trial is still required to adequately determine the differences between the surgical options available and determine the best possible surgical approach to these cases. Level of evidence is III.

Introduction

Enchondromas are benign tumors of hyaline cartilage most frequently arising in the bones of the hand. They are the most common primary bone tumor seen in the bones of the hand and are frequently seen in hand surgery units. 1 2 3 4 While there is a risk of malignant transformation, this is low with very low potential for metastasis, and therefore, there is ongoing debate between conservative and surgical management for these lesions. 3

We advocate surgical management both due to the risk of recurrent pathological fractures through these lesions if managed conservatively and the difficulty in distinguishing benign enchondroma from malignant chondrosarcoma. Surgical management allows diagnosis of these rare cases of malignant chondrosarcoma which can be difficult to distinguish clinically or radiologically without tissue diagnosis. 5 Furthermore, there is potential for chondrosarcomas to arise from benign existing enchondromas and surgical management has the potential to reduce this risk versus conservative management. 6 7 8 9

The gold standard of surgical management for enchondromas has been excision by curettage and reconstruction of the bony defect with autograft bone graft. 10 However, recently, questions have been raised regarding whether bone grafting is necessary at all, or whether similar results can be obtained through the use of autograft or bone substitutes without the need for bone graft donor-site surgery. 11 12 13 Despite several of these articles concluding that grafting is not necessary, others continue to advocate the use of grafting for these defects. The question of to graft or not to graft these defects remains contentious.

We have audited the surgical management of enchondromas referred to our tertiary hand surgery department over a period of 12 years (2008–2020) and describe our surgical technique for this procedure. We have reviewed our outcomes and evaluate our experience using the “coffin-lid technique” against others in the published literature.

Methods

Institutional approval was granted for a retrospective audit of our practice. Data were extracted from our institutional operative database to identify all patients undergoing surgical management of enchondromas during the time period. The individual electronic patient records were then evaluated to extract demographics and outcome data.

The sizes of the lesions were estimated by the measurement of the lesions on preoperative plain radiographs in three dimensions. Between September 2008 and August 2020, a total of 47 patients underwent surgery for management of enchondroma of the hand in our unit. Our practice is to perform these procedures under general or regional anesthesia with arm tourniquet. Our surgical technique is the “coffin-lid” method.

We approach these lesions dorsally exposing the bone through a longitudinal incision through the extensor tendon. Using a mini saw or osteotomes, a window of bone is excised allowing the enchondroma to be removed by curettage. The specimen is sent for histological examination to confirm the diagnosis. If used, bone graft is harvested and fragments inset and compressed into the defect before the bony window is replaced and secured with PDS sutures ( Fig. 1 ). The extensor tendon is repaired with PDS and skin closed. The patient is usually splinted postoperatively and attends hand therapy for follow-up.

Fig. 1.

Operative technique: the “coffin-lid” method: ( A ) Dorsal exposure and marking of the cortical window—the coffin lid (where possible, the periosteum is left intact on one side of the window to hold the lid in place), ( B ) cortical window opened allowing curettage of lesion, ( C ) lesion completely excised ready to receive bone graft, ( D ) bone graft (auto- or allograft compressed into defect), and ( E ) coffin lid closed and sutured into position.

Our decision on whether to use or not to use bone graft is predominantly down to the size of the lesion and the involvement of the cortex. In general, smaller lesions do not require grafting. The senior author advocates the use of bone graft in any cases with prior fracture due to the extension into the cortex. Where patients present with pathological fracture, these are initially managed conservatively, and excision surgery is undertaken approximately 3 months later following fracture union. It is our usual follow-up protocol to take plain radiographs at 6 months postoperatively both to determine radiological resolution of the lesion and also as a new baseline image of the “new normal” following grafting, to allow comparison if the patient develops any further problems the digit in future.

Results

Average age at presentation was 37 years (range: 8–76 years) with a female-to-male ratio of 28:19. There were five pediatric patients (age ≤ 16 years), two of whom had a known prior diagnosis of Ollier's disease. The majority presented with solitary enchondromas; however, three patients presented with multiple lesions. Due to these multiple cases, a total of 57 enchondromas were operated on during this time period.

The location of these enchondromas was distributed across all bones of the hand (11 in distal phalanges, 14 in middle phalanges, 16 in proximal phalanges, and 11 in the metacarpals). There was a preponderance for the ulnar-sided digits ( Fig. 2 ).

Fig. 2.

Distribution of enchondromas in our study across the bones of the hand.

The majority of patients presented following pathological fracture through the lesion (74%). The remaining patients presented due to progressive lump (8.5%), pain (4.3%), or due to recurrence of lesions previously operated on in other centers. Four cases (8.5%) presented as an incidental finding on imaging.

Two patients underwent manipulation under anesthetic of pathological fractures only with no excision of the lesion. Forty-five patients underwent surgery to excise the enchondroma ± reconstruction of the defect with a bone graft.

Forty-two of these patients underwent surgery using the coffin-lid technique described. Fourteen patients underwent excision without grafting. In the remaining 33 patients, bone graft was used to fill the defect; in 21 patients, the iliac crest was used as the donor site, and in 3, this was harvested from the distal radius. Decellularized cadaveric graft was used in seven cases. The average size of grafted defects was 1.58 cm ³ compared with 1.30 cm for ungrafted defects. Grafted defects were consistently larger than ungrafted defects across all bones; however, this difference was more marked for metacarpal lesions ( Table 1 ). Three patients had very extensive distal phalanx lesions and we opted for terminalization in two cases and one patient underwent excision of the distal phalanx of the thumb and reconstruction with a custom osseointegrated prosthetic implant. Over time, we note a shift in our practice away from the use of allograft toward no grafting or decellularized graft; however, for very large defects, allograft remains our preference.

Table 1. Average sizes of the lesions that were treated with grafting (autograft or allograft) versus those managed with no graft.

	Average size of grafted lesion	Average size of ungrafted lesion
Total	1.58 cm 3	1.30 cm 3
Distal phalanx	0.67 cm 3	0.58 cm 3
Middle phalanx	0.79 cm 3	0.76 cm 3
Proximal phalanx	1.90 cm 3	1.88 cm 3
Metacarpal	2.71 cm 3	1.40 cm 3

Mean length of follow-up was 10 months postsurgery (range: 1–33 months). Complication rates were low with no episodes of infection, nonunion, or subsequent fracture in any patient. Six patients suffered stiffness/contracture, and of these, three opted to undergo tenolysis surgery to improve their hand function. Rates of stiffness were slightly higher in the autograft group (20%) compared with those where no graft was used (7%).

There were very few donor-site complications. One patient suffered neuropraxia of the superficial radial nerve following graft harvest from the distal radius. One patient suffered allograft leakage causing delayed wound healing.

Follow-up X-rays were obtained for 51% of patients. These demonstrated radiological clearance of the enchondroma (Tordai group 1 11 ) in 74% of cases ( Fig. 3 ). There were no confirmed cases of recurrence at the same site; however, on follow-up X-ray, one patient developed a small area of lucency considered to be a possible recurrence, this was managed conservatively and required no further surgical intervention. Both patients with Ollier's disease remain under active surveillance for other lesions, and one patient underwent surgery on both hands during this time period.

Fig. 3.

Left middle finger metacarpal enchondroma treated with excision and iliac crest bone graft. Preoperative versus 1-year follow-up showing radiological resolution (Tordai group 1).

There were no significant differences in outcome (radiological resolution) depending on type of graft used (autograft 83%, bone substitute 60%, and no graft 80%). Table 2 shows the comparison between the grafted and ungrafted groups (numbers are too low to reach statistical significance).

Table 2. Comparison of outcomes between grafted and ungrafted cohorts in this study.

	Total ( n  = 45)	Graft ( n  = 31)	No graft ( n  = 14)	Autograft ( n  = 24)	Allograft ( n  = 7)
Radiographic resolution (Tordai group 1)	74%	76%	80%	83%	60%
Infection rate	0%	0%	0%	0%	0%
Fracture rate	0%	0%	0%	0%	0%
Donor-site complication	4%	3%	n/a	4%	14% (local reaction to allograft)
Recurrence	2%	3%	0%	0%	14%
Stiffness	13%	16%	7%	21%	0%
Tenolysis	7%	10%	0%	13%	0%

Histological analysis confirmed the diagnosis of enchondroma in 42 patients. Two patients were diagnosed with chondrosarcoma grade 1 and subsequently followed up in the regional sarcoma center. One patient was found to have an osteoclast-rich lesion with no evidence of malignancy.

Discussion

This is one of the largest case series from a single unit detailing the surgical management of enchondromas and our results compare favorably with other studies published in the literature. Table 3 shows the comparison of our reported results with other studies in the literature reporting on more than 20 cases of surgical management of enchondroma. 10 12 14 15 16 17 18 19 20 21 22 23 24 25 26

Table 3. [CE6]Comparison of current study with previously published results in the hand literature.

Authors	Journal	Year	No. of patients	No. of enchondromas managed surgically	Presented with pathological fracture	Graft used	Criteria for grafting	Donor-site complications	Histology	Average length of follow-up	Infection	Fracture	Stiffness and tenolysis	Radiological union	Recurrence
Our study			47	57	74%	14 no graft, 33 graft (21 iliac, 3 radius, 7 bone substitute)	See text	1	42 confirmed enchondroma 2 chondrosarcoma grade 1, 1 osteoclast-rich lesion (no malignancy)	10 mo	0	0	10% stiffness, 5% tenolysis	Follow-up X-rays for 51% of patients. Of these, 74% Tordai group 1	1
Çapkin et al	Cureus	2020	32	32	25%	Iliac 24, radius 8	All grafted	3	All confirmed enchondroma	54 mo	6%	0	16% stiffness, no tenolysis	Tordai group 1 in 88%, group 2 in 12%	0
Sollaci and Araújo	Revista Brasileira de Ortopedia	2019	48	48	31%	Iliac crest	All grafted	Not reported	Not reported	20 mo	0	2%	6% stiffness, 2% tenolysis	All fully integrated	1
Sun et al	Journal of Orthopaedics, Trauma and Rehabilitation	2017	20	20	70%	16 autograft, 3 bone substitute, 1 cement	All grafted	2	All confirmed enchondroma	23 mo	5%	Not reported	35% stiffness, 15% tenolysis	Trabecular remodeling in all cases except cement	0
Zhou et al	Medicine	2017	92	92	29%	No graft 26, autograft 37, bone substitute 29	Not reported	Not reported	Not reported	At least 6 mo	1%	0	0	Healing progressive and complete in all cases	0
Lu et al	Medicine	2016	34	34	0%	10 no graft, 24 calcium phosphate cement	Grafting large defects or pathological fracture	Not reported	All confirmed enchondroma	86 mo	9%	3% delayed union	Not reported	Not reported	0
Bachoura et al	Hand	2015	24	26	50%	No graft	n/a	n/a	All confirmed enchondroma	26 mo	0	0	12%	68%	1
Hung et al	Hong Kong Medical Journal	2015	24	24	42%	13 autologous (iliac) graft, 11 bone substitute	Surgeon and patient preference	4 (3 numbness, 1 pain)	All confirmed enchondroma	59 mo	8%	0	13%	Bone incorporation in all	1
Georgiannos et al	Hand	2015	82	82	15%	Phenol washout then bone substitute	All bone substitute	n/a	All confirmed enchondroma	Minimum 60 mo	0	0	All patients excellent functional outcome	Healing confirmed radiologically	0
Sassoon et al	Journal of Hand Surgery - American Volume	2012	80	102	40%	Autograft 54 (iliac 26, radius 26, other 2), bone substitute 40, no graft 8	Surgeon choice	Not reported	All confirmed enchondroma	38 mo	5%	1%	29% stiffness, 3% tenolysis	61% grade 1, 25% grade 2, and 13% grade 3	7
Morii et al	Journal of Orthopaedic Science	2010	38	38	50%	No graft	n/a	n/a	All confirmed enchondroma	24 mo	0	0	0	All	0
Figl and Leixnering	Archives of Orthopaedic & Trauma Surgery	2009	35	29	10%	3 no graft, 26 iliac crest autograft	No graft if minor defect and bone stability preserved	None	All confirmed enchondroma	47 mo	Not reported	Not reported	7%	Not reported	0
Gaulke and Suppelna	Journal of Hand Surgery - British Volume	2004	21	21	43%	20 cancellous bone graft 1, artificial	Not reported	Not reported	Not reported	108 mo	Not reported	Not reported	0	Seven patients had persisting bone defects	3 (2 requiring reoperation)
Goto et al	Journal of Hand Surgery - British Volume	2002	23	25	40%	No grafting	N/a	N/a	All confirmed enchondroma	19 mo	0	0	4%	Tordai group 1 in 84%, group 2 in 16%	0
Kuur et al	Journal of Hand Surgery - British Volume	1989	21	21	38%	15 bone grafting (iliac crest 8, radius 7), 5 no graft/bone chips, 1 amputation	Large area involved - cancellous bone graft was used	None	Not reported	55 mo	Not reported	Not reported	10%	Three patients had small persisting bone defects	0
Bauer et al	Journal of Hand Surgery - American Volume	1988	30	30	50%	15 bank bone graft, 15 iliac crest	Surgeon dependent	2, 1 numbness/pain, 1 infection	Not reported	35 mo	0	0	0	Time to incorporation 2–3 mo longer for bank graft than cancellous	0

Abbreviation: n/a, not applicable.

The distribution of lesions in our study correlates to the previous experience in the literature demonstrating both a preponderance for the ulnar digits and for the proximal phalanges. 27 However, while the results of Gaulke suggest this difference is significant and cannot be attributed to chance, there does not appear to be an accepted explanation or mechanism by which this occurs. Further studies, for example, at a molecular signaling level, may be necessary to elucidate such a mechanism. However, due to the bias in this data (collected from published surgical studies), it is possible that this does not reflect the true distribution of enchondromata but that ulnar-sided lesions are more likely to present for surgical intervention, for example, through higher rate of pathological fracture in ulnar-sided lesions.

Our study also demonstrates the importance of surgical management of enchondromas versus the conservative “watch-and-wait” approach. Many studies in the literature specifically exclude lesions that were not proven enchondromas from their analysis; therefore, the rates of chondrosarcomas identified at this type of surgery are not well documented. In this series of only 57 lesions, 2 (3.5%) were found to be malignant chondrosarcomas with no suspicion of this on preoperative imaging. This highlights the difficulties in distinguishing enchondromas from their malignant counterparts on clinical and radiological examinations, and without histological confirmation, it is impossible to be certain of the diagnosis. Grade 1 chondrosarcomas have good prognoses if detected and managed early, and given the relatively low complication rates of enchondroma excision surgery, we believe the ability to detect these rare malignant cases justifies surgical management of all enchondromas of the hand. If opting for conservative treatment, patients must be counseled of this risk and should be kept under radiographic surveillance with a low threshold for excision if lesions are rapidly changing.

We believe our coffin-lid technique allows curative resection of the lesion with low rates of recurrence and of complications. Indeed, there is evidence that replacement of the cortical window in a technique such as this improves time to regain mechanical strength and is, therefore, beneficial for patient recovery. 12 Where their technique is described, many units appear to use a variation on this technique. 14 15 16

There is ongoing debate in the literature about the optimal strategy to approach reconstruction of the defect following enchondroma excision, whether grafting is necessary at all and the relative merits of autograft versus allograft/bone substitutes versus no graft. However, there exist no large-scale randomized studies appropriately designed to investigate this question and many studies are vague on their criteria for grafting/choice of graft. Few studies have directly compared the use of autograft with allograft or artificial bone substitutes and where these have occurred, there have been no significant differences in outcomes and complication rates. 19 21 23 26 However, as in our current study, all these studies are limited by grafting decisions, being purely surgeon's choice, leading to a failure to standardize for variables such as size of lesion.

Further work must be conducted to determine whether there is truly no difference between the use of autograft and allograft/bone substitutes as, if this is the case, the latter avoids any morbidity associated with donor-site surgery. Donor-site complications following bone graft harvest from the iliac crest are reported in up to 20% of cases in the literature. 28 29 There are a wide range of allografts and bone substitutes on the market with varying properties; however, their complication rates are not yet well established. 30 There are, however, reports of allograft reactions/leakage which are not experienced with autografts and this does appear to be more problematic in the hand than at other sites due to the thin soft tissue envelope. 31 Indeed, we experienced this in one patient who had significantly prolonged wound healing due to allograft leakage. We believe care must be taken to ensure allograft is placed in the bone cavity alone without contamination of the soft tissues to prevent this. Lu et al have also experienced similar reactions when using bone cement to fill the defect and advocate its use only for unicortical defects to avoid leakage into soft tissue and increasing infection rates. 20 A further benefit of allograft/bone substitutes is that procedures can be performed under local anesthesia which reduces operative time and anesthetic risk to the patient. 21 A further limitation of allograft use is that this is relatively expensive compared with the use of autograft and this may not be a financially viable option in many centers.

There is a relatively high rate of stiffness reported following surgical excision of enchondroma ranging from 0 to 35% of patients in the literature 14 15 19 23 to which our rate of 10% compares favorably. This is despite all our patients undergoing regular hand therapy follow-up postoperatively. It is the practice of the senior author to counsel patients of this risk prior to the initial surgery and advising that a secondary tenolysis procedure is often required, presenting this as a two-stage procedure (initial excision and secondary tenolysis). This can help manage patient's expectations, satisfaction, and compliance with hand therapy (although this was not formally assessed in this study).

It is our practice to allow a period of fracture healing following pathological fractures (usually 4–6 months) prior to completing excision ± grafting as we believe this allows easier excision and reduces the risk of further intra- or postoperative fracture due to the cortical window. However, Zhou et al have demonstrated no significant differences in outcomes between those operated at less than 4 weeks and more than 4 weeks from pathological fracture suggesting that this may be unnecessary and prolongs the overall time to healing for these patients. 19 It is possible to postulate that performing excision at fracture presentation could be expected to reduce postoperative stiffness by allowing patients to engage with hand therapy rehabilitation sooner following initial injury, rather than having two separate periods of downtime following the initial fracture and the subsequent excision surgery. However, it is not possible to comment on this from the results of that study as they report no incidence of functional limitation or stiffness in any cases from either the early or delayed surgery group. A further study with adequate follow-up would be necessary to determine early surgery has any benefit over our delayed approach.

We do note certain limitations of our study. The retrospective design has meant that we do not have complete datasets for all patients, particularly in regard to postoperative imaging and our length of follow-up is somewhat shorter than in other studies. This is confounded by the fact that while the majority of our patients are operated on at our central hospital, many undergo their follow-up in peripheral centers. Due to the relatively low incidence of the condition and despite being one of the largest studies published to date, the absolute number of patients in this study is relatively low, and as such, we are unable to reach any statistical significance. This is a consistent problem across the enchondroma literature with the majority also reporting retrospective cohort studies.

Conclusion

In conclusion, while we believe our technique (± grafting for larger defects) is a satisfactory method for treatment of enchondroma of the hand, we believe a multicenter prospective randomized controlled trial would be necessary to formally determine any significant differences in outcomes (resolution, recurrence rates, and complication rates) between the various surgical techniques employed for this condition (excision and no grafting vs. autograft vs. allograft). Any such study would need to be appropriately powered to achieve statistically significant results and would need an adequate follow-up period to accurately detect recurrence and long-term functional impact of surgery.